HomeMy WebLinkAboutAttachment 4a - G Geotechnical Report
Appendix G
Geotechnical Investigation Report
GEOTECHNICAL INVESTIGATION
SUNBOW II
PHASE 3
CHULA VISTA, CALIFORNIA
PREPARED FOR
LENNAR HOMES
SAN DIEGO, CALIFORNIA
APRIL 10, 2020
PROJECT NO. G2452-32-02
GROCON
INCORPORATED
GEOTECHNICAL • ENVIRONMENTAL MATERIALSO
6960 Flanders Drive • San Diego, California 92121-2974 • Telephone 858.558.6900 • Fax 858.558.6159
Project No. G2452-32-02
April 10, 2020
Lennar Homes
16465 Via Esprillo, Suite 150
San Diego, California 92127
Attention: Mr. David Shepherd
Subject: GEOTECHNICAL INVESTIGATION
SUNBOW II
PHASE 3
CHULA VISTA, CALIFORNIA
Dear Mr. Shepherd:
In accordance with your request, and our Proposal No. LG-19430 dated November 4, 2019, we have
performed a geotechnical investigation on the subject property. The accompanying report presents our
findings, conclusions and recommendations relative to the geotechnical aspects of developing the
property as presently proposed.
The results of our study indicate that the site can be developed as planned, provided the
recommendations of this report are incorporated into the design and construction of the project. An
update to this report should be performed once the final grading plans have been prepared.
If there are any questions regarding this report, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Troy K. Reist
CEG 2408
Trevor E. Myers
RCE 63773
David B. Evans
CEG 1860
TKR:TEM:DBE:arm
(e-mail) Addressee
TABLE OF CONTENTS
1. PURPOSE AND SCOPE ...................................................................................................................... 1
2. SITE AND PROJECT DESCRIPTION ................................................................................................ 2
3. PREVIOUS GEOTECHNICAL STUDIES .......................................................................................... 2
4. SOIL AND GEOLOGIC CONDITIONS ............................................................................................. 3
4.1 Previously Placed Fill (Qpf) ....................................................................................................... 3
4.2 Topsoil (Unmapped) ................................................................................................................... 3
4.3 Alluvium (Qal) ........................................................................................................................... 3
4.4 Colluvium (Qcol) ........................................................................................................................ 3
4.5 San Diego Formation (Tsd) ........................................................................................................ 3
4.6 Otay Formation (To) ................................................................................................................... 4
4.7 Sweetwater Formation (Tsw) ..................................................................................................... 5
5. GEOLOGIC STRUCTURE .................................................................................................................. 5
6. GROUNDWATER/SEEPAGE ............................................................................................................. 5
7. SLOPE STABILITY ............................................................................................................................. 6
8. GEOLOGIC HAZARDS ...................................................................................................................... 8
8.1 Faulting and Seismicity .............................................................................................................. 8
8.2 Seismicity-Deterministic Analysis ............................................................................................. 9
8.3 Liquefaction .............................................................................................................................. 10
8.4 Landslides ................................................................................................................................. 10
9. CONCLUSIONS AND RECOMMENDATIONS .............................................................................. 11
9.1 General ...................................................................................................................................... 11
9.2 Settlement Considerations ........................................................................................................ 12
9.3 Settlement Monitoring .............................................................................................................. 13
9.4 Excavation and Soil Characteristics ......................................................................................... 13
9.5 Corrosion .................................................................................................................................. 14
9.6 Canyon Subdrains ..................................................................................................................... 15
9.7 Buttresses, Shear Keys, and Stability Fills ............................................................................... 15
9.8 Grading ..................................................................................................................................... 15
9.9 Seismic Design Criteria ............................................................................................................ 18
9.10 Foundation and Concrete Slabs-On-Grade Recommendations ................................................ 20
9.11 Retaining Walls and Lateral Loads Recommendations ............................................................ 25
9.12 Storm Water Management BMP’s ............................................................................................ 27
9.13 Slope Maintenance.................................................................................................................... 28
9.14 Site Drainage and Moisture Protection ..................................................................................... 28
9.15 Grading and Foundation Plan Review ...................................................................................... 28
LIMITATIONS AND UNIFORMITY OF CONDITIONS
TABLE OF CONTENTS (Concluded)
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2, Geotechnical Map (Map Pocket)
Figure 3, Geology Map (Map Pocket)
Figures 4 – 8, Geologic Cross-Sections A-A′ through K-K′ (Map Pocket)
Figure 9, Trench No. T-19 (Map Pocket)
Figure 10, Fill Slope Stability Analysis
Figure 11, Typical Buttress Fill Detail
Figure 12, Typical Shear Key Detail
Figure 13, Typical Stability Fill Detail
Figure 14, Wall/Column Footing Dimension Detail
Figure 15, Typical Retaining Wall Drain Detail
APPENDIX A
FIELD INVESTIGATION
Figures A-1 – A-7, (Logs of Boring Nos. LB-1 through LB-7)
Figures A-8 – A-25, (Logs of Trench Nos. T-1 through T-18)
APPENDIX B
LABORATORY TESTING
Table B-I, Summary of Laboratory Direct Shear Test Results
Table B-II, Summary of Laboratory Maximum Dry Density and Optimum Moisture Content Test Results
Table B-III, Summary of Laboratory Expansion Index Test Results
Table B-IV, Summary of Laboratory Water-Soluble Sulfate Test Results
Table B-V, Summary of Laboratory Plasticity Index Test Results
Figure B-1, Gradation Curves
Figures B-2 – B-7, Composite Direct Shear Graphs
APPENDIX C
SLOPE STABILITY ANALYSES
Figures C-1 – C-29
APPENDIX D STORM WATER MANAGEMENT I-8A (WORKSHEET C.4-1) FORMS
APPENDIX E
PREVIOUSLY REPORTED TRENCH AND BORING LOGS (Prepared by Geocon Incorporated)
APPENDIX F
RECOMMENDED GRADING SPECIFICATIONS
LIST OF REFERENCES
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GEOTECHNICAL INVESTIGATION
1. PURPOSE AND SCOPE
This report presents the results of a geotechnical investigation for the proposed Sunbow II, Phase 3
project located in Chula Vista, California (see Vicinity Map, Figure 1). The purpose of our study was
to evaluate the soil and geologic conditions at the site, as well as geotechnical constraints, if any, that
could impact the proposed project. This report provides recommendations relative to the geotechnical
engineering aspects of the development as presently proposed based on the conditions encountered. As
project plans progress, this study should be updated as necessary.
The scope of our work consisted of the following:
Reviewing aerial photographs and readily available published and unpublished geologic
literature.
Reviewing the digital plans prepared by Hunsaker & Associates.
Sampling and down-hole logging 7 large-diameter borings (see Appendix A).
Performing 19 exploratory trenches using an excavator to evaluate the general extent and condition
of surficial deposits. The study also included a 234-foot-long trench (Trench No. T-19) to evaluate
the presence or absence of a fault mapped within the eastern portion of the property (see
Appendix A).
Performing laboratory tests on selected soil samples to evaluate their physical and chemical
characteristics for engineering analysis (see Appendix B).
Performing slope stability analyses along Geologic Cross Sections A-A′ through K-K′ (see
Appendix C).
Performing an infiltration test within one of the proposed water quality basins and providing
storm water BMP design information (See Appendix D).
Preparing this report, geologic cross sections and geologic maps presenting our exploratory
information and our conclusions and recommendations regarding the geotechnical aspects of
developing the property as presently proposed.
The approximate location of the subsurface excavations as well as the proposed development is shown
on the Geotechnical Map, Figure 2. The Geology Map, Figure 3, presents pertinent geologic
information obtained during our field investigation without the proposed development layer. Geologic
Cross-Sections A-A′ through K-K′ (Figures 4 through 8) represent our interpretation of the subsurface
conditions across the site and served as the basis for our slope stability analysis. The ultimate finish
grade configuration is shown on these figures.
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It should be noted that several of the originally proposed borings and trenches during our study
required relocation or elimination due to environmental restrictions (i.e. sensitive habitat, nesting
birds). Where this occurred, geologic information from adjacent areas was extrapolated or inferred as
part of our geotechnical analysis.
2. SITE AND PROJECT DESCRIPTION
The proposed Sunbow II, Phase 3 development is located south of Olympic Parkway, north of the
Otay Landfill, east of Brandywine Avenue and west of Heritage Road in Chula Vista, California. The
property is essentially undeveloped except for the two existing embankments and box culvert
structures that abut Olympic Parkway located along the northern property boundary.
Based on a review of the plans provided by Hunsaker and Associates, we understand the property will
be developed to create 718 attached condominium units with associated infrastructure improvements,
a recreation area and water quality basins. Ingress and egress to the site will be provided by
two primary roadways that intersect with Olympic Parkway. The mass grading study indicates
that approximately 1,200,000 cubic yards of cut and fill, respectively, will be required to
develop the project. We understand this estimate does not include remedial grading.
The locations and descriptions of the site and proposed development are based on our field
investigation, site reconnaissance, a review of the available plans and our understanding of the project.
If project details vary significantly from those described herein, Geocon Incorporated should be
consulted to provide additional recommendations and/or analysis.
3. PREVIOUS GEOTECHNICAL STUDIES
A preliminary geotechnical investigation was performed by Geocon Incorporated in 1986 as part of an
overall study for the 600-acre Rancho Del Sur property and included advancing three large diameter
borings on a portion of the property (Reference No. 13). In addition, several monitoring wells (gas,
vadose, and groundwater) were installed on the property between 1989 and 1994 as part of an
environmental study adjacent to the Otay Landfill (Reference Nos. 8 and 14). We also performed a
geotechnical investigation in 2006 on the adjacent Otay Ranch Village 2 West project located along
the eastern boundary of the site (Reference No. 12). The subsurface information and as-graded
geologic mapping from these studies was reviewed and incorporated into a geologic reconnaissance
report for Sunbow, Planning Area 23 in November 2019 (Reference No. 11). The approximate
location of the borings and trenches from the referenced reports has been incorporated onto Figures 2
and 3 and the logs have been included for reference in Appendix E.
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4. SOIL AND GEOLOGIC CONDITIONS
Based on our investigation, previous geotechnical studies and observations during our reconnaissance,
the geology underlying the property consists of surficial soil (previously placed fill, topsoil, alluvium
and colluvium) and the San Diego, Otay and Sweetwater Formations. The surficial soils and geologic
formations are discussed below in order of increasing age. The estimated extent of these units is
shown on Figures 2 and 3, with the exception of topsoil.
4.1 Previously Placed Fill (Qpf)
Compacted fill associated with previous grading operations for Olympic Parkway is present along the
northern project boundary. The northern portion of these embankments is underlain by alluvium,
however, the potentially compressible portions of this unit were removed or compressed by
surcharging during prior grading operations. Geocon Incorporated provided testing and observation
services during placement of the embankments and information pertaining to the grading is included in
Reference Nos. 9 and 10. Processing of the upper surface of these embankments will be required prior
to additional fill placement.
4.2 Topsoil (Unmapped)
Topsoil was encountered in several of the exploratory borings and trenches with a maximum thickness
of 4 feet. These deposits, in general, consist of unconsolidated, clayey sands to sandy clays with a high
expansion potential and will require remedial grading where present within the development footprint.
4.3 Alluvium (Qal)
Alluvium is present within the three main drainages on the site and along Olympic Parkway. These
deposits vary in thickness from 6 to 12 feet and primarily consist of expansive, silty to sandy clays to
clayey sands. The alluvium will require remedial grading where structural improvements are planned.
4.4 Colluvium (Qcol)
Colluvial deposits are present along the hillsides above the alluvial drainages. These deposits consist
of clayey sands to silty clays with a high expansion potential and vary from 3½ to 8-feet-thick.
Remedial grading will be required where colluvium is located in areas of planned development.
4.5 San Diego Formation (Tsd)
The San Diego Formation overlies the Otay Formation and typically consists of dense, fine to
medium-grained sandstone with relatively low cohesion and moderate to high permeability. In general,
the San Diego Formation exhibits adequate shear strength and “very low” to “low” expansion
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characteristics in either an undisturbed or properly compacted condition. Due to the potentially friable
and higher permeability characteristics of this unit, stability fills will be required where the San Diego
Formation is exposed in cut slopes.
4.6 Otay Formation (To)
The Otay Formation, which overlies the Sweetwater Formation and underlies the San Diego
Formation, is the predominant geologic unit on the site. This formation consists of dense, silty to
clayey, sandstone and hard, siltstone and claystone beds with continuous to discontinuous interbeds of
weak, highly-plastic bentonitic claystone. In some instances, the bentonite beds contain bedding plane
shears as observed in the majority of the exploratory borings during our study.
The sandy portions of the Otay Formation typically possess a “very low” to “low” expansion potential
and adequate shear strength. The siltstone and claystone portions of the formation can exhibit a
“medium” to “very high” expansion potential. With the possible exception of the bentonitic claystone,
the Otay Formation is suitable for the support of compacted fill and structural loads.
The laterally extensive bentonitic claystone beds, which are well documented in the area, can vary in
thickness from several inches up to 7 feet (see Boring No. LB-7). The beds are typically flat lying to
gently dipping (0 to 3 degrees) and possess a very high expansion potential and very low shear
strength. A laterally continuous bentonitic claystone bed is mapped across the site between elevations
341 feet and 371 feet above mean sea level (see Figures 2 and 3). This unit will require important
consideration with respect to slope stability and its expansion potential, and will require remedial
grading measures.
The Otay Mesa Lateral Spread, commonly referred to as an ancient “intra-formational landslide” by
geologists, is mapped within the site boundary (Reference No. 24). This ancient landslide, which is
over 8-miles wide and approximately 2½-miles long, is entirely contained within the Otay Formation
and terminates along the La Nación Fault to the west. We have also observed and mapped this feature
during the grading operations for Olympic Parkway (Reference No. 9) and other neighboring
residential developments.
The basal surface of the ancient “intra-formational landslide” occurred along a single, continuous,
bentonitic clay bed that coincides with the bentonitic clay bed mapped on Figures 2 and 3. The slide
mass consists of relatively undisturbed consolidated blocks of the Otay Formation that have low to
very low compressibility characteristics. Some areas exhibit plastically deformed bentonite which has
been squeezed into the overlying mass creating unpredictable diapirs and flame structures that vary in
dimension and orientation. If present, these features can create problems for site improvements due to
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their expansion potential. Although not observed within the exploratory borings and trenches, the
potential for these conditions will be evaluated during the grading phase of project development.
4.7 Sweetwater Formation (Tsw)
The Sweetwater Formation, commonly referred to as the “gritstone layer” of the Otay Formation,
underlies the Otay Formation and is characterized as dense to very dense, gravelly, fine to coarse
sandstone that is locally cemented. The Sweetwater Formation generally has a high shear strength and
a low expansive potential.
5. GEOLOGIC STRUCTURE
The published regional dip of the Otay Formation and bentonitic claystone is generally 1 to 2 degrees
to the west-southwest (Reference No. 24). During our study, we identified a prominent contact
between a laterally continuous white bentonitic claystone bed and reddish-brown claystone (further
described as the “key marker bed” herein) which revealed gently dipping strata to the southeast. This
relationship was observed in Boring Nos. LB-1, LB-2, LB-5, LB-7 and Trench No. T-18. Further
evidence of this orientation was observed in a study on the easterly adjacent Otay Ranch Village 2
West property and from the contact elevations measured between the Otay and Sweetwater Formations
during our study (Boring Nos. LB-1, LB-2 and LB-7).
A computer-generated elevation contour plot of the “key marker bed” based on the piercing points
from the borings is presented in green on Figure 3. Although general, this information was used as the
basis for mapping the outcrop location of the bentonitic claystone shown in red on Figures 2 and 3.
We also used geomorphic interpretation and information from Trench No. T-18 during this evaluation.
The bentonitic claystone bed varied in thickness from 4½ feet to 7 feet as observed in the borings and
Trench T-18. In order to account for these variations, we added 5 feet above and below the “key
marker bed” so the projected bed thickness shown on the Geologic Cross Sections will not necessarily
match what is shown at the boring location. It should be noted that the exercise of creating the contour
map and outcrop location of the bentonitic claystone is to evaluate its general trend and assist in future
field identification/recommendations that will occur during site grading.
6. GROUNDWATER/SEEPAGE
Groundwater was identified in the monitoring wells MW-1 and MW-2 (1989, 1994) on-site at depths
of 165 and 275 feet, respectively, below the existing ground surface. Minor seepage was observed in
Trench Nos. T-1 and T-2 along the alluvium and bedrock contact approximately 7 feet below existing
grade. Subdrain systems will be required in the main drainages, along with proposed buttress, shear
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key and stability fill excavations, and possibly where impervious layers daylight near the ultimate
graded surface.
The groundwater elevations and seepage conditions are expected to fluctuate seasonally and may
affect remedial grading. In this regard, remedial grading may encounter wet soils and excavation and
compaction difficulty, particularly if grading is planned during the winter months. It should also be
noted that areas where perched water or seepage was not encountered may exhibit groundwater during
rainy periods.
7. SLOPE STABILITY
Eleven geologic cross-sections, A-A′ through K-K′ (Figures 4 and 8), were prepared to aid in
evaluating the stability of proposed and natural slopes. Shear strength parameters for the soil and
geologic materials encountered were determined from laboratory direct shear tests and engineering
judgment. Residual shear strengths were used for bedding plane shear features and were determined
from laboratory test results and using the Journal of Geotechnical and Geoenvironmental
Engineering, Drained Shear Strength Parameters for Analysis of Landslides (Stark, Choi, McCone,
2005) and engineering judgment.
Table 7.1 presents the soil strength parameters that were utilized in the slope stability analyses. The
values were derived from laboratory test results and experience with similar soil and geologic
conditions.
TABLE 7.1
SOIL STRENGTH PARAMETERS
Geologic Unit (Geologic Unit Symbol/USCS Soil Type) Angle of Internal
Friction (degrees) Cohesion C (psf)
Compacted Fill (Qcf) 29 300
San Diego Formation- Sandstone (Tsd-SM) 31 300
Otay Formation Sandstone (To-SM) 30 300
Otay Formation Siltstone/Claystone (To-ML/CL) 23 400
Otay Formation Bentonitic Claystone-Unsheared (To-MH/CH) 22 500
Bedding Plane Shear (BPS) 7 0
Sweetwater Formation (Tsw-SM) 36 500
The output files and calculated factor of safety for the cross sections used for the stability analyses are
presented in Appendix C (Figures C-1 through C-29) and summarized in Table 7.2.
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TABLE 7.2
SLOPE STABILITY SUMMARY
Cross
Section
Figure
Number Condition Analyzed Factor
of Safety
A-A′
C-1 Proposed condition-block type thru BPS 1.2
C-2 Proposed condition with buttress-block type thru BPS 1.6
C-3 Proposed condition with buttress-block type thru To (MH/CH) 2.4
B-B′
C-4 Proposed condition-block type thru BPS 1.7
C-5 Proposed condition-block type thru To (MH/CH) 3.4
C-6 Proposed condition-circular type 2.6
C-C′
C-7 Proposed condition-block type thru To (MH/CH) 2.1
C-8 Proposed condition with stability fill-block type thru To (MH/CH) 2.2
C-9 Proposed condition with stability fill-circular type 1.9
D-D′ C-10 Proposed condition with stability fill-block type on To (ML/CL) 2.4
C-11 Proposed condition with stability fill-circular type 1.8
E-E′ C-12 Proposed condition with stability fill-block type on To (ML/CL) 2.0
C-13 Proposed condition with stability fill-circular type 1.8
F-F′
C-14 Proposed condition with stability fill-block type on lower To
(ML/CL) 2.0
C-15 Proposed condition with stability fill-block type on upper To
(ML/CL) 2.1
C-16 Proposed condition with stability fill-circular type 1.7
G-G′ C-17 Proposed condition-block type thru To (ML/CL) 2.4
C-18 Proposed condition-circular type 1.9
H-H′ C-19 Proposed condition-circular type 2.2
I-I′
C-20 Proposed condition-block type thru BPS 2.4
C-21 Proposed condition-block type thru To (MH/CH) 2.8
C-22 Proposed condition-circular type 1.8
J-J′
C-23 Proposed condition-cut slope, block type thru To (MH/CH) 2.9
C-24 Proposed condition-cut slope, circular type 2.7
C-25 Proposed condition-cut slope, optimized circular type thru BPS 2.1
C-26 Proposed condition-fill slope, circular type 2.1
K-K′
C-27 Proposed condition-block type thru BPS 1.2
C-28 Proposed condition with shear key-block type on BPS 1.6
C-29 Proposed condition with shear key-circular type 2.1
The results of the analyses indicate that a buttress, two shear keys, and stability fills will be required to
achieve surficial stability or a static factor of safety of at least 1.5. The approximate limits of these
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features are shown on Figure 2 and/or depicted on the Geologic Cross-Sections. The extent of
remedial grading in these areas may need to be modified depending on the conditions observed during
grading.
Slope stability analyses for the proposed fill slopes were performed utilizing average drained direct
shear strength parameters from the laboratory test results. These analyses indicate that the proposed
2:1 fill slopes, constructed of on-site materials, should have calculated factors of safety of at least 1.5
under static conditions for both deep-seated failure and shallow sloughing conditions to a height of
100 feet. Generalized slope stability calculations for both deep-seated and surficial fill slope stability
are presented on Figure 10.
The outer 15 feet (or a distance equal to the height of the slope, whichever is less) of fill slopes should
be composed of properly compacted granular "soil" fill to reduce the potential for surficial sloughing.
In general, soils with an Expansion Index of less than 90 or at least 35 percent sand size particles
should be acceptable as "granular" fill. Fill slopes with a height over 50 feet will require soil with a
minimum phi angle of 29 degrees and cohesion of 300 psf. The horizontal width of this material
should be one-half the slope height. Soils of questionable strength to satisfy surficial stability should
be tested in the laboratory for acceptable drained shear strength.
8. GEOLOGIC HAZARDS
8.1 Faulting and Seismicity
A review of geologic literature indicates that the Newport-Inglewood Fault Zone, located
approximately 9 miles west of the site, is the closest known “active fault”. An active fault is defined
by the California Geologic Survey (CGS), as a fault showing evidence of activity roughly within the
last 11,000 years (Holocene time). In addition, the main strand of the La Nación Fault is mapped
approximately 1/3 of a mile west of the site and has been classified as “potentially active”, which is
defined by CGS as a fault showing evidence of activity within the last 1.8 million years.
Published geologic maps depict a north-south striking fault within the eastern portion of the site. Our
research did not reveal any discussion regarding the origin or activity of the fault other than it was
“inferred from photographic evidence” (Reference No. 18). As part of our study we performed a 234-
foot-long trench (Trench No. T-19) across the mapped fault trace within the eastern portion of the
property. We did not observe any evidence of faulting in the trench. The detailed log for Trench No.
T-19 is presented on Figure 9.
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8.2 Seismicity-Deterministic Analysis
We used the computer program EZ-FRISK (Version 7.65) to determine the distance of known faults to
the site and to estimate ground accelerations at the site for the maximum anticipated seismic event.
According to the results, 6 known active faults are located within a search radius of 50 miles from the
property. We used acceleration attenuation relationships developed by Boore-Atkinson (2008) NGA
USGS2008, Campbell-Bozorgnia (2008) NGA USGS, and Chiou-Youngs (2008) NGA in our
analysis. The nearest known active faults are the Newport-Inglewood and Rose Canyon Fault Zones,
located approximately 9 miles west of the site, respectively, and are the dominant sources of potential
ground motion. Table 8.2.1 lists the estimated maximum earthquake magnitudes and PGA’s for the
most dominant faults for the site location calculated for Site Class C as defined by Table 1613.3.2 of
the 2019 California Building Code (CBC).
TABLE 8.2.1
DETERMINISTIC SEISMIC SITE PARAMETERS
Fault Name Distance from
Site (miles)
Maximum
Earthquake
Magnitude (Mw)
Peak Ground Acceleration
Boore-
Atkinson
2008 (g)
Campbell-
Bozorgnia
2008 (g)
Chiou-
Youngs
2008 (g)
Newport-Inglewood 9 7.5 0.26 0.24 0.30
Rose Canyon 9 6.9 0.22 0.22 0.23
Coronado Bank 17 7.4 0.18 0.14 0.16
Palos Verdes 17 7.7 0.20 0.15 0.19
Elsinore 42 7.85 0.11 0.08 0.09
Earthquake Valley 46 6.8 0.06 0.05 0.04
We performed a site-specific probabilistic seismic hazard analysis using the computer program
EZ-FRISK. Geologic parameters not addressed in the deterministic analysis are included in this
analysis. The program operates under the assumption that the occurrence rate of earthquakes on each
mappable Quaternary fault is proportional to the faults slip rate. The program accounts for fault
rupture length as a function of earthquake magnitude, and site acceleration estimates are made using
the earthquake magnitude and distance from the site to the rupture zone. The program also accounts
for uncertainty in each of following: (1) earthquake magnitude, (2) rupture length for a given
magnitude, (3) location of the rupture zone, (4) maximum possible magnitude of a given earthquake,
and (5) acceleration at the site from a given earthquake along each fault. By calculating the expected
accelerations from considered earthquake sources, the program calculates the total average annual
expected number of occurrences of site acceleration greater than a specified value. We utilized
acceleration-attenuation relationships suggested by Boore-Atkinson (2008) NGA USGS 2008,
Campbell-Bozorgnia (2008) NGA USGS 2008, and Chiou-Youngs (2008) NGA in the analysis.
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Table 8.2.2 presents the site-specific probabilistic seismic hazard parameters including acceleration-
attenuation relationships and the probability of exceedance.
TABLE 8.2.2
PROBABILISTIC SEISMIC HAZARD PARAMETERS
Probability of Exceedance
Peak Ground Acceleration
Boore-Atkinson,
2008 (g)
Campbell-Bozorgnia,
2008 (g)
Chiou-Youngs,
2008 (g)
2% in a 50 Year Period 0.37 0.36 0.40
5% in a 50 Year Period 0.26 0.25 0.27
10% in a 50 Year Period 0.19 0.19 0.19
While listing peak accelerations is useful for comparison of potential effects of fault activity in a
region, other considerations are important in seismic design, including the frequency and duration of
motion and the soil conditions underlying the site. Seismic design of the structures should be evaluated
in accordance with the California Building Code (CBC) guidelines currently adopted by the City of
Chula Vista.
8.3 Liquefaction
Liquefaction typically occurs when a site is located in a zone with seismic activity, onsite soils are
cohesionless, groundwater is encountered within 50 feet of the surface, and soil densities are less than
about 70 percent of the relative density. If all four criteria are met, a seismic event could result in a
rapid increase in pore water pressure from the earthquake-generated ground accelerations. The
potential for liquefaction at the site is considered to be negligible due to the dense formational material
encountered, remedial grading, and lack of a shallow groundwater condition.
8.4 Landslides
No evidence of landslide deposits were encountered during the geotechnical investigation, or geologic
literature review other than the ancient “intra-formational landslide” within the Otay Formation that
underlies the region.
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9. CONCLUSIONS AND RECOMMENDATIONS
9.1 General
9.1.1 No soil or geologic conditions were encountered that, in the opinion of Geocon
Incorporated, would preclude the development of the property as proposed, provided the
recommendations of this report are followed.
9.1.2 Due to the presence of weak bentonitic claystones and bedding plane shears within the Otay
Formation, two drained shear keys and a buttress will be necessary in select areas of the site
to provide adequate slope stability. In addition, due to lower cohesion and high permeability
characteristics of the San Diego Formation, stability fills will be required where this
formation is exposed in cut slopes.
9.1.3 The approximate location of the shear keys, buttress and stability fills are shown on the
Geotechnical Map and Geologic Cross-Sections. The detailed geometry of these features
should be refined as grading plans progress. In addition, the anticipated remedial grading
areas, including drain locations and connection points should be shown on the 40-scale
grading plans.
9.1.4 Segmental excavation of the buttress proposed in the southwest portion of the site (Geologic
Cross Section A-A’) may be necessary to provide an adequate temporary factor of safety
during grading. We anticipate the buttress could be excavated in two segments, however,
specific recommendations in this regard can be provided in an update correspondence as
grading plans progress.
9.1.5 The proposed buttress and shear key located within the southwest and northeast portion of
the property, respectively, will require grading beyond the property boundaries. In addition,
the proposed grades for the northeast portion of site will require embankments that extend
onto the adjacent property (see Geologic Cross Section K-K’).
9.1.6 Where bentonitic claystone is present near finish grade, removal and placement of these
materials in deeper fills will be required. In some areas, mixing of the bentonite with
granular materials at a prescribed ratio and placement at a designated depth below finish
grade will be necessary.
9.1.7 The site is underlain by compressible surficial deposits (topsoil, alluvium and colluvium)
that are unsuitable in their present condition and will require remedial grading in the form of
removal and compaction where improvements are planned.
Project No. G2452-32-02 - 12 - April 10, 2020
9.1.8 Excavations for cut lots, slopes, buttresses, shear keys and stability fills should be observed
by an engineering geologist to verify that the soil and geologic conditions do not differ
significantly from those anticipated. Particular attention should be given to cut lots exposing
the Otay Formation where potholing may be necessary to verify that bentonitic claystone is
not present near finish grade. In the event that unanticipated conditions are encountered,
modifications to our recommendations (e.g. stability fills, additional undercutting, etc.) may
be required.
9.1.9 Evaluation of the suitable and unsuitable soil types (i.e. bentonitic clay, sand, etc.) and how
they relate to the project grading requirements (e.g. capping, buttress, shear key and stability
fill material requirements) will require careful management by the contractor during
grading. Special handling and/or stockpiling may be necessary to achieve the project
recommendations.
9.1.10 Proposed grading will result in fills up to approximately 100-feet-thick. The settlement
potential of these embankments will be an important design consideration. In addition,
special foundation design considerations (i.e. total and differential settlements across the
building footprints) may be required for buildings supported by fills greater than 75 feet
thick.
9.1.11 The existing 12 monitoring wells (gas, vadose, and groundwater) installed on the property
as part of a previous environmental study adjacent to the Otay Landfill will need to be
destroyed in accordance with the County of San Diego Department of Environmental Health
requirements. Once the project has been approved, a C57-licensed drilling contractor will
need to be contracted to properly destroy the wells.
9.1.12 We understand that the existing reclaimed water line along the western project boundary
may need to be removed and placed in a new location within the proposed development. If
this procedure requires phased grading, buttress construction and bentonite undercutting in
the vicinity of Geologic Cross Section A-A’ should be considered during the planning of this
procedure.
9.2 Settlement Considerations
9.2.1 Fill embankments up to approximately 100-feet-thick are proposed during site grading. As a
consequence, the potential for total and differential settlement beneath proposed buildings
and underground improvements (i.e. sewer, storm drain, etc.) in deep fill areas should be a
consideration. Foundation design criteria taking into account the anticipated total and
differential settlement can be provided as project plans progress. Based on our experience
Project No. G2452-32-02 - 13 - April 10, 2020
with similar fill depths and soil conditions, the estimated settlement of a compacted fill may
vary between approximately 0.2 and 0.3 percent of the fill thickness, depending on the
relative compaction and overburden load. We recommend a minimum relative compaction
of 90 percent at or slightly above optimum moisture content for fills less than 50-feet-thick
and a minimum of 93 percent at two percent above optimum moisture content for fills
deeper than 50 feet. Based on these criteria, the estimated ultimate settlement potential for
fills less than 50 feet is 0.3 percent of the fill thickness and 0.2 percent of the fill thickness
for fills greater than 50 feet. Therefore, compacted fill up to 100-feet-thick may settle up to
approximately 3-inches when fully wetted.
9.2.2 The settlement of compacted fill is expected to occur over a relatively extended time period
resulting from both gravity loading and hydrocompression upon wetting from rainfall and/or
landscape irrigation.
9.3 Settlement Monitoring
9.3.1 The proposed structural areas underlain by fills thicker than 50 feet should be monitored for
settlement. In general, surface settlement plates should be installed at several locations within the
development footprint and read periodically until primary consolidation has essentially ceased.
Survey readings should be performed regularly following placement of the proposed fill.
Specific details regarding the location and type of monitoring device as well as monitoring
frequency will be provided once the development plans have been finalized.
9.4 Excavation and Soil Characteristics
9.4.1 Excavation of the surficial deposits (previously placed fill, topsoil, alluvium and colluvium)
should be possible with light to moderate effort using conventional heavy-duty equipment.
These deposits may be very moist to saturated during the winter or early spring depending
on preceding precipitation. Overly wet soils will require drying or mixing with drier
material prior to their use as compacted fill.
9.4.2 Excavating within the formational units should be possible with moderate to heavy effort using
conventional heavy-duty excavation equipment. Cemented zones requiring very heavy effort
may be encountered, however, it is anticipated that these conditions would be localized.
9.4.3 The soils encountered in the field investigation are considered to be “non-expansive”
(expansion index [EI] of 20 or less) and “expansive” (expansion index [EI] of 130 or more)
as defined by 2019 California Building Code (CBC) Section 1803.5.3. The soil materials
collected and tested for expansion index indicate a “very low” to “very high” expansion,
which are defined in Table 9.4 below.
Project No. G2452-32-02 - 14 - April 10, 2020
TABLE 9.4
EXPANSION CLASSIFICATION BASED ON EXPANSION INDEX
Expansion Index (EI) ASTM 4829
Expansion Classification
2019 CBC
Expansion Classification
0 – 20 Very Low Non-Expansive
21 – 50 Low
Expansive 51 – 90 Medium
91 – 130 High
Greater Than 130 Very High
9.5 Corrosion
9.5.1 Selected samples were subjected to laboratory water-soluble sulfate content tests. The
results of the water-soluble sulfate tests are summarized in Appendix B. The test results
indicate the on-site materials at the locations tested possess “S0” sulfate exposure to
concrete structures as defined by 2019 CBC Section 1904 and ACI 318-14 Chapter 19 (see
Appendix B for test results). Table 9.5 presents a summary of concrete requirements set
forth by 2019 CBC Section 1904 and ACI 318. The presence of water-soluble sulfates is not
a visually discernible characteristic; therefore, other soil samples from the site could yield
different concentrations. Additionally, over time landscaping activities (i.e., addition of
fertilizers and other soil nutrients) may affect the concentration.
TABLE 9.5
REQUIREMENTS FOR CONCRETE EXPOSED TO
SULFATE-CONTAINING SOLUTIONS
Exposure
Class
Water-Soluble
Sulfate (SO4)
Percent by Weight
Cement Type
(ASTM C 150)
Maximum
Water to
Cement Ratio
by Weight1
Minimum
Compressive
Strength (psi)
S0 SO4<0.10 No Type Restriction n/a 2,500
S1 0.10<SO4<0.20 II 0.50 4,000
S2 0.20<SO4<2.00 V 0.45 4,500
S3 SO4>2.00 V+Pozzolan or Slag 0.45 4,500
1 Maximum water to cement ratio limits do not apply to lightweight concrete
9.5.2 Geocon Incorporated does not practice in the field of corrosion engineering; therefore,
further evaluation by a corrosion engineer may be needed to incorporate the necessary
precautions to avoid premature corrosion of underground pipes and buried metal in direct
contact with the soils.
Project No. G2452-32-02 - 15 - April 10, 2020
9.6 Canyon Subdrains
9.6.1 The geologic units encountered on the site have permeability characteristics and/or fracture
systems that could be susceptible to groundwater transmission. Canyon subdrains are
recommended to collect subsurface water within areas of planned development. The
recommended canyon subdrain locations are presented on Figure 2, however, the locations
are subject to change depending on the conditions encountered in the field. Section 7 in
Appendix F provides recommendations for canyon subdrains.
9.6.2 Upon completion of remedial excavations and subdrain installation, the project civil
engineer should survey the drain locations and prepare an “as-built” map depicting their
location and elevation.
9.7 Buttresses, Shear Keys, and Stability Fills
9.7.1 A 20-foot-wide drained buttress (shown in purple on Figure 2) will be required in the
vicinity of Geologic Cross Section I-I’ to provide an acceptable factor of safety for the
proposed slope. As mentioned previously, segmental excavations may be necessary to
provide adequate temporary stability during grading.
9.7.2 A 15-foot-wide and 40-foot-wide drained shear key will be required to obtain an acceptable
factor of safety for two proposed fill slope areas (shown in blue on Figure 2).
9.7.3 A 15-foot-wide drained stability fill (shown in yellow on Figure 2) will be required on
proposed cut slopes along the southern/southeastern portions of the property which will
expose the San Diego and Otay Formations.
9.7.4 Typical buttress, shear key and stability fill details are shown on Figures 11 through 13,
respectively. Section 7 in Appendix F provides cut off wall and headwall details for the heel
drains, if required. Depending on the geologic conditions exposed, deeper and/or wider
keyways may be necessary. The actual recommended keyway dimensions, as well as
backdrain geometry and connection points should be determined as grading plans progress.
9.8 Grading
9.8.1 All grading should be performed in accordance with the attached Recommended Grading
Specifications (Appendix F). Where the recommendations of this section conflict with
Appendix F, the recommendations of this section take precedence. All earthwork should be
observed and all fills tested for proper compaction by Geocon Incorporated.
Project No. G2452-32-02 - 16 - April 10, 2020
9.8.2 Prior to commencing grading, a preconstruction conference should be held at the site with
the owner or developer, grading contractor, civil engineer, and engineering
geologist/geotechnical engineer in attendance. Special soil handling and/or the grading plans
can be discussed at that time.
9.8.3 Site preparation should begin with the removal of all deleterious material and vegetation.
The depth of removal should be such that material exposed in cut areas or soils to be used as
fill are relatively free of organic matter. Material generated during stripping and/or site
demolition should be exported from the site.
9.8.4 All potentially compressible surficial soils (topsoil, alluvium, and colluvium) within areas
where structural improvements are planned, or where discussed herein, should be removed
to firm natural ground and properly compacted prior to placing additional fill and/or
structural loads. Deeper than normal benching and/or stripping operations for sloping
ground surfaces will be required where the thickness of potentially compressible surficial
deposits exceeds 3 feet. In addition, processing of the upper 12 inches of the previously
placed fill surface will be required prior to additional fill placement. The actual extent of
unsuitable soil removals will be determined in the field during grading by the engineering
geologist and/or geotechnical engineer.
9.8.5 After removal of unsuitable materials is performed, the site should then be brought to final
subgrade elevations with structural fill compacted in layers. In general, soils native to the
site are suitable for re-use as fill if free from vegetation, debris and other deleterious
material. Layers of fill should be no thicker than will allow for adequate bonding and
compaction. All fill, including backfill and scarified ground surfaces, should be compacted
to at least 90 percent of maximum dry density at or above optimum moisture content, as
determined in accordance with ASTM Test Procedure D1557. Fills greater than 50-feet-
thick (based on the ultimate design grades) should be compacted to at least 93 percent
of the laboratory maximum dry density at a minimum of 2 percent above the optimum
moisture content. Fill materials below optimum moisture content will require additional
moisture conditioning prior to placing additional fill.
9.8.6 Bentonitic claystone and/or other expansive claystone/siltstone that occurs within 5 feet of
finish grade on cut lots should be removed and replaced with properly compacted fill that
possesses a “very low” to “low” expansion potential (EI of 50 or less). Grading operations
should be managed to allow for placement of these expansive soils in the deeper fill areas.
9.8.7 Bentonitic claystone placed in fills should be mixed with granular materials at a ratio of at
least two parts sand to one-part bentonitic clay. This material should be placed at least 5 feet
Project No. G2452-32-02 - 17 - April 10, 2020
below finish grade, at least 15 feet from the slope face and not within a buttress, shear key
or stability fill areas. Mixing of bentonitic clays will not be required if placed at least 10 feet
below finish grade.
9.8.8 The City of Chula Vista requires that the upper 5 feet of fill, and the upper 3 feet of
formational materials within the public right-of-way or public easement possess an
expansion index of 90 or less. If material with an expansion index greater than 90 is exposed
within the right-of-ways, the upper 5 feet of compacted fills and the upper 3 feet of
formational materials should be removed and replaced with fill possessing an expansion
index of 90 or less. Alternative methods, if proposed, should be approved by the City of
Chula Vista within the right-of-way areas.
9.8.9 The outer 15 feet (or a distance equal to the height of the slope, whichever is less) of fill
slopes should be composed of properly compacted granular "soil" fill to reduce the potential
for surficial sloughing. In general, soils with an Expansion Index of less than 90 or at least
35 percent sand size particles should be acceptable as "granular" fill. Fill slopes with a
height over 50 feet will require soil with a minimum phi angle of 29 degrees and cohesion
of 300 psf. The horizontal width of this material should be one-half the slope height. Soils of
questionable strength to satisfy surficial stability should be tested in the laboratory for
acceptable drained shear strength.
9.8.10 If encountered, oversize material (i.e. cobbles, boulders and concretions) greater than 6
inches in maximum dimension should not be placed within 5 feet of finish grade. Rock
greater than 12 inches in maximum dimension should not be placed within 10 feet of finish
pad grade or within 2 feet of the deepest utility.
9.8.11 To reduce the potential for differential settlement, it is recommended that the cut portion of
cut/fill transition building pads be undercut at least 3 feet and replaced with properly
compacted “very low” to “low” expansive fill soils. Where the thickness of the fill below
the building pad exceeds 15 feet, the depth of the undercut should be increased to one-fifth
of the maximum fill thickness.
9.8.12 It is the responsibility of the contractor and their competent person to ensure that all
excavations, temporary slopes and trenches are properly constructed and maintained in
accordance with applicable OSHA regulations in order to maintain safety and the stability of
adjacent existing improvements.
9.8.13 Import materials should consist of “very low” to “low” expansive (Expansion Index of 50 or
less) soils. Prior to importing the material, samples from proposed borrow areas should be
Project No. G2452-32-02 - 18 - April 10, 2020
obtained and subjected to laboratory testing to determine whether the material conforms to
the recommended criteria. At least 5 working days should be allowed for laboratory testing
of the soil prior to its importation. Import materials should be free of oversize rock and
construction debris.
9.9 Seismic Design Criteria
9.9.1 Table 9.9.1 summarizes site-specific design criteria obtained from the 2019 California
Building Code (CBC; Based on the 2018 International Building Code [IBC] and ASCE 7-16),
Chapter 16 Structural Design, Section 1613 Earthquake Loads. We used the computer
program Seismic Design Maps, provided by the Structural Engineers Association (SEA) to
calculate the seismic design parameters. The short spectral response uses a period of 0.2
second. We evaluated the Site Class based on the discussion in Section 1613.2.2 of the 2019
CBC and Table 20.3-1 of ASCE 7-16. The values presented herein are for the risk-targeted
maximum considered earthquake (MCER) for Site Class C. The project structural engineer
and architect should evaluate the appropriate Risk Category and Seismic Design Category
for the planned structures. The values presented herein assume a Risk Category of II and
resulting in a Seismic Design Category D.
TABLE 9.9.1
2019 CBC SEISMIC DESIGN PARAMETERS
Parameter Value 2019 CBC Reference
Site Class C Section 1613.3.2
MCER Ground Motion Spectral Response Acceleration – Class B (short), SS 0.817 Figure 1613.2.1(1)
MCER Ground Motion Spectral Response Acceleration – Class B (1 sec), S1 0.292g Figure 1613.2.1(2)
Site Coefficient, FA 1.2 Table 1613.2.3(1)
Site Coefficient, FV 1.5 Table 1613.2.3(2)
Site Class Modified MCER Spectral Response Acceleration (short), SMS 0.98g Section 1613.2.3 (Eqn 16-36)
Site Class Modified MCER Spectral Response Acceleration (1 sec), SM1 0.437g Section 1613.2.3 (Eqn 16-37)
5% Damped Design Spectral Response Acceleration (short), SDS 0.653g Section 1613.2.4 (Eqn 16-38)
5% Damped Design Spectral Response Acceleration (1 sec), SD1 0.292g Section 1613.2.4 (Eqn 16-39)
* Using the code-based values presented in this table, in lieu of a performing a ground motion hazard
analysis, requires the exceptions outlined in ASCE 7-16 Section 11.4.8 be followed by the project
structural engineer. Per Section 11.4.8 of ASCE/SEI 7-16, a ground motion hazard analysis should
be performed for projects for Site Class “E” sites with Ss greater than or equal to 1.0g and for Site
Class “D” and “E” sites with S1 greater than 0.2g; however, Section 11.4.8 also provides
exceptions which indicates that the ground motion hazard analysis may be waived provided the
exceptions are followed.
Project No. G2452-32-02 - 19 - April 10, 2020
9.9.2 Table 9.9.2 presents the mapped maximum considered geometric mean (MCEG) seismic
design parameters for projects located in Seismic Design Categories of D through F in
accordance with ASCE 7-16.
TABLE 9.9.2
2019 CBC SITE ACCELERATION PARAMETERS
Parameter Value ASCE 7-16 Reference
Mapped MCEG Peak Ground
Acceleration, PGA 0.356g Figure 22-7
Site Coefficient, FPGA 1.2 Table 11.8-1
Site Class Modified MCEGPeak Ground Acceleration, PGAM 0.428g Section 11.8.3 (Eqn 11.8-1)
9.9.3 Conformance to the criteria in Tables 9.9.1 and 9.9.2 for seismic design does not constitute
any kind of guarantee or assurance that significant structural damage or ground failure will
not occur if a large earthquake occurs. The primary goal of seismic design is to protect life,
not to avoid all damage, since such design may be economically prohibitive.
9.9.4 The project structural engineer and architect should evaluate the appropriate Risk Category
and Seismic Design Category for the planned structures. The values presented herein
assume a Risk Category of II and resulting in a Seismic Design Category D. Table 9.9.3
presents a summary of the risk categories in accordance with ASCE 7-16.
TABLE 9.9.3
ASCE 7-16 RISK CATEGORIES
Risk
Category Building Use Examples
I Low risk to Human Life at Failure Barn, Storage Shelter
II Nominal Risk to Human Life at Failure
(Buildings Not Designated as I, III or IV)
Residential, Commercial and
Industrial Buildings
III Substantial Risk to Human Life at Failure
Theaters, Lecture Halls, Dining Halls,
Schools, Prisons, Small Healthcare
Facilities, Infrastructure Plants,
Storage for Explosives/Toxins
IV Essential Facilities
Hazardous Material Facilities,
Hospitals, Fire and Rescue,
Emergency Shelters, Police Stations,
Power Stations, Aviation Control
Facilities, National Defense, Water
Storage
Project No. G2452-32-02 - 20 - April 10, 2020
9.10 Foundation and Concrete Slabs-On-Grade Recommendations
9.10.1 The following foundation recommendations are for proposed one- to three-story residential
structures. For buildings greater than three stories, or two to three-story buildings supported
by fills with a thickness in excess of 75 feet, additional recommendations should be
provided considering the anticipated total and differential settlement. This information can
be provided once the project foundation engineer is selected and total and differential
settlement tolerances for each building are discussed. The foundation recommendations
presented below have been separated into three categories based on either the maximum and
differential fill thickness or Expansion Index. The foundation category criteria are presented
in Table 9.10.1.
TABLE 9.10.1
FOUNDATION CATEGORY CRITERIA
Foundation
Category
Maximum Fill
Thickness, T (Feet)
Differential Fill
Thickness, D (Feet)
Expansion Index
(EI)
I T<20 -- EI<50
II 20<T<50 10<D<20 50<EI<90
III 75>T>50 D>20 90<EI<130
9.10.2 Final foundation categories for each building or lot will be provided after finish pad grades
have been achieved and laboratory testing of the subgrade soil has been completed.
9.10.3 Table 9.10.2 presents minimum foundation and interior concrete slab design criteria for
conventional foundation systems.
TABLE 9.10.2
CONVENTIONAL FOUNDATION RECOMMENDATIONS BY CATEGORY
Foundation
Category
Minimum Footing
Embedment Depth
(inches)
Continuous Footing
Reinforcement
Interior Slab
Reinforcement
I 12 Two No. 4 bars,
one top and one bottom
6 x 6 - 10/10 welded wire
mesh at slab mid-point
II 18 Four No. 4 bars,
two top and two bottom
No. 3 bars at 24 inches on
center, both directions
III 24 Four No. 5 bars,
two top and two bottom
No. 3 bars at 18 inches on
center, both directions
Project No. G2452-32-02 - 21 - April 10, 2020
9.10.4 The embedment depths presented in Table 9.10.2 should be measured from the lowest
adjacent pad grade for both interior and exterior footings. The conventional foundations
should have a minimum width of 12 inches and 24 inches for continuous and isolated
footings, respectively. A typical wall/column footing detail is presented on Figure 14.
9.10.5 The concrete slabs-on-grade should be a minimum of 4 inches thick for Foundation
Categories I and II and 5 inches thick for Foundation Category III. The concrete slabs-on-
grade should be underlain by 4 inches and 3 inches of clean sand for 4-inch thick and
5-inch-thick slabs, respectively. Slabs expected to receive moisture sensitive floor coverings
or used to store moisture sensitive materials should be underlain by a vapor inhibitor covered
with at least 2 inches of clean sand or crushed rock. If crushed rock will be used, the thickness
of the vapor inhibitor should be at least 10 mil to prevent possible puncturing.
9.10.6 As a substitute, the layer of clean sand (or crushed rock) beneath the vapor inhibitor
recommended in the previous section can be omitted if a vapor inhibitor that meets or
exceeds the requirements of ASTM E 1745-97 (Class A), and that exhibits permeance not
greater than 0.012 perm (measured in accordance with ASTM E 96-95) is used. This vapor
inhibitor may be placed directly on properly compacted fill or formational materials. The
vapor inhibitor should be installed in general conformance with ASTM E 1643-98 and the
manufacturer’s recommendations. Two inches of clean sand should then be placed on top of
the vapor inhibitor to reduce the potential for differential curing, slab curl, and cracking.
Floor coverings should be installed in accordance with the manufacturer’s
recommendations.
9.10.7 As an alternative to the conventional foundation recommendations, consideration should be
given to the use of post-tensioned concrete slab and foundation systems for the support of
the proposed structures. The post-tensioned systems should be designed by a structural
engineer experienced in post-tensioned slab design and design criteria of the Post-
Tensioning Institute (PTI) DC10.5 as required by the 2019 California Building Code (CBC
Section 1808.6.2). Although this procedure was developed for expansive soil conditions, we
understand it can also be used to reduce the potential for foundation distress due to
differential fill settlement. The post-tensioned design should incorporate the geotechnical
parameters presented on Table 9.10.3. The parameters presented in Table 9.10.3 are based
on the guidelines presented in the PTI, DC10.5 design manual.
Project No. G2452-32-02 - 22 - April 10, 2020
TABLE 9.10.3
POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS
Post-Tensioning Institute (PTI),
Third Edition Design Parameters
Foundation Category
I II III
Thornthwaite Index -20 -20 -20
Equilibrium Suction 3.9 3.9 3.9
Edge Lift Moisture Variation Distance, eM (feet) 5.3 5.1 4.9
Edge Lift, yM (inches) 0.61 1.10 1.58
Center Lift Moisture Variation Distance, eM (feet) 9.0 9.0 9.0
Center Lift, yM (inches) 0.30 0.47 0.66
9.10.8 Foundation systems for the lots that possess a foundation Category I and a “very low”
expansion potential (expansion index of 20 or less) can be designed using the method
described in Section 1808 of the 2019 CBC. If post-tensioned foundations are planned, an
alternative, commonly accepted design method (other than PTI DC 10.5) can be used.
However, the post-tensioned foundation system should be designed with a total and
differential deflection of 1 inch. Geocon Incorporated should be contacted to review the
plans and provide additional information, if necessary.
9.10.9 The foundations for the post-tensioned slabs should be embedded in accordance with the
recommendations of the structural engineer. If a post-tensioned mat foundation system is
planned, the slab should possess a thickened edge with a minimum width of 12 inches and
extend below the clean sand or crushed rock layer.
9.10.10 If the structural engineer proposes a post-tensioned foundation design method other than
PTI, Third Edition:
The deflection criteria presented in Table 9.10.3 are still applicable.
Interior stiffener beams should be used for Foundation Categories II and III.
The width of the perimeter foundations should be at least 12 inches.
The perimeter footing embedment depths should be at least 12 inches, 18 inches and
24 inches for foundation categories I, II, and III, respectively. The embedment
depths should be measured from the lowest adjacent pad grade.
9.10.11 Our experience indicates post-tensioned slabs are susceptible to excessive edge lift,
regardless of the underlying soil conditions. Placing reinforcing steel at the bottom of the
Project No. G2452-32-02 - 23 - April 10, 2020
perimeter footings and the interior stiffener beams may mitigate this potential. Current PTI
design procedures primarily address the potential center lift of slabs but, because of the
placement of the reinforcing tendons in the top of the slab, the resulting eccentricity after
tensioning reduces the ability of the system to mitigate edge lift. The structural engineer
should design the foundation system to reduce the potential of edge lift occurring for the
proposed structures.
9.10.12 During the construction of the post-tension foundation system, the concrete should be
placed monolithically. Under no circumstances should cold joints be allowed to form
between the footings/grade beams and the slab during the construction of the post-tension
foundation system.
9.10.13 Category I, II, or III foundations may be designed for an allowable soil bearing pressure of
2,000 pounds per square foot (psf) (dead plus live load). This bearing pressure may be
increased by one-third for transient loads due to wind or seismic forces.
9.10.14 Isolated footings, if present, should have the minimum embedment depth and width
recommended for conventional foundations for a particular foundation category. The use of
isolated footings, which are located beyond the perimeter of the building and support
structural elements connected to the building, are not recommended for Category III. Where
this condition cannot be avoided, the isolated footings should be connected to the building
foundation system with grade beams.
9.10.15 For Foundation Category III, consideration should be given to using interior stiffening
beams and connecting isolated footings and/or increasing the slab thickness. In addition,
consideration should be given to connecting patio slabs, which exceed 5 feet in width, to the
building foundation to reduce the potential for future separation to occur.
9.10.16 Special subgrade presaturation is not deemed necessary prior to placing concrete; however,
the exposed foundation and slab subgrade soil should be moisture conditioned, as necessary,
to maintain a moist condition as would be expected in any such concrete placement.
9.10.17 Where buildings or other improvements are planned near the top of a slope steeper than 3:1
(horizontal:vertical), special foundations and/or design considerations are recommended due
to the tendency for lateral soil movement to occur.
For fill slopes less than 20 feet high, building footings should be deepened such that
the bottom outside edge of the footing is at least 7 feet horizontally from the face of
the slope.
Project No. G2452-32-02 - 24 - April 10, 2020
When located next to a descending 3:1 (horizontal:vertical) fill slope or steeper, the
foundations should be extended to a depth where the minimum horizontal distance
is equal to H/3 (where H equals the vertical distance from the top of the fill slope to
the base of the fill soil) with a minimum of 7 feet but need not exceed 40 feet. The
horizontal distance is measured from the outer, deepest edge of the footing to the
face of the slope. An acceptable alternative to deepening the footings would be the
use of a post-tensioned slab and foundation system or increased footing and slab
reinforcement. Specific design parameters or recommendations for either of these
alternatives can be provided once the building location and fill slope geometry have
been determined.
If swimming pools are planned, Geocon Incorporated should be contacted for a
review of specific site conditions.
Swimming pools located within 7 feet of the top of cut or fill slopes are not
recommended. Where such a condition cannot be avoided, the portion of the
swimming pool wall within 7 feet of the slope face be designed assuming that the
adjacent soil provides no lateral support. This recommendation applies to fill
slopes up to 30 feet in height, and cut slopes regardless of height. For swimming
pools located near the top of fill slopes greater than 30 feet in height, additional
recommendations may be required and Geocon Incorporated should be contacted for a
review of specific site conditions.
Although other improvements, which are relatively rigid or brittle, such as concrete
flatwork or masonry walls, may experience some distress if located near the top of a
slope, it is generally not economical to mitigate this potential. It may be possible,
however, to incorporate design measures which would permit some lateral soil
movement without causing extensive distress. Geocon Incorporated should be
consulted for specific recommendations.
9.10.18 The recommendations of this report are intended to reduce the potential for cracking of slabs
due to expansive soil (if present), differential settlement of existing soil or soil with varying
thicknesses. However, even with the incorporation of the recommendations presented
herein, foundations, stucco walls, and slabs-on-grade placed on such conditions may still
exhibit some cracking due to soil movement and/or shrinkage. The occurrence of concrete
shrinkage cracks is independent of the supporting soil characteristics. Their occurrence may
be reduced and/or controlled by limiting the slump of the concrete, proper concrete
placement and curing, and by the placement of crack control joints at periodic intervals, in
particular, where re-entrant slab corners occur.
9.10.19 Geocon Incorporated should be consulted to provide additional design parameters as
required by the structural engineer.
Project No. G2452-32-02 - 25 - April 10, 2020
9.11 Retaining Walls and Lateral Loads Recommendations
9.11.1 Retaining walls not restrained at the top and having a level backfill surface should be
designed for an active soil pressure equivalent to the pressure exerted by a fluid with a
density of 35 pounds per cubic foot (pcf). Where the backfill will be inclined at
2:1 (horizontal:vertical), an active soil pressure of 50 pcf is recommended. These soil
pressures assume that the backfill materials within an area bounded by the wall and a 1:1
plane extending upward from the base of the wall possess an Expansion Index <50. Geocon
Incorporated should be consulted for additional recommendations if backfill materials have
an EI >50.
9.11.2 Retaining walls shall be designed to ensure stability against overturning sliding, excessive
foundation pressure and water uplift. Where a keyway is extended below the wall base with
the intent to engage passive pressure and enhance sliding stability, it is not necessary to
consider active pressure on the keyway.
9.11.3 Where walls are restrained from movement at the top, an additional uniform pressure of
8H psf (where H equals the height of the retaining wall portion of the wall in feet) should be
added to the active soil pressure where the wall possesses a height of 8 feet or less and 12H
where the wall is greater than 8 feet. For retaining walls subject to vehicular loads within a
horizontal distance equal to two-thirds the wall height, a surcharge equivalent to two feet of
fill soil should be added (total unit weight of soil should be taken as 130 pcf).
9.11.4 Soil contemplated for use as retaining wall backfill, including import materials, should be
identified in the field prior to backfill. At that time Geocon Incorporated should obtain
samples for laboratory testing to evaluate its suitability. Modified lateral earth pressures
may be necessary if the backfill soil does not meet the required expansion index or shear
strength. City or regional standard wall designs, if used, are based on a specific active lateral
earth pressure and/or soil friction angle. In this regard, on-site soil to be used as backfill may
or may not meet the values for standard wall designs. Geocon Incorporated should be
consulted to assess the suitability of the on-site soil for use as wall backfill if standard wall
designs will be used.
9.11.5 Unrestrained walls will move laterally when backfilled and loading is applied. The amount
of lateral deflection is dependent on the wall height, the type of soil used for backfill, and
loads acting on the wall. The wall designer should provide appropriate lateral deflection
quantities for planned retaining walls structures, if applicable. These lateral values should be
considered when planning types of improvements above retaining wall structures.
Project No. G2452-32-02 - 26 - April 10, 2020
9.11.6 Retaining walls should be provided with a drainage system adequate to prevent the buildup
of hydrostatic forces and should be waterproofed as required by the project architect. The
use of drainage openings through the base of the wall (weep holes) is not recommended
where the seepage could be a nuisance or otherwise adversely affect the property adjacent to
the base of the wall. The above recommendations assume a properly compacted granular
(EI <50) free-draining backfill material with no hydrostatic forces or imposed surcharge
load. A typical retaining wall drainage detail is presented on Figure 15. If conditions
different than those described are expected, or if specific drainage details are desired,
Geocon Incorporated should be contacted for additional recommendations.
9.11.7 In general, wall foundations having a minimum depth and width of one foot may be
designed for an allowable soil bearing pressure of 2,000 psf, provided the soil within three
feet below the base of the wall has an Expansion Index < 90. The recommended allowable
soil bearing pressure may be increased by 300 psf and 500 psf for each additional foot of
foundation width and depth, respectively, up to a maximum allowable soil bearing pressure
of 4,000 psf.
9.11.8 The proximity of the foundation to the top of a slope steeper than 3:1 could impact the
allowable soil bearing pressure. Therefore, Geocon Incorporated should be consulted where
such a condition is anticipated. As a minimum, wall footings should be deepened such that
the bottom outside edge of the footing is at least seven feet from the face of slope when
located adjacent and/or at the top of descending slopes.
9.11.9 The structural engineer should determine the Seismic Design Category for the project in
accordance with Section 1613.3.5 of the 2019 CBC or Section 11.6 of ASCE 7-10. For
structures assigned to Seismic Design Category of D, E, or F, retaining walls that support
more than 6 feet of backfill should be designed with seismic lateral pressure in accordance
with Section 1803.5.12 of the 2019 CBC. The seismic load is dependent on the retained
height where H is the height of the wall, in feet, and the calculated loads result in pounds per
square foot (psf) exerted at the base of the wall and zero at the top of the wall. A seismic
load of 15H should be used for design. We used the peak ground acceleration adjusted for
Site Class effects, PGAM, of 0.428g calculated from ASCE 7-10 Section 11.8.3 and applied
a pseudo-static coefficient of 0.3.
9.11.10 For resistance to lateral loads, a passive earth pressure equivalent to a fluid density of 350 pcf
is recommended for footings or shear keys poured neat against properly compacted granular
fill soils or undisturbed formational materials. The passive pressure assumes a horizontal
surface extending away from the base of the wall at least five feet or three times the surface
Project No. G2452-32-02 - 27 - April 10, 2020
generating the passive pressure, whichever is greater. The upper 12 inches of material not
protected by floor slabs or pavement should not be included in the design for lateral resistance.
9.11.11 An ultimate friction coefficient of 0.35 may be used for resistance to sliding between soil
and concrete. This friction coefficient may be combined with the passive earth pressure
when determining resistance to lateral loads.
9.11.12 The recommendations presented above are generally applicable to the design of rigid
concrete or masonry retaining walls having a maximum height of 12 feet. In the event that
walls higher than 12 feet are planned, Geocon Incorporated should be consulted for
additional recommendations.
9.12 Storm Water Management BMP’s
9.12.1 Based on the City of Chula Vista storm water standards manual, full or partial infiltration is
infeasible and the site exhibits a “no infiltration” condition. The City of Chula Vista
Categorization of Infiltration Feasibility Condition Based on Geotechnical Conditions I-8A
(Worksheet C.4-1) forms are provided in Appendix D.
9.12.2 Both basins are located within 50 feet of a natural slope and are supported by the Otay and
Sweetwater Formations. Highly expansive bentonitic clays are present in the Otay
Formation beneath the basins. Water infiltration into highly expansive bentonite and
bedding plane shear zones may result in soil heaving and distress to nearby public and
private improvements and structures, lateral migration, daylight water seepage and slope
instability. In addition, the eastern basin would be supported on a cut-fill transition resulting
in approximately 20 feet of compacted fill or Otay Formation sandstone and claystone.
9.12.3 Due to the site geologic conditions, liners and subdrains should be incorporated into the
design and construction of the planned storm water devices. The liners should be
impermeable (e.g. High-density polyethylene, HDPE, with a thickness of about 30 mil or
equivalent Polyvinyl Chloride, PVC) to prevent water migration. The subdrains should be
perforated within the liner area, installed at the base and above the liner, be at least 4 inches
in diameter and consist of Schedule 40 PVC pipe. The subdrains outside of the liner should
consist of solid pipe. Seams and penetrations of the liners should be properly waterproofed.
The subdrains should be connected to a proper outlet. The devices should also be installed in
accordance with the manufacturer’s recommendations. In addition, civil engineering
provisions should be implemented to assure that the capacity of the system is never
exceeded resulting in over topping or malfunctioning of the device. The system should also
Project No. G2452-32-02 - 28 - April 10, 2020
include a long-term maintenance program or periodic cleaning to prevent clogging of the
filter media or drain envelope.
9.13 Slope Maintenance
9.13.1 Slopes that are steeper than 3:1 (horizontal:vertical) may, under conditions that are both
difficult to prevent and predict, be susceptible to near-surface (surficial) slope instability.
The instability is typically limited to the outer 3 feet of a portion of the slope and usually
does not directly impact the improvements on the pad areas above or below the slope. The
occurrence of surficial instability is more prevalent on fill slopes and is generally preceded
by a period of heavy rainfall, excessive irrigation, or the migration of subsurface seepage.
The disturbance and/or loosening of the surficial soils, as might result from root growth, soil
expansion, or excavation for irrigation lines and slope planting, may also be a significant
contributing factor to surficial instability. It is, therefore, recommended that, to the
maximum extent practical: (a) disturbed/loosened surficial soils be either removed or
properly recompacted, (b) irrigation systems be periodically inspected and maintained to
eliminate leaks and excessive irrigation, and (c) surface drains on and adjacent to slopes be
periodically maintained to preclude ponding or erosion. It should be noted that although the
incorporation of the above recommendations should reduce the potential for surficial slope
instability, it will not eliminate the possibility, and, therefore, it may be necessary to rebuild
or repair a portion of the project's slopes in the future.
9.14 Site Drainage and Moisture Protection
9.14.1 Adequate site drainage is critical to reduce the potential for differential soil movement,
erosion and subsurface seepage. Under no circumstances should water be allowed to pond
adjacent to footings. The site should be graded and maintained such that surface drainage is
directed away from structures in accordance with 2019 CBC 1804.4 or other applicable
standards. In addition, surface drainage should be directed away from the top of slopes into
swales or other controlled drainage devices. Roof and pavement drainage should be directed
into conduits that carry runoff away from the proposed structure.
9.14.2 Underground utilities should be leak free. Utility and irrigation lines should be checked
periodically for leaks, and detected leaks should be repaired promptly. Detrimental soil
movement could occur if water is allowed to infiltrate the soil for prolonged periods of time.
9.15 Grading and Foundation Plan Review
9.15.1 Geocon Incorporated should review the grading plans and foundation plans for the project
prior to final design submittal to evaluate whether additional analyses and/or
recommendations are required.
Project No. G2452-32-02 April 10, 2020
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1. The firm that performed the geotechnical investigation for the project should be retained to
provide testing and observation services during construction to provide continuity of
geotechnical interpretation and to check that the recommendations presented for geotechnical
aspects of site development are incorporated during site grading, construction of
improvements, and excavation of foundations. If another geotechnical firm is selected to
perform the testing and observation services during construction operations, that firm should
prepare a letter indicating their intent to assume the responsibilities of project geotechnical
engineer of record. A copy of the letter should be provided to the regulatory agency for their
records. In addition, that firm should provide revised recommendations concerning the
geotechnical aspects of the proposed development, or a written acknowledgement of their
concurrence with the recommendations presented in our report. They should also perform
additional analyses deemed necessary to assume the role of Geotechnical Engineer of Record.
2. The recommendations of this report pertain only to the site investigated and are based upon
the assumption that the soil conditions do not deviate from those disclosed in the
investigation. If any variations or undesirable conditions are encountered during construction,
or if the proposed construction will differ from that anticipated herein, Geocon Incorporated
should be notified so that supplemental recommendations can be given. The evaluation or
identification of the potential presence of hazardous or corrosive materials was not part of the
scope of services provided by Geocon Incorporated.
3. This report is issued with the understanding that it is the responsibility of the owner, or of his
representative, to ensure that the information and recommendations contained herein are
brought to the attention of the architect and engineer for the project and incorporated into the
plans, and that the necessary steps are taken to see that the contractor and subcontractors
carry out such recommendations in the field.
4. The findings of this report are valid as of the present date. However, changes in the
conditions of a property can occur with the passage of time, whether they are due to natural
processes or the works of man on this or adjacent properties. In addition, changes in
applicable or appropriate standards may occur, whether they result from legislation or the
broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly
or partially by changes outside our control. Therefore, this report is subject to review and
should not be relied upon after a period of three years.
SITESITE
NO SCALE
FIG. 1
THE GEOGRAPHICAL INFORMATION MADE AVAILABLE FOR DISPLAY WAS PROVIDED BY GOOGLE EARTH,
SUBJECT TO A LICENSING AGREEMENT. THE INFORMATION IS FOR ILLUSTRATIVE PURPOSES ONLY; IT IS
NOT INTENDED FOR CLIENT'S USE OR RELIANCE AND SHALL NOT BE REPRODUCED BY CLIENT. CLIENT
SHALL INDEMNIFY, DEFEND AND HOLD HARMLESS GEOCON FROM ANY LIABILITY INCURRED AS A RESULT
OF SUCH USE OR RELIANCE BY CLIENT.
VICINITY MAP
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2452 - 32 - 02TR / RA
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:06/10/2020 8:08AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\DETAILS\G2452-32-02 VicinityMap.dwg
DATE 04 - 10 - 2020
427.00'2
EL-PNT2
448.00'3
EL-PNT3
451.00'4
EL-PNT4
433.00'6
EL-PNT6
462.00'7
EL-PNT7
470.00'8
EL-PNT8
453.00'9
EL-PNT9
447.00'10
EL-PNT10
447.00'11
EL-PNT11
STREET
'
A
'
(
P
U
B
L
I
C
)
STREET 'A
'
(
P
U
B
L
I
C
)STREET 'B
'STREET
'B
'
(PUBL
IC)STREET 'A' (PUBLIC)R-5
R-1
R-1
R-4
R-4
R-6
R-6
R-3
R-2
OS-1
OS-2
OS-2
OS-3
OS-3
OS-5
O
S
-
5
OS-6
OS-7OS-8OS-9
OS-10
OS-10 OS-11
OS-12
OS-13
OS-14OS-14
MSCP
MSCP
MSCP
MSCP
MSCP
CPF-1(PUBLIC)MBFPMB
F
P
STREET
'
B
'
(
P
U
B
L
I
C
)MMOS-7OS-10
OS-15
OLYMPIC
P
K
W
Y
OLYM
P
I
C
P
K
W
Y
427.00'2
EL-PNT2
448.00'3
EL-PNT3
451.00'4
EL-PNT4
433.00'6
EL-PNT6
462.00'7
EL-PNT7
470.00'8
EL-PNT8
453.00'9
EL-PNT9
447.00'10
EL-PNT10
447.00'11
EL-PNT11
QcolEXISTING
RECLAIMED
WATER MAIN
AA'BB'CC'DD'EE'F'
F
G
G'JHH'II'J'KK'Qal Qpf Qal
Tsw
Q
a
l
Q
c
o
l
Tsw
To
To
Tsw
Qpf
Qal
Tsw
To
Qal
Qcol
Qcol
Qcol
QcolQal
Qal
Tsw
To
QalQal
To
Tsd
Tsd Tsd
Tsd
To
To
Qpf
TswQal
To
LB-1
LB-2
LB-6
LB-3
LB-4
LB-5
LB-7
2'
2'
4'
3'
4'
4'
4'
B-77
B-6
B-3
B-2
G-6
G-5G-4
G-3G-2G-1
V-1
V-2V-3 MW-1
MW-2
G-7
3'
1'
2'
I-1
T-169
T-168
T-167
2'
3'
2'
T-4
8'
T-3
10'
T-2
7'
-7'
T-5
2'
T-1
7'
-7'
T-10
T-9
11'
T-8
8'
T-7
10'
T-6
10'
T-17
2'
T-12
10'
T-11
12'
T-13
11'
T-15
3.5'
T-14
6'
T-16
7'
T-18
T-19
2'
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF
PROJECT NO.
SCALE DATE
FIGURE
Plotted:06/17/2020 9:29AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\SHEETS\G2452-32-02 GeotechnicalMap.dwg
GEOTECHNICAL ENVIRONMENTAL MATERIALS
1" =
........APPROX. LOCATION OF CANYON SUBDRAIN
T-19
GEOCON LEGEND
........PREVIOUSLY PLACED FILLQpf
K K'
B-77
G-7
MW-2
V-3
B-6
T-169
........ALLUVIUMQal
........COLLUVIUMQcol
........OTAY FORMATIONTo
........SWEETWATER FORMATIONTsw
........APPROX. LOCATION OF LARGE DIAMETER
BORING (GEOCON 2020)
LB-7
........APPROX. LOCATION OF EXPLORATORY TRENCH (GEOCON 2020)
........APPROX. LOCATION OF LARGE - DIAMETER BORING
(GEOCON 1986)
........APPROX. LOCATION OF LARGE - DIAMETER BORING
(GEOCON 2006)
........APPROX. LOCATION OF EXPLORATORY TRENCH
(GEOCON 2006)
........APPROX. LOCATION OF GAS MONITORING WELL
(GEOCON 1989)
........APPROX. LOCATION OF VADOSE MONITORING WELL
(GEOCON 1989)
........APPROX. LOCATION OF MONITORING WELL
(GEOCON 1994)
........APPROX. LOCATION OF GEOLOGIC CONTACT
........APPROX. LOCATION OF GEOLOGIC CROSS-SECTION
........APPROX. THICKNESS OF SURFICIAL DEPOSITS REQUIRING
REMEDIAL GRADING (In Feet)
12'
........APPROX. DEPTH TO GROUNDWATER (In Feet)
........SAN DIEGO FORMATIONTsd
-7'
........ESTIMATED DAYLIGHT LOCATION OF BENTONITIC CLAYSTONE
AND KEY MARKER BED AT NATURAL GRADE BASED ON
INFORMATION PROJECTED FROM BORINGS
........SPOT ELEVATION FROM GOOGLE EARTH447.00'
10
EL-PNT10
........APPROX. LOCATION OF INFILTRATION TEST (GEOCON 2020)I-1
........CUT/FILL LINE||
........PROPOSED STABILITY FILL
........PROPOSED BASE OF SHEAR KEY
........PROPOSED BUTTRESS
........ESTIMATED AREA WHERE BENTONITIC CLAYSTONE BED
WILL REQUIRE 5-FOOT UNDERCUT
GEOTECHNICAL MAP
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIA
100' 04 - 10 - 2020
G2452 - 32 - 02
1 1 2
427.00'2
EL-PNT2
448.00'3
EL-PNT3
451.00'4
EL-PNT4
433.00'6
EL-PNT6
462.00'7
EL-PNT7
470.00'8
EL-PNT8
453.00'9
EL-PNT9
447.00'10
EL-PNT10
447.00'11
EL-PNT11 355360365370356357358359361362363364366367368369371372340345350355360365337338339341342343344346347348349351352353354356357358359361362363364366367340
345
350
337
338
339
341
342
343
344
346
347
348
349351
360365361362363364366367368369348
349
350
351
352
372373374371370QcolEXISTING
RECLAIMED
WATER MAIN
AA'BB'CC'DD'EE'F'
F
G
G'JHH'II'J'KK'Qal Qpf Qal
Tsw
Q
a
l
Q
c
o
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Tsw
To
To
Tsw
Qpf
Qal
Tsw
To
Qal
Qcol
Qcol
Qcol
QcolQal
Qal
Tsw
To
QalQal
To
Tsd
Tsd Tsd
Tsd
To
To
Qpf
TswQal
To
368'
344'
348'
352'
366'
LB-1
LB-2
LB-6
LB-3
LB-4
LB-5
LB-7
2'
2'
4'
3'
4'
4'
4'
B-77
B-6
B-3
B-2
G-6
G-5G-4
G-3G-2G-1
V-1
V-2V-3 MW-1
MW-2
G-7
3'
1'
2'
I-1
T-169
T-168
T-167
2'
3'
2'
T-4
8'
T-3
10'
T-2
7'
-7'
T-5
2'
T-1
7'
-7'
T-10
T-9
11'
T-8
8'
T-7
10'
T-6
10'
T-17
2'
T-12
10'
T-11
12'
T-13
11'
T-15
3.5'
T-14
6'
T-16
7'
T-18
T-19
2'
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF
PROJECT NO.
SCALE DATE
FIGURE
Plotted:06/17/2020 9:31AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\SHEETS\G2452-32-02 GeologyMap.dwg
GEOTECHNICAL ENVIRONMENTAL MATERIALS
1" =
T-19
GEOCON LEGEND
........PREVIOUSLY PLACED FILLQpf
K K'
B-77
G-7
MW-2
V-3
B-6
T-169
........ALLUVIUMQal
........COLLUVIUMQcol
........OTAY FORMATIONTo
........SWEETWATER FORMATIONTsw
........APPROX. LOCATION OF LARGE DIAMETER
BORING (GEOCON 2020)
LB-7
........APPROX. LOCATION OF EXPLORATORY TRENCH (GEOCON 2020)
........APPROX. LOCATION OF LARGE - DIAMETER BORING
(GEOCON 1986)
........APPROX. LOCATION OF LARGE - DIAMETER BORING
(GEOCON 2006)
........APPROX. LOCATION OF EXPLORATORY TRENCH
(GEOCON 2006)
........APPROX. LOCATION OF GAS MONITORING WELL
(GEOCON 1989)
........APPROX. LOCATION OF VADOSE MONITORING WELL
(GEOCON 1989)
........APPROX. LOCATION OF MONITORING WELL
(GEOCON 1994)
........APPROX. LOCATION OF GEOLOGIC CONTACT
........APPROX. LOCATION OF GEOLOGIC CROSS-SECTION
........APPROX. THICKNESS OF SURFICIAL DEPOSITS REQUIRING
REMEDIAL GRADING (In Feet)
12'
........APPROX. DEPTH TO GROUNDWATER (In Feet)
........SAN DIEGO FORMATIONTsd
-7'
........ESTIMATED DAYLIGHT LOCATION OF BENTONITIC CLAYSTONE
AND KEY MARKER BED AT NATURAL GRADE BASED ON
INFORMATION PROJECTED FROM BORINGS
........SPOT ELEVATION FROM GOOGLE EARTH
........ELEVATION CONTOUR OF KEY MARKER BED (In Feet)
447.00'10
EL-PNT10
353
348'........ELEVATION OF KEY MARKER BED ENCOUNTERED IN
BORING/TRENCH (In Feet)
........APPROX. LOCATION OF INFILTRATION TEST (GEOCON 2020)I-1
GEOLOGY MAP
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIA
100' 04 - 10 - 2020
G2452 - 32 - 02
1 1 3
A A'
B B'ELEVATION (MSL)ELEVATION (MSL)DISTANCE (FEET)
SCALE: 1" = 20' (Vert. = Horiz.)
GEOLOGIC CROSS-SECTION A-A'
300
320
340
360
380
400
420
440
460
480
300
320
340
360
380
400
420
440
460
480
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600
ELEVATION (MSL)ELEVATION (MSL)DISTANCE (FEET)
SCALE: 1" = 20' (Vert. = Horiz.)
GEOLOGIC CROSS-SECTION B-B'
300
320
340
360
380
400
420
440
460
480
300
320
340
360
380
400
420
440
460
480
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600
???
PL
Tsw Tsw Tsw
To
To
Tsd
To
???
???
PL
Tsd Tsd
To To
To
TswTswTsw
LB-7
(Proj. ~5' East)
EXISTING TOPO BASED ON GOOGLE EARTH
EXISTING TOPO BASED ON GOOGLE EARTH
EXISTING
GRADE
PROPOSED
GRADE
EXISTING
GRADE
PROPOSED
GRADE
PROPOSED
RETAINING WALL
ASSUMED BPS
AT EL 372'
PROPOSED
RETAINING WALL
KEY MARKER
BED
BPS AT
EL 368.5'KEY MARKER
BED ·······························································································································································································································································?
??
?
Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)
15'
UNDERCUT BENTONITIC
CLAYSTONE TO A DEPTH
OF AT LEAST 5-FEET BELOW
FINISH GRADE
?
1
1
1
1
20' WIDE
?
?
?
?
?
?
Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)
Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)
Bentonitic Claystone Bed
(MH/CH, Observed in Boring)
?
?
SM
CL
ML
SM
SM
SM
CL
ML
SM
SM ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~1 4
Plotted:06/10/2020 8:11AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\SHEETS\G2452-32-02 Cross-Sections.dwg
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF
PROJECT NO.
SCALE DATE
FIGURE
GEOTECHNICAL ENVIRONMENTAL MATERIALS
1" =
GEOLOGIC CROSS - SECTIONS
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIA
20' 04 - 10 - 2020
G2452 - 32 - 02
5
T-19
GEOCON LEGEND
........ALLUVIUMQal
........OTAY FORMATIONTo
........SWEETWATER FORMATIONTsw
........APPROX. LOCATION OF LARGE DIAMETER
BORING (GEOCON 2020)
LB-7
........APPROX. LOCATION OF TRENCH (GEOCON 2020)
........APPROX. LOCATION OF LARGE - DIAMETER BORING
(GEOCON 1986)
........APPROX. LOCATION OF GEOLOGIC CONTACT
(Queried Where Uncertain)
........SAN DIEGO FORMATIONTsd
B-6
?
........APPROX. LOCATION OF INTRAFORMATIONAL CONTACT·················........APPROX. LOCATION OF BEDDING PLANE SHEAR
~~~~~~........PROPOSED STABILITY FILL
........PROPOSED SHEAR KEY
........PROPOSED BUTTRESS
C C'
D D'ELEVATION (MSL)ELEVATION (MSL)DISTANCE (FEET)
SCALE: 1" = 20' (Vert. = Horiz.)
GEOLOGIC CROSS-SECTION C-C'
300
320
340
360
380
400
420
440
460
480
300
320
340
360
380
400
420
440
460
480
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600
ELEVATION (MSL)ELEVATION (MSL)DISTANCE (FEET)
SCALE: 1" = 20' (Vert. = Horiz.)
GEOLOGIC CROSS-SECTION D-D'
300
320
340
360
380
400
420
440
460
480
300
320
340
360
380
400
420
440
460
480
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600
PL
To To To
Tsd
· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·
LB-6
(Proj. ~45' East
along contour)
??????
PL
Tsd
To To
LB-5
(Proj. ~190' East
along contour)
Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)
EXISTING
GRADE
EXISTING
GRADE
PROPOSED
GRADE
PROPOSED
GRADE
PROPOSED
RETAINING WALLS
6-INCH THICK
BENTONITIC CLAYSTONE
BED AT EL 372'
BPS
AT EL 349'
BPS
AT EL 352.3'
PROPOSED
RETAINING
WALLS
MULTIPLE DISCONTINUOUS
BPS AT EL 346.5'
KEY MARKER
BED
KEY MARKER
BED
KEY MARKER
BEDKEY MARKER
BED
KEY MARKER
BED ·········································································································································································································································································································································································?
?
???
?
Bentonitic Claystone Bed
(MH/CH, Observed in Boring)
???
Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)
2:1
STEEPER
THAN 2:1
TO PL
PLACEMENT OF BACK DRAIN
SYSTEM TO BE DETERMINED
AFTER CONSTRUCTION OF
TEMPORARY WALL BACKCUT
??
?
?
?
?
Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)
Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)
Bentonitic Claystone Bed
(MH/CH, Observed in Boring)
2:1
STEEPER
THAN 2:1
TO PL
PLACEMENT OF BACK DRAIN
SYSTEM TO BE DETERMINED
AFTER CONSTRUCTION OF
TEMPORARY WALL BACKCUT
SM, ML&CL
SM
SM&ML
SM&ML
SM, ML&CL
CL&MLCL&ML
SMSM
MLML
SMSM
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2 5
Plotted:06/10/2020 8:11AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\SHEETS\G2452-32-02 Cross-Sections.dwg
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF
PROJECT NO.
SCALE DATE
FIGURE
GEOTECHNICAL ENVIRONMENTAL MATERIALS
1" =
GEOLOGIC CROSS - SECTIONS
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIA
20' 04 - 10 - 2020
G2452 - 32 - 02
5
T-19
GEOCON LEGEND
........ALLUVIUMQal
........OTAY FORMATIONTo
........SWEETWATER FORMATIONTsw
........APPROX. LOCATION OF LARGE DIAMETER
BORING (GEOCON 2020)
LB-7
........APPROX. LOCATION OF TRENCH (GEOCON 2020)
........APPROX. LOCATION OF LARGE - DIAMETER BORING
(GEOCON 1986)
........APPROX. LOCATION OF GEOLOGIC CONTACT
(Queried Where Uncertain)
........SAN DIEGO FORMATIONTsd
B-6
?
........APPROX. LOCATION OF INTRAFORMATIONAL CONTACT·················........APPROX. LOCATION OF BEDDING PLANE SHEAR
~~~~~~........PROPOSED STABILITY FILL
........PROPOSED SHEAR KEY
........PROPOSED BUTTRESS
E E'
F F'ELEVATION (MSL)ELEVATION (MSL)DISTANCE (FEET)
SCALE: 1" = 20' (Vert. = Horiz.)
GEOLOGIC CROSS-SECTION E-E'
340
360
380
400
420
440
460
480
500
340
360
380
400
420
440
460
480
500
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600
ELEVATION (MSL)ELEVATION (MSL)DISTANCE (FEET)
SCALE: 1" = 20' (Vert. = Horiz.)
GEOLOGIC CROSS-SECTION F-F'
300
320
340
360
380
400
420
440
460
480
300
320
340
360
380
400
420
440
460
480
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600
PL
To
To
To
Tsd
Tsd
LB-3
(Proj. ~110' SW
along contour)LB-4
T-14
(Proj. ~10' North)Qal
To To
To
Tsd
PL
LB-4
(Projected ~55' North
along contour)
320 320
????
EXISTING
GRADE
EXISTING
GRADE
PROPOSED
GRADE
PROPOSED
GRADE
BPS
AT EL 351.9'
KEY MARKER
BED
BPS
AT EL 351.9'
PROPOSED
CANYON
SUBDRAIN
KEY MARKER
BED·······································································································································································································································································································································································································································································································································································································································································································································································································································································································································································································································································································································?
??
?
?
?
?
????
?
Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)
15'
WIDE
2:1
STEEPER
THAN 2:1
TO PL
?
?
?
?
??
??
??
??
?
?
?
?
?
Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)
Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)
Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)
15'
WIDE
2:1
STEEPER
THAN 2:1
TO PL
SMSM
ML&CLML&CL
SM&MLSM&ML
CH/MHCH/MH
ML&CL&SMML&CL&SM
SM
SMSM
SMSM
SMSM
ML&CLML&CL
CL/MLCL/ML
CHCH
SMSM
ML&CL&SMML&CL&SM
SM
SMSM
SMSM
SMSM
ML&CLML&CL
CL/MLCL/ML ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~3 6
Plotted:06/10/2020 8:11AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\SHEETS\G2452-32-02 Cross-Sections.dwg
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF
PROJECT NO.
SCALE DATE
FIGURE
GEOTECHNICAL ENVIRONMENTAL MATERIALS
1" =
GEOLOGIC CROSS - SECTIONS
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIA
20' 04 - 10 - 2020
G2452 - 32 - 02
5
T-19
GEOCON LEGEND
........ALLUVIUMQal
........OTAY FORMATIONTo
........SWEETWATER FORMATIONTsw
........APPROX. LOCATION OF LARGE DIAMETER
BORING (GEOCON 2020)
LB-7
........APPROX. LOCATION OF TRENCH (GEOCON 2020)
........APPROX. LOCATION OF LARGE - DIAMETER BORING
(GEOCON 1986)
........APPROX. LOCATION OF GEOLOGIC CONTACT
(Queried Where Uncertain)
........SAN DIEGO FORMATIONTsd
B-6
?
........APPROX. LOCATION OF INTRAFORMATIONAL CONTACT·················........APPROX. LOCATION OF BEDDING PLANE SHEAR
~~~~~~........PROPOSED STABILITY FILL
........PROPOSED SHEAR KEY
........PROPOSED BUTTRESS
G G'ELEVATION (MSL)ELEVATION (MSL)DISTANCE (FEET)
SCALE: 1" = 20' (Vert. = Horiz.)
GEOLOGIC CROSS-SECTION G-G'
260
280
300
320
340
360
380
400
420
260
280
300
320
340
360
380
400
420
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600
H H'ELEVATION (MSL)ELEVATION (MSL)DISTANCE (FEET)
SCALE: 1" = 20' (Vert. = Horiz.)
GEOLOGIC CROSS-SECTION H-H'
260
280
300
320
340
360
380
400
420
440
260
280
300
320
340
360
380
400
420
440
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600
WATER QUALITY BASIN
To
Tsw Tsw
B-3
LB-1
(Proj. ~60' West)
Tsw Tsw Tsw
ToTo
To
EXISTING
GRADE
PROPOSED
GRADE
PROPOSED
GRADE
EXISTING
GRADE
BPS
AT EL 367.9'
KEY MARKER
BED
ASSUMED BPS ALONG
KEY MARKER BED
KEY MARKER
BED
··················································································································································································································
········································
?
??
?
Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)
UNDERCUT BENTONITIC
CLAYSTONE TO A DEPTH
OF AT LEAST 5-FEET BELOW
FINISH GRADE
?
?
?
?
?
?
Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)
Bentonitic Claystone Bed
(MH/CH, Computer Generated Contour)
UNDERCUT BENTONITIC
CLAYSTONE TO A DEPTH
OF AT LEAST 5-FEET BELOW
FINISH GRADE
Bentonitic Claystone Bed
(MH/CH, Observed in Boring)
SMSM
SMSM
CLCL
SMSM
SMSM
SMSM
SMSM
MH/CHMH/CH
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~4 7
Plotted:06/10/2020 8:11AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\SHEETS\G2452-32-02 Cross-Sections.dwg
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF
PROJECT NO.
SCALE DATE
FIGURE
GEOTECHNICAL ENVIRONMENTAL MATERIALS
1" =
GEOLOGIC CROSS - SECTIONS
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIA
20' 04 - 10 - 2020
G2452 - 32 - 02
5
T-19
GEOCON LEGEND
........ALLUVIUMQal
........OTAY FORMATIONTo
........SWEETWATER FORMATIONTsw
........APPROX. LOCATION OF LARGE DIAMETER
BORING (GEOCON 2020)
LB-7
........APPROX. LOCATION OF TRENCH (GEOCON 2020)
........APPROX. LOCATION OF LARGE - DIAMETER BORING
(GEOCON 1986)
........APPROX. LOCATION OF GEOLOGIC CONTACT
(Queried Where Uncertain)
........SAN DIEGO FORMATIONTsd
B-6
?
........APPROX. LOCATION OF INTRAFORMATIONAL CONTACT·················........APPROX. LOCATION OF BEDDING PLANE SHEAR
~~~~~~........PROPOSED STABILITY FILL
........PROPOSED SHEAR KEY
........PROPOSED BUTTRESS
II'KK'ELEVATION (MSL)
ELEVATION (MSL)DISTANCE (FEET)SCALE: 1" = 20' (Vert. = Horiz.)GEOLOGIC CROSS-SECTION I-I'280300320340360380400420440460280300320340360380400420440460020406080100120140160180200220240260280300320340360380400420440460480500520540560580600ELEVATION (MSL)
ELEVATION (MSL)DISTANCE (FEET)SCALE: 1" = 20' (Vert. = Horiz.)GEOLOGIC CROSS-SECTION K-K'220240260280300320340360380400420220240260280300320340360380400420020406080100120140160180200220240260280300320340360380400420440460480500520540560580600TswTswTswToToToToToTswTswTswJJ'ELEVATION (MSL)
ELEVATION (MSL)DISTANCE (FEET)SCALE: 1" = 20' (Vert. = Horiz.)GEOLOGIC CROSS-SECTION J-J'260280300320340360380400420440260280300320340360380400420440020406080100120140160180200220240260280300320340360380400420440460480500520540560580600620640660680700720740760780800LB-2(Proj. ~20' NEalong contour)TswTswTswToToToToPROPOSEDGRADEPROPOSEDGRADEEXISTINGGRADEEXISTINGGRADEASSUMED BPSAT EL 364.5'KEY MARKERBEDKEY MARKERBEDASSUMED BPSAT EL 353'EXISTINGGRADEPROPOSEDGRADEBPSAT EL 353'KEY MARKERBEDBPS ZONE FROMEL 351' TO 351.8'·············································································································································································································································································································································?????Bentonitic Claystone Bed(MH/CH, Computer Generated Contour)15'WIDE????????Bentonitic Claystone Bed(MH/CH, Computer Generated Contour)Bentonitic Claystone Bed(MH/CH, Computer Generated Contour)Bentonitic Claystone Bed(MH/CH, Observed in Boring)T-18WATER QUALITY BASINPL????Bentonitic Claystone Bed(MH/CH, Computer Generated Contour)1140' WIDESMSMSMSMSMML/CLML/CLSMSMSMSMSMSMMH/CHMH/CHSMSM11~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~NEED TO VERIFY BENTONITIC CLAYSTONE BEDELEVATION DURING GRADING TO DETERMINEIF SHEAR KEY IS NEEDED6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974PHONE 858 558-6900 - FAX 858 558-6159SHEET OFPROJECT NO.SCALEDATEFIGUREPlotted:06/10/2020 8:11AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\SHEETS\G2452-32-02 Cross-Sections.dwgGEOTECHNICAL ENVIRONMENTAL MATERIALS1" = T-19GEOCON LEGEND........ALLUVIUMQal........OTAY FORMATIONTo........SWEETWATER FORMATIONTsw........APPROX. LOCATION OF LARGE DIAMETER BORING (GEOCON 2020)LB-7........APPROX. LOCATION OF TRENCH (GEOCON 2020)........APPROX. LOCATION OF LARGE - DIAMETER BORING (GEOCON 1986)........APPROX. LOCATION OF GEOLOGIC CONTACT (Queried Where Uncertain)........SAN DIEGO FORMATIONTsdB-6?........APPROX. LOCATION OF INTRAFORMATIONAL CONTACT·················........APPROX. LOCATION OF BEDDING PLANE SHEAR~~~~~~........PROPOSED STABILITY FILL........PROPOSED SHEAR KEY........PROPOSED BUTTRESSGEOLOGIC CROSS - SECTIONSSUNBOW II, PHASE 3CHULA VISTA, CALIFORNIA20' 04 - 10 - 2020G2452 - 32 - 02558
ELEVATION (MSL)370
375
380
385
390
395
400
405
410
0+00 0+05 0+10 0+15 0+20 0+25 0+30 0+35 0+40 0+45 0+50 0+55 0+60 0+65 0+70 0+75 0+80 0+85 0+90 0+95 1+00 1+05 1+10 1+15 1+20
PROPOSED
GRADE
EXISTING
GRADE
B
C
B
C
A
B
F
D
E
B
ELEVATION (MSL)370
375
380
385
390
395
400
405
410
1+20 1+25 1+30 1+35 1+40 1+45 1+50 1+55 1+60 1+65 1+70 1+75 1+80 1+85 1+90 1+95 2+00 2+05 2+10 2+15 2+20 2+25 2+30 2+34
EXISTING
GRADE
PROPOSED
GRADE
AB
B
E C
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF
PROJECT NO.
SCALE DATE
FIGURE
Plotted:06/10/2020 8:11AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\SOURCE\SECTION\G2452-32-02 FaultTrench.dwg
GEOTECHNICAL ENVIRONMENTAL MATERIALS
1" = MATCHLINEMATCHLINE1+20
1+20
DISTANCE (FEET)
TRENCH NO. T-19
SCALE: 1" = 5' (Vert. = Horiz.)
DISTANCE (FEET)
TRENCH NO. T-19
SCALE: 1" = 5' (Vert. = Horiz.)
GEOCON LEGEND
TOPSOIL/ALLUVIUM
........Sandy CLAY (CH) - Soft, damp, very dark grayish brown,
fine-grained; clear, smooth contact below, thin zone of weathering at base.
A
To - OTAY FORMATION
........Silty SANDSTONE (SM) - Dense to very dense, damp, light gray, Silty,
fine- to medium-grained; massive to crudely stratified; abundant random
calcium-carbonate stringers throughout; abrupt, smooth contact.
B
........Sandy SILTSTONE (ML) - Very stiff, damp, grayish brown, fine-grained;
blocky texture; abrupt, smooth contact.
C
........Sandy CLAYSTONE (CL) - Very stiff, damp, brown, fine-grained;
basal contact not visible.
D
........Sandy SILTSTONE (ML) - Very stiff to hard, damp, grayish to greenish brown,
fine-grained, abundant random calcium-carbonate stringers throughout; clear,
smooth contact.
E
........Clayey SAND (SC) - Paleo-channel; stiff, damp, greenish brown,
fine- to medium-grained; rounded cobbles near base, up to 2-inch size;
abundant random calcium-carbonate stringers throughout; upper portion
is very diffuse with overlying topsoil.
F
........APPROX. LOCATION OF GEOLOGIC CONTACT
........APPROX. LOCATION OF INTERFORMATIONAL CONTACT
TRENCH NO. T-19
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIA
5' 04 - 10 - 2020
G2452 - 32 - 02
1 1 9
Slope Height, H (feet)∞
Vertical Depth of Stauration, Z (feet)3
Slope Inclination 2.00 :1
Slope Inclination, I (degrees)26.6
Unit Weight of Water, W (pcf)62.4
Total Unit Weight of Soil, T (pcf)120
Friction Angle, (degrees)29
Cohesion, C (psf) 300
Factor of Safety = (C+(T-W)Z cos2i tan)/(TZ sin i cos i)2.62
References:
Slope Height, H (feet)100
Slope Inclination 2.0 :1
Total Unit Weight of Soil, T (pcf)120
Friction Angle, (degrees)29
Cohesion, C (psf) 300
CHtanC 22.2
NCf (from Chart)60
Factor of Safety = (NCfC)/(H)1.50
References:(1) Janbu, N. Stability Analysis of Slopes with Dimensionless Parameters, Harvard Soil Mechanics, Series No.
46, 1954.
(2) Janbu, N. Discussion of J.M. Bell, DimensionlessParameters for Homogeneous Earth Slopes, Journal of Soil
Mechanics and Foundation Design, No. SM6, November 1967.
Surficial Fill Slope Stability Evaluation
Fill Slope Stability Evaluation
(1) Haefeli, R. The Stability of Slopes Acted Upon by Parallel Seepage , Proc. Second International Conference,
SMFE, Rotterdam, 1948, 1, 57-62.
(2) Skempton, A. W., and F. A. Delory, Stability of Natural Slopes in London Clay , Proc. Fourth International
Conference, SMFE, London, 1957, 2, 378-81.
FILL SLOPE STABILITY ANALYSIS
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIA
DATE 04-10-2020 PROJECT NO. G2452-32-02 FIG. 10
2
1
NOTE 5
NOTE 4
NOTE 6
2% Min.
DETAIL
BACKCUT
(NOTE 1)
NOTE 4
2" MIN.
1.5'
MIN.
1.5'
MIN.
20' MIN.
KEYWAY WIDTH
OR AS SPECIFIED
SEE
DETAIL
PROPOSED
FINISHED SLOPE
BU
T
T
R
E
S
S
F
I
L
L
(N
O
T
E
3
)
NOTE 2
FIG. 11
TYPICAL BUTTRESS FILL DETAIL
NO SCALE
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2452 - 32 - 02TR / RA
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:06/10/2020 8:12AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\DETAILS\Typical Buttress Fill Detail.dwg
DATE 04 - 10 - 2020
NOTES:
1.....EXCAVATE BACKCUT IN ACCORDANCE WITH GEOTECHNICAL CONSULTANTS RECOMMENDATION TO ACHIEVE REQUIRED KEY WIDTH.
2.....BASE OF BUTTRESS KEY TO EXPOSE DENSE, FORMATIONAL MATERIAL SLOPING A MINIMUM 2%
INTO SLOPE. FORECUT MAY BE SLOPED PER GEOTECHNICAL ENGINEERS RECOMMENDATIONS.
3.....BUTTRESS FILL TO BE COMPOSED OF PROPERLY COMPACTED, GRANULAR SOIL WITH MINIMUM SHEAR
STRENGTH AS SPECIFIED.
4.....CHIMNEY DRAINS TO BE APPROVED, PREFABRICATED DOUBLE SIDED CHIMNEY DRAIN PANELS (MIRADRAIN,
TENSAR, OR EQUIVALENT) SPACED APPROXIMATELY 30 FEET CENTER TO CENTER. ADDITIONAL DRAINS WILL
BE REQUIRED WHERE AREAS OF SEEPAGE ARE ENCOUNTERED.
5.....DRAIN MATERIAL (9 CUBIC FEET) TO BE 3/4-INCH, OPEN-GRADED, CRUSHED ROCK ENCLOSED IN APPROVED FILTER FABRIC .
6.....COLLECTOR PIPE TO BE 4-INCH MINIMUM DIAMETER, PERFORATED, THICK-WALLED PVC SCHEDULE 40 OR
EQUIVALENT, AND SLOPED TO DRAIN AT 1 PERCENT MINIMUM TO APPROVED OUTLET.
NOTE 5
1
1
NOTE 4
NOTE 6
2% Min.
DETAIL
2" MIN.
1.5'
MIN.
1.5'
MIN.
15' MIN.
KEYWAY WIDTH
OR AS SPECIFIED
SEE
DETAIL
EXISTING
GROUND SURFACE
1
1
NOTE 1 NOTE 4
FORECUT
1
1
NOTE 3
BACKCUT
FIG. 12
TYPICAL SHEAR KEY DETAIL
NO SCALE
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2452 - 32 - 02TR / RA
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:06/10/2020 8:12AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\DETAILS\Typical Shear Key Detail.dwg
DATE 04 - 10 - 2020
NOTES:
1.....EXCAVATE BACKCUT IN ACCORDANCE WITH GEOTECHNICAL CONSULTANTS RECOMMENDATION TO ACHIEVE
REQUIRED KEY WIDTH.
2.....BASE OF SHEAR KEY TO EXPOSE DENSE, FORMATIONAL MATERIAL SLOPING A MINIMUM 2%
INTO SLOPE.
3.....COMPACTED FILL TO BE COMPOSED OF PROPERLY COMPACTED, GRANULAR SOIL WITH MINIMUM SHEAR
STRENGTH AS SPECIFIED.
4.....CHIMNEY DRAINS TO BE APPROVED, PREFABRICATED DOUBLE SIDED CHIMNEY DRAIN PANELS (MIRADRAIN,
TENSAR, OR EQUIVALENT) SPACED APPROXIMATELY 30 FEET CENTER TO CENTER. ADDITIONAL DRAINS WILL
BE REQUIRED WHERE AREAS OF SEEPAGE ARE ENCOUNTERED. HEIGHT OF CHIMNEY DRAINS TO BE DETERMINED
BY GEOTECHNICAL ENGINEER.
5.....DRAIN MATERIAL (9 CUBIC FEET) TO BE 3/4-INCH, OPEN-GRADED, GRAVEL SURROUNDED BY MIRAFI
140N OR EQUIVALENT FILTER FABRIC.
6.....COLLECTOR PIPE TO BE 4-INCH MINIMUM DIAMETER, SCHEDULE 40 PVC, AND SLOPED TO DRAIN AT 1
PERCENT MINIMUM TO SUITABLE TIGHT LINE OUTLET.
2
1
NOTE 5
NOTE 4
NOTE 6
2% Min.
DETAIL
BACKCUT
(NOTE 1)
NOTE 4
2" MIN.
1.5'
MIN.
1.5'
MIN.
15' MIN.
KEYWAY WIDTH
SEE
DETAIL
NOTE 2
1
2
1
1
FINISHED
PAD GRADE
CUT SLOPE
15'
MIN.STA
B
I
L
I
T
Y
F
I
L
L
(NO
T
E
3
)
FIG. 13
TYPICAL STABILITY FILL DETAIL
NO SCALE
NOTES:
1.....EXCAVATE BACKCUT IN ACCORDANCE WITH GEOTECHNICAL CONSULTANTS RECOMMENDATION.
2.....BASE OF STABILITY FILL TO BE INTO DENSE, FORMATIONAL MATERIAL SLOPING A MINIMUM 2%
INTO SLOPE.
3.....STABILITY FILL TO BE COMPOSED OF PROPERLY COMPACTED, GRANULAR SOIL WITH MINIMUM SHEAR
STRENGTH AS SPECIFIED.
4.....CHIMNEY DRAINS TO BE APPROVED, PREFABRICATED DOUBLE SIDED CHIMNEY DRAIN PANELS (MIRADRAIN,
TENSAR, OR EQUIVALENT) SPACED APPROXIMATELY 30 FEET CENTER TO CENTER. ADDITIONAL DRAINS WILL
BE REQUIRED WHERE AREAS OF SEEPAGE ARE ENCOUNTERED.
5.....DRAIN MATERIAL (9 CUBIC FEET) TO BE 3/4-INCH, OPEN-GRADED, CRUSHED ROCK ENCLOSED IN APPROVED FILTER FABRIC .
6.....COLLECTOR PIPE TO BE 4-INCH MINIMUM DIAMETER, PERFORATED, THICK-WALLED PVC SCHEDULE 40 OR
EQUIVALENT, AND SLOPED TO DRAIN AT 1 PERCENT MINIMUM TO APPROVED OUTLET.
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2452 - 32 - 02TR / RA
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:06/10/2020 8:12AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\DETAILS\Typical Stability Fill Detail-4.dwg
DATE 04 - 10 - 2020
CONCRETE SLAB
FOOTING*DEPTHFOOTING WIDTH*
SAND AND VAPOR
RETARDER IN
ACCORDANCE WITH ACI
FOOTING*
WIDTH
CONCRETE SLAB
PAD GRADE
FOOTING*DEPTHSAND AND VAPOR
RETARDER IN
ACCORDANCE WITH ACI
FIG. 14
WALL / COLUMN FOOTING DIMENSION DETAIL
NO SCALE
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2452 - 32 - 02TR / RA
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:06/10/2020 8:12AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\DETAILS\Wall-Column Footing Dimension Detail (COLFOOT2).dwg
DATE 04 - 10 - 2020
*....SEE REPORT FOR FOUNDATION WIDTH AND DEPTH RECOMMENDATION
PROPERLY
COMPACTED
BACKFILL
CONCRETE
BROWDITCH
2/3 H
PROPOSED
RETAINING WALL
PROPOSED
GRADE 1"
FOOTING 4" DIA. PERFORATED SCHEDULE
40 PVC PIPE EXTENDED TO
APPROVED OUTLET
MIRAFI 140N FILTER FABRIC
(OR EQUIVALENT)
1" MAX. AGGREGATE
OPEN GRADED
GROUND SURFACE
TEMPORARY BACKCUT
PER OSHA
12"
WATER PROOFING
PER ARCHITECT
H
FOOTING
PROPOSED
GRADE
4" DIA. SCHEDULE 40
PERFORATED PVC PIPE
OR TOTAL DRAIN
EXTENDED TO
APPROVED OUTLET
DRAINAGE PANEL
(MIRADRAIN 6000
OR EQUIVALENT)
RETAINING
WALL
3/4" CRUSHED ROCK
(1 CU.FT./FT.)
NOTE :
DRAIN SHOULD BE UNIFORMLY SLOPED TO GRAVITY OUTLET
OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING
CONCRETE
BROWDITCH
WATER PROOFING
PER ARCHITECT
GROUND SURFACE
12"
2/3 H 2/3 H
FOOTING
PROPOSED
GRADE
RETAINING
WALL
CONCRETE
BROWDITCH
WATER PROOFING
PER ARCHITECT
GROUND SURFACE
FILTER FABRIC
ENVELOPE
MIRAFI 140N OR
EQUIVALENT
4" DIA. SCHEDULE 40
PERFORATED PVC PIPE
OR TOTAL DRAIN
EXTENDED TO
APPROVED OUTLET
DRAINAGE PANEL
(MIRADRAIN 6000
OR EQUIVALENT)
FIG. 15
TYPICAL RETAINING WALL DRAIN DETAIL
NO SCALE
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2452 - 32 - 02TR / RA
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:06/10/2020 8:12AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\DETAILS\Typical Retaining Wall Drainage Detail (RWDD7A).dwg
DATE 04 - 10 - 2020
APPENDIX A
Project No. G2452-32-02 April 10, 2020
APPENDIX A
FIELD INVESTIGATION
Our field investigation was performed between March 20 and 25, 2020, and consisted of a site
reconnaissance, the excavation of 7 large-diameter borings (Boring Nos. LB-1 through LB-7) and 19
exploratory trenches (Trench Nos. T-1 through T-19). In addition, an infiltration test (I-1) was
performed within Trench No. T-17 in order to provide storm water BMP design information. The
results and discussion of the infiltration testing is discussed in Appendix D of this report. The
approximate locations of the subsurface excavations are shown on Figures 2 and 3, including our
previous borings and trenches (see Appendix E for these logs).
The 7 large-diameter borings were performed by Dave’s Drilling and advanced to a maximum depth
of 103 feet below existing grade using an EasyBore 120 truck-mounted drill rig equipped with a 30-
inch-diameter bucket auger. Relatively undisturbed samples were obtained by driving a 3-inch, O.D.,
split-tube sampler into the “undisturbed” soil mass with the drill rig kelly bar. The sampler was
equipped with 1-inch by 2⅜-inch brass sampler rings to facilitate removal and testing. Bulk samples
were also obtained. In general, a dip and dip direction convention was used to present the orientation
of bedding and structural features measured in the borings. The logs of the borings depicting the soil
and geologic conditions encountered and the depth at which samples were obtained are presented on
Figures A-1 through A-7.
The trenches were advanced by LB3 Enterprises Inc. using a John Deere 135G excavator equipped
with a 30-inch-wide bucket. Trench No. T-18 was performed specifically to identify where the
continuous bentonitic claystone bed was exposed at the surface. Trench No. T-19 consisted of a 234-
foot-long excavation that included detail mapping of the exposed geology to evaluate the absence or
presence of a mapped fault within the eastern portion of the site (no faulting was observed). Bulk
samples were also collected for laboratory analysis. The logs of the trenches depicting the soil and
geologic conditions encountered and the depth at which samples were obtained are presented on
Figures A-8 through A-25, and Figure 9 depicts the detail log for Trench No. T-19.
The soils encountered in the excavations were visually classified and logged in general accordance
with American Society for Testing and Materials (ASTM) practice for Description and Identification
of Soils (Visual Manual Procedure D 2488).
TOPSOIL
Stiff, moist, dark brown, Sandy CLAY
OTAY FORMATION (To)
Dense to very dense, damp, light gray, Silty, fine to medium SANDSTONE;
with calcium carbonate in upper 5 feet
-Bedding from 4.8 to 5.3 feet (6º, S60ºE)
-6-inch thick, olive gray, clayey siltstone bed at 5.5 feet
-6 to 8-inch thick, claystone bed at 6.5 feet
-3 to 5-inch-thick, brown claystone bed with irregular thickness at 9.1 feet
-3 to 4-inch-thick, brown clayey sandstone bed at 23 feet; contact slightly
undulatory and near horizontal
-Some 1/8-1/4-inch wide, high angle sand filled fractures present from 28 to
32 feet; 1/8-inch of aperture observed on portion of fracture
CL/CH
SM
LB1-1
LB1-2
LB1-3
LB1-4
LB1-5
LB1-6
LB1-7 10.7
3
5
7
5
5 116.4
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
Figure A-1,
Log of Boring LB 1, Page 1 of 3 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 1
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)415'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
-Poor recovery
-1 to 3-inch thick, olive brown, claystone bed at 32.5 feet; contact slightly
undulatory, (2º-3º, due South); no remolding
-Becomes slightly coarser grained below 37 feet
-Cemented; highly undulatory contact (10º, N75ºW)
Hard, gray, brown and white, BENTONITIC CLAYSTONE; waxy and
highly plastic; blocky
-BEDDING PLANE SHEAR at 47.1 feet; (7º, N45ºE); 1/2 to 1-inch thick,
soft, moist, white, moderately remolded and moderately developed plastic
clay gouge; 18-inch thick, reddish brown claystone bed (key marker bed el.
367.9') below BPS
-4-inch thick, pink, bentonitic claystone bed at 48.8 feet; no remolding
Very dense, damp, gray, Silty, fine to medium SANDSTONE
-Becomes dark brown below 59.8 feet
SM
MH/CH
SM
LB1-8
LB1-9
LB1-10
LB1-11
LB1-11A
LB1-12
LB1-13
LB1-14
7.1
50.5
51.4
18.0
6.9
8
10
10
4
10
15/7"
116.7
70.9
69.7
115.2
114.4
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
Figure A-1,
Log of Boring LB 1, Page 2 of 3 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 1
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)415'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
-Becomes gray below 62 feet
-Becomes finer grained below 67 feet
-Becomes fine to coarse grained below 75 feet
SWEETWATER FORMATION (Tsw)
Very dense, damp, light brown, Silty, fine to coarse SANDSTONE
PRACTICAL REFUSAL AT 82 FEET
SM
SM
LB1-15
LB1-16
LB1-17
LB1-18
LB1-19
7.6
12.7
15/10"
15/8"
20/6"
20/5"
25/6"
123.9
111.8
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
60
62
64
66
68
70
72
74
76
78
80
82
Figure A-1,
Log of Boring LB 1, Page 3 of 3 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 1
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)415'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
TOPSOIL
Stiff, very moist, black, Silty CLAY
OTAY FORMATION (To)
Very dense, damp, light gray, Silty, fine to medium SANDSTONE; calcium
carbonate veining, massive
-One-foot-thick cemented bed at 5.5 feet
-4 to 6-inch thick, horizontal, olive gray, siltstone/claystone bed at 12 feet
-Continued high angle calcium carbonate fracture infillings at 17'
-1 to 4-inch thick, near horizontal bed with reddish-brown claystone rip-up
clasts at 19 feet
-Sharp contact (6º, S80ºE)
Very hard, damp, olive gray, fine, Sandy SILTSTONE/CLAYSTONE;
slightly fractured and micaceous; gunbarrel appearance
-Becomes blocky at 24 feet
-POORLY DEVELOPED BEDDING PLANE SHEAR at 25.9 feet; 1/16"
to 1/8" thick, reddish brown, poorly remolded clay, well defined and
horizontal
-Gradational contact at 27 feet
Very dense, damp, light gray, fine to medium SANDSTONE
-1 to 3-inch thick, horizontal CLAYSTONE bed at 28.7'
CH
SM
ML/CL
SM
LB2-1
LB2-2
LB2-3
LB2-4
LB2-5
LB2-6
LB2-7
11.9
16.7
21.1
5/7"
4
5
4
5
120.0
116.2
104.8
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
Figure A-2,
Log of Boring LB 2, Page 1 of 3 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 2
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERD. EVANS CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)390'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
-Becomes massive below 30 feet
-At 35 feet; irregular near horizontal contact
Hard, damp, pink to green, BENTONITIC CLAYSTONE; highly fractured,
crumbles under blow of hammer; shiny parting surfaces; manganese staining
-BEDDING PLANE SHEAR at 37 feet (horizontal); 1/4" to 3/4" thick,
highly remolded plastic clay gouge; grayish green, well developed and
continuous
BEDDING PLANE SHEAR ZONE from 38.2 to 39 feet (horizontal); zone
containing 4 to 5, remolded clay gouge planes; highly sheared and
continuous; irregular thickness
-Base of bentonitic claystone at 41.6 feet with 5-inch thick white bed (key
marker bed at el. 348.6')
Hard, damp, reddish-brown, silty claystone
-Grades to siltstone/claystone at 43 feet
Very dense, damp, light gray, Silty, fine to medium SANDSTONE
-Becomes very silty below 54 feet
-3-inch thick, siltstone/claystone bed at 56.5 feet
SM
CH/MH
CH
SM
LB2-8
LB2-9
LB2-10
LB2-10A
LB2-11
LB2-12
LB2-13
LB2-14
LB2-15
54.4
29.5
16.0
19.6
6
4
6
10
10/10"
10/10"
67.5
91.0
111.3
105.6
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
Figure A-2,
Log of Boring LB 2, Page 2 of 3 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 2
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERD. EVANS CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)390'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
-Concretionary bed at 61'
SWEETWATER FORMATION (Tsw)
Very dense, damp, light brown, Silty, fine to coarse SANDSTONE
BORING TERMINATED AT 70 FEET
SM
SM
LB2-16
LB2-17
10/10"
10/8"
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
60
62
64
66
68
70
Figure A-2,
Log of Boring LB 2, Page 3 of 3 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 2
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERD. EVANS CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)390'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
TOPSOIL
Loose, moist, reddish brown, Clayey, fine SAND
SAN DIEGO FORMATION (Tsd)
Dense, damp, light brown, Silty, fine to medium SANDSTONE; micaceous
-Orange oxidation present below 8 feet
-Trace gravel present at 11 feet
-Scoured, undulatory contact with gravel at base
OTAY FORMATION (To)
Hard, moist, olive gray, Clayey SILTSTONE/Silty CLAYSTONE
-Bedding at 15.6 feet with olive green claystone (4º, S25ºE); no remolding
Very dense, damp, light gray, Silty, fine to medium SANDSTONE; massive
-4-inch thick, brown claystone bed at 27.5 feet
Hard, damp, olive gray to brown, Clayey SILTSTONE with interbedded Silty
CLAYSTONE
SC
SM
ML/CL
SM
ML&CL
LB3-1
LB3-2
LB3-3
LB3-4
LB3-5
LB3-6
LB3-7
10.5
28.9
7.9
4
5
6
6/6"
6/6"
106.4
95.8
114.8
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
Figure A-3,
Log of Boring LB 3, Page 1 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 3
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)444'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
-Difficult drilling below 35 feet; auger used
Very dense, damp, light gray and olive brown, Silty, fine to medium
SANDSTONE
-4-inch thick, dark brown claystone bed at 44.5 feet; horizontal; no remolding
Hard, moist, dark brown, Silty CLAYSTONE
-Gradational contact
Very dense, damp, light gray to olive gray, Silty, fine SANDSTONE/fine
Sandy SILTSTONE
ML&CL
SM
CL
SM/ML
LB3-8
LB3-9
LB3-10
LB3-11
LB3-12
LB3-13
18.1
13.7
8/10"
10/10"
10/8"
10/7"
10
15
111.6
118.7
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
Figure A-3,
Log of Boring LB 3, Page 2 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 3
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)444'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
-Becomes fine to medium grained sandstone below 63 feet
-Dark brown rip-up clasts present at 73 feet
-10-inch thick, dark brown claystone bed at 74.3 feet
-Becomes fine to coarse grained below 85 feet
-6 to 7-inch thick, dark brown claystone bed at 88 feet
SM/ML
SM
LB3-14
LB3-15
LB3-16
LB3-17
LB3-18
LB3-19
15/7"
15/7"
15
15/8"
20/7"
20/5"
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
Figure A-3,
Log of Boring LB 3, Page 3 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 3
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)444'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
Very stiff, moist, white, BENTONITIC CLAYSTONE; plastic
BORING TERMINATED AT 103 FEET
SM
MH/CH
LB3-20
LB3-21
LB3-22
LB3-23
20/8"
25/8"
30/8"
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
90
92
94
96
98
100
102
Figure A-3,
Log of Boring LB 3, Page 4 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 3
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)444'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
TOPSOIL
Loose, moist, light reddish brown, Clayey SAND
SAN DIEGO FORMATION (Tsd)
Dense, damp, light brown with orange staining, Silty, fine to medium
SANDSTONE; micaceous
-Lower cohesion below 12 feet
-Trace gravel present below 16 feet
-4 to 5-inch thick, gravel bed present at 17.5 feet
-Scoured, undulatory contact
OTAY FORMATION (To)
Dense, damp, light gray, Silty, fine to medium SANDSTONE
Hard, moist, reddish brown and olive green, Silty CLAYSTONE and Clayey
SILTSTONE with some interbedded sandstones
SC
SM
SM
CL/ML&
SM
LB4-1
LB4-2
LB4-3
LB4-4
LB4-5
LB4-6
LB4-8
8.2
9.9
2
2
5
3
4
86.9
112.6
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
Figure A-4,
Log of Boring LB 4, Page 1 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 4
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)448'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
Dense, damp, light gray, Silty, fine to medium SANDSTONE; massive
-1/8-inch wide, high angle clay filled fracture from 37.5 to 39.8 feet with soft
clay gouge present along trace
Hard, moist, gray-brown, Clayey SILTSTONE
Dense, damp, light gray, Silty SANDSTONE
Hard, moist, dark brown, Silty CLAYSTONE and Clayey SILTSTONE
-Becomes reddish brown and olive green below 50 feet
Dense, damp, light gray, Silty, fine to medium SANDSTONE
Hard, moist, olive green and reddish brown, Silty CLAYSTONE/Clayey
SILTSTONE
SM
ML
SM
CL/ML
SM
CL/ML
LB4-7
LB4-9
LB4-10
LB4-11
LB4-12
LB4-13
LB4-14
16.9
20.9
25.9
8/8"
8/10"
8
8/8"
4
10/8"
112.0
107.9
99.0
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
Figure A-4,
Log of Boring LB 4, Page 2 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 4
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)448'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
-18-inch thick, light gray sandstone bed at 63.5 feet
-1/8 to 1/4-inch wide, clay filled fracture from 64 to 67.1 feet; (50º, N45ºW)
with soft clay gouge along trace
Dense, damp, light gray, Silty, fine to medium SANDSTONE
-12-inch thick, weak, waxy, olive green claystone bed at 75.5 feet; contact
slightly undulatory (18º, N8ºW)
-12-inch thick, brown siltstone/claystone bed at 87 feet
CL/ML
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
Figure A-4,
Log of Boring LB 4, Page 3 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 4
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)448'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
Hard, moist, brown, Silty CLAYSTONE/Clayey SILTSTONE
-POORLY DEVELOPED BEDDING PLANE SHEAR at 96.1 feet;
(undulatory); 1-inch thick, soft, moist, poorly remolded in areas and poorly
developed plastic clay gouge
Dense, damp, light gray, Silty, fine to medium SANDSTONE
BORING TERMINATED AT 103 FEET
CL/ML
SM
LB4-15
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
90
92
94
96
98
100
102
Figure A-4,
Log of Boring LB 4, Page 4 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 4
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)448'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
TOPSOIL
Loose, moist, reddish brown, Clayey, fine to medium SAND
SAN DIEGO FORMATION (Tsd)
Dense, damp, light brown with orange staining, Silty, fine to medium
SANDSTONE; micaceous
-1 to 2-inch thick, gravel bed at 6.8 feet
-Sharp, horizontal contact
OTAY FORMATION (To)
Dense, damp, light gray, Silty, fine to medium SANDSTONE
-4-inch thick, clayey siltstone bed at 14.8 feet
-3-inch thick, light brown clayey siltstone bed at 16.5 feet
-4-inch thick, olive gray, clayey siltstone bed at 22.5 feet
-5-inch thick, light brown, clayey siltstone bed at 28.9 feet
SC
SM
SM
LB5-1
LB5-2
LB5-3
LB5-4
LB5-5
11.3
12.2
18.0
4
5/10"
6
5/8"
6
101.6
108.9
110.1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
Figure A-5,
Log of Boring LB 5, Page 1 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 5
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-22-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)442'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
-5-inch thick, brown, clayey siltstone bed at 36.8 feet
-5-inch thick, olive brown, clayey siltstone bed at 42 feet
Hard, moist, gray-brown, Silty CLAYSTONE/Clayey SILTSTONE
Dense, damp, light gray, Silty, fine to medium SANDSTONE
-4-inch thick, gray-brown, clayey siltstone bed at 58.2 feet
SM
CL/ML
SM
LB5-6
LB5-7
LB5-8
LB5-9
LB5-10
12.4
27.4
25.4
8/8"
10
10/10"
10
8
117.9
96.1
99.3
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
Figure A-5,
Log of Boring LB 5, Page 2 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 5
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-22-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)442'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
-6-inch thick, gray-brown clayey siltstone bed at 71.5 feet
-Becomes fine to coarse below 78 feet
-Sharp and undulatory contact
Hard, moist, gray-brown, Silty CLAYSTONE with bentonitic claystone
rip-ups
Dense, damp, light gray, Silty, fine to medium SANDSTONE
SM
CL
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
Figure A-5,
Log of Boring LB 5, Page 3 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 5
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-22-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)442'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
-12-inch thick, olive green, clayey siltstone bed at 90 feet
-Slightly scoured, partially, undulatory contact
Hard, white gray and pink, BENTONITIC CLAYSTONE; highly plastic
with manganese staining
-BEDDING PLANE SHEAR ZONE at 95.5 feet (horizontal); 4 to 6-inch
thick zone of multiple, poorly developed and poorly remolded plastic clay
gouge planes
-18-inch thick, reddish brown claystone bed at 98.3 feet (key marker bed el.
343.7')
-3-inch white to pink bentonitic claystone bed at 99.5 feet
Hard, moist, olive brown, fine, Sandy/Clayey SILTSTONE
BORING TERMINATED AT 103 FEET
SM
MH/CH
ML
LB5-11
LB5-11A
LB5-12
20
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
90
92
94
96
98
100
102
Figure A-5,
Log of Boring LB 5, Page 4 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 5
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-22-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)442'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
TOPSOIL
Loose, moist, reddish brown, Clayey, fine to medium SAND
SAN DIEGO FORMATION (Tsd)
Dense, damp, light brown with orange staining, Silty, fine to medium
SANDSTONE; micaceous with some calcium carbonate stringers
-1 to 2-inch thick, gravel bed at 17.7 feet
-Scoured contact
OTAY FORMATION (To)
Dense/hard, damp, light gray, Silty, fine SANDSTONE/fine, Sandy
SILTSTONE
-5-inch thick, brown claystone bed at 20.2 feet
-3-inch thick, brown claystone bed at 24.3 feet
SC
SM
SM/ML
LB6-1
LB6-2
LB6-3
LB6-4
LB6-5
LB6-6
LB6-7
LB6-8
5.1
7.3
10.8
6.1
3
5
8
8
8/10"
94.7
110.3
115.1
112.7
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
Figure A-6,
Log of Boring LB 6, Page 1 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 6
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-24-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)450'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
Hard, moist, gray-brown, Clayey SILTSTONE
-2 to 3-inch thick, brown claystone bed at 33.9 feet
Dense, damp, light gray, Silty, fine to medium SANDSTONE
-2-inch thick, brown claystone bed at 38.1 feet
Hard, damp, reddish brown, Silty CLAYSTONE/Clayey SILTSTONE
-6-inch thick, pink and white, BENTONITIC CLAYSTONE bed at 40.5
feet; (7º, N35ºE); no remolding
Hard, moist, gray-brown, Clayey SILTSTONE
-2-inch thick, brown claystone beds at 45.4 and 45.9 feet
-3-inch thick, brown claystone beds at 50 and 50.7 feet
Very dense, damp, light gray, Silty, fine to medium SANDSTONE with
random interbedded claystone and siltstone beds
SM/ML
ML
SM
CL/ML
ML
SM&CL&
ML
LB6-9
LB6-10
LB6-11
LB6-12
LB6-12A
LB6-13
LB6-14
LB6-15
LB6-16
20.9
18.4
21.7
22.1
8
10
8
10
10
15/8"
104.8
104.5
106.2
101.8
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
Figure A-6,
Log of Boring LB 6, Page 2 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 6
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-24-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)450'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
Hard, moist, gray-brown, Clayey SILTSTONE
SM&CL&
ML
ML
LB6-17
LB6-18
LB6-19
LB6-20
15/10"
20/10"
20/8"
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
Figure A-6,
Log of Boring LB 6, Page 3 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 6
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-24-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)450'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
Dense, damp, light gray, Silty, fine to medium SANDSTONE
Very stiff to hard, moist, pink, white and gray, BENTONITIC
CLAYSTONE; waxy and highly plastic
-BEDDING PLANE SHEAR at 97.7 feet; (2º, N65ºE); 1/2 to 3/4-inch
thick, soft, moist, highly remolded and well developed plastic clay gouge
-12-inch thick, light gray sandstone bed at 98.5 feet
-POORLY DEVELOPED BEDDING PLANE SHEAR at 101 feet; 1/4-inch
thick, soft, moderately remolded, poorly developed plastic clay gouge
ML
SM
CLLB621
LB6-22
LB6-23
25/10"
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
90
92
94
96
98
100
102
Figure A-6,
Log of Boring LB 6, Page 4 of 4 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 6
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-24-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)450'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
TOPSOIL
Stiff, moist, black, Silty CLAY
OTAY FORMATION (To)
Dense, damp, light gray, Silty, fine to medium SANDSTONE with calcium
carbonate stringers present to 6 feet
-6 to 10-inch thick, reddish brown and olive green siltstone/claystone bed at
15.5 feet
-Random high angle, 1/4 to 1/2-inch wide, sand filled fractures present below
23.5 feet
Hard, moist, brown, Silty CLAYSTONE/Clayey SILTSTONE
CH
SM
ML/CL
LB7-1
LB7-2
LB7-3
LB7-4
LB7-5
LB7-6
7.5
11.8
8
4
4
4
4
116.3
120.0
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
Figure A-7,
Log of Boring LB 7, Page 1 of 3 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 7
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-25-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)404'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
Hard, moist, gray and white, BENTONITIC CLAYSTONE
-POORLY DEVELOPED BEDDING PLANE SHEAR at 35.5 feet; (10º,
S85ºW); paper thin to 1/4-inch thick, soft, gray, poorly remolded and
developed plastic clay gouge
-18-inch thick, reddish brown claystone bed at 38.2 feet (key marker bed el.
365.8')
-2 to 3-inch thick, pink bentonitic claystone bed at 40 feet
Hard, moist, gray-brown, Clayey SILTSTONE
-2 to 3-inch thick, brown claystone bed at 44 feet
Dense, damp, light gray, Silty, fine to medium SANDSTONE
-2-foot thick, gray-brown, clayey siltstone bed at 52 feet
-Becomes fine to coarse grained below 58 feet
-12-inch thick, gray-brown, clayey siltstone bed at 59.7 feet
ML/CL
MH/CH
ML
SM
LB7-7
LB7-8
LB7-9
LB7-10
LB7-11
LB7-12
LB7-13
LB7-14
30.4
43.2
6
4
10
10
10
15/8"
90.2
78.0
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
Figure A-7,
Log of Boring LB 7, Page 2 of 3 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 7
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-25-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)404'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
SWEETWATER FORMATION (Tsw)
Very dense, damp, light brown, Silty, fine to coarse SANDSTONE
PRACTICAL REFUSAL AT 73 FEET
SM
SM
LB7-15
LB7-16
LB7-17
11.5
15/8"
15/6" 122.8
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
60
62
64
66
68
70
72
Figure A-7,
Log of Boring LB 7, Page 3 of 3 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
30" BUCKET AUGER PENETRATIONRESISTANCE(BLOWS/FT.)BORING LB 7
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERA. REKANI CONTENT (%)SAMPLE
NO.03-25-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)404'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
ALLUVIUM (Qal)
Soft, moist to wet, dark grayish brown, Silty CLAY; free water at surface
-Minor seepage along contact at 7 feet
OTAY FORMATION (To)
Very dense, moist, light brown, Silty, fine SANDSTONE
TRENCH TERMINATED AT 9 FEET
Minor seepage at 7 feet
CL/CH
SM
T1-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-8,
Log of Trench T 1, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 1
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)357'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
ALLUVIUM (Qal)
Soft, moist to wet, dark grayish brown, Silty CLAY
-Minor seepage along contact at 7 feet
SWEETWATER FORMATION (Tsw)
Very dense, moist, light brown, Silty, fine SANDSTONE
TRENCH TERMINATED AT 9 FEET
Minor seepage at 7 feet
CL/CH
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-9,
Log of Trench T 2, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 2
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)317'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
ALLUVIUM (Qal)
Soft, moist to wet, dark grayish brown, Silty CLAY
Loose to medium-dense, moist to wet, dark grayish brown, Clayey, fine to
medium SAND
SWEETWATER FORMATION (Tsw)
Very dense, moist, grayish brown, Silty, fine to coarse SANDSTONE with
trace gravel
TRENCH TERMINATED AT 12 FEET
Groundwater not encountered
CL/CH
SC
SM
T3-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
Figure A-10,
Log of Trench T 3, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 3
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)281'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
COLLUVIUM (Qcol)
Loose to medium-dense, damp, grayish brown, Clayey, fine to medium
SAND
SWEETWATER FORMATION (Tsw)
Very dense, damp, grayish brown, Silty, fine to coarse SANDSTONE with
trace gravel
TRENCH TERMINATED AT 10 FEET
Groundwater not encountered
SC
SM
T4-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
Figure A-11,
Log of Trench T 4, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 4
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)289'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
TOPSOIL
Loose, damp, grayish brown, Clayey, fine to medium SAND
OTAY FORMATION (To)
Dense, damp, light gray, Silty, fine to medium SANDSTONE
TRENCH TERMINATED AT 4 FEET
Groundwater not encountered
SC
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
Figure A-12,
Log of Trench T 5, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 5
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)362'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
ALLUVIUM (Qal)
Soft, moist to wet, dark grayish brown, fine, Sandy CLAY
Medium dense, moist, grayish brown, Clayey, fine to medium SAND
OTAY FORMATION (To)
Dense, most, light gray to light grayish brown, Silty, fine to medium
SANDSTONE
TRENCH TERMINATED AT 12 FEET
Groundwater not encountered
CL
SC
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
Figure A-13,
Log of Trench T 6, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 6
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)386'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
ALLUVIUM (Qal)
Soft, moist to wet, dark grayish brown, fine, Sandy CLAY
Stiff, moist, brown, fine, Sandy SILT
OTAY FORMATION (To)
Hard, damp, light brown, fine, Sandy SILTSTONE
TRENCH TERMINATED AT 12 FEET
Groundwater not encountered
CL
ML
ML
T7-1
T7-2
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
Figure A-14,
Log of Trench T 7, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 7
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)354'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
ALLUVIUM (Qal)
Soft, moist, dark grayish brown, fine, Sandy CLAY
SWEETWATER FORMATION (Tsw)
Dense, damp, brown, Silty, fine to coarse SANDSTONE with trace gravel
TRENCH TERMINATED AT 10 FEET
Groundwater not encountered
CL
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
Figure A-15,
Log of Trench T 8, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 8
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)328'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
ALLUVIUM (Qal)
Soft, moist, dark grayish brown, fine, Sandy CLAY
SWEETWATER FORMATION (Tsw)
Dense, damp, brown, Silty, fine to coarse SANDSTONE with trace gravel
TRENCH TERMINATED AT 13 FEET
Groundwater not encountered
CL
SM
T9-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
Figure A-16,
Log of Trench T 9, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 9
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)278'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
TOPSOIL
Loose, damp, dark grayish brown, Clayey, fine to medium SAND
SWEETWATER FORMATION (Tsw)
Dense, damp, brown, Silty, fine to coarse SANDSTONE with trace gravel
TRENCH TERMINATED AT 7 FEET
Groundwater not encountered
SC
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
Figure A-17,
Log of Trench T 10, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 10
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)319'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
ALLUVIUM (Qal)
Soft, moist, dark grayish brown, fine, Sandy CLAY
SWEETWATER FORMATION (Tsw)
Dense, damp, brown, Silty, fine to coarse SANDSTONE with trace gravel
TRENCH TERMINATED AT 13 FEET
Groundwater not encountered
CL
SM
T11-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
Figure A-18,
Log of Trench T 11, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 11
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-20-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)303'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
ALLUVIUM (Qal)
Soft, moist, black, fine, Sandy/Silty CLAY
SWEETWATER FORMATION (Tsw)
Very dense, damp, light brown, Silty, fine to coarse SANDSTONE
TRENCH TERMINATED AT 12 FEET
Groundwater not encountered
CL/CH
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
Figure A-19,
Log of Trench T 12, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 12
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)320'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
ALLUVIUM (Qal)
Soft, moist, black, fine, Sandy/Silty CLAY
OTAY FORMATION (To)
Hard, damp, olive brown, fine, Sandy CLAYSTONE
TRENCH TERMINATED AT 13 FEET
Groundwater not encountered
CL/CH
CL
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
Figure A-20,
Log of Trench T 13, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 13
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)346'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
ALLUVIUM (Qal)
Soft, wet, black, fine, Sandy/Silty CLAY with some gravel and cobble
OTAY FORMATION (To)
Dense, moist, light gray, Silty, fine to medium SANDSTONE
TRENCH TERMINATED AT 7 FEET
Groundwater not encountered
CL/CH
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
Figure A-21,
Log of Trench T 14, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 14
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)372'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
COLLUVIUM (Qcol)
Soft, damp, dark grayish brown, fine, Sandy CLAY
OTAY FORMATION (To)
Dense, damp, light gray, Silty, fine to medium SANDSTONE
TRENCH TERMINATED AT 8 FEET
Groundwater not encountered
CL
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-22,
Log of Trench T 15, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 15
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)376'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
COLLUVIUM (Qcol)
Soft, very moist, black, Clayey SILT/Silty CLAY
Loose, moist, brown, Clayey, fine to medium SAND
OTAY FORMATION (To)
Dense, damp, light brown, Silty, fine to medium SANDSTONE
TRENCH TERMINATED AT 8 FEET
Groundwater not encountered
ML/CL
SC
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-23,
Log of Trench T 16, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 16
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)380'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
TOPSOIL
Loose, very moist, brown, Clayey, fine to medium SAND
OTAY FORMATION (To)
Dense, damp, light gray, Silty, fine to medium SANDSTONE
TRENCH TERMINATED AT 2.5 FEET
Groundwater not encountered
SC
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
Figure A-24,
Log of Trench T 17, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 17
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERJ. PAGNILLO CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)376'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
TOPSOIL
Loose, moist, dark brown, Clayey, fine to medium SAND
OTAY FORMATION (To)
Dense, damp, light gray, Clayey, fine to medium SANDSTONE/Sandy
CLAYSTONE
Very stiff to stiff, moist, white, gray and pink, BENTONITIC
CLAYSTONE; waxy and highly plastic
-18-inch thick, reddish brown claystone bed at 6.5 feet; contact (3-10°, SE)
(key marker bed el. 352.5')
-4-inch thick, pink bentonitic claystone bed at base
Dense, damp, gray, Silty, fine to medium SANDSTONE
TRENCH TERMINATED AT 10 FEET
Groundwater not encountered
*Logged from elevation 359'
SC
SC/CL
MH/CH
SM
T18-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
Figure A-25,
Log of Trench T 18, Page 1 of 1 DRY DENSITY(P.C.F.)... DRIVE SAMPLE (UNDISTURBED)
JD 135G EXCAVATOR W/30" BUCKET PENETRATIONRESISTANCE(BLOWS/FT.)TRENCH T 18
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)GROUNDWATERT. REIST CONTENT (%)SAMPLE
NO.03-21-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE MOISTUREBY:EQUIPMENT
ELEV. (MSL.)359'
G2452-32-02.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2452-32-02
APPENDIX B
Project No. G2452-32-02 - B-1 - April 10, 2020
APPENDIX B
LABORATORY TESTING
Laboratory tests were performed in accordance with generally accepted test methods of the American
Society for Testing and Materials (ASTM) or other suggested procedures. Selected relatively undisturbed
ring and bulk samples were tested for their in-place dry density and moisture content, maximum dry
density and optimum moisture content, gradation, plasticity index, water-soluble sulfate content,
expansion index and shear strength characteristics.
The results of our laboratory tests are summarized on Tables B-I through B-V and Figure B-1. A
composite graph depicting the direct shear test results for the geologic units is presented on Figures B-2
through B-7. The results of the dry density and moisture content tests are presented on the boring logs in
Appendix A.
TABLE B-I
SUMMARY OF LABORATORY DIRECT SHEAR TEST RESULTS
Sample No.
Geologic Unit
Symbol
(USCS Soil Type)
Dry Density
(pcf)
Moisture
Content (%)
Peak
[Ultimate]
Cohesion (psf)
Peak [Ultimate]
Angle of Shear
Resistance (degrees)
*LB1-3 To (SM) 98.5 17.6 400 [450] 32 [30]
LB1-7 To (SM) 116.4 10.7 1,200 [800] 31 [31]
LB1-11 To (MH/CH) 70.9 50.5 750 [550] 40 [40]
LB1-11A To (MH/CH) 69.7 51.5 1,450 [1,200] 24 [25]
LB1-13 To (SM) 115.2 18.0 1,470 [400] 32 [36]
LB1-19 Tsw (SM) 111.8 12.7 1,100 [1,000] 30 [31]
LB2-7 To (ML/CL) 104.8 21.1 1,700 [1,100] 35 [32]
LB2-11 To (MH/CH) 91.0 29.5 500 [550] 33 [26]
LB2-13 To (CH) 111.3 16.0 0 [0] 55 [52]
LB2-15 To (SM) 105.6 19.6 550 [450] 28 [27]
*LB3-3 Tsd (SM) 99.3 15.5 400 [450] 32 [29]
LB3-5 To (ML/CL) 95.8 28.9 1,450 [750] 17 [23]
LB3-8 To (ML/CL) 111.6 18.1 450 [425] 36 [34]
LB4-3 Tsd (SM) 86.9 8.2 300 [300] 32 [32]
*LB4-8 To (ML/CL) 99.8 17.2 650 [600] 28 [29]
LB4-9 To (SM) 112.0 16.9 500 [400] 31 [31]
LB4-12 To (ML/CL) 99.0 25.9 450 [650] 34 [25]
Project No. G2452-32-02 - B-2 - April 10, 2020
TABLE B-I (Concluded)
SUMMARY OF LABORATORY DIRECT SHEAR TEST RESULTS
Sample No.
Geologic Unit
Symbol
(USCS Soil Type)
Dry Density
(pcf)
Moisture
Content (%)
Peak [Ultimate]
Cohesion (psf)
Peak [Ultimate]
Angle of Shear
Resistance (degrees)
LB5-1 Tsd (SM) 101.6 11.3 650 [500] 31 [31]
LB5-5 To (SM) 110.1 18.0 900 [600] 30 [33]
LB5-10 To (ML/CL) 99.3 25.4 700 [400] 28 [30]
*LB6-3 Tsd (SM) 98.3 15.0 400 [400] 32 [32]
LB6-4 Tsd (SM) 94.7 5.1 600 [450] 33 [35]
*LB6-7 To (SM/ML) 94.0 20.8 650 [650] 27 [27]
LB6-8 To (SM/ML) 112.7 6.1 750 [700] 40 [33]
*LB6-10 To (ML) 92.4 19.6 1,110 [750] 22 [25]
LB6-12 To (MH/CH) 104.5 18.4 600 [100] 42 [42]
LB6-14 To (ML) 106.2 21.7 1,700 [500] 40 [38]
LB7-7 To (ML/CL) 90.2 30.4 800 [550] 30 [30]
LB7-9 To (MH/CH) 78.0 43.2 1,300 [1,100] 28 [22]
LB7-16 Tsw (SM) 122.8 11.5 700 [750] 42 [36]
*T7-1 Qal (CL) 102.8 14.1 1,020 [1,070] 28 [27]
*T7-2 Qal (ML) 103.1 15.5 550 [550] 21 [21]
*T18-1 To (SC/CL) 99.3 15.4 780 [600] 27 [29]
*Sample was remolded to 90 percent relative compaction at near optimum moisture content.
TABLE B-II
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
Sample No. Description (Geologic Unit) Maximum Dry
Density (pcf)
Optimum
Moisture Content
(% dry wt.)
LB1-3 Light gray, Silty, fine to medium SAND (To) 109.4 17.4
LB3-3 Light brown, Silty, fine to medium SAND (Tsd) 110.5 14.7
LB4-8 Reddish brown, Clayey SILT (To) 111.9 16.6
LB6-3 Light brown, Silty, fine to medium SAND (Tsd) 109.0 15.5
LB6-7 Light gray, Silty, fine SAND (To) 106.4 18.6
LB6-10 Light grayish brown, Clayey SILT 102.8 19.6
T1-1 Dark brown, Silty CLAY (Qal) 112.6 15.7
T7-1 Dark brown, Sandy CLAY (Qal) 115.3 13.2
T7-2 Brown, fine, Sandy SILT (Qal) 115.1 15.5
T18-1 Gray, Clayey, fine to medium SAND (To) 110.2 15.7
Project No. G2452-32-02 - B-3 - April 10, 2020
TABLE B-III
SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS
TABLE B-IV
SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE CALIFORNIA TEST NO. 417
Sample No. (Geologic Unit) Water-Soluble Sulfate (%) Classification
LB1-3 (To) 0.0003 Not Applicable (S0)
LB3-3 (Tsd) 0.035 Not Applicable (S0)
LB4-8 (To) 0.008 Not Applicable (S0)
T18-1 (To) 0.004 Not Applicable (S0)
TABLE B-V
SUMMARY OF LABORATORY PLASTICITY INDEX TEST RESULTS
Sample
No. Geologic Unit Liquid Limit
(LL)
Plastic Limit
(PL)
Plasticity
Index (PI)
Unified Soil
Classification
(Group
Symbol)
LB2-10A To- (Bentonitic Claystone) 122 52 70 MH
LB3-23 To- (Bentonitic Claystone) 103 50 53 MH
LB5-12 To- (Bentonitic Claystone) 128 57 71 MH
LB7-10 To- (Bentonitic Claystone) 121 56 65 MH
Sample No. Geologic Unit
(USCS Soil Type)
Moisture Content (%) Dry Density
(pcf)
Expansion
Index Before Test After Test
LB1-3 To (SM) 14.6 25.9 94.1 25
LB1-12 To (MH/CH) 26.1 65.7 69.4 174
LB3-3 Tsd (SM) 12.7 21.8 100.0 1
LB4-8 To (ML/CL) 14.6 28.5 96.9 66
LB6-10 To (ML) 17.7 39.9 88.5 109
LB7-8 To (ML/CL) 13.1 26.5 99.1 49
T1-1 Qal (CL/CH) 13.9 31.4 95.1 88
T18-1 To (SC/CL) 14.2 33.1 95.4 95
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110
3/8" 4
103.0 103
PROJECT NO. G2452-32-02
U. S. STANDARD SIEVE SIZE
COARSE
3"3/4"1-1/2"8 16 20 30 40
52
57
PL
71
FINE
NAT WCPERCENT FINER BY WEIGHT128
122
95.5
MH - Elastic SILT38.2
PI
COARSE
53
GRAVEL
50
70
G2452-32-02.GPJ
LB2-10A
CHULA VISTA, CALIFORNIA
MH - Elastic SILT
SAND
MEDIUM
5060 100 200
SAMPLE
GEOCON
SILT OR CLAYFINE
GRAIN SIZE IN MILLIMETERS
CLASSIFICATION
LB3-23
LB5-12
LL
MH - Elastic SILT
10
DEPTH (ft)
SUNBOW II, PHASE 3
GRADATION CURVE
Figure B-1
ASTM D422
FIG. B-2
COMPOSITE DIRECT SHEAR TEST RESULTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2452 - 32 - 02TR / RA
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:06/10/2020 8:53AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\DirectShearTestResults\DirectShearTestResults-Qcf-Ultimate.dwg
DATE 04 - 10 - 2020
FIG. B-3
COMPOSITE DIRECT SHEAR TEST RESULTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2452 - 32 - 02TR / RA
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:06/10/2020 8:54AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\DirectShearTestResults\DirectShearTestResults-Tsd(SM)-Peak.dwg
DATE 04 - 10 - 2020
FIG. B-4
COMPOSITE DIRECT SHEAR TEST RESULTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2452 - 32 - 02TR / RA
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:06/10/2020 8:54AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\DirectShearTestResults\DirectShearTestResults-To(SM)-Peak.dwg
DATE 04 - 10 - 2020
FIG. B-5
COMPOSITE DIRECT SHEAR TEST RESULTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2452 - 32 - 02TR / RA
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:06/10/2020 8:54AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\DirectShearTestResults\DirectShearTestResults-To(ML-CL)-Ultimate.dwg
DATE 04 - 10 - 2020
FIG. B-6
COMPOSITE DIRECT SHEAR TEST RESULTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2452 - 32 - 02TR / RA
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:06/10/2020 8:54AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\DirectShearTestResults\DirectShearTestResults-To(MH-CH)-Ultimate.dwg
DATE 04 - 10 - 2020
FIG. B-7
COMPOSITE DIRECT SHEAR TEST RESULTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2452 - 32 - 02TR / RA
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:06/10/2020 8:53AM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2452-32-02 Sunbow II, Ph.3\DirectShearTestResults\DirectShearTestResults-Tsw(SM)-Peak.dwg
DATE 04 - 10 - 2020
APPENDIX C
Project No. G2452-32-02 April 10, 2020
APPENDIX C
SLOPE STABILITY ANALYSES
The slope stability analyses utilized the computer software program Geostudio 2018 to calculate the
factor of safety with respect to deep-seated instability. This program uses conventional slope stability
equations and a two-dimensional, limit-equilibrium method. For our analyses, Spencer’s Method with
a block-failure mode was used to analyze the slope stability along assumed continuous weak clay
beds. Circular failure surfaces were also utilized to evaluate cut and fill slopes. Shear strength
parameters were assigned using average shear strength parameters for sandstone, siltstone, and
claystone and engineering judgment. Residual shear strengths were used for bedding plane shears and
were determined from the Journal of Geotechnical and Geoenvironmental Engineering, Drained
Shear Strength Parameters for Analysis of Landslides (Stark, Choi, McCone, 2005) and engineering
judgment.
Based on our experience, we have observed that bedding plane shears can undulate with orientations
varying up to 15 degrees over tens of feet, however, when averaged over a greater distance they are
generally horizontal or dipping only a few degrees. Therefore, projection or modeling the orientation
of these features on the Geologic Cross Sections was based on piercing points and/or graphical
methods (i.e., 3-point solutions) between the exploratory borings in lieu of projection along strike
measured in the borings. In addition, to be conservative, bedding plane shears that dipped into slope
were conservatively modeled flat, and those dipping out of slope were modeled out of slope in our
slope stability analysis.
The results of the slope stability analyses performed on Cross-Sections A-A’ through K-K’ are
presented in Figures C-1 through C-29.
1.2Distance (ft)0100200300400500600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section A-A'Name: AA-Case1.gszDate: 04/07/2020 Time: 05:05:28 PMColor NameUnit Weight (pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Otay Formation (MH/CH) 120 500 22Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Sweetwater Formation (SM) 130 500 36Proposed ConditionBlock AnalysisX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-1AA'To (SM)To (SM)TswTswPLExisting GradeProposed GradeBPSTo (MH/CH)TsdTswRetaining WallTo (SM)To (SM)To (MH/CH)
1.6Distance (ft)0100200300400500600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section A-A'Name: AA-Case3.gszDate: 04/08/2020 Time: 11:50:07 AMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Sweetwater Formation (SM) 130 500 36Proposed Condition with ButtressBlock Analysis Thru BPSX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-2AA'To (SM)To (SM)TswTswPLExisting GradeProposed GradeBPSTo (MH/CH)TsdTswRetaining WallTo (SM)To (SM)To (MH/CH)Qcf20 ft15 ft
2.4Distance (ft)0100200300400500600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section A-A'Name: AA-Case4.gszDate: 04/08/2020 Time: 12:22:33 PMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Sweetwater Formation (SM) 130 500 36Proposed Condition with ButtressBlock Analysis Thru To (MH/CH)X:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-3AA'To (SM)To (SM)TswTswPLExisting GradeProposed GradeBPSTo (MH/CH)TsdTswRetaining WallTo (SM)To (SM)To (MH/CH)Qcf20 ft15 ft
1.7Distance (ft)0100200300400500600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480QcfSunbow II, Phase 3Project No. G2452-32-02Section B-B'Name: BB-Case1.gszDate: 04/07/2020 Time: 05:14:02 PMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (ML/CL) 125 400 23Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Sweetwater Formation (SM) 130 500 36Proposed ConditionBlock Analysis Thru BPSX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-4BB'To (SM)To (SM)TswTswPLExisting GradeProposed GradeBPSTo (MH/CH)TsdTswTo (SM)To (SM)To (MH/CH)To (ML/CL)
3.4Distance (ft)0100200300400500600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480QcfSunbow II, Phase 3Project No. G2452-32-02Section B-B'Name: BB-Case3.gszDate: 04/08/2020 Time: 12:32:09 PMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (ML/CL) 125 400 23Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Sweetwater Formation (SM) 130 500 36Proposed ConditionBlock Analysis Thru To (MH/CH)X:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-5BB'To (SM)To (SM)TswTswPLExisting GradeProposed GradeBPSTo (MH/CH)TsdTswTo (SM)To (SM)To (MH/CH)To (ML/CL)
2.6Distance (ft)0100200300400500600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480QcfSunbow II, Phase 3Project No. G2452-32-02Section B-B'Name: BB-Case2.gszDate: 04/07/2020 Time: 05:18:48 PMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (ML/CL) 125 400 23Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Sweetwater Formation (SM) 130 500 36Proposed ConditionCircular AnalysisX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-6BB'To (SM)To (SM)TswTswPLExisting GradeProposed GradeBPSTo (MH/CH)TsdTswTo (SM)To (SM)To (MH/CH)To (ML/CL)
2.1Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section C-C'Name: CC-Case0 - Block Failure.gszDate: 04/08/2020 Time: 12:39:12 PMColor NameUnit Weight (pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Otay Formation (MH/CH) 120 500 22Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Proposed ConditionBlock Analysis Thru To (MH/CH)X:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-7CC'To (SM)To (SM)Existing GradeProposed GradeBPSTsdRetaining WallsTo (SM)To (SM)To (MH/CH)To (SM)PL
2.2Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section C-C'Name: CC-Case1.gszDate: 04/08/2020 Time: 12:56:59 PMColor NameUnit Weight (pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Proposed Condition with Stability FillBlock Analysis Thru To (MH/CH)X:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-8CC'To (SM)To (SM)Existing GradeProposed GradeBPSTsdTo (SM)To (SM)To (MH/CH)To (SM)PLQcf
1.9Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section C-C'Name: CC-Case2.gszDate: 04/08/2020 Time: 01:05:26 PMColor NameUnit Weight (pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Proposed Condition with Stability FillCircular AnalysisX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-9CC'To (SM)To (SM)Existing GradeProposed GradeBPSTsdTo (SM)To (SM)To (MH/CH)To (SM)PLQcf
2.4Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section D-D'Name: DD-Case1.gszDate: 04/08/2020 Time: 01:18:56 PMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 400 29Otay Formation (MH/CH) 120 500 25Otay Formation (ML/CL) 125 500 28Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Proposed Condition with Stability FillBlock Analysis Thru To (ML/CL)X:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-10DD'To (SM)To (SM)PLExisting GradeProposed GradeBPSTo (MH/CH)TsdTo (SM)To (SM)To (ML/CL)To (MH/CH)Qcf
1.8Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section D-D'Name: DD-Case0.gszDate: 04/08/2020 Time: 01:22:26 PMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 400 29Otay Formation (MH/CH) 120 500 25Otay Formation (ML/CL) 125 500 28Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Proposed Condition with Stability FillCircular AnalysisX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-11DD'To (SM)To (SM)PLExisting GradeProposed GradeBPSTo (MH/CH)TsdTo (SM)To (SM)To (ML/CL)To (MH/CH)Qcf
2.0Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section E-E'Name: EE-Case0.gszDate: 04/09/2020 Time: 09:56:46 AMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (ML/CL) 125 400 23Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Proposed Condition with Stability FillBlock Analysis Thru To (ML/CL)X:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-12EE'To (SM)To (SM)PLExisting GradeProposed GradeBPSTsdTo (SM)To (SM)To (ML/CL)To (MH/CH)To (ML/CL)To (MH/CH)BPSTo (ML/CL)TsdTo (MH/CH)Qcf
1.8Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section E-E'Name: EE-Case1.gszDate: 04/09/2020 Time: 10:00:26 AMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (ML/CL) 125 400 23Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Proposed Condition with Stability FillCircular AnalysisX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-13EE'To (SM)To (SM)PLExisting GradeProposed GradeBPSTsdTo (SM)To (SM)To (ML/CL)To (MH/CH)To (ML/CL)To (MH/CH)BPSTo (ML/CL)TsdTo (MH/CH)Qcf
2.0Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section F-F'Name: FF-Case0.gszDate: 04/08/2020 Time: 01:37:24 PMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (ML/CL) 125 400 23Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Proposed Condition with Stability FillBlock Analysis Thru Lower To (ML/CL)X:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-14FF'To (SM)To (SM)PLExisting GradeProposed GradeBPSTo (SM)To (SM)To (ML/CL)To (MH/CH)To (ML/CL)To (MH/CH)BPSTo (ML/CL)TsdTo (MH/CH)QcfTo (SM)Qcf
2.1Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section F-F'Name: FF-Case2.gszDate: 04/08/2020 Time: 01:40:18 PMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (ML/CL) 125 400 23Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Proposed Condition with Stability FillBlock Analysis Thru Upper To (ML/CL)X:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-15FF'To (SM)To (SM)PLExisting GradeProposed GradeBPSTo (SM)To (SM)To (ML/CL)To (MH/CH)To (ML/CL)To (MH/CH)BPSTo (ML/CL)TsdTo (MH/CH)QcfTo (SM)Qcf
1.7Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section F-F'Name: FF-Case1.gszDate: 04/08/2020 Time: 01:45:54 PMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (ML/CL) 125 400 23Otay Formation (SM) 130 300 30San Diego Formation (SM) 120 300 31Proposed Condition with Stability FillCircular AnalysisX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-16FF'To (SM)To (SM)PLExisting GradeProposed GradeBPSTo (SM)To (SM)To (ML/CL)To (MH/CH)To (ML/CL)To (MH/CH)BPSTo (ML/CL)TsdTo (MH/CH)QcfTo (SM)Qcf
2.4Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600260270280290300310320330340350360370380390400410420430440Elevation (MSL)260270280290300310320330340350360370380390400410420430440Sunbow II, Phase 3Project No. G2452-32-02Section G-G'Name: GG-Case0.gszDate: 04/08/2020 Time: 12:59:50 AMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (ML/CL) 125 400 23Otay Formation (SM) 130 300 30Sweetwater Formation (SM) 130 500 36Proposed ConditionBlock Analysis Thru To (ML/CL)X:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-17GG'To (SM)Existing GradeProposed GradeBPSTo (ML/CL)To (ML/CL)To (MH/CH)To (SM)TswTswQcf
1.9Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600260270280290300310320330340350360370380390400410420430440Elevation (MSL)260270280290300310320330340350360370380390400410420430440Sunbow II, Phase 3Project No. G2452-32-02Section G-G'Name: GG-Case1.gszDate: 04/08/2020 Time: 12:55:18 AMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (ML/CL) 125 400 23Otay Formation (SM) 130 300 30Sweetwater Formation (SM) 130 500 36Proposed ConditionCircular AnalysisX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-18GG'To (SM)Existing GradeProposed GradeBPSTo (ML/CL)To (ML/CL)To (MH/CH)To (SM)TswTswQcf
2.2Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600260270280290300310320330340350360370380390400410420430440Elevation (MSL)260270280290300310320330340350360370380390400410420430440Sunbow II, Phase 3Project No. G2452-32-02Section H-H'Name: HH-Case0.gszDate: 04/08/2020 Time: 01:47:54 AMColor NameUnit Weight (pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (SM) 130 300 30Sweetwater Formation (SM) 130 500 36Proposed ConditionCircular AnalysisX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-19HH'To (SM)To (SM)Existing GradeProposed GradeTo (SM)To (MH/CH)BPSTo (MH/CH)TswTswTswQcf15 ft
2.4Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section I-I'Name: II-Case1.gszDate: 04/08/2020 Time: 02:06:47 PMColor NameUnit Weight (pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (SM) 130 300 30Sweetwater Formation (SM) 130 500 36Proposed ConditionBlock Analysis Thru BPSX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-20II'To (SM)To (SM)Existing GradeProposed GradeTo (SM)To (MH/CH)BPSTo (MH/CH)TswTswTswQcf15 ft
2.8Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section I-I'Name: II-Case3.gszDate: 04/08/2020 Time: 02:10:41 PMColor NameUnit Weight (pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (SM) 130 300 30Sweetwater Formation (SM) 130 500 36Proposed ConditionBlock Analysis Thru To (MH/CH)X:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-21II'To (SM)To (SM)Existing GradeProposed GradeTo (SM)To (MH/CH)BPSTo (MH/CH)TswTswTswQcf15 ft
1.8Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600300310320330340350360370380390400410420430440450460470480Elevation (MSL)300310320330340350360370380390400410420430440450460470480Sunbow II, Phase 3Project No. G2452-32-02Section I-I'Name: II-Case2.gszDate: 04/08/2020 Time: 02:17:17 PMColor NameUnit Weight (pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (SM) 130 300 30Sweetwater Formation (SM) 130 500 36Proposed ConditionCircular AnalysisX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-22II'To (SM)To (SM)Existing GradeProposed GradeTo (SM)To (MH/CH)BPSTo (MH/CH)TswTswTswQcf15 ft
2.9Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800260270280290300310320330340350360370380390400410420430440Elevation (MSL)260270280290300310320330340350360370380390400410420430440Sunbow II, Phase 3Project No. G2452-32-02Section J-J'Name: JJ-Case0.gszDate: 04/07/2020 Time: 10:35:09 PMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (ML/CL) 125 400 23Otay Formation (SM) 130 300 30Sweetwater Formation (SM) 130 500 36Proposed ConditionBlock Analysis Thru To (MH/CH)X:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-23JJ'To (SM)Existing GradeProposed GradeBPSTo (MH/CH)TswTswTswTo (SM)To (SM)QcfQcfQcf
2.7Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800260270280290300310320330340350360370380390400410420430440Elevation (MSL)260270280290300310320330340350360370380390400410420430440Sunbow II, Phase 3Project No. G2452-32-02Section J-J'Name: JJ-Case1.gszDate: 04/07/2020 Time: 10:37:43 PMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (ML/CL) 125 400 23Otay Formation (SM) 130 300 30Sweetwater Formation (SM) 130 500 36Proposed ConditionCircular Analysis Thru To (MH/CH)X:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-24JJ'To (SM)Existing GradeProposed GradeBPSTo (MH/CH)TswTswTswTo (SM)To (SM)QcfQcfQcfTo (ML/CL)
2.1Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800260270280290300310320330340350360370380390400410420430440Elevation (MSL)260270280290300310320330340350360370380390400410420430440Sunbow II, Phase 3Project No. G2452-32-02Section J-J'Name: JJ-Case2.gszDate: 04/07/2020 Time: 10:46:51 PMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (ML/CL) 125 400 23Otay Formation (SM) 130 300 30Sweetwater Formation (SM) 130 500 36Proposed ConditionCircular Analysis Thru BPSX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-25JJ'To (SM)Existing GradeProposed GradeBPSTo (MH/CH)TswTswTswTo (SM)To (SM)QcfQcfQcfTo (ML/CL)
2.1Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800260270280290300310320330340350360370380390400410420430440Elevation (MSL)260270280290300310320330340350360370380390400410420430440Sunbow II, Phase 3Project No. G2452-32-02Section J-J'Name: JJ-Case5.gszDate: 04/07/2020 Time: 11:00:10 PMColor NameUnit Weight(pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (ML/CL) 125 400 23Otay Formation (SM) 130 300 30Sweetwater Formation (SM) 130 500 36Proposed ConditionCircular AnalysisX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-26JJ'To (SM)Existing GradeProposed GradeBPSTo (MH/CH)TswTswTswTo (SM)To (SM)QcfQcfQcfTo (ML/CL)
1.2Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600220230240250260270280290300310320330340350360370380390400410420Elevation (MSL)220230240250260270280290300310320330340350360370380390400410420Sunbow II, Phase 3Project No. G2452-32-02Section K-K'Name: KK-Case0.gszDate: 04/08/2020 Time: 03:01:16 PMColor NameUnit Weight (pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (SM) 130 300 30Sweetwater Formation (SM) 130 500 36Proposed ConditionBlock Analysis Thru BPSX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-27KK'To (SM)Existing GradeProposed GradeBPSTo (MH/CH)TswTswTswTo (SM)QcfQcf15 ft
1.6Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600220230240250260270280290300310320330340350360370380390400410420Elevation (MSL)220230240250260270280290300310320330340350360370380390400410420Sunbow II, Phase 3Project No. G2452-32-02Section K-K'Name: KK-Case1.gszDate: 04/08/2020 Time: 02:41:31 PMColor NameUnit Weight (pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (SM) 130 300 30Sweetwater Formation (SM) 130 500 36Proposed Condition with Shear KeyBlock Analysis Thru BPSX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-28KK'To (SM)Existing GradeProposed GradeBPSTo (MH/CH)TswTswTswTo (SM)QcfQcf40 ft
2.1Distance (ft)0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600220230240250260270280290300310320330340350360370380390400410420Elevation (MSL)220230240250260270280290300310320330340350360370380390400410420Sunbow II, Phase 3Project No. G2452-32-02Section K-K'Name: KK-Case2.gszDate: 04/08/2020 Time: 02:47:44 PMColor NameUnit Weight (pcf)Cohesion'(psf)Phi' (°)Bedding Plane Shear (BPS) 120 0 7Compacted Fill (Qcf) 120 300 29Otay Formation (MH/CH) 120 500 22Otay Formation (SM) 130 300 30Sweetwater Formation (SM) 130 500 36Proposed Condition with Shear KeyCircular AnalysisX:\Engineering and Geology\ENGINEER PROGRAMS, GUIDES, ETC\EngrgPrg\GEO-SLOPE2018\G2452-32-02 Sunbow\Figure C-29KK'To (SM)Existing GradeProposed GradeBPSTo (MH/CH)TswTswTswTo (SM)QcfQcf40 ft
APPENDIX D
APPENDIX D
STORM WATER MANAGEMENT I-8A (WORKSHEET C.4-1) FORMS
FOR
SUNBOW II
PHASE 3
CHULA VISTA, CALIFORNIA
PROJECT NO. G2452-32-02
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
Part 1 - Full Infiltration Feasibility Screening Criteria
DMA(s) Being Analyzed: Project Phase:
Criteria 1: Infiltration Rate Screening
1A
Is the mapped hydrologic soil group according to the NRCS Web Soil Survey or UC Davis Soil
Web Mapper Type A or B and corroborated by available site soil data2?
Yes; the DMA may feasibly support full infiltration. Answer “Yes” to Criteria 1 Result or
continue to Step 1B if the applicant elects to perform infiltration testing.
No; the mapped soil types are A or B but is not corroborated by available site soil data
(continue to Step 1B).
No; the mapped soil types are C, D, or “urban/unclassified” and is corroborated by
available site soil data. Answer “No” to Criteria 1 Result.
No; the mapped soil types are C, D, or “urban/unclassified” but is not corroborated by
available site soil data (continue to Step 1B).
1B
Is the reliable infiltration rate calculated using planning phase methods from Table D.3-1?
Yes; Continue to Step 1C.
No; Skip to Step 1D.
1C
Is the reliable infiltration rate calculated using planning phase methods from Table D.3-1 greater
than 0.5 inches per hour?
Yes; the DMA may feasibly support full infiltration. Answer “Yes” to Criteria 1 Result.
No; full infiltration is not required. Answer “No” to Criteria 1 Result.
1D
Infiltration Testing Method. Is the selected infiltration testing method suitable during the
design phase (see Appendix D.3)? Note: Alternative testing standards may be allowed with
appropriate rationales and documentation.
Yes; continue to Step 1E.
No; select an appropriate infiltration testing method.
1E
Number of Percolation/Infiltration Tests. Does the infiltration testing method performed
satisfy the minimum number of tests specified in Table D.3-2?
Yes; continue to Step 1F.
No; conduct appropriate number of tests.
1 This form must be completed each time there is a change to the site layout that would affect the infiltration feasibility
condition. Previously completed forms shall be retained to document the evolution of the site storm water design.
2 Available data includes site-specific sampling or observation of soil types or texture classes, such as obtained from
borings or test pits necessary to support other design elements.
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
IF
Factor of Safety. Is the suitable Factor of Safety selected for full infiltration design? See
guidance in D.5; Tables D.5-1 and D.5-2; and Worksheet D.5-1 (Form I-9).
Yes; continue to Step 1G.
No; select appropriate factor of safety.
1G
Full Infiltration Feasibility. Is the average measured infiltration rate divided by the Factor of
Safety greater than 0.5 inches per hour?
Yes; answer “Yes” to Criteria 1 Result.
No; answer “No” to Criteria 1 Result.
Criteria 1
Result
Is the estimated reliable infiltration rate greater than 0.5 inches per hour within the DMA where
runoff can reasonably be routed to a BMP?
Yes; the DMA may feasibly support full infiltration. Continue to Criteria 2.
No; full infiltration is not required. Skip to Part 1 Result.
Summarize infiltration testing methods, testing locations, replicates, and results and summarize estimates of
reliable infiltration rates according to procedures outlined in D.5. Documentation should be included in
project geotechnical report.
Criteria 2: Geologic/Geotechnical Screening
2A
If all questions in Step 2A are answered “Yes,” continue to Step 2B.
For any “No” answer in Step 2A answer “No” to Criteria 2 and submit an “Infiltration Feasibility
Condition Letter” that meets the requirements in Appendix C.1.1.
The geologic/geotechnical analyses listed in Appendix C.2.1 do not apply to the DMA because
one of the following setbacks cannot be avoided and therefore result in the DMA being in a no
infiltration condition. The setbacks must be the closest horizontal radial distance from the surface
edge (at the overflow elevation) of the BMP.
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
2A-1 Can the proposed full infiltration BMP(s) avoid areas with existing fill
materials greater than 5 feet thick below the infiltrating surface? ☐ Yes ☐ No
2A-2 Can the proposed full infiltration BMP(s) avoid placement within 10 feet of
existing underground utilities, structures, or retaining walls? ☐ Yes ☐ No
2A-3
Can the proposed full infiltration BMP(s) avoid placement within 50 feet of a
natural slope (>25%) or within a distance of 1.5H from fill slopes where H is
the height of the fill slope?
☐ Yes ☐ No
2B
When full infiltration is determined to be feasible, a geotechnical investigation report must be
prepared that considers the relevant factors identified in Appendix C.2.1.
If all questions in Step 2B are answered “Yes,” then answer “Yes” to Criteria 2 Result.
If there are “No” answers continue to Step 2C.
2B-1
Hydroconsolidation. Analyze hydroconsolidation potential per approved
ASTM standard due to a proposed full infiltration BMP.
Can full infiltration BMPs be proposed within the DMA without increasing
hydroconsolidation risks?
☐ Yes ☐ No
2B-2
Expansive Soils. Identify expansive soils (soils with an expansion index
greater than 20) and the extent of such soils due to proposed full infiltration
BMPs.
Can full infiltration BMPs be proposed within the DMA without increasing
expansive soil risks?
☐ Yes ☐ No
2B-3
Liquefaction. If applicable, identify mapped liquefaction areas. Evaluate
liquefaction hazards in accordance with Section 6.4.2 of the City of San Diego's
Guidelines for Geotechnical Reports (2011 or most recent edition).
Liquefaction hazard assessment shall take into account any increase in
groundwater elevation or groundwater mounding that could occur as a result
of proposed infiltration or percolation facilities.
Can full infiltration BMPs be proposed within the DMA without increasing
liquefaction risks?
☐ Yes ☐ No
2B-4
Slope Stability. If applicable, perform a slope stability analysis in accordance
with the ASCE and Southern California Earthquake Center (2002)
Recommended Procedures for Implementation of DMG Special Publication
117, Guidelines for Analyzing and Mitigating Landslide Hazards in California
to determine minimum slope setbacks for full infiltration BMPs. See the City
of San Diego's Guidelines for Geotechnical Reports (2011) to determine which
type of slope stability analysis is required.
Can full infiltration BMPs be proposed within the DMA without increasing
slope stability risks?
☐ Yes ☐ No
2B-5
Other Geotechnical Hazards. Identify site-specific geotechnical hazards not
already mentioned (refer to Appendix C.2.1).
Can full infiltration BMPs be proposed within the DMA without increasing
risk of geologic or geotechnical hazards not already mentioned?
☐ Yes ☐ No
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
2B-6
Setbacks. Establish setbacks from underground utilities, structures, and/or
retaining walls. Reference applicable ASTM or other recognized standard in
the geotechnical report.
Can full infiltration BMPs be proposed within the DMA using established
setbacks from underground utilities, structures, and/or retaining walls?
☐ Yes ☐ No
2C
Mitigation Measures. Propose mitigation measures for each
geologic/geotechnical hazard identified in Step 2B. Provide a discussion of
geologic/geotechnical hazards that would prevent full infiltration BMPs that
cannot be reasonably mitigated in the geotechnical report. See Appendix
C.2.1.8 for a list of typically reasonable and typically unreasonable mitigation
measures.
Can mitigation measures be proposed to allow for full infiltration BMPs? If
the question in Step 2 is answered “Yes,” then answer “Yes” to Criteria 2
Result.
If the question in Step 2C is answered “No,” then answer “No” to Criteria 2
Result.
☐ Yes ☐ No
Criteria 2
Result
Can infiltration greater than 0.5 inches per hour be allowed without increasing
risk of geologic or geotechnical hazards that cannot be reasonably mitigated to
an acceptable level?
☐ Yes ☐ No
Summarize findings and basis; provide references to related reports or exhibits.
Part 1 Result – Full Infiltration Geotechnical Screening 3 Result
If answers to both Criteria 1 and Criteria 2 are “Yes”, a full
infiltration design is potentially feasible based on Geotechnical
conditions only.
If either answer to Criteria 1 or Criteria 2 is “No”, a full infiltration
design is not required.
Full infiltration Condition
Complete Part 2
3 To be completed using gathered site information and best professional judgement consider ing the definition of MEP in
the MS4 Permit. Additional testing and/or studies may be required by City Engineer to substantiate findings.
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
Part 2 – Partial vs. No Infiltration Feasibility Screening Criteria
DMA(s) Being Analyzed: Project Phase:
Criteria 3 : Infiltration Rate Screening
3A
NRCS Type C, D, or “urban/unclassified”: Is the mapped hydrologic soil group according
to the NRCS Web Soil Survey or UC Davis Soil Web Mapper is Type C, D, or
“urban/unclassified” and corroborated by available site soil data?
Yes; the site is mapped as C soils and a reliable infiltration rate of 0.15 in/hr. is used to
size partial infiltration BMPS. Answer “Yes” to Criteria 3 Result.
Yes; the site is mapped as D soils or “urban/unclassified” and a reliable infiltration rate
of 0.05 in/hr. is used to size partial infiltration BMPS. Answer “Yes” to Criteria 3
Result.
No; infiltration testing is conducted (refer to Table D.3-1), continue to Step 3B.
3B
Infiltration Testing Result: Is the reliable infiltration rate (i.e. average measured infiltration
rate/2) greater than 0.05 in/hr. and less than or equal to 0.5 in/hr?
Yes; the site may support partial infiltration. Answer “Yes” to Criteria 3 Result.
No; the reliable infiltration rate (i.e. average measured rate/2) is less than 0.05 in/hr.,
partial infiltration is not required. Answer “No” to Criteria 3 Result.
Criteria 3
Result
Is the estimated reliable infiltration rate (i.e., average measured infiltration rate/2) greater than or
equal to 0.05 inches/hour and less than or equal to 0.5 inches/hour at any location within each
DMA where runoff can reasonably be routed to a BMP?
Yes; Continue to Criteria 4.
No: Skip to Part 2 Result.
Summarize infiltration testing and/or mapping results (i.e. soil maps and series description used for
infiltration rate).
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
Criteria 4: Geologic/Geotechnical Screening
4A
If all questions in Step 4A are answered “Yes,” continue to Step 2B.
For any “No” answer in Step 4A answer “No” to Criteria 4 Result, and submit an “Infiltration
Feasibility Condition Letter” that meets the requirements in Appendix C.1.1. The
geologic/geotechnical analyses listed in Appendix C.2.1 do not apply to the DMA because one of
the following setbacks cannot be avoided and therefore result in the DMA being in a no
infiltration condition. The setbacks must be the closest horizontal radial distance from the surface
edge (at the overflow elevation) of the BMP.
4A-1 Can the proposed partial infiltration BMP(s) avoid areas with existing fill
materials greater than 5 feet thick? ☐ Yes ☐ No
4A-2 Can the proposed partial infiltration BMP(s) avoid placement within 10
feet of existing underground utilities, structures, or retaining walls? ☐ Yes ☐ No
4A-3
Can the proposed partial infiltration BMP(s) avoid placement within 50
feet of a natural slope (>25%) or within a distance of 1.5H from fill slopes
where H is the height of the fill slope?
☐ Yes ☐ No
4B
When full infiltration is determined to be feasible, a geotechnical investigation report must be
prepared that considers the relevant factors identified in Appendix C.2.1.
If all questions in Step 4B are answered “Yes,” then answer “Yes” to Criteria 4 Result. If there
are any “No” answers continue to Step 4C.
4B-1
Hydroconsolidation. Analyze hydroconsolidation potential per
approved ASTM standard due to a proposed full infiltration BMP.
Can partial infiltration BMPs be proposed within the DMA without
increasing hydroconsolidation risks?
☐ Yes ☐ No
4B-2
Expansive Soils. Identify expansive soils (soils with an expansion index
greater than 20) and the extent of such soils due to proposed full
infiltration BMPs.
Can partial infiltration BMPs be proposed within the DMA without
increasing expansive soil risks?
☐ Yes ☐ No
4B-3
Liquefaction. If applicable, identify mapped liquefaction areas. Evaluate
liquefaction hazards in accordance with Section 6.4.2 of the City of San
Diego's Guidelines for Geotechnical Reports (2011). Liquefaction hazard
assessment shall take into account any increase in groundwater elevation
or groundwater mounding that could occur as a result of proposed
infiltration or percolation facilities.
Can partial infiltration BMPs be proposed within the DMA without
increasing liquefaction risks?
☐ Yes ☐ No
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
4B-4
Slope Stability. If applicable, perform a slope stability analysis in
accordance with the ASCE and Southern California Earthquake Center
(2002) Recommended Procedures for Implementation of DMG Special
Publication 117, Guidelines for Analyzing and Mitigating Landslide
Hazards in California to determine minimum slope setbacks for full
infiltration BMPs. See the City of San Diego's Guidelines for Geotechnical
Reports (2011) to determine which type of slope stability analysis is
required.
Can partial infiltration BMPs be proposed within the DMA without
increasing slope stability risks?
☐ Yes ☐ No
4B-5
Other Geotechnical Hazards. Identify site-specific geotechnical hazards
not already mentioned (refer to Appendix C.2.1).
Can partial infiltration BMPs be proposed within the DMA without
increasing risk of geologic or geotechnical hazards not already mentioned?
☐ Yes ☐ No
4B-6
Setbacks. Establish setbacks from underground utilities, structures,
and/or retaining walls. Reference applicable ASTM or other recognized
standard in the geotechnical report.
Can partial infiltration BMPs be proposed within the DMA using
recommended setbacks from underground utilities, structures, and/or
retaining walls?
☐ Yes ☐ No
4C
Mitigation Measures. Propose mitigation measures for each
geologic/geotechnical hazard identified in Step 4B. Provide a discussion
on geologic/geotechnical hazards that would prevent partial infiltration
BMPs that cannot be reasonably mitigated in the geotechnical report. See
Appendix C.2.1.8 for a list of typically reasonable and typically
unreasonable mitigation measures.
Can mitigation measures be proposed to allow for partial infiltration
BMPs? If the question in Step 4C is answered “Yes,” then answer “Yes”
to Criteria 4 Result.
If the question in Step 4C is answered “No,” then answer “No” to Criteria
4 Result.
☐ Yes ☐ No
Criteria 4
Result
Can infiltration of greater than or equal to 0.05 inches/hour and less than
or equal to 0.5 inches/hour be allowed without increasing the risk of
geologic or geotechnical hazards that cannot be reasonably mitigated to an
acceptable level?
☐ Yes ☐ No
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
Summarize findings and basis; provide references to related reports or exhibits.
Part 2 – Partial Infiltration Geotechnical Screening Result4 Result
If answers to both Criteria 3 and Criteria 4 are “Yes”, a partial
infiltration design is potentially feasible based on geotechnical
conditions only.
If answers to either Criteria 3 or Criteria 4 is “No”, then
infiltration of any volume is considered to be infeasible within the
site.
Partial Infiltration
Condition
No Infiltration Condition
4 To be completed using gathered site information and best professional judgement considering the definition of MEP i n
the MS4 Permit. Additional testing and/or studies may be required by City Engineer to substantiate findings.
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
Part 1 - Full Infiltration Feasibility Screening Criteria
DMA(s) Being Analyzed: Project Phase:
Criteria 1: Infiltration Rate Screening
1A
Is the mapped hydrologic soil group according to the NRCS Web Soil Survey or UC Davis Soil
Web Mapper Type A or B and corroborated by available site soil data2?
Yes; the DMA may feasibly support full infiltration. Answer “Yes” to Criteria 1 Result or
continue to Step 1B if the applicant elects to perform infiltration testing.
No; the mapped soil types are A or B but is not corroborated by available site soil data
(continue to Step 1B).
No; the mapped soil types are C, D, or “urban/unclassified” and is corroborated by
available site soil data. Answer “No” to Criteria 1 Result.
No; the mapped soil types are C, D, or “urban/unclassified” but is not corroborated by
available site soil data (continue to Step 1B).
1B
Is the reliable infiltration rate calculated using planning phase methods from Table D.3-1?
Yes; Continue to Step 1C.
No; Skip to Step 1D.
1C
Is the reliable infiltration rate calculated using planning phase methods from Table D.3-1 greater
than 0.5 inches per hour?
Yes; the DMA may feasibly support full infiltration. Answer “Yes” to Criteria 1 Result.
No; full infiltration is not required. Answer “No” to Criteria 1 Result.
1D
Infiltration Testing Method. Is the selected infiltration testing method suitable during the
design phase (see Appendix D.3)? Note: Alternative testing standards may be allowed with
appropriate rationales and documentation.
Yes; continue to Step 1E.
No; select an appropriate infiltration testing method.
1E
Number of Percolation/Infiltration Tests. Does the infiltration testing method performed
satisfy the minimum number of tests specified in Table D.3-2?
Yes; continue to Step 1F.
No; conduct appropriate number of tests.
1 This form must be completed each time there is a change to the site layout that would affect the infiltration feasibility
condition. Previously completed forms shall be retained to document the evolution of the site storm water design.
2 Available data includes site-specific sampling or observation of soil types or texture classes, such as obtained from
borings or test pits necessary to support other design elements.
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
IF
Factor of Safety. Is the suitable Factor of Safety selected for full infiltration design? See
guidance in D.5; Tables D.5-1 and D.5-2; and Worksheet D.5-1 (Form I-9).
Yes; continue to Step 1G.
No; select appropriate factor of safety.
1G
Full Infiltration Feasibility. Is the average measured infiltration rate divided by the Factor of
Safety greater than 0.5 inches per hour?
Yes; answer “Yes” to Criteria 1 Result.
No; answer “No” to Criteria 1 Result.
Criteria 1
Result
Is the estimated reliable infiltration rate greater than 0.5 inches per hour within the DMA where
runoff can reasonably be routed to a BMP?
Yes; the DMA may feasibly support full infiltration. Continue to Criteria 2.
No; full infiltration is not required. Skip to Part 1 Result.
Summarize infiltration testing methods, testing locations, replicates, and results and summarize estimates of
reliable infiltration rates according to procedures outlined in D.5. Documentation should be included in
project geotechnical report.
Criteria 2: Geologic/Geotechnical Screening
2A
If all questions in Step 2A are answered “Yes,” continue to Step 2B.
For any “No” answer in Step 2A answer “No” to Criteria 2 and submit an “Infiltration Feasibility
Condition Letter” that meets the requirements in Appendix C.1.1.
The geologic/geotechnical analyses listed in Appendix C.2.1 do not apply to the DMA because
one of the following setbacks cannot be avoided and therefore result in the DMA being in a no
infiltration condition. The setbacks must be the closest horizontal radial distance from the surface
edge (at the overflow elevation) of the BMP.
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
2A-1 Can the proposed full infiltration BMP(s) avoid areas with existing fill
materials greater than 5 feet thick below the infiltrating surface? ☐ Yes ☐ No
2A-2 Can the proposed full infiltration BMP(s) avoid placement within 10 feet of
existing underground utilities, structures, or retaining walls? ☐ Yes ☐ No
2A-3
Can the proposed full infiltration BMP(s) avoid placement within 50 feet of a
natural slope (>25%) or within a distance of 1.5H from fill slopes where H is
the height of the fill slope?
☐ Yes ☐ No
2B
When full infiltration is determined to be feasible, a geotechnical investigation report must be
prepared that considers the relevant factors identified in Appendix C.2.1.
If all questions in Step 2B are answered “Yes,” then answer “Yes” to Criteria 2 Result.
If there are “No” answers continue to Step 2C.
2B-1
Hydroconsolidation. Analyze hydroconsolidation potential per approved
ASTM standard due to a proposed full infiltration BMP.
Can full infiltration BMPs be proposed within the DMA without increasing
hydroconsolidation risks?
☐ Yes ☐ No
2B-2
Expansive Soils. Identify expansive soils (soils with an expansion index
greater than 20) and the extent of such soils due to proposed full infiltration
BMPs.
Can full infiltration BMPs be proposed within the DMA without increasing
expansive soil risks?
☐ Yes ☐ No
2B-3
Liquefaction. If applicable, identify mapped liquefaction areas. Evaluate
liquefaction hazards in accordance with Section 6.4.2 of the City of San Diego's
Guidelines for Geotechnical Reports (2011 or most recent edition).
Liquefaction hazard assessment shall take into account any increase in
groundwater elevation or groundwater mounding that could occur as a result
of proposed infiltration or percolation facilities.
Can full infiltration BMPs be proposed within the DMA without increasing
liquefaction risks?
☐ Yes ☐ No
2B-4
Slope Stability. If applicable, perform a slope stability analysis in accordance
with the ASCE and Southern California Earthquake Center (2002)
Recommended Procedures for Implementation of DMG Special Publication
117, Guidelines for Analyzing and Mitigating Landslide Hazards in California
to determine minimum slope setbacks for full infiltration BMPs. See the City
of San Diego's Guidelines for Geotechnical Reports (2011) to determine which
type of slope stability analysis is required.
Can full infiltration BMPs be proposed within the DMA without increasing
slope stability risks?
☐ Yes ☐ No
2B-5
Other Geotechnical Hazards. Identify site-specific geotechnical hazards not
already mentioned (refer to Appendix C.2.1).
Can full infiltration BMPs be proposed within the DMA without increasing
risk of geologic or geotechnical hazards not already mentioned?
☐ Yes ☐ No
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
2B-6
Setbacks. Establish setbacks from underground utilities, structures, and/or
retaining walls. Reference applicable ASTM or other recognized standard in
the geotechnical report.
Can full infiltration BMPs be proposed within the DMA using established
setbacks from underground utilities, structures, and/or retaining walls?
☐ Yes ☐ No
2C
Mitigation Measures. Propose mitigation measures for each
geologic/geotechnical hazard identified in Step 2B. Provide a discussion of
geologic/geotechnical hazards that would prevent full infiltration BMPs that
cannot be reasonably mitigated in the geotechnical report. See Appendix
C.2.1.8 for a list of typically reasonable and typically unreasonable mitigation
measures.
Can mitigation measures be proposed to allow for full infiltration BMPs? If
the question in Step 2 is answered “Yes,” then answer “Yes” to Criteria 2
Result.
If the question in Step 2C is answered “No,” then answer “No” to Criteria 2
Result.
☐ Yes ☐ No
Criteria 2
Result
Can infiltration greater than 0.5 inches per hour be allowed without increasing
risk of geologic or geotechnical hazards that cannot be reasonably mitigated to
an acceptable level?
☐ Yes ☐ No
Summarize findings and basis; provide references to related reports or exhibits.
Part 1 Result – Full Infiltration Geotechnical Screening 3 Result
If answers to both Criteria 1 and Criteria 2 are “Yes”, a full
infiltration design is potentially feasible based on Geotechnical
conditions only.
If either answer to Criteria 1 or Criteria 2 is “No”, a full infiltration
design is not required.
Full infiltration Condition
Complete Part 2
3 To be completed using gathered site information and best professional judgement consider ing the definition of MEP in
the MS4 Permit. Additional testing and/or studies may be required by City Engineer to substantiate findings.
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
Part 2 – Partial vs. No Infiltration Feasibility Screening Criteria
DMA(s) Being Analyzed: Project Phase:
Criteria 3 : Infiltration Rate Screening
3A
NRCS Type C, D, or “urban/unclassified”: Is the mapped hydrologic soil group according
to the NRCS Web Soil Survey or UC Davis Soil Web Mapper is Type C, D, or
“urban/unclassified” and corroborated by available site soil data?
Yes; the site is mapped as C soils and a reliable infiltration rate of 0.15 in/hr. is used to
size partial infiltration BMPS. Answer “Yes” to Criteria 3 Result.
Yes; the site is mapped as D soils or “urban/unclassified” and a reliable infiltration rate
of 0.05 in/hr. is used to size partial infiltration BMPS. Answer “Yes” to Criteria 3
Result.
No; infiltration testing is conducted (refer to Table D.3-1), continue to Step 3B.
3B
Infiltration Testing Result: Is the reliable infiltration rate (i.e. average measured infiltration
rate/2) greater than 0.05 in/hr. and less than or equal to 0.5 in/hr?
Yes; the site may support partial infiltration. Answer “Yes” to Criteria 3 Result.
No; the reliable infiltration rate (i.e. average measured rate/2) is less than 0.05 in/hr.,
partial infiltration is not required. Answer “No” to Criteria 3 Result.
Criteria 3
Result
Is the estimated reliable infiltration rate (i.e., average measured infiltration rate/2) greater than or
equal to 0.05 inches/hour and less than or equal to 0.5 inches/hour at any location within each
DMA where runoff can reasonably be routed to a BMP?
Yes; Continue to Criteria 4.
No: Skip to Part 2 Result.
Summarize infiltration testing and/or mapping results (i.e. soil maps and series description used for
infiltration rate).
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
Criteria 4: Geologic/Geotechnical Screening
4A
If all questions in Step 4A are answered “Yes,” continue to Step 2B.
For any “No” answer in Step 4A answer “No” to Criteria 4 Result, and submit an “Infiltration
Feasibility Condition Letter” that meets the requirements in Appendix C.1.1. The
geologic/geotechnical analyses listed in Appendix C.2.1 do not apply to the DMA because one of
the following setbacks cannot be avoided and therefore result in the DMA being in a no
infiltration condition. The setbacks must be the closest horizontal radial distance from the surface
edge (at the overflow elevation) of the BMP.
4A-1 Can the proposed partial infiltration BMP(s) avoid areas with existing fill
materials greater than 5 feet thick? ☐ Yes ☐ No
4A-2 Can the proposed partial infiltration BMP(s) avoid placement within 10
feet of existing underground utilities, structures, or retaining walls? ☐ Yes ☐ No
4A-3
Can the proposed partial infiltration BMP(s) avoid placement within 50
feet of a natural slope (>25%) or within a distance of 1.5H from fill slopes
where H is the height of the fill slope?
☐ Yes ☐ No
4B
When full infiltration is determined to be feasible, a geotechnical investigation report must be
prepared that considers the relevant factors identified in Appendix C.2.1.
If all questions in Step 4B are answered “Yes,” then answer “Yes” to Criteria 4 Result. If there
are any “No” answers continue to Step 4C.
4B-1
Hydroconsolidation. Analyze hydroconsolidation potential per
approved ASTM standard due to a proposed full infiltration BMP.
Can partial infiltration BMPs be proposed within the DMA without
increasing hydroconsolidation risks?
☐ Yes ☐ No
4B-2
Expansive Soils. Identify expansive soils (soils with an expansion index
greater than 20) and the extent of such soils due to proposed full
infiltration BMPs.
Can partial infiltration BMPs be proposed within the DMA without
increasing expansive soil risks?
☐ Yes ☐ No
4B-3
Liquefaction. If applicable, identify mapped liquefaction areas. Evaluate
liquefaction hazards in accordance with Section 6.4.2 of the City of San
Diego's Guidelines for Geotechnical Reports (2011). Liquefaction hazard
assessment shall take into account any increase in groundwater elevation
or groundwater mounding that could occur as a result of proposed
infiltration or percolation facilities.
Can partial infiltration BMPs be proposed within the DMA without
increasing liquefaction risks?
☐ Yes ☐ No
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
4B-4
Slope Stability. If applicable, perform a slope stability analysis in
accordance with the ASCE and Southern California Earthquake Center
(2002) Recommended Procedures for Implementation of DMG Special
Publication 117, Guidelines for Analyzing and Mitigating Landslide
Hazards in California to determine minimum slope setbacks for full
infiltration BMPs. See the City of San Diego's Guidelines for Geotechnical
Reports (2011) to determine which type of slope stability analysis is
required.
Can partial infiltration BMPs be proposed within the DMA without
increasing slope stability risks?
☐ Yes ☐ No
4B-5
Other Geotechnical Hazards. Identify site-specific geotechnical hazards
not already mentioned (refer to Appendix C.2.1).
Can partial infiltration BMPs be proposed within the DMA without
increasing risk of geologic or geotechnical hazards not already mentioned?
☐ Yes ☐ No
4B-6
Setbacks. Establish setbacks from underground utilities, structures,
and/or retaining walls. Reference applicable ASTM or other recognized
standard in the geotechnical report.
Can partial infiltration BMPs be proposed within the DMA using
recommended setbacks from underground utilities, structures, and/or
retaining walls?
☐ Yes ☐ No
4C
Mitigation Measures. Propose mitigation measures for each
geologic/geotechnical hazard identified in Step 4B. Provide a discussion
on geologic/geotechnical hazards that would prevent partial infiltration
BMPs that cannot be reasonably mitigated in the geotechnical report. See
Appendix C.2.1.8 for a list of typically reasonable and typically
unreasonable mitigation measures.
Can mitigation measures be proposed to allow for partial infiltration
BMPs? If the question in Step 4C is answered “Yes,” then answer “Yes”
to Criteria 4 Result.
If the question in Step 4C is answered “No,” then answer “No” to Criteria
4 Result.
☐ Yes ☐ No
Criteria 4
Result
Can infiltration of greater than or equal to 0.05 inches/hour and less than
or equal to 0.5 inches/hour be allowed without increasing the risk of
geologic or geotechnical hazards that cannot be reasonably mitigated to an
acceptable level?
☐ Yes ☐ No
Project Name: _____________________________________________________
CCV BMP Design Manual
Form I-8A (Worksheet C.4-1) March 2019 Update
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Form I-8A1
(Worksheet C.4-1)
Summarize findings and basis; provide references to related reports or exhibits.
Part 2 – Partial Infiltration Geotechnical Screening Result4 Result
If answers to both Criteria 3 and Criteria 4 are “Yes”, a partial
infiltration design is potentially feasible based on geotechnical
conditions only.
If answers to either Criteria 3 or Criteria 4 is “No”, then
infiltration of any volume is considered to be infeasible within the
site.
Partial Infiltration
Condition
No Infiltration Condition
4 To be completed using gathered site information and best professional judgement considering the definition of MEP i n
the MS4 Permit. Additional testing and/or studies may be required by City Engineer to substantiate findings.
APPENDIX E
APPENDIX E
PREVIOUSLY REPORTED TRENCH AND BORING LOGS
PREPARED BY GEOCON INCORPORATED
FOR
SUNBOW II
PHASE 3
CHULA VISTA, CALIFORNIA
PROJECT NO. G2452-32-02
APPENDIX F
APPENDIX F
RECOMMENDED GRADING SPECIFICATIONS
FOR
SUNBOW II
PHASE 3
CHULA VISTA, CALIFORNIA
PROJECT NO. G2452-32-02
GI rev. 07/2015
RECOMMENDED GRADING SPECIFICATIONS
1. GENERAL
1.1 These Recommended Grading Specifications shall be used in conjunction with the
Geotechnical Report for the project prepared by Geocon. The recommendations contained
in the text of the Geotechnical Report are a part of the earthwork and grading specifications
and shall supersede the provisions contained hereinafter in the case of conflict.
1.2 Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be
employed for the purpose of observing earthwork procedures and testing the fills for
substantial conformance with the recommendations of the Geotechnical Report and these
specifications. The Consultant should provide adequate testing and observation services so
that they may assess whether, in their opinion, the work was performed in substantial
conformance with these specifications. It shall be the responsibility of the Contractor to
assist the Consultant and keep them apprised of work schedules and changes so that
personnel may be scheduled accordingly.
1.3 It shall be the sole responsibility of the Contractor to provide adequate equipment and
methods to accomplish the work in accordance with applicable grading codes or agency
ordinances, these specifications and the approved grading plans. If, in the opinion of the
Consultant, unsatisfactory conditions such as questionable soil materials, poor moisture
condition, inadequate compaction, and/or adverse weather result in a quality of work not in
conformance with these specifications, the Consultant will be empowered to reject the
work and recommend to the Owner that grading be stopped until the unacceptable
conditions are corrected.
2. DEFINITIONS
2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading
work is being performed and who has contracted with the Contractor to have grading
performed.
2.2 Contractor shall refer to the Contractor performing the site grading work.
2.3 Civil Engineer or Engineer of Work shall refer to the California licensed Civil Engineer
or consulting firm responsible for preparation of the grading plans, surveying and verifying
as-graded topography.
2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm
retained to provide geotechnical services for the project.
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2.5 Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner,
who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be
responsible for having qualified representatives on-site to observe and test the Contractor's
work for conformance with these specifications.
2.6 Engineering Geologist shall refer to a California licensed Engineering Geologist retained
by the Owner to provide geologic observations and recommendations during the site
grading.
2.7 Geotechnical Report shall refer to a soil report (including all addenda) which may include
a geologic reconnaissance or geologic investigation that was prepared specifically for the
development of the project for which these Recommended Grading Specifications are
intended to apply.
3. MATERIALS
3.1 Materials for compacted fill shall consist of any soil excavated from the cut areas or
imported to the site that, in the opinion of the Consultant, is suitable for use in construction
of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock fills, as
defined below.
3.1.1 Soil fills are defined as fills containing no rocks or hard lumps greater than
12 inches in maximum dimension and containing at least 40 percent by weight of
material smaller than ¾ inch in size.
3.1.2 Soil-rock fills are defined as fills containing no rocks or hard lumps larger than
4 feet in maximum dimension and containing a sufficient matrix of soil fill to allow
for proper compaction of soil fill around the rock fragments or hard lumps as
specified in Paragraph 6.2. Oversize rock is defined as material greater than
12 inches.
3.1.3 Rock fills are defined as fills containing no rocks or hard lumps larger than 3 feet
in maximum dimension and containing little or no fines. Fines are defined as
material smaller than ¾ inch in maximum dimension. The quantity of fines shall be
less than approximately 20 percent of the rock fill quantity.
3.2 Material of a perishable, spongy, or otherwise unsuitable nature as determined by the
Consultant shall not be used in fills.
3.3 Materials used for fill, either imported or on-site, shall not contain hazardous materials as
defined by the California Code of Regulations, Title 22, Divi sion 4, Chapter 30, Articles 9
GI rev. 07/2015
and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall
not be responsible for the identification or analysis of the potential presence of hazardous
materials. However, if observations, odors or soil discoloration cause Consultant to suspect
the presence of hazardous materials, the Consultant may request from the Owner the
termination of grading operations within the affected area. Prior to resuming grading
operations, the Owner shall provide a written report to the Consultant indicating that the
suspected materials are not hazardous as defined by applicable laws and regulations.
3.4 The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of
properly compacted soil fill materials approved by the Consultant. Rock fill may extend to
the slope face, provided that the slope is not steeper than 2:1 (horizontal:vertical) and a soil
layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This
procedure may be utilized provided it is acceptable to the governing agency, Owner and
Consultant.
3.5 Samples of soil materials to be used for fill should be tested in the laboratory by the
Consultant to determine the maximum density, optimum moisture content, and, where
appropriate, shear strength, expansion, and gradation characteristics of the soil.
3.6 During grading, soil or groundwater conditions other than those identified in the
Geotechnical Report may be encountered by the Contractor. The Consultant shall be
notified immediately to evaluate the significance of the unanticipated condition.
4. CLEARING AND PREPARING AREAS TO BE FILLED
4.1 Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of
complete removal above the ground surface of trees, stumps, brush, vegetation, man-made
structures, and similar debris. Grubbing shall consist of removal of stumps, roots, buried
logs and other unsuitable material and shall be performed in areas to be graded. Roots and
other projections exceeding 1½ inches in diameter shall be removed to a depth of 3 feet
below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to
provide suitable fill materials.
4.2 Asphalt pavement material removed during clearing operations should be properly
disposed at an approved off-site facility or in an acceptable area of the project evaluated by
Geocon and the property owner. Concrete fragments that are free of reinforcing steel may
be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3 of this
document.
GI rev. 07/2015
4.3 After clearing and grubbing of organic matter and other unsuitable material, loose or
porous soils shall be removed to the depth recommended in the Geotechnical Report. The
depth of removal and compaction should be observed and approved by a representative of
the Consultant. The exposed surface shall then be plowed or scarified to a minimum depth
of 6 inches and until the surface is free from uneven features that would tend to prevent
uniform compaction by the equipment to be used.
4.4 Where the slope ratio of the original ground is steeper than 5:1 (horizontal:vertical), o r
where recommended by the Consultant, the original ground should be benched in
accordance with the following illustration.
TYPICAL BENCHING DETAIL
Remove All
Unsuitable Material
As Recommended By
Consultant
Finish Grade Original Ground
Finish Slope Surface
Slope To Be Such That
Sloughing Or Sliding
Does Not Occur Varies
“B”
See Note 1
No Scale
See Note 2
1
2
DETAIL NOTES: (1) Key width "B" should be a minimum of 10 feet, or sufficiently w ide to permit complete coverage with the compaction equipment used. The base of the key should be graded horizontal, or inclined slightly into the natural slope.
(2) The outside of the key should be below the topsoil or unsuitable surficial material and at least 2 feet into dense formational material. Where hard rock is exposed in the bottom of the key, the depth and configuration of the key may be modified as approved by the Consultant.
4.5 After areas to receive fill have been cleared and scarified, the surface should be moisture
conditioned to achieve the proper moisture content, and compacted as recommended in
Section 6 of these specifications.
GI rev. 07/2015
5. COMPACTION EQUIPMENT
5.1 Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented-steel
wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of
acceptable compaction equipment. Equipment shall be of such a design that it will be
capable of compacting the soil or soil-rock fill to the specified relative compaction at the
specified moisture content.
5.2 Compaction of rock fills shall be performed in accordance with Section 6.3.
6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL
6.1 Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with
the following recommendations:
6.1.1 Soil fill shall be placed by the Contractor in layers that, when compacted, sh ould
generally not exceed 8 inches. Each layer shall be spread evenly and shall be
thoroughly mixed during spreading to obtain uniformity of material and moisture
in each layer. The entire fill shall be constructed as a unit in nearly level lifts. Rock
materials greater than 12 inches in maximum dimension shall be placed in
accordance with Section 6.2 or 6.3 of these specifications.
6.1.2 In general, the soil fill shall be compacted at a moisture content at or above the
optimum moisture content as determined by ASTM D 1557.
6.1.3 When the moisture content of soil fill is below that specified by the Consultant,
water shall be added by the Contractor until the moisture content is in the range
specified.
6.1.4 When the moisture content of the soil fill is above the range specified by the
Consultant or too wet to achieve proper compaction, the soil fill shall be aerated by
the Contractor by blading/mixing, or other satisfactory methods until the moisture
content is within the range specified.
6.1.5 After each layer has been placed, mixed, and spread evenly, it shall be thoroughly
compacted by the Contractor to a relative compaction of at least 90 percent.
Relative compaction is defined as the ratio (expressed in percent) of the in -place
dry density of the compacted fill to the maximum laboratory dry density as
determined in accordance with ASTM D 1557. Compaction shall be continuous
over the entire area, and compaction equipment shall make sufficient passes so that
the specified minimum relative compaction has been achieved throughout the
entire fill.
GI rev. 07/2015
6.1.6 Where practical, soils having an Expansion Index greater than 50 should be placed
at least 3 feet below finish pad grade and should be compacted at a moisture
content generally 2 to 4 percent greater than the optimum moisture content for the
material.
6.1.7 Properly compacted soil fill shall extend to the design surface of fill slopes. To
achieve proper compaction, it is recommended that fill slopes be over-built by at
least 3 feet and then cut to the design grade. This procedure is considered
preferable to track-walking of slopes, as described in the following paragraph.
6.1.8 As an alternative to over-building of slopes, slope faces may be back-rolled with a
heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height
intervals. Upon completion, slopes should then be track-walked with a D-8 dozer
or similar equipment, such that a dozer track covers all slope surfaces at least
twice.
6.2 Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance
with the following recommendations:
6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be
incorporated into the compacted soil fill, but shall be limited to the area measured
15 feet minimum horizontally from the slope face and 5 feet below finish grade or
3 feet below the deepest utility, whichever is deeper.
6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be
individually placed or placed in windrows. Under certain conditions, rocks or rock
fragments up to 10 feet in maximum dimension may be placed using similar
methods. The acceptability of placing rock materials greater than 4 feet in
maximum dimension shall be evaluated during grading as specific cases arise and
shall be approved by the Consultant prior to placement.
6.2.3 For individual placement, sufficient space shall be provided between rocks to allow
for passage of compaction equipment.
6.2.4 For windrow placement, the rocks should be placed in trenches excavated in
properly compacted soil fill. Trenches should be approximately 5 feet wide and
4 feet deep in maximum dimension. The voids around and beneath rocks should be
filled with approved granular soil having a Sand Equivalent of 30 or greater and
should be compacted by flooding. Windrows may also be placed utilizing an
"open-face" method in lieu of the trench procedure, however, this method should
first be approved by the Consultant.
GI rev. 07/2015
6.2.5 Windrows should generally be parallel to each other and may be placed either
parallel to or perpendicular to the face of the slope depending on the site geometry.
The minimum horizontal spacing for windrows shall be 12 feet center-to-center
with a 5-foot stagger or offset from lower courses to next overlying course. The
minimum vertical spacing between windrow courses shall be 2 feet from the top of
a lower windrow to the bottom of the next higher windrow.
6.2.6 Rock placement, fill placement and flooding of approved granular soil in the
windrows should be continuously observed by the Consultant.
6.3 Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with
the following recommendations:
6.3.1 The base of the rock fill shall be placed on a sloping surface (minimum slope of 2
percent). The surface shall slope toward suitable subdrainage outlet facilities. The
rock fills shall be provided with subdrains during construction so that a hydrostatic
pressure buildup does not develop. The subdrains shall be permanently connected
to controlled drainage facilities to control post-construction infiltration of water.
6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock
trucks traversing previously placed lifts and dumping at the edge of the currently
placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the
rock. The rock fill shall be watered heavily during placement. Watering shall
consist of water trucks traversing in front of the current rock lift face and spraying
water continuously during rock placement. Compaction equipment with
compactive energy comparable to or greater than that of a 20-ton steel vibratory
roller or other compaction equipment providing suitable energy to achieve the
required compaction or deflection as recommended in Paragraph 6.3.3 shall be
utilized. The number of passes to be made should be determined as described in
Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional
rock fill lifts will be permitted over the soil fill.
6.3.3 Plate bearing tests, in accordance with ASTM D 1196, may be performed in both
the compacted soil fill and in the rock fill to aid in determining the required
minimum number of passes of the compaction equipment. If performed, a
minimum of three plate bearing tests should be performed in the properly
compacted soil fill (minimum relative compaction of 90 percent). Plate bearing
tests shall then be performed on areas of rock fill having two passes, four passes
and six passes of the compaction equipment, respectively. The number of passes
required for the rock fill shall be determined by comparing the results of the plate
bearing tests for the soil fill and the rock fill and by evaluating the deflection
GI rev. 07/2015
variation with number of passes. The required number of passes of the compaction
equipment will be performed as necessary until the plate bearing deflections are
equal to or less than that determined for the properly compacted soil fill. In no case
will the required number of passes be less than two.
6.3.4 A representative of the Consultant should be present during rock fill operations to
observe that the minimum number of “passes” have been obtained, that water is
being properly applied and that specified procedures are being followed. The actual
number of plate bearing tests will be determined by the Consultant during grading.
6.3.5 Test pits shall be excavated by the Contractor so that the Consultant can state that,
in their opinion, sufficient water is present and that voids between large rocks are
properly filled with smaller rock material. In-place density testing will not be
required in the rock fills.
6.3.6 To reduce the potential for “piping” of fines into the rock fill from overlying soil
fill material, a 2-foot layer of graded filter material shall be placed above the
uppermost lift of rock fill. The need to place graded filter material below the rock
should be determined by the Consultant prior to commencing grading. The
gradation of the graded filter material will be determined at the time the rock fill is
being excavated. Materials typical of the rock fill should be submitted to the
Consultant in a timely manner, to allow design of the graded filter prior to the
commencement of rock fill placement.
6.3.7 Rock fill placement should be continuously observed during placement by the
Consultant.
7. SUBDRAINS
7.1 The geologic units on the site may have permeability characteristics and/or fracture
systems that could be susceptible under certain conditions to seepage. The use of canyon
subdrains may be necessary to mitigate the potential for adverse impacts associated with
seepage conditions. Canyon subdrains with lengths in excess of 500 feet or extensions of
existing offsite subdrains should use 8-inch-diameter pipes. Canyon subdrains less than 500
feet in length should use 6-inch-diameter pipes.
GI rev. 07/2015
TYPICAL CANYON DRAIN DETAIL
7.2 Slope drains within stability fill keyways should use 4-inch-diameter (or lager) pipes.
GI rev. 07/2015
TYPICAL STABILITY FILL DETAIL
7.3 The actual subdrain locations will be evaluated in the field during the remedial grading
operations. Additional drains may be necessary depending on the conditions observed and
the requirements of the local regulatory agencies. Appropriate subdrain outlets should be
evaluated prior to finalizing 40-scale grading plans.
7.4 Rock fill or soil-rock fill areas may require subdrains along their down-slope perimeters to
mitigate the potential for buildup of water from construction or landscape irrigation. The
subdrains should be at least 6-inch-diameter pipes encapsulated in gravel and filter fabric.
Rock fill drains should be constructed using the same requirements as canyon subdrains.
GI rev. 07/2015
7.5 Prior to outletting, the final 20-foot segment of a subdrain that will not be extended during
future development should consist of non-perforated drainpipe. At the non-perforated/
perforated interface, a seepage cutoff wall should be constructed on the downslope side of
the pipe.
TYPICAL CUT OFF WALL DETAIL
7.6 Subdrains that discharge into a natural drainage course or open space area should be
provided with a permanent headwall structure.
GI rev. 07/2015
TYPICAL HEADWALL DETAIL
7.7 The final grading plans should show the location of the proposed subdrains. After
completion of remedial excavations and subdrain installation, the project civil engineer
should survey the drain locations and prepare an “as-built” map showing the drain
locations. The final outlet and connection locations should be determined during grading
operations. Subdrains that will be extended on adjacent projects after grading can be placed
on formational material and a vertical riser should be placed at the end of the subdrain . The
grading contractor should consider videoing the subdrains shortly after burial to check
proper installation and functionality. The contractor is responsible for the performance of
the drains.
GI rev. 07/2015
8. OBSERVATION AND TESTING
8.1 The Consultant shall be the Owner’s representative to observe and perform tests during
clearing, grubbing, filling, and compaction operations. In general, no more than 2 feet in
vertical elevation of soil or soil-rock fill should be placed without at least one field density
test being performed within that interval. In addition, a minimum of one field density test
should be performed for every 2,000 cubic yards of soil or soil-rock fill placed and
compacted.
8.2 The Consultant should perform a sufficient distribution of field density tests of the
compacted soil or soil-rock fill to provide a basis for expressing an opinion whether the fill
material is compacted as specified. Density tests shall be performed in the compacted
materials below any disturbed surface. When these tests indicate that the density of any
layer of fill or portion thereof is below that specified, the particular layer or areas
represented by the test shall be reworked until the specified density has been achieved.
8.3 During placement of rock fill, the Consultant should observe that the minimum number of
passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant
should request the excavation of observation pits and may perform plate bearing tests on
the placed rock fills. The observation pits will be excavated to provide a basis for
expressing an opinion as to whether the rock fill is properly seated and sufficient moisture
has been applied to the material. When observations indicate that a layer of rock fill or any
portion thereof is below that specified, the affected layer or area shall be reworked until the
rock fill has been adequately seated and sufficient moisture applied.
8.4 A settlement monitoring program designed by the Consultant may be conducted in areas of
rock fill placement. The specific design of the monitoring program shall be as
recommended in the Conclusions and Recommendations section of the project
Geotechnical Report or in the final report of testing and observation services performed
during grading.
8.5 We should observe the placement of subdrains, to check that the drainage devices have
been placed and constructed in substantial conformance with project specifications.
8.6 Testing procedures shall conform to the following Standards as appropriate:
8.6.1 Soil and Soil-Rock Fills:
8.6.1.1 Field Density Test, ASTM D 1556, Density of Soil In-Place By the
Sand-Cone Method.
GI rev. 07/2015
8.6.1.2 Field Density Test, Nuclear Method, ASTM D 6938, Density of Soil and
Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth).
8.6.1.3 Laboratory Compaction Test, ASTM D 1557, Moisture-Density
Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound
Hammer and 18-Inch Drop.
8.6.1.4. Expansion Index Test, ASTM D 4829, Expansion Index Test.
9. PROTECTION OF WORK
9.1 During construction, the Contractor shall properly grade all excavated surfaces to provide
positive drainage and prevent ponding of water. Drainage of surface water shall be
controlled to avoid damage to adjoining properties or to finished work on the site. The
Contractor shall take remedial measures to prevent erosion of freshly graded areas until
such time as permanent drainage and erosion control features have been installed. Areas
subjected to erosion or sedimentation shall be properly prepared in accordance with the
Specifications prior to placing additional fill or structures.
9.2 After completion of grading as observed and tested by the Consultant, no further
excavation or filling shall be conducted except in conjunction with the services of the
Consultant.
10. CERTIFICATIONS AND FINAL REPORTS
10.1 Upon completion of the work, Contractor shall furnish Owner a certification by the Civil
Engineer stating that the lots and/or building pads are graded to within 0.1 foot vertically of
elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot
horizontally of the positions shown on the grading plans. After installation of a section of
subdrain, the project Civil Engineer should survey its location and prepare an as-built plan
of the subdrain location. The project Civil Engineer should verify the proper outlet for the
subdrains and the Contractor should ensure that the drain system is free of obstructions.
10.2 The Owner is responsible for furnishing a final as-graded soil and geologic report
satisfactory to the appropriate governing or accepting agencies. The as-graded report
should be prepared and signed by a California licensed Civil Engineer experienced in
geotechnical engineering and by a California Certified Engineering Geologist, indicating
that the geotechnical aspects of the grading were performed in substantial conformance
with the Specifications or approved changes to the Specifications.
Project No. G2452-32-02 April 10, 2020
LIST OF REFERENCES
1. Anderson, J. G., Synthesis of Seismicity and Geologic Data in California, U. S. Geologic
Survey Open-File Report 84-424, 1984, pp. 1-186.
2. Boore, D. M., and G. M Atkinson (2008), Ground-Motion Prediction for the Average
Horizontal Component of PGA, PGV, and 5%-Damped PSA at Spectral Periods Between 0.01
and 10.0 S, Earthquake Spectra, Volume 24, Issue 1, pages 99-138, February 2008.
3. California Department of Conservation, Division of Mines and Geology, Probabilistic Seismic
Hazard Assessment for the State of California, Open File Report 96-08, 1996.
4. California Department of Water Resources, Water Data Library.
http://www.water.ca.gov/waterdatalibrary.
5. California Geological Survey, Seismic Shaking Hazards in California, Based on the
USGS/CGS Probabilistic Seismic Hazards Assessment (PSHA) Model, 2002 (revised April
2003). 10% probability of being exceeded in 50 years.
http://redirect.conservation.ca.gov/cgs/rghm/pshamap/pshamain.html
6. Campbell, K. W. and Y. Bozorgnia, NGA Ground Motion Model for the Geometric Mean
Horizontal Component of PGA, PGV, PGD and 5% Damped Linear Elastic Response Spectra
for Periods Ranging from 0.01 to 10 s, Preprint of version submitted for publication in the
NGA Special Volume of Earthquake Spectra, Volume 24, Issue 1, pages 139-171, February
2008.
7. Chiou, Brian S. J. and Robert R. Youngs, A NGA Model for the Average Horizontal
Component of Peak Ground Motion and Response Spectra, preprint for article to be published
in NGA Special Edition for Earthquake Spectra, Spring 2008.
8. Geocon Incorporated, Final Consolidated Environmental Assessment Including Remedial Cost
Estimates for Rancho Del Sur Phase II, Chula Vista, California, dated October 13, 1994
(Project No. 08080-06-07).
9. Geocon Incorporated, Final Report of Testing and Observation Services During Installation of
Vertical Wick Drains, Site Grading, and Crib Wall Construction, Olympic Parkway 43 to 131,
Chula Vista, California, dated November 29, 2000 (Project No. 06217-52-02).
10. Geocon Incorporated, Final Report of Testing and Observation Services During Site Grading,
Sunbow II, Poggi Canyon Wetland Vegetation Plan, Olympic Parkway Stations 57+30
through 89+80, Chula Vista, California, dated October 6, 1998 (Project No. 06020-52-01).
11. Geocon Incorporated, Geologic Reconnaissance, Sunbow Planning Area 23, Chula Vista,
California, dated November 14, 2019 (Project No. G2452-32-01).
12. Geocon Incorporated, Geotechnical Investigation, Otay Ranch Village 2 West, Chula Vista,
California, dated October 20, 2006 (Project No. 06862-52-09).
13. Geocon Incorporated, Rancho Del Sur, 600 Acre Parcel, San Diego County, California, dated
September 22, 1986 (Project No. D-3763-M01).
LIST OF REFERENCES (Concluded)
Project No. G2452-32-02 April 10, 2020
14. Geocon Incorporated, Rancho Del Sur Phase II, Land Adjacent to the Otay Landfill, San
Diego County, California, dated December 13, 1989 (Project No. D-8080-602).
15. Hart, Michael, Radiocarbon Ages of Alluvium Overlying La Nacion Fault, San Diego, in
Geological Society of America Bulletin, v. 85, p. 1329-1332, dated August 1974.
16. Jennings, C. W., 1994, California Division of Mines and Geology, Fault Activity Map of
California and Adjacent Areas, California Geologic Data Map Series Map No. 6.
17. Kahle, James, A Geomorphic Analysis of the Rose Canyon, La Nacion and Related Faults in
the San Diego Area, California, dated June 30, 1988.
18. Kennedy, M. P. et al., Character and Recency of Faulting, San Diego Metropolitan Area,
California, California Division of Mines and Geology Special Report 123, 1975.
19. Kennedy, M. P., and S. S. Tan, Geologic Map of the San Diego 30’x60’ Quadrangle,
California, USGS Regional Map Series Map No. 3, Scale 1:100,000, 2008.
20. Risk Engineering, EZ-FRISK, 2017.
21. Unpublished reports and maps on file with Geocon Incorporated.
22. USGS computer program, Seismic Hazard Curves and Uniform Hazard Response Spectra.
23. United States Department of Agriculture, 1953 Stereoscopic Aerial Photographs, Flight AXN-
10M, Photos Nos. 1 and 2 (scale 1:20,000).
24. Vanderhurst, W. L., M. W. Hart, and C. Warren, The Otay Mesa Lateral Spread, a Late
Tertiary Mega-Landslide in Metropolitan San Diego County, CA, in Environmental &
Engineering Geoscience, Vol. XVII, No. 3, pp. 241-253, August 2011.
Project No. G2452-32-02
March 10, 2021
Lennar Homes
16465 Via Esprillo, Suite 150
San Diego, California 92127
Attention: Mr. David Shepherd
Subject: RESPONSE TO CITY OF CHULA VISTA GEOTECHNICAL REVIEW COMMENTS
SUNBOW II, PHASE 3
CHULA VISTA, CALIFORNIA
Reference: Geotechnical Investigation, Sunbow II, Phase 3, Chula Vista, California, prepared by
Geocon Incorporated, dated April 10, 2020 (Project No. G2452-32-02).
Dear Mr. Shepherd:
This correspondence has been prepared to respond to geotechnical review comments contained in the
City of Chula Vista 4th Submittal Issues Matrix (MPA20-0006) dated March 4, 2021. Specifically, we
are addressing Geotechnical Comments 1 and 2. The comments along with our responses are
presented below.
Comment 1:Provide recommendations for off-site grading to the east. Specifically, if proposed
shear key onsite is to be extended offsite.
Response:At the time of our report, the off-site area to the east had not been designed.
Geologic Cross-Section K-K’ was prepared to depict this area. As stated in
Section 9.1.5, we recognize the shear key will need to wrap around the knoll
beneath the offsite embankment. Final geotechnical design of this feature should
be done as plans progress to 40-scale. We do not anticipate any issues with
constructing this mitigation feature.
Comment 2:Provide recommendations for fill settlement to eliminate potential 3” settlement
as stated in Section 9.2.1. Add notes to grading plans for contractor to eliminate
this settlement. We cannot have 3” of settlement for public infrastructure.
Response:Based on a review of the grading plans, the thickest fill embankments that will
support public improvements occur along Street A, Stations 33+50 through 34+80
and 39+00 through 39+50. The fill in these areas has a maximum thickness of
approximately 47 feet.
Assuming 0.3 percent hydro-compression over time, the total estimated settlement
beneath improvements along the referenced areas is approximately 1.7 inches.
The magnitude of settlement would gradually diminish laterally and is expected to
occur over a relatively extended period. It should be noted that this empirical
estimate assumes that the entire fill column will become saturated over time.
Based on the discussion above, it is our opinion the recommendations presented in
our geotechnical report remain applicable and no additional measures are
necessary to address potential settlement beneath proposed public improvements.
Project No. G2452-32-02 - 2 - March 10, 2021
If there are any questions regarding this correspondence, or if we may be of further service, please
contact the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Trevor E. Myers
RCE 63773
David B. Evans
CEG 1860
TEM:DBE:arm
(e-mail) Addressee