HomeMy WebLinkAboutAttachment 3a-05 - Geotechnical Investigation redactedGEOTECHNICAL INVESTIGATION
SHINOHARA INDUSTRIAL BUILDING
517 SHINOHARA LANE
INDUSTRIAL BUILDING
CHULA VISTA, CALIFORNIA
PREPARED FOR
VWP-OP SHINOHARA OWNER, LLC
PHOENIX, ARIZONA
JULY 28, 2021
PROJECT NO. G2762-42-01
APPENDIX G
GROCON
INCORPORATED
GEOTECHNICAL • ENVIRONMENTAL MATERIALSO
6960 Flanders Drive • San Diego, California 92121-2974 • Telephone 858.558.6900 • Fax 858.558.6159
Project No. G2762-42-01
July 28, 2021
VWP-OP Shinohara Owner, LLC
2390 East Camelback Road, Suite 305
Phoenix, Arizona 85016
Attention: Mr. Steven Schwarz
Subject: GEOTECHNICAL INVESTIGATION
SHINOHARA INDUSTRIAL BUILDING
517 SHINOHARA LANE
CHULA VISTA, CALIFORNIA
Dear Mr. Schwarz:
In accordance with your request, we have prepared this geotechnical investigation report for the
proposed industrial building at the subject site. The site is underlain by Tertiary age San Diego
Formation mantled by Very Old Paralic Deposits, alluvium, and topsoil. Undocumented fill berms are
present on the property.
This report is based on our observations made during our field investigation performed between June
30 and July 7, 2021, and laboratory testing. Based on the results of this study, we opine that the
subject site is suitable for construction of the proposed industrial building. The accompanying report
includes the results of our study and conclusions and recommendations regarding geotechnical aspects
of site development.
Should you have questions regarding this investigation, or if we may be of further service, please
contact the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Rodney C. Mikesell
GE 2533
Rupert S. Adams
CEG 2561
RCM:RSA:arm
e-mail) Addressee
TABLE OF CONTENTS
1. PURPOSE AND SCOPE ...................................................................................................................... 1
2. SITE AND PROJECT DESCRIPTION ................................................................................................ 2
3. SOIL AND GEOLOGIC CONDITIONS ............................................................................................. 2
3.1 Undocumented Fill (Qudf) ......................................................................................................... 3
3.2 Previously Placed Fill (Qpf) ....................................................................................................... 3
3.3 Topsoil (Unmapped) ................................................................................................................... 3
3.4 Alluvium (Qal) ........................................................................................................................... 3
3.5 Terrace Deposits (Qt) ................................................................................................................. 3
3.6 Very Old Paralic Deposits (Qvop) .............................................................................................. 4
3.7 San Diego Formation (Tsd) ........................................................................................................ 4
4. GROUNDWATER ............................................................................................................................... 4
5. GEOLOGIC HAZARDS ...................................................................................................................... 4
5.1 Faulting and Seismicity .............................................................................................................. 4
5.2 Ground Rupture .......................................................................................................................... 6
5.3 Storm Surge, Tsunamis, and Seiches .......................................................................................... 6
5.4 Flooding ...................................................................................................................................... 7
5.5 Liquefaction ................................................................................................................................ 7
5.6 Landslides ................................................................................................................................... 7
6. CONCLUSIONS AND RECOMMENDATIONS ................................................................................ 8
6.1 General ........................................................................................................................................ 8
6.2 Soil and Excavation Characteristics ........................................................................................... 9
6.3 Grading Recommendations ...................................................................................................... 11
6.4 Slopes ........................................................................................................................................ 13
6.5 Earthwork Grading Factors ....................................................................................................... 15
6.6 Subdrains .................................................................................................................................. 15
6.7 Settlement Monitoring .............................................................................................................. 15
6.8 Seismic Design Criteria ............................................................................................................ 17
6.9 Shallow Foundations ................................................................................................................ 19
6.10 Conventional Retaining Wall Recommendations ..................................................................... 21
6.11 Lateral Loading ......................................................................................................................... 24
6.12 Mechanically Stabilized Earth (MSE) Retaining Walls ........................................................... 25
6.13 Soil Nail Walls .......................................................................................................................... 27
6.14 Preliminary Pavement Recommendations ................................................................................ 29
6.15 Exterior Concrete Flatwork ...................................................................................................... 32
6.16 Slope Maintenance.................................................................................................................... 33
6.17 Storm Water Management ........................................................................................................ 34
6.18 Site Drainage and Moisture Protection ..................................................................................... 34
6.19 Grading and Foundation Plan Review ...................................................................................... 35
MAPS AND ILLUSTRATIONS
Figure 1, Geologic Map
Figure 2, Geologic Cross Section A-A’
TABLE OF CONTENTS (Concluded)
APPENDIX A
FIELD INVESTIGATION
Figure A-1, Log of Small Diameter Boring
Figures A-2 and A-3, Logs of Large Diameter Boring
Figures A-4 to A-23, Logs of Exploratory Test Pits
APPENDIX B
LABORATORY TESTING
Summary of Laboratory Maximum Dry Density and Optimum Moisture Content Test Results
Summary of Laboratory Expansion Index Test Results
Summary of Laboratory Water-Soluble Sulfate Test Results
Summary of Laboratory Chloride Ion Content Test Results
Summary of Laboratory pH and Resistivity Test Results
Summary of Laboratory Atterberg Test Results
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
LIST OF REFERENCES
Geocon Project No. G2762-42-01 - 1 - July 28, 2021
GEOTECHNICAL INVESTIGATION
1. PURPOSE AND SCOPE
This report contains the results of our geotechnical investigation for a proposed industrial building
located at the terminus of Shinohara Lane, in Chula Vista, California (see Vicinity Map).
Vicinity Map
The purpose of our investigation was to evaluate subsurface soil and geologic conditions at the site,
and provide conclusions and recommendations pertaining to geotechnical aspects of developing the
property as proposed.
The scope of our investigation included a site reconnaissance, excavating and logging 20 backhoe test
pits, 2 large diameter borings, 1 small diameter boring, and reviewing published and unpublished
geologic literature and reports (see List of References). Appendix A presents a discussion of our field
investigation. We performed laboratory tests on soil samples obtained from the exploratory test pits to
evaluate pertinent physical properties for engineering analyses. The results of laboratory testing are
presented in Appendix B.
Site geologic conditions are depicted on Figure 1 (Geologic Map). A CAD file of the preliminary
grading plan prepared by Pasco Laret Suiter & Associates was utilized as a base map to plot geologic
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contacts and exploratory excavation locations. It is our understanding the site plan has not yet been
finalized and building configuration and location might be adjusted from what is shown on our
geologic map. An updated geologic map can be provided once final site configuration is known.
The conclusions and recommendations presented herein are based on our analysis of the data obtained
during the investigation, and our experience with similar soil and geologic conditions on this and
adjacent properties.
2. SITE AND PROJECT DESCRIPTION
The property consists of a rectangular parcel located west of the terminus of Shinohara Lane, north of
Main Street and west of Brandywine Avenue, in Chula Vista, California (see Vicinity Map). The
approximately 10-acre parcel is currently undeveloped except for minor surface drainage
improvements. The property is fenced with gated access via Shinohara Lane at the southeast corner.
Based on review of historical aerial photographs, the site was partially graded circa 1992 when it was
used as a borrow site. Except for the graded area in the north-central area of the property, the site
slopes moderately to steeply from north to south. Site elevations range from approximately 250 feet
mean sea level (MSL) at the north end to 145 feet MSL at the south end. The site is boarded by
residential developments to the north and west, and commercial/industrial buildings to the south and
east.
The current proposed improvements consist of a single-story approximately 190,000 square-foot
industrial warehouse building with associated improvements including utilities, paving, storm water
management devices, and landscape improvements. Proposed cuts and fills are estimated to be up to
50 feet, with new slopes being up to approximately 10 feet in height. Retaining walls will be requied
along the perimeter of the site to reach pad grades. We understand the walls will likely be soil nail
walls and mechanically stabilized earth (MSE) walls. Paved parking lots and driveways are planned
along the perimeter of the site.
The locations and descriptions of the site and proposed development are based on our site
reconnaissance and recent field investigations, and our understanding of site development as shown on
the preliminary grading study plans prepared Pasco Laret Suiter & Associates. If project details vary
significantly from those described, Geocon Incorporated should be contacted to review the changes
and provide additional analyses and/or revisions to this report, if warranted.
3. SOIL AND GEOLOGIC CONDITIONS
Based on the results of the field investigation, the site is underlain by Tertiary San Diego Formation
capped with Very Old Paralic Deposits, terrace deposits, alluvium, topsoil, previously placed fill and
undocumented fill, which are described below in order of increasing age. Mapped geologic conditions
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are depicted on the Geologic Map (Figure 1), and on the Geologic Cross Section (Figure 2).
Exploratory test pit and boring logs are presented in Appendix A.
3.1 Undocumented Fill (Qudf)
The southeast and central portions of the site have soil berms that appear to have been constructed
during previous grading to control surface water runoff. The undocumented soil generally consists of
loose to medium dense, dry to damp, clayey sand with cobble. Several small trash piles are also
present at the site. The undocumented fill and trash are unsuitable for support of structural fill or other
improvements in their present condition. Undocumented fill should be removed and replaced as
compacted fill. Trash should be hauled offsite prior to grading. Soil berms can be incorporated into fill
areas during grading, provided they are free of trash and/or hazardous substances.
3.2 Previously Placed Fill (Qpf)
Previously placed compacted fill (by others) associated with a sewer easement adjacent to the
northwest corner of the site extends on to the site. We did not evaluate the condition of this fill during
our subsurface exploration. However, it is located behind the proposed soil nail wall and will likely
not be encountered during grading operations. It might be encountered when drilling soil nails.
3.3 Topsoil (Unmapped)
Topsoil mantles the site, typically consisting of loose/soft to stiff, dry to damp, silty and clayey sand
and sandy silt and clay with gravel. Topsoil ranges from one to three feet thick across the site.
Remedial grading in the form of removal and recompaction will be required in areas receiving
improvements. Portions of the topsoils are highly expansive.
3.4 Alluvium (Qal)
Alluvium is present in the shallow drainages along the east and west sides of the site, and across most
of the southern portion of the site. The alluvium ranges in thickness from 2 feet to greater than 20 feet.
The alluvium generally consist of medium dense to dense, silty to clayey sand with minor amounts of
gravel and cobble. The upper five feet of the alluvium is unsuitable for the support of foundations or
structural fills and will require removal during remedial grading operations. Deeper removals may be
required if pockets of loose/soft alluvium extend below the recommended remedial depth.
3.5 Terrace Deposits (Qt)
Pleistocene-age Terrace Deposits are present in limited area the site, consisting of loose to medium
dense, damp, sand with gravel and cobble up to 10-inches in diameter. The Terrace Deposits are
considered suitable for support or structural loads but may require some remedial grading in the upper
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five feet. Remedial grading depths in Terrace Deposits should be verified by a Geocon representative
during grading operations.
3.6 Very Old Paralic Deposits (Qvop)
Quaternary-age Very Old Paralic Deposits caps the San Diego Formation in the northwest portion of
the site. The Very Old Paralic Deposits were up to approximately 8 feet thick in the areas explored and
consisted of dense to very dense, medium to coarse grained sandstone with cobble. We expect grading
will remove the majority of the Very Old Paralic Deposits within the building pad area. Vertical wall
cuts may expose Very Old Paralic Deposits in the northwest corner of the site.
3.7 San Diego Formation (Tsd)
Tertiary-age San Diego Formation underlies the Very Old Paralic Deposits and surficial deposits, is
exposed at grade in the central and northern portions of the site, and was identified in most of test pits
in the southern portion of the site. The San Diego Formation generally consists of weakly to
moderately cemented, massive to laminated/cross-bedded, micaceous, damp to moist, fine- to
medium-grained sandstone and silty sandstone, with occasional gravel and cobble beds. The San
Diego Formation possesses a “very low” to “low” expansion potential (expansion index of 50 or less).
The San Diego Formation is considered suitable for support of structural loads.
Bedding attitudes measured in Test Pit No. 11 and in both large diameter borings (Appendix A) range
from approximately N10E to N30W, with dips between 9 and 20 degrees to the west. Measured
bedding attitudes were similar to those reported on regional geologic maps of the area.
4. GROUNDWATER
We did not encounter groundwater or seepage during our site investigation. However, it is not
uncommon for shallow seepage conditions to develop where none previously existed when sites are
irrigated or infiltration is implemented. Seepage is dependent on seasonal precipitation, irrigation, land
use, among other factors, and varies as a result. Proper surface drainage will be important to future
performance of the project.
5. GEOLOGIC HAZARDS
5.1 Faulting and Seismicity
A review of the referenced geologic materials and our knowledge of the general area indicates that the
site is not underlain by active, potentially active, or inactive faults. However, a strand of the
potentially active La Nacion Fault is mapped approximately 400 feet east of the site. An active fault is
defined by the California Geological Survey (CGS) as a fault showing evidence for activity within the
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last 11,700 years. The closest active fault is Newport Inglewood-Rose Canyon Fault zone, located
approximately eight miles west of the site. The site is not located within a State of California
Earthquake Fault Zone.
The United States Geological Survey (USGS) has developed a program to evaluate the approximate
location of faulting in the area of properties. The following figure shows the location of the existing
faulting in the San Diego County and Southern California region. The faults are shown as solid,
dashed and dotted traces representing well constrained, moderately constrained and inferred faults,
respectively. The fault line colors represent faults with ages less than 150 years (red), 15,000 years
orange), 130,000 years (green), 750,000 years (blue) and 1.6 million years (black).
Faults in the San Diego Area
The San Diego County and Southern California region is seismically active. The following figure
presents the occurrence of earthquakes with a magnitude greater than 2.5 from the period of 1900
through 2015 according to the Bay Area Earthquake Alliance website.
Geocon Project No. G2762-42-01 - 6 - July 28, 2021
Earthquakes in Southern California
Considerations important in seismic design include the frequency and duration of motion and the soil
conditions underlying the site. Seismic design of structures should be evaluated in accordance with the
California Building Code (CBC) guidelines currently adopted by the local agency.
5.2 Ground Rupture
The risk associated with ground rupture hazard is very low due to the absence of active faults at the
subject site.
5.3 Storm Surge, Tsunamis, and Seiches
Storm surges are large ocean waves that sweep across coastal areas when storms make landfall. Storm
surges can cause inundation, severe erosion and backwater flooding along the waterfront. The site is
located over six miles from the Pacific Ocean and is at an elevation of about 145 feet or greater above
Mean Sea Level (MSL). Therefore, the potential of storm surges affecting the site is considered low.
A tsunami is a series of long period waves generated in the ocean by a sudden displacement of large
volumes of water. Causes of tsunamis include underwater earthquakes, volcanic eruptions, or offshore
slope failures. The potential for the site to be affected by a tsunami is negligible due to the distance
from the Pacific Ocean and the site elevation.
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A seiche is a run-up of water within a lake or embayment triggered by fault- or landslide-induced
ground displacement. The site is not located in the vicinity of or downstream from such bodies of
water. Therefore, the risk of seiches affecting the site is negligible.
5.4 Flooding
According to maps produced by the Federal Emergency Management Agency (FEMA), the site is
zoned as “Zone X – Minimal Flood Hazard.” Based on our review of FEMA flood maps, the risk of
site flooding is considered low.
5.5 Liquefaction
Liquefaction typically occurs when a site is located in a zone with seismic activity, onsite soils are
cohesionless or silt/clay with low plasticity, groundwater is encountered within 50 feet of the surface
and soil densities are less than about 70 percent of the maximum dry densities. If the four previous
criteria are met, a seismic event could result in a rapid pore water pressure increase from the
earthquake-generated ground accelerations. Due to the lack of a permanent, near-surface groundwater
table and the dense nature of the underlying geologic units on the property, liquefaction potential for
the site is considered very low.
5.6 Landslides
We did not observe evidence of previous or incipient slope instability at the site during our study.
Published geologic mapping indicates landslides are not present on or immediately adjacent to the site.
Therefore, the risk of landsliding at the site is considered low.
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6. CONCLUSIONS AND RECOMMENDATIONS
6.1 General
6.1.1 No soil or geologic conditions were observed that would preclude the development of the
property as presently proposed provided that the recommendations of this report are
followed.
6.1.2 The site is underlain by compressible surficial deposits consisting of undocumented fill,
topsoil and alluvium, overlying Quaternary-age Terrace Deposits, Very Old Paralic
Deposits, and Tertiary-age San Diego Formation. The undocumented fill and topsoil range
from approximately one to 4 feet thick. The alluvium extends to depths greater than 20 feet
thick in the southeast corner of the site, but may be thicker in unexplored areas of the site.
Additionally, minor amounts of trash and construction debris have been placed at the site.
6.1.3 Undocumented fill, topsoil, and the upper five feet of alluvium and Terrace Deposits are
unsuitable in their present condition to receive additional fill or settlement-sensitive
structures and will require removal and recompaction. Portions of the topsoil are highly
expansive. To reduce the potential for soil heave impacting foundations and site
improvements, we recommend burial of clayey topsoil at least five feet below design pad
grade and outside of the foundation, reinforced, and retained zones of MSE walls.
6.1.4 We did not encounter groundwater during our subsurface exploration, and groundwater
should not be a constraint to project development. However, seepage within surficial soils
and formational materials may be encountered during the grading operations, especially
during the rainy seasons.
6.1.5 Except for possible strong seismic shaking, no significant geologic hazards were observed
or are known to exist on the site that would adversely affect the site. No special seismic
design considerations, other than those recommended herein, are required.
6.1.6 Proper drainage should be maintained in order to preserve the engineering properties of the
fill in both the building pads and slope areas. Recommendations for site drainage are
provided herein.
6.1.7 We did not perform infiltration testing as part of this study as preliminary design plans were
not available. Due to the proposed MSE walls and deep fills required in the south (down-
gradient) portion of the site needed to create a level building pad, infiltration of storm water
is not recommended on this site.
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6.1.8 Provided the recommendations of this report are followed, it is our opinion that the
proposed development will not destabilize or result in settlement of adjacent properties and
City right-of-way.
6.1.9 Subsurface conditions observed may be extrapolated to reflect general soil/geologic
conditions; however, some variations in subsurface conditions between trench locations
should be anticipated.
6.2 Soil and Excavation Characteristics
6.2.1 The recommendations included herein are provided for stable excavations. It is the
responsibility of the contractor and their competent person to ensure all excavations,
temporary slopes and trenches are properly constructed and maintained in accordance with
applicable OSHA guidelines in order to maintain safety and the stability of the excavations
and adjacent improvements. These excavations should not be allowed to become saturated
or to dry out. Surcharge loads should not be permitted to a distance equal to the height of the
excavation from the top of the excavation. The top of the excavation should be a minimum
of 15 feet from the edge of existing improvements. Excavations steeper than those
recommended or closer than 15 feet from an existing surface improvement should be shored
in accordance with applicable OSHA codes and regulations.
6.2.2 The stability of the excavations is dependent on the design and construction of the shoring
system and site conditions. Therefore, Geocon Incorporated cannot be responsible for site
safety and the stability of the proposed excavations.
6.2.3 Excavation of existing undocumented fill and surficial deposits should be possible with
moderate to heavy effort using conventional heavy-duty equipment. We expect excavation
of the Terrace Deposits, Very Old Paralic Deposits, and the San Diego Formation will
require moderate to very heavy effort. Weakly to moderately cemented gravel and/or cobble
and zones may be encountered requiring very heavy effort to excavate.
6.2.4 The soil encountered in the field investigation is considered to be both “non-expansive”
expansion index [EI] of 20 and less) and “expansive” (EI greater than 20) as defined by
2019 California Building Code (CBC) Section 1803.5.3. Table 6.2.1 presents soil
classifications based on the expansion index. We expect the majority of the soils that will be
encountered in remedial grading and cut areas will have a “low” expansion potential.
Portions of the topsoil possess a “medium” to “high” expansion potential (EI of 51 or
greater).
Geocon Project No. G2762-42-01 - 10 - July 28, 2021
TABLE 6.2.1
EXPANSION CLASSIFICATION BASED ON EXPANSION INDEX
Expansion Index (EI) ASTM D 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
6.2.5 We performed laboratory tests on samples of the site materials to evaluate the percentage of
water-soluble sulfate content. Appendix B presents results of the laboratory water-soluble
sulfate content tests. 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. Table 6.2.2 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 6.2.2
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
6.2.6 We tested samples for potential of hydrogen (pH) and resistivity and chloride to aid in
evaluating the corrosion potential. Appendix B presents the laboratory test results.
6.2.7 Geocon Incorporated does not practice in the field of corrosion engineering. Therefore,
further evaluation by a corrosion engineer may be needed if improvements susceptible to
corrosion are planned.
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6.3 Grading Recommendations
6.3.1 Grading should be performed in accordance with the recommendations provided in this
report, the Recommended Grading Specifications contained in Appendix C and the City of
Chula Vista’s Grading Ordinance. Where the recommendations of this section conflict with
those of Appendix C, the recommendations of this section take precedence. Geocon
Incorporated should observe the grading operations on a full-time basis and provide testing
during the fill placement.
6.3.2 Prior to commencing grading, a preconstruction conference should be held at the site with
the City inspector, developer, grading and underground contractors, civil engineer, and
geotechnical engineer in attendance. Special soil handling and/or the grading plans can be
discussed at that time.
6.3.3 Site preparation should begin with the removal of deleterious material, trash and debris, and
vegetation. The depth of vegetation removal should be such that material exposed in cut areas
or soil to be used as fill is relatively free of organic matter. Material generated during stripping
and/or site demolition should be exported from the site. Asphalt and concrete (if encountered)
should not be mixed with the fill soil unless approved by the Geotechnical Engineer.
6.3.4 Abandoned foundations and buried utilities (if encountered) should be removed and the
resultant depressions and/or trenches should be backfilled with properly compacted material
as part of the remedial grading.
6.3.5 We recommend undocumented fill, topsoil, and the upper five feet of alluvium and Terrace
Deposits be removed and replaced as compacted fill throughout the site. Trash and debris
may be encountered in the undocumented fill. Trash and debris, if encountered, should be
removed from the fill and exported.
6.3.6 Estimated remedial removal depths are shown on the Geologic Map (Figure 1). The actual
depth of remedial removals should be determined in the field during grading by a
representative of Geocon Incorporated prior to placement and compaction of fill.
6.3.7 Based on the existing site conditions, we expect grading will result in cuts and fills from
existing grade up to approximately 50 feet to create a level building pad. A cut-to-fill
transition will be created in the proposed building pad resulting in San Diego Formation at
grade in the north portion of the site and compacted fills up to 50 feet deep in the south
portion of the site. Undercutting of the north side of the building pad will be required as
shown in Table 6.3.1 below.
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6.3.8 Expansive soils found in the upper three to four feet below existing site grades should be
buried in deep fills and outside of the foundation, reinforced and retained zones of MSE
walls, and at least five feet below pad grade or three feet below the deepest foundation
element, whichever is deeper.
6.3.9. Removals at the toes of proposed fill slopes and in front of retaining walls should extend
horizontally beyond the edge of the slope toe or wall a distance equal to the depth of
removal. A typical detail of remedial grading beyond slope toes is presented below.
TABLE 6.3.1
SUMMARY OF GRADING RECOMMENDATIONS
Area Removal Requirements
All Structural Improvement Areas All undocumented fill and topsoil and the Upper
5 feet of Alluvium and Terrace Deposits
Building Pad (North Side [Cut]) Undercut building pad 5 feet below bottom of
building footings to remove cut to fill transition
Fill Areas Expansive Soil Buried at Least 5 Feet Below Pad
Grade or at Least 3 Feet Below Bottom of Footings
Remedial Grading Limits
10 Feet Outside of Building Pads;
2 Feet Outside of Improvement Areas;
Beyond toe of slopes and retaining walls a
distance equal to the depth of the remedial
excavation, where possible
Exposed Bottoms of Remedial Grading Scarify Upper 12 Inches
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6.3.10 Along the south side of the site an existing retaining wall adjacent to the property margin
may impact remedial grading limits. Deepened wall footings may be required so as to not
impact the existing retaining wall.
6.3.11 Excavation bottoms should be sloped 1 percent to the adjacent street or deepest fill. Prior to
fill soil being placed, the existing ground surface should be scarified, moisture conditioned
as necessary, and compacted to a depth of at least 12 inches. Deeper removals may be
required if saturated or loose fill soil is encountered. A representative of Geocon should be
on-site during removals to evaluate the limits of the remedial grading.
6.3.12 The site should then be brought to final subgrade elevations with fill compacted in layers. In
general, soil native to the site is suitable for use from a geotechnical engineering standpoint as
fill if relatively free from vegetation, debris and other deleterious material. Layers of fill should
be no thicker than will allow for adequate bonding and compaction. Fill, including backfill and
scarified ground surfaces, should be compacted to a dry density of at least 90 percent of the
laboratory maximum dry density near to slightly above optimum moisture content in accordance
with ASTM Test Procedure D 1557. Fill materials placed below optimum moisture content may
require additional moisture conditioning prior to placing additional fill.
6.3.13 Imported fill (if necessary) should consist of the characteristics presented in Table 6.3.2. Geocon
Incorporated should be notified of the import soil source and should perform laboratory testing
of import soil prior to its arrival at the site to determine its suitability as fill material.
TABLE 6.3.2
SUMMARY OF IMPORT FILL RECOMMENDATIONS
Soil Characteristic Values
Expansion Potential “Very Low” to “Low” (Expansion Index of 50 or less)
Particle Size
Maximum Dimension Less Than 3 Inches
Generally Free of Debris
6.4 Slopes
6.4.1 Slope stability analyses were performed for proposed cut and fill slopes up to 10 feet high
2:1 gradient). The stability analyses were performed using simplified Janbu analysis. Our
analyses utilized average drained direct shear strength parameters based on laboratory tests
performed for this project and our experience with similar soils. The analyses indicate
planned cut and fill slopes, and the existing native perimeter slope will have a calculated
factors of safety in excess of 1.5 under static conditions for both deep-seated failure and
shallow sloughing conditions. Table 6.4.1 presents the slope stability analysis. Slope
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stability analysis for MSE walls should be performed once the wall design is complete and
grid locations and lengths are known.
TABLE 6.4.1
SLOPE STABILITY EVALUATION
Parameter Value
Slope Height, H 20 Feet
Slope Inclination, I (Horizontal to Vertical) 2:1
Total Soil Unit Weight, 125 pcf
Friction Angle, 30 Degrees
Cohesion, C 200 psf
Slope Factor C 7.2
NCf (From Chart) 25
Factor of Safety = (NCfC)/(2.0
6.4.2 Table 6.4.2 presents the surficial slope stability analysis for the proposed sloping conditions.
TABLE 6.4.2
SURFICIAL SLOPE STABILITY EVALUATION
Parameter Value
Slope Height, H
Vertical Depth of Saturation, Z 3 Feet
Slope Inclination, I (Horizontal to Vertical) 2:1 (26.6 Degrees)
Total Soil Unit Weight, 125 pcf
Water Unit Weight, 62.4 pcf
Friction Angle, 30 Degrees
Cohesion, C 200 psf
Factor of Safety = (C+(Zcos2I tan)/(cosI) 1.9
6.4.3 All cut slope excavations should be observed during grading by an engineering geologist to
verify that soil and geologic conditions do not differ significantly from those anticipated.
6.4.4 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. Granular “soil” fill is defined as a well-graded soil mix with less than 20
percent fines (silt and clay particles). Poorly graded soils with less than 5 percent fines should
not be used in the slope zone due to high erosion potential. All slopes should be compacted by
backrolling with a loaded sheepsfoot roller at vertical intervals not to exceed 4 feet and should
Geocon Project No. G2762-42-01 - 15 - July 28, 2021
be track-walked at the completion of each slope such that the fill soils are uniformly
compacted to at least 90 percent relative compaction to the face of the finished sloped.
6.4.5 All slopes should be landscaped with drought-tolerant vegetation, having variable root
depths and requiring minimal landscape irrigation. In addition, all slopes should be drained
and properly maintained to reduce erosion.
6.5 Earthwork Grading Factors
6.5.1 Estimates of shrink-swell factors are based on comparing laboratory compaction tests with the
density of the material in its natural state and experience with similar soil types. Variations in
natural soil density and compacted fill render shrinkage value estimates very approximate. As an
example, the contractor can compact fill to a density of 90 percent or higher of the laboratory
maximum dry density. Thus, the contractor has at least a 10 percent range of control over the fill
volume. Based on the work performed to date and considering the discussion herein, the
earthwork factors in Table 6.5 may be used as a basis for estimating how much the on-site soils
may shrink or swell when removed from their natural state and placed as compacted fill.
TABLE 6.5
SHRINKAGE AND BULK FACTORS
Soil Unit Shrink/Bulk Factor
Undocumented Fill (Qudf) 10-15% Shrink
Previously Placed Fill (Qpf) 0-3% Shrink
Topsoil (unmapped) 5-10% Shrink
Alluvium (Qal) 4-8% Shrink
Terrace Deposits (Qt) 0-5% Bulk
Very Old Paralic Deposits (Qvop) 3-5% Bulk
San Diego Formation (Tsd) 3-5% Bulk
6.6 Subdrains
6.6.1 With the exception of retaining wall drains, we do not expect subdrains will be required. We
should be contacted to provide recommendations for subdrains if field conditions differ
from those described herein.
6.7 Settlement Monitoring
6.7.1 At the completion of grading, the south side of the site will be underlain by up to 50 feet of
compacted fill behind MSE walls. Post-grading settlement (hydro-compression) of properly
compacted new fill with a maximum thickness of 50 feet could be up to about 2.5 inches.
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We expect the settlement could occur over 20+ years depending on the influx of rain and
irrigation water into the fill mass. This settlement will likely be linear from the time the fill
is placed to the end of the settlement period. We do not expect the settlement will impact
proposed utilities with proposed gradients of 1 percent or greater. The building foundation
design should be designed to account for potential hydro-compression settlement. It has
been our experience that developments/improvements, such as proposed, can be constructed
with the planned fill depths and proposed settlements.
6.7.2 We expect settlement in the fill as a result of self-weight compression could take up to 3 to 9
months. If building foundations will be constructed shortly after completion of the fill mass,
building foundations will need to be designed to accommodate differential settlement as a
result of self-weight compression. If the planned structures cannot tolerate the expected
movement, a construction waiting period should be implemented until settlement monitoring
indicates self-weight compression has essentially ceased.
6.7.3 At the south end of the property where fills are the greatest, we recommend settlement
monuments be installed subsequent to the wall construction. A typical settlement monument
is shown below.
Settlement Plate Detail
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6.7.4 Surveying of the surface monument should be performed by the project civil engineer every
two weeks for at least three months with the results provided to Geocon for review.
Settlement due to primary consolidation will be considered to have ceased when survey
readings show a relatively level plateau of settlement data over 4 consecutive readings.
6.8 Seismic Design Criteria
6.8.1 Table 6.8.1 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 Classes C and D. The southern portion of the building will be
underlain by compacted fill in excess of 40 feet. A Site Class D is appropriate for this condition.
The northern portion of the building pad will be underlain by shallow compacted fills. Site Class
C is appropriate for this condition.
TABLE 6.8.1
2019 CBC SEISMIC DESIGN PARAMETERS
Parameter Value 2019 CBC Reference
Site Class C D Section 1613.2.2
MCER Ground Motion Spectral Response
Acceleration – Class B (short), SS 0.896g 0.896g Figure 1613.2.1(1)
MCER Ground Motion Spectral Response
Acceleration – Class B (1 sec), S1 0.313g 0.313g Figure 1613.2.1(2)
Site Coefficient, FA 1.2 1.142 Table 1613.2.3(1)
Site Coefficient, FV 1.5 1.987* Table 1613.2.3(2)
Site Class Modified MCER Spectral
Response Acceleration (short), SMS 1.075g 1.023g Section 1613.2.3 (Eqn 16-36)
Site Class Modified MCER Spectral
Response Acceleration – (1 sec), SM1 0.47g 0.622g* Section 1613.2.3 (Eqn 16-37)
5% Damped Design Spectral Response
Acceleration (short), SDS 0.717g 0.682g Section 1613.2.4 (Eqn 16-38)
5% Damped Design Spectral Response
Acceleration (1 sec), SD1 0.313g 0.415g* 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. Section 11.4.8 also provides exceptions which indicates
that the ground motion hazard analysis may be waived provided the exceptions are followed.
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6.8.2 Table 6.8.2 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 6.8.2
ASCE 7-16 PEAK GROUND ACCELERATION
Parameter Value ASCE 7-16 Reference
Site Class C D Section 1613.2.2 (2019 CBC)
Mapped MCEG Peak Ground
Acceleration, PGA 0.394g 0.394g Figure 22-7
Site Coefficient, FPGA 1.2 1.206 Table 11.8-1
Site Class Modified MCEG Peak
Ground Acceleration, PGAM 0.473g 0.475g Section 11.8.3 (Eqn 11.8-1)
6.8.3 Conformance to the criteria in Tables 6.8.1 and 6.8.2 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.
6.8.4 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 6.8.3
presents a summary of the risk categories.
TABLE 6.8.3
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
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6.9 Shallow Foundations
6.9.1 The proposed structure can be supported on a shallow foundation system founded in
compacted fill provided the grading recommendations provided in Section 6.3 are followed.
Foundations for the structure should consist of continuous strip footings and/or isolated
spread footings. Table 6.9.1 provides a summary of the foundation design
recommendations.
TABLE 6.9.1
SUMMARY OF FOUNDATION RECOMMENDATIONS
Parameter Value
Minimum Continuous Foundation Width 12 inches
Minimum Isolated Foundation Width 24 inches
Minimum Foundation Depth 24 Inches Below Lowest Adjacent Grade
Minimum Steel Reinforcement 4 No. 5 Bars, 2 at the Top and 2 at the Bottom
Allowable Bearing Capacity 2,500 psf
Bearing Capacity Increase
500 psf per Foot of Depth
300 psf per Foot of Width
Maximum Allowable Bearing Capacity 4,000 psf
Estimated Total Settlement 1 Inch
Estimated Differential Settlement ½ Inch in 40 Feet
Footing Size Used for Settlement 9-Foot Square
Design Expansion Index 50 or less
6.9.2 Additional settlement as a result of self-weight compression and hydro-compression could
occur over the life of the structure. We estimate approximately 0.4 percent of the total fill
thickness underlying the building pad. Self-weight compression is expected to occur over 3
to 9 months. Hydro-compression is expected to occur over a 20 year or more duration. The
estimated fill thickness and total settlement as a result of self-weight compression and
hydro-compression is shown on Table 6.9.2 and is in addition to the static settlement
indicated on Table 6.9.1. An estimate of total and differential fill settlement, including
settlement contours thickness and final foundation recommendations to be used in design
can be provided, if desired.
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TABLE 6.9.2
ESTIMATED FILL THICKNESS AND TOTAL AND DIFFERENTIAL FILL SETTLEMENT
AS A RESULT OF SELF-WEIGHT AND HYDRO-COMPRESSION
Estimated Compacted Fill
Thickness
after grading)
feet)
Estimated Total Fill
Settlement
Self-Weight and
Hydro-Compression)
inches)
Estimated Differential Fill
Settlement
Self-Weight and
Hydro-Compression)
inches)
0 to 50 0 to 2.5
2.5 inches over a span of
200 feet (angular distortion
of 1/960)
6.9.3 The foundations should be embedded in accordance with the recommendations herein and
the Wall/Column Footing Dimension Detail. The embedment depths should be measured
from the lowest adjacent pad grade for both interior and exterior footings. 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 (unless designed with a post-tensioned foundation system as
discussed herein).
Wall/Column Footing Dimension Detail
6.9.4 The bearing capacity values presented herein are for dead plus live loads and may be
increased by one-third when considering transient loads due to wind or seismic forces.
6.9.5 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 or cut slopes regardless of height, 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.
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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. A post-tensioned slab and foundation system or mat foundation
system can be used to reduce the potential for distress in the structures associated
with strain softening and lateral fill extension. Specific design parameters or
recommendations for either of these alternatives can be provided once the building
location and fill slope geometry have been determined.
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 that would permit some lateral soil
movement without causing extensive distress. Geocon Incorporated should be
consulted for specific recommendations.
6.9.6 We should observe the foundation excavations prior to the placement of reinforcing steel
and concrete to check that the exposed soil conditions are similar to those expected and that
they have been extended to the appropriate bearing strata. Foundation modifications may be
required if unexpected soil conditions are encountered.
6.9.7 Geocon Incorporated should be consulted to provide additional design parameters as
required by the structural engineer.
6.10 Conventional Retaining Wall Recommendations
6.10.1 Retaining walls should be designed using the values presented in Table 6.10.1. Soil with an
expansion index (EI) of greater than 50 should not be used as backfill soil behind retaining
walls.
TABLE 6.10.1
RETAINING WALL DESIGN RECOMMENDATIONS
Parameter Value
Active Soil Pressure, A (Fluid Density, Level Backfill) 35 pcf
Active Soil Pressure, A (Fluid Density, 2:1 Sloping Backfill) 50 pcf
Seismic Pressure, S 18H psf
At-Rest/Restrained Walls Additional Uniform Pressure (0 to 8 Feet High) 7H psf
At-Rest/Restrained Walls Additional Uniform Pressure (8+ Feet High) 13H psf
Expected Expansion Index for the Subject Property EI<50
H equals the height of the retaining portion of the wall
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6.10.2 The project retaining walls should be designed as shown in the Retaining Wall Loading
Diagram.
Retaining Wall Loading Diagram
6.10.3 Unrestrained walls are those that are allowed to rotate more than 0.001H (where H equals
the height of the retaining portion of the wall) at the top of the wall. Where walls are
restrained from movement at the top (at-rest condition), an additional uniform pressure
should be applied to the wall. For retaining walls subject to vehicular loads within a
horizontal distance equal to two-thirds the wall height, a surcharge equivalent to 2 feet of fill
soil should be added.
6.10.4 The structural engineer should determine the Seismic Design Category for the project in
accordance with Section 1613.2.5 of the 2019 CBC or Section 11.6 of ASCE 7-16. 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.
6.10.5 Retaining walls should be designed to ensure stability against overturning sliding, and
excessive foundation pressure. 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.
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6.10.6 Drainage openings through the base of the wall (weep holes) should not be used where the
seepage could be a nuisance or otherwise adversely affect the property adjacent to the base
of the wall. The recommendations herein assume a properly compacted granular (EI of 50 or
less) free-draining backfill material with no hydrostatic forces or imposed surcharge load.
The retaining wall should be properly drained as shown in the Typical Retaining Wall
Drainage Detail. If conditions different than those described are expected, or if specific
drainage details are desired, Geocon Incorporated should be contacted for additional
recommendations.
Typical Retaining Wall Drainage Detail
6.10.7 The retaining walls may be designed using either the active and restrained (at-rest) loading
condition or the active and seismic loading condition as suggested by the structural
engineer. Typically, it appears the design of the restrained condition for retaining wall
loading may be adequate for the seismic design of the retaining walls. However, the active
earth pressure combined with the seismic design load should be reviewed and also
considered in the design of the retaining walls.
6.10.8 In general, wall foundations having should be designed in accordance with Table 6.10.2.
The proximity of the foundation to the top of a slope steeper than 3:1 could impact the
allowable soil bearing pressure. Therefore, retaining wall foundations should be deepened
such that the bottom outside edge of the footing is at least 7 feet horizontally from the face
of the slope.
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TABLE 6.10.2
SUMMARY OF RETAINING WALL FOUNDATION RECOMMENDATIONS
Parameter Value
Minimum Retaining Wall Foundation Width 12 inches
Minimum Retaining Wall Foundation Depth 12 Inches
Minimum Steel Reinforcement Per Structural Engineer
Bearing Capacity 2,500 psf
Bearing Capacity Increase
500 psf per additional foot of footing depth
300 psf per additional foot of footing width
Maximum Bearing Capacity 4,000 psf
Estimated Total Settlement 1 Inch
Estimated Differential Settlement ½ Inch in 40 Feet
6.10.9 The recommendations presented herein are generally applicable to the design of rigid
concrete or masonry retaining walls. Additional recommendations for MSE walls and soil
nail walls are provided in Sections 6.12 and 6.13.
6.10.10 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 retaining walls and improvements above the retaining walls
should be designed to incorporate an appropriate amount of lateral deflection as determined
by the structural engineer.
6.10.11 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.
6.11 Lateral Loading
6.11.1 Table 6.11 should be used to help design the proposed structures and improvements to resist
lateral loads for the design of footings or shear keys. The allowable passive pressure
assumes a horizontal surface extending at least 5 feet, or three times the surface generating
the passive pressure, whichever is greater. The upper 12 inches of material in areas not
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protected by floor slabs or pavement should not be included in design for passive resistance.
Where walls are planned adjacent to and/or on descending slopes, a passive pressure of 150
pcf should be used in design.
TABLE 6.11
SUMMARY OF LATERAL LOAD DESIGN RECOMMENDATIONS
Parameter Value
Passive Pressure Fluid Density 350 pcf
Passive Pressure Fluid Density Adjacent to and/or on
Descending Slopes 150 pcf
Coefficient of Friction (Concrete and Soil) 0.35
Coefficient of Friction (Along Vapor Barrier) 0.2 to 0.25*
Per manufacturer’s recommendations.
6.11.2 The passive and frictional resistant loads can be combined for design purposes. The lateral
passive pressures may be increased by one-third when considering transient loads due to
wind or seismic forces.
6.12 Mechanically Stabilized Earth (MSE) Retaining Walls
6.12.1 Mechanized stabilized earth (MSE) retaining walls are planned for the project. MSE
retaining walls are alternative walls that consist of modular block facing units with geogrid
reinforced earth behind the block. The reinforcement grid attaches to the block units and is
typically placed at specified vertical intervals and embedment lengths. The grid length and
spacing will be determined by the wall designer.
6.12.2 The geotechnical parameters listed in Table 6.12.1 can be used for preliminary design of the
MSE walls. Once actual soil to be used as backfill has been determined and stockpiled,
laboratory testing should be performed to check that the soil meets the parameters used in
the design of the MSE walls.
TABLE 6.12.1
GEOTECHNICAL PARAMETERS FOR MSE WALLS
Parameter Reinforced Zone Retained Zone Foundation Zone
Angle of Internal Friction 30 degrees 30 degrees 30 degrees
Cohesion 100 psf 100 psf 100 psf
Wet Unit Density 125 pcf 125 pcf 125 pcf
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6.12.3 The soil parameters presented in Table 6.12.1 are based on our experience and direct shear-
strength tests performed during the geotechnical investigation and represent some of the on-
site materials. The wet unit density values presented in Table 6.12.1 can be used for design
but actual in-place densities may range from approximately 110 to 130 pounds per cubic
foot. Geocon has no way of knowing which materials will actually be used as backfill
behind the wall during construction. It is up to the wall designers to use their judgment in
selection of the design parameters. As such, once backfill materials have been selected
and/or stockpiled, sufficient shear tests should be conducted on samples of the proposed
backfill materials to check that they conform to actual design values. Results should be
provided to the designer to re-evaluate stability of the walls. Dependent upon test results, the
designer may require modifications to the original wall design (e.g., longer reinforcement
embedment lengths and/or steel reinforcement).
6.12.4 Wall foundations should be designed in accordance with Table 6.12.2 The walls should be
deepened such that the bottom outside edge of the footing is at least 7 feet horizontally from
the face of the slope.
TABLE 6.12.2
SUMMARY OF MSE RETAINING WALL FOUNDATION RECOMMENDATIONS
Parameter Value
Minimum Retaining Wall Foundation Width 12 inches
Minimum Retaining Wall Foundation Depth 12 Inches
Bearing Capacity 2,000 psf
Bearing Capacity Increase
500 psf per Foot of Depth
300 psf per Foot of Width
Maximum Bearing Capacity 4,000 psf
Estimated Total Settlement 1 Inch
Estimated Differential Settlement ½ Inch in 40 Feet
6.12.5 Backfill materials within the reinforced zone should be compacted to a dry density of at
least 90 percent of the laboratory maximum dry density near to slightly above optimum
moisture content in accordance with ASTM D 1557. This is applicable to the entire
embedment width of the reinforcement. Typically, wall designers specify no heavy
compaction equipment within 3 feet of the face of the wall. However, smaller equipment
e.g., walk-behind, self-driven compactors or hand whackers) can be used to compact the
materials without causing deformation of the wall. If the designer specifies no compactive
effort for this zone, the materials are essentially not properly compacted and the
reinforcement grid within the uncompacted zone should not be relied upon for
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reinforcement, and overall embedment lengths will have to be increased to account for the
difference.
6.12.6 The wall should be provided with a drainage system sufficient to prevent excessive seepage
through the wall and the base of the wall, thus preventing hydrostatic pressures behind
the wall.
6.12.7 Geosynthetic reinforcement must elongate to develop full tensile resistance. This elongation
generally results in movement at the top of the wall. The amount of movement is dependent
on the height of the wall (e.g., higher walls rotate more) and the type of reinforcing grid
used. In addition, over time the reinforcement grid has been known to exhibit creep
sometimes as much as 5 percent) and can undergo additional movement. Given this
condition, the owner should be aware that structures and pavement placed within the
reinforced and retained zones of the wall may undergo movement.
6.12.8 The MSE wall contractor should provide the estimated deformation of wall and adjacent
ground in associated with wall construction. The calculated horizontal and vertical
deformations should be determined by the wall designer. Where buildings are located
adjacent to the walls, the estimated movements should be provided to the project structural
engineer to evaluate if the building foundation can tolerate the expected movements. With
respect to improvements adjacent to the wall, cracking and/or movement should be
expected.
6.12.9 The MSE wall designer/contractor should review this report, including the slope stability
requirements, and incorporate our recommendations as presented herein. We should be
provided the plans for the MSE walls to check if they are in conformance with our
recommendations prior to issuance of a permit and construction.
6.13 Soil Nail Walls
6.13.1 We understand soil nail walls are planned for the project. Soil nail walls consist of installing
closely spaced steel bars (nails) into a slope or excavation in a top-down construction
sequence. Following installation of a horizontal row of nails, drains, waterproofing and wall
reinforcing steel are placed and shotcrete applied to create a final wall. The wall should be
designed by an engineer familiar with the design of soil nail walls.
6.13.2 In general, ground conditions are moderately suited to soil nail wall construction techniques.
However, localized gravel, cobble and oversized material could be encountered in the
existing materials that could be difficult to drill. Additionally, relatively clean sands may be
Geocon Project No. G2762-42-01 - 28 - July 28, 2021
encountered that may result in some raveling of the unsupported excavation. Casing or
specialized drilling techniques should be planned where raveling exists (e.g. casing).
6.13.3 Testing of the soil nails should be performed in accordance with the guidelines of the
Federal Highway Administration or similar guidelines. At least two verification tests should
be performed to confirm design assumptions for each soil/rock type encountered.
Verification tests nails should be sacrificial and should not be used to support the proposed
wall. The bond length should be adjusted to allow for pullout testing of the verification nails
to evaluate the ultimate bond stress. A minimum of 5 percent of the production nails should
also be proof tested and a minimum of 4 sacrificial nails should be tested at the discretion of
Geocon Incorporated. Consideration should be given to testing sacrificial nails with an
adjusted bond length rather than testing production nails. Geocon Incorporated should
observe the nail installation and perform the nail testing.
6.13.4 The soil strength parameters listed in Table 6.13 can be used in design of the soil nails. The
bond stress is dependent on drilling method, diameter, and construction method. Therefore,
the designer should evaluate the bond stress based on soil conditions and the construction
method.
TABLE 6.13
SOIL STRENGTH PARAMETERS FOR SOIL NAIL WALLS
Description Cohesion (psf) Friction Angle
degrees)
Estimated
Ultimate Bond
Stress (psi)*
Previously Placed Fill 100 28 10
Alluvium 100 28 10
Very Old Paralic Deposits 200 33 20
San Diego Formation 200 33 20
Assuming gravity fed, open hole drilling techniques.
6.13.5 A wall drain system should be incorporated into the design of the soil nail wall as shown
herein. Corrosion protection should be provided for the nails.
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Soil Nail Wall Drainage Detail
6.14 Preliminary Pavement Recommendations
6.14.1 Preliminary pavement recommendations for the driveways and parking areas are provided
below. The final pavement sections should be based on the R-Value of the subgrade soil
encountered at final subgrade elevation. For preliminary design, we used a laboratory
R-Value of 15. We calculated the preliminary flexible pavement sections for asphalt
concrete using varying traffic indices (TIs) in general conformance with the Caltrans
Method of Flexible Pavement Design (Highway Design Manual, Section 608.4). The project
civil engineer or traffic engineer should determine the appropriate Traffic Index (TI) or
traffic loading expected on the project for the various pavement areas that will be
constructed. Recommended preliminary asphalt concrete pavement sections are provided on
Table 6.14.1.
TABLE 16.14.1
PRELIMINARY ASPHALT CONCRETE PAVEMENT SECTIONS
Traffic Index Asphalt Concrete (inches) Class 2 Base (inches)
4.5 3 6
5 3 8
5.5 3 10
6 3.5 10.5
6.5 3.5 12.5
7 4 13
7.5 4.5 15
8 5 15
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6.14.2 Asphalt concrete should conform to Section 203-6 of the Standard Specifications for Public
Works Construction (Green Book). Class 2 aggregate base materials should conform to
Section 26-1.02B of the Standard Specifications of the State of California, Department of
Transportation (Caltrans).
6.14.3 Prior to placing base material, the subgrade should be scarified, moisture conditioned and
recompacted to a minimum of 95 percent relative compaction. The depth of compaction
should be at least 12 inches. The base material should be compacted to at least 95 percent
relative compaction. Asphalt concrete should be compacted to a density of at least
95 percent of the laboratory Hveem density in accordance with ASTM D 2726.
6.14.4 A rigid Portland Cement concrete (PCC) pavement section can also be used. We calculated
the rigid pavement section in general conformance with the procedure recommended by the
American Concrete Institute report ACI 330R-08 Guide for Design and Construction of
Concrete Parking Lots using the parameters presented in Table 6.14.2.
TABLE 6.14.2
PRELIMINARY RIGID PAVEMENT DESIGN PARAMETERS
Design Parameter Design Value
Modulus of subgrade reaction, k 100 pci
Modulus of rupture for concrete, MR 500 psi
Concrete Compressive Strength 3,000 psi
Traffic Category, TC A and C
Average daily truck traffic, ADTT 10 and 300
6.14.5 Based on the criteria presented herein, the PCC pavement sections should have a minimum
thickness as presented in Table 6.14.3.
TABLE 6.14.3
RIGID VEHICULAR PAVEMENT RECOMMENDATIONS
Location Portland Cement Concrete (inches)
Automobile Parking Stalls (TC=A, ADTT=10) 5.5
Driveways (TC=C, ADTT=100) 7.5
Geocon Project No. G2762-42-01 - 31 - July 28, 2021
6.14.6 The PCC vehicular pavement should be placed over subgrade soil that is compacted to a dry
density of at least 95 percent of the laboratory maximum dry density near to slightly above
optimum moisture content.
6.14.7 The rigid pavement should also be designed and constructed incorporating the parameters
presented in Table 6.14.4.
TABLE 6.14.4
ADDITIONAL RIGID PAVEMENT RECOMMENDATIONS
Subject Value
Thickened Edge
1.2 Times Slab Thickness
Minimum Increase of 2 Inches
4 Feet Wide
Crack Control Joint Spacing
30 Times Slab Thickness
Max. Spacing of 12 feet for 5.5-Inch-Thick
Max. Spacing of 15 Feet for Slabs 6 Inches
and Thicker
Crack Control Joint Depth
Per ACI 330R-08
1 Inch Using Early-Entry Saws on Slabs Less
Than 9 Inches Thick
Crack Control Joint Width
Inch for Sealed Joints
Inch is Common for Sealed Joints
1/10- to 1/8-Inch is Common for Unsealed
Joints
6.14.8 Reinforcing steel will not be necessary within the concrete for geotechnical purposes with
the possible exception of dowels at construction joints as discussed herein.
6.14.9 To control the location and spread of concrete shrinkage cracks, crack-control joints
weakened plane joints) should be included in the design of the concrete pavement slab.
Crack-control joints should be sealed with an appropriate sealant to prevent the migration of
water through the control joint to the subgrade materials. The depth of the crack-control
joints should be determined by the referenced ACI report.
6.14.10 To provide load transfer between adjacent pavement slab sections, a butt-type construction
joint should be constructed. The butt-type joint should be thickened by at least 20 percent at
the edge and taper back at least 4 feet from the face of the slab. As an alternative to the butt-
type construction joint, dowelling can be used between construction joints for pavements of
7 inches or thicker. As discussed in the referenced ACI guide, dowels should consist of
Geocon Project No. G2762-42-01 - 32 - July 28, 2021
smooth, 1-inch-diameter reinforcing steel 14 inches long embedded a minimum of 6 inches
into the slab on either side of the construction joint. Dowels should be located at the
midpoint of the slab, spaced at 12 inches on center and lubricated to allow joint movement
while still transferring loads. In addition, tie bars should be installed as recommended in
Section 3.8.3 of the referenced ACI guide. The structural engineer should provide other
alternative recommendations for load transfer.
6.14.11 Concrete curb/gutter should be placed on soil subgrade compacted to a dry density of at
least 90 percent of the laboratory maximum dry density near to slightly above optimum
moisture content. Cross-gutters that receives vehicular should be placed on subgrade soil
compacted to a dry density of at least 95 percent of the laboratory maximum dry density
near to slightly above optimum moisture content. Base materials should not be placed below
the curb/gutter, or cross-gutters so water is not able to migrate from the adjacent parkways
to the pavement sections. Where flatwork is located directly adjacent to the curb/gutter, the
concrete flatwork should be structurally connected to the curbs to help reduce the potential
for offsets between the curbs and the flatwork.
6.15 Exterior Concrete Flatwork
6.15.1 Exterior concrete flatwork not subject to vehicular traffic should be constructed in
accordance with the recommendations presented in Table 6.15. The recommended steel
reinforcement would help reduce the potential for cracking.
TABLE 6.15
MINIMUM CONCRETE FLATWORK RECOMMENDATIONS
Expansion
Index, EI Minimum Steel Reinforcement* Options Minimum
Thickness
EI < 90
6x6-W2.9/W2.9 (6x6-6/6) welded wire mesh
4 Inches
No. 3 Bars 18 inches on center, Both Directions
EI < 130
4x4-W4.0/W4.0 (4x4-4/4) welded wire mesh
No. 4 Bars 12 inches on center, Both Directions
In excess of 8 feet square.
6.15.2 Even with the incorporation of the recommendations of this report, the exterior concrete
flatwork has a potential to experience some uplift due to expansive soil beneath grade. The
steel reinforcement should overlap continuously in flatwork to reduce the potential for
vertical offsets within flatwork. Additionally, flatwork should be structurally connected to
the curbs, where possible, to reduce the potential for offsets between the curbs and the
flatwork.
Geocon Project No. G2762-42-01 - 33 - July 28, 2021
6.15.3 Concrete flatwork should be provided with crack control joints to reduce and/or control
shrinkage cracking. Crack control spacing should be determined by the project structural
engineer based upon the slab thickness and intended usage. Criteria of the American
Concrete Institute (ACI) should be taken into consideration when establishing crack control
spacing. Subgrade soil for exterior slabs not subjected to vehicle loads should be compacted
in accordance with criteria presented in the grading section prior to concrete placement.
Subgrade soil should be properly compacted, and the moisture content of subgrade soil
should be verified prior to placing concrete. Base materials will not be required below
concrete improvements.
6.15.4 Where exterior flatwork abuts the structure at entrant or exit points, the exterior slab should
be dowelled into the structure’s foundation stemwall. This recommendation is intended to
reduce the potential for differential elevations that could result from differential settlement
or minor heave of the flatwork. Dowelling details should be designed by the project
structural engineer.
6.15.5 The recommendations presented herein are intended to reduce the potential for cracking of
exterior slabs as a result of differential movement. However, even with the incorporation of
the recommendations presented herein, slabs-on-grade will still crack. The occurrence of
concrete shrinkage cracks is independent of the soil supporting characteristics. Their
occurrence may be reduced and/or controlled by limiting the slump of the concrete, the use
of crack control joints and proper concrete placement and curing. Crack control joints
should be spaced at intervals no greater than 12 feet. Literature provided by the Portland
Concrete Association (PCA) and American Concrete Institute (ACI) present
recommendations for proper concrete mix, construction, and curing practices, and should be
incorporated into project construction.
6.16 Slope Maintenance
6.16.1 Slopes that are steeper than 3:1 (horizontal:vertical) may, under conditions which are both
difficult to prevent and predict, be susceptible to near surface (surficial) slope instability.
The instability is typically limited to the outer three 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
Geocon Project No. G2762-42-01 - 34 - July 28, 2021
eliminate leaks and excessive irrigation, and (c) surface drains on and adjacent to slopes be
periodically maintained to preclude ponding or erosion. 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.
6.17 Storm Water Management
6.17.1 If storm water management devices are not properly designed and constructed, there is a
risk for distress to improvements and property located hydrologically down gradient or
adjacent to these devices. Factors such as the amount of water being detained, its residence
time, and soil permeability have an important effect on seepage transmission and the
potential adverse impacts that may occur if the storm water management features are not
properly designed and constructed. We have not performed a hydrogeological study at the
site. If infiltration of storm water runoff into the subsurface occurs, downstream
improvements may be subjected to seeps, springs, slope instability, raised groundwater,
movement of foundations and slabs, or other undesirable impacts as a result of water
infiltration.
6.17.2 We did not perform an infiltration study on the property. However, based on predicted site
conditions at the completion of grading, full and partial infiltration is considered infeasible
due to the presence of deep fills surrounded by MSE walls at the down-gradient end of the
site. Basins or other storm water devices should utilize a liner to prevent infiltration from
causing adverse settlement and heave, and migrating to utilities, and foundations.
6.18 Site Drainage and Moisture Protection
6.18.1 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 1803.3 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.
6.18.2 In the case of basement walls or building walls retaining landscaping areas, a water-proofing
system should be used on the wall and joints, and a Miradrain drainage panel (or similar)
should be placed over the waterproofing. The project architect or civil engineer should
provide detailed specifications on the plans for all waterproofing and drainage.
Geocon Project No. G2762-42-01 - 35 - July 28, 2021
6.18.3 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.
6.18.4 Landscaping planters adjacent to paved areas are not recommended due to the potential for
surface or irrigation water to infiltrate the pavement's subgrade and base course. We
recommend that subdrains to collect excess irrigation water and transmit it to drainage
structures, or impervious above-grade planter boxes be used. In addition, where landscaping
is planned adjacent to the pavement, we recommend construction of a cutoff wall along the
edge of the pavement that extends at least 6 inches below the bottom of the base material.
6.19 Grading and Foundation Plan Review
6.19.1 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.
Geocon Project No. G2762-42-01 July 28, 2021
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 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 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 be 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.
238.3 TW
195.7 FS
H=42.6'
150.57 FG)
6%
149.12 FG)
6%
6%
213.0 TW
195.5 FS
H=17.5'
195.1 TW
162.4 FS
H=32.7'
194.6 TW
154.0 FS
H=40.6'
INDUSTRIAL
BLDG
197.5 FF
191.1 TW
191.1 FS
H=0'
194.9 TW
152.7 FS
H=42.2'
195.0 TW
195.0 FS
H=0'
254.0 TW
195.7 FS
H=58.3'
194.6 TW
151.1 FS
H=43.5'
NOPARKINGNOPARKINGNOPARKINGNOPARKINGNOPARKING296'-00"
63'-00"
635'-00"··
B-1
TP-20
TP-3
TP-2
TP-19
TP-4TP-
18 TP-
5 TP-6TP-1
TP-7 TP-8
TP-9TP-
12TP-13
TP-14TP-
15 TP-
16TP-
17
TP-
11
TP-
10
Tsd
Tsd
Tsd
Tsd
Tsd
TsdTsd
QtQvop
Qvop
Qpf
Tsd
Qudf/
Qal/
Qal/Qal/
Qal/Qudf
Qudf Qudf
LB-
1
LB-
2
A
A'
5')
3')
5')
5')
5')(
5')4')(
4')
4')
10')
6')
0')(
0')5')
5')
3')
4')
4')7')(1')0')0')5')6960 FLANDERS
DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 -
FAX 858
558-6159
SHEET
OF PROJECT NO.SCALE DATE FIGURE Plotted:07/27/2021 9:20AM | By:ALVIN LADRILLONO | File Location:Y:\PROJECTS\G2762-42-01 (517 Shinohara Lane)\SHEETS\
G2762-42-01
Geo
Map.dwg
GEOTECHNICAL ENVIRONMENTAL MATERIALS
1" = GEOLOGIC 1AP
SHINOHARA INDUSTRIAL BUILDING
517 SHINOHARA LANE SAN
DIEGO, CALIFORNIA 40'
07 - 28 -
2021
G2762 - 42 -
01 1 1
1
UNDOCUMENTED FILL PREVIOUSLY PLACED
FILL ALLUVIUM
VERY OLD PARALIC
DEPOSITS TERRACE DEPOSITS
Dotted Where Buried)
SAN DIEGO FORMATION Dotted Where
Buried)APPROX. LOCATION OF GEOLOGIC CONTACT
Dotted Where Buried, Queried
Where Uncertain)APPROX. LOCATION OF BORING
APPROX. LOCATION OF LARGE
DIAMETER BORING APPROX. LOCATION OF TRENCH APPROX.
DEPTH OF REMEDIAL GRADING (In
Feet)APPROX.
LOCATION OFGEOLOGIC
CROSS
SECTION TP-
20
GEOCON LEGEND
Qudf B-
1
5')
A
A'
LB-
NORTH0804012016020024028032036048040044052056060064076068072080084088080120160200240A280A'E L E V A T I O N (M S
L)E L E V A T I O N (M S
APPENDIX A
Geocon Project No. G2762-42-01 July 28, 2021
APPENDIX A
FIELD INVESTIGATION
We performed our field investigation between June 30 and July 7, 2021. Our investigation consisted of
a site reconnaissance, logging of 20 exploratory test pits, two large diameter borings and one small
diameter boring. The exploratory test pits were excavated to depths between 2- and 16-feet using a
rubber-tire Caterpillar 430F backhoe. Exploratory borings were drilled to depths between 20- and 92-
feet using truck mounted hollow stem and bucket auger drill rigs. The approximate locations of the
exploratory test pits borings tests are shown on Figure 1.
The soil conditions encountered in the trenches were visually examined, classified, and logged in
general conformance with the American Society for Testing and Materials (ASTM) Practice for
Description and Identification of Soils (Visual-Manual Procedure D 2488). Exploratory boring logs
are presented in Figures A-1 through A-3, and test pit logs are presented on Figures A-4 through A-23.
The logs depict the various soil types encountered and indicate the depths at which samples were
obtained.
ALLUVIUM (Qal)
Medium dense, moist, reddish-brown, Clayey, fine to medium SAND; little
silt
At 5.5 feet: becomes dense
At 10.5 feet: becomes very dense
BORING TERMINATED AT 20 FEET
Groundwater not encountered
Backfilled with drill cuttings on 07-07-2021
SC
120.0
117.7
120.0
8.3
8.1
9.5
B1-1
B1-2
B1-3
B1-4
B1-5
B1-6
37
67
78
91/11.5"
50/6"
78/10"
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
20
Figure A-1,
Log of Boring B 1, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)IR
A-300
PENETRATIONRESISTANCE(BLOWS/
FT.)BORING
B
1
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERB.
KUNACONTENT (%)
SAMPLE NO.07-
07-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)153'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
SAN DIEGO FORMATION (Tsd)
Dense, damp, pale yellowish-brown to grayish-brown, Silty, very fine grained
SANDSTONE; massive, powdery texture, micaceous
At 7.5 feet: 1-inch thick orangish-brown sand bed; Bedding: N28W/14ºSW Dense,
damp, pale yellowish-brown to orangish-brown, Silty, fine to medium SANDSTONE;
trace gravel (subrounded) up to 4-inch diameter; trace clay,few
closed fractures <1/16" thick Dense,
damp, grayish-white, Silty, very fine grained SANDSTONE; massive,highly
micaceous Dense,
damp, white to blackish-brown, medium to coarse SANDSTONE;laminated,
low cohesion, trace fine gravel; Bedding: N25W/9ºSW At 21
feet: band of orangish-brown, coarse sand; cross-bedded with subangular gravel
lenses, very low cohesion Dense, dry
to damp, orange to dark reddish-brown, medium coarse SANDSTONE; laminated
and cross bedded, micaceous, low cohesion, basal contact N30W/
20ºSW Dense, damp, grayish-
white, Silty, very fine grained SANDSTONE;micaceous SM SM
SM
SP
SP
SM
104.
7
97.
8 12.
8 4.
3 LB1-
1 LB1-
2 3
5 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 1, Page 1 of 4 DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)
EZ BORE PENETRATIONRESISTANCE(
BLOWS/FT.)
BORING LB
1 CHUNK
SAMPLE
DATE
COMPLETED
SAMPLING UNSUCCESSFUL
SOIL
CLASS USCS)GROUNDWATERR. ADAMS
CONTENT (%)SAMPLE
NO.07-
05-2021 SAMPLE
SYMBOLS MOISTUREBY:EQUIPMENT ELEV. (
MSL.)233'
G2762-42-01.
GPJ MATERIAL DESCRIPTIONLITHOLOGY STANDARD
PENETRATION
TEST WATER
TABLE OR ... SEEPAGE 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
Dense to very dense, damp, dark reddish-brown to orangish-brown, fine to
medium SANDSTONE; massive to weakly laminated, bottom contact
N11W/17ºW Dense,
damp, whitish-gray, Silty, very fine grained SANDSTONE; laminated,highly
micaceous with pockets of 100% biotite/muscovite mica At
36 feet: 2-inch thick fine gravel bed; <1/2" subrounded to subangular gravel
At
40 feet: becomes weakly cemented with moderate cohesion At
44 feet: trace subrounded gravel At
46 feet: multiple krotovina At
48 to 50 feet: few dark reddish-brown to orangish-brown, fine sandstone interbeds,
laminated, soft sediment load structures present; Bedding:N30W/
7ºSW Dense to
very dense, damp, grayish-white, Silty, very fine grained SANDSTONE; massive,
micaceous, small irregular pockets of yellowish white, silt
present white some oxidation staining, trace subangular fine gravel SP SM
SM
87.
3
5.7 LB1-3
LB1-4
LB1-5
7 8
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-
2,Log of
Boring LB 1, Page 2 of 4 DRY DENSITY(
P.C.F.)...
DRIVE SAMPLE (
UNDISTURBED)EZ BORE
PENETRATIONRESISTANCE(BLOWS/
FT.)BORING
LB 1
CHUNK
SAMPLE
DATE
COMPLETED SAMPLING
UNSUCCESSFUL
SOIL CLASS USCS)GROUNDWATERR.
ADAMS CONTENT (%)
SAMPLENO.
07-05-2021
SAMPLE SYMBOLS MOISTUREBY:EQUIPMENT
ELEV. (MSL.)
233'G2762-42-
01.GPJ MATERIAL DESCRIPTIONLITHOLOGY
STANDARD
PENETRATION TEST
WATER TABLE OR ... SEEPAGE 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
Very dense, damp, orange-brown to reddish-brown, Silty, fine to medium
SANDSTONE; several coarse sand interbeds, massive, micaceous
At 71 to 72 feet: 1-foot thick yellowish-orange, siltstone bed; Bedding:
N20W/14ºSW Dense,
damp, grayish-white, Silty, very fine grained SANDSTONE; massive,micaceous,
low cohesion; Bedding: N10W/21ºW At 84
to 88 feet: few thin subrounded gravel beds SM SM
SM
LB1-
6
15 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-
2,Log of
Boring LB 1, Page 3 of 4 DRY DENSITY(
P.C.F.)...
DRIVE SAMPLE (
UNDISTURBED)EZ BORE
PENETRATIONRESISTANCE(BLOWS/
FT.)BORING
LB 1
CHUNK
SAMPLE
DATE
COMPLETED SAMPLING
UNSUCCESSFUL
SOIL CLASS USCS)GROUNDWATERR.
ADAMS CONTENT (%)
SAMPLENO.
07-05-2021
SAMPLE SYMBOLS MOISTUREBY:EQUIPMENT
ELEV. (MSL.)
233'G2762-42-
01.GPJ MATERIAL DESCRIPTIONLITHOLOGY
STANDARD
PENETRATION TEST
WATER TABLE OR ... SEEPAGE 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
BORING TERMINATED AT 92 FEET
Groundwater not encountered
Backfilled on 07-05-2021
SMLB1-7 20
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
90
92
Figure A-2,
Log of Boring LB 1, Page 4 of 4
DRY DENSITY(P.
C.F.)...
DRIVE SAMPLE (UNDISTURBED)
EZ BORE
PENETRATIONRESISTANCE(BLOWS/
FT.)BORING
LB
1
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.07-
05-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)233'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
SAN DIEGO FORMATION (Tsd)
Dense, dry to damp, orange-brown to reddish-brown, Silty, fine to medium
SANDSTONE; laminated, slightly bioturbated with pockets of
biotite/muscovite mica; Bedding: N30W/14ºSW Dense,
dry to damp, orange-brown, Silty, medium coarse SANDSTONE;some
subrounded gravel, laminated, low cohesion Dense
to very dense, damp, grayish-white to pale yellowish-white, sitly, fine SANDSTONE;
highly micaceous, cross-bedded At
9 feet: becomes orange-brown to reddish-brown At
10 feet: 2-inch thick subrounded/subangular gravel bed Dense,
damp, whitish-gray, Sitly, very fine grained SANDSTONE; highly micaceous,
powdery texture, moderate cohesion, pocket of biotite/muscovite,mica
throughout, trace 1/4"-1/5" subrounded gravel At
22 feet: medium to coarse, reddish-brown sandstone bed; Bedding:N5E/
11ºW At 24
to 26 feet: some bioturation At 27
feet: becomes massive SM SP
SM
SM
LB2-
1
LB2-2
5 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-
3,Log of
Boring LB 2, Page 1 of 3 DRY DENSITY(
P.C.F.)...
DRIVE SAMPLE (
UNDISTURBED)EZ BORE
PENETRATIONRESISTANCE(BLOWS/
FT.)BORING
LB 2
CHUNK
SAMPLE
DATE
COMPLETED SAMPLING
UNSUCCESSFUL
SOIL CLASS USCS)GROUNDWATERR.
ADAMS CONTENT (%)
SAMPLENO.
07-06-2021
SAMPLE SYMBOLS MOISTUREBY:EQUIPMENT
ELEV. (MSL.)
204'G2762-42-
01.GPJ MATERIAL DESCRIPTIONLITHOLOGY
STANDARD
PENETRATION TEST
WATER TABLE OR ... SEEPAGE 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
Dense, damp, bluish-gray, Silty, fine to medium SANDSTONE; some
subrounded cobble up to 8-inch diameter, moderately lubricated; Bedding:
N10E/15ºW Dense,
damp, whitish-gray, Silty, very fine grained SANDSTONE; massive to weakly
laminated, minor bioturation Very
dense, damp, pale yellowish-brown, Silty, fine to medium SANDSTONE;
few coarse grained laminate Dense,
dry to damp, orange-brown to gayish-brown, medium to coarse SANDSTONE;
cross-bedded, low cohesion, few subrounded and imbricated clay
rip clasts 1/2"-3" long; Bedding: NS/10ºW Very dense,
damp, orange-brown, Silty, very fine grained SANDSTONE;massive At
49
feet: contact is offset 4-inch along high angle closed fracture; Fracture:N310E/Vertical,
Bedding: N10W/11ºW At 59 to
60 feet: trace subrounded cobble up to 4-inch diameter SM SM SM
SM
SP
SM
LB2-
3
10
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 2, Page 2 of 3 DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)
EZ BORE PENETRATIONRESISTANCE(
BLOWS/FT.)
BORING LB
2 CHUNK
SAMPLE
DATE
COMPLETED
SAMPLING UNSUCCESSFUL
SOIL
CLASS USCS)GROUNDWATERR. ADAMS
CONTENT (%)SAMPLE
NO.07-
06-2021 SAMPLE
SYMBOLS MOISTUREBY:EQUIPMENT ELEV. (
MSL.)204'
G2762-42-01.
GPJ MATERIAL DESCRIPTIONLITHOLOGY STANDARD
PENETRATION
TEST WATER
TABLE OR ... SEEPAGE 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
At 64 feet: becomes bluish-gray to whitish-gray, Silty, very fine grained
SANDSTONE; Bedding: N10W/12ºW Very
dense, damp, grayish-brown to bluish-gray, Silty, fine to meduim SANDSTONE;
massive, oxidation mottling in bioturbated areas BORING
TERMINATED AT 81 FEET Groundwater
not encountered Backfilled
on 07-06-2021 SM
SM
LB2-
4 LB2-
5 18
20
DISTURBED
OR BAG SAMPLE GEOCON
DEPTH
IN
FEET
60
62
64
66
68
70
72
74
76
78
80
Figure
A-3,Log
of Boring LB 2, Page 3 of 3 DRY
DENSITY(P.C.
F.)... DRIVE
SAMPLE (UNDISTURBED)EZ
BORE PENETRATIONRESISTANCE(
BLOWS/FT.)
BORING LB
2
CHUNK
SAMPLE
DATE COMPLETED
SAMPLING
UNSUCCESSFUL SOIL CLASS USCS)
GROUNDWATERR. ADAMS
CONTENT (%)SAMPLE
NO.07-06-
2021 SAMPLE SYMBOLS MOISTUREBY:
EQUIPMENTELEV. (
MSL.)204'G2762-
42-01.GPJ MATERIAL
DESCRIPTIONLITHOLOGY
STANDARD PENETRATION
TEST WATER TABLE OR ... SEEPAGE 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
ALLUVIUM (Qal)
Medium dense, dry to damp, reddish-brown, Clayey, fine to medium SAND;
abundant caliche, some silt, blocky, slightly porous.
At 2 feet: becomes moist
At 3 feet: clay films and manganese films on parting surface pockets/lenses of
sandy clay present
At 6 feet: occasional subrounded gravel
At 9 feet: pin-hole porosity and manganese films present with blocky
structure and trace subrounded gravel, no caliche
Dense, damp, yellowish-brown, Silty, fine to medium SAND; trace clay, trace
subrounded gravel
At 11 feet: becomes weakly cemented, cobble up to 6-inch diameter
SAN DIEGO FORMATION (Tsd)
Dense, damp, pale yellowish-brown to whitish-brown, Sitly, fine
SANDSTONE; massive, weakly bioturbated, trace angular gravel
TRENCH TERMINATED AT 16 FEET
Groundwater not encountered
Backfilled on 06-30-2021
SC
SM
SM
TP1-1
TP1-2
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
Figure A-4,
Log of Test Pit TP 1, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
1
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)152'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
TOPSOIL
Firm, dry, pale brown, fine Sandy SILT; trace gravel and cobble
ALLUVIUM (Qal)
Dense, dry to damp, yellowish-brown, Sitly, fine SAND; trace subrounded to
subangular gravel, some porosity
SAN DIEGO FORMATION (Tsd)
Very dense, damp, yellowish-brown, Silty, very fine grained SAND; trace
porosity, few clay lined burrows and abundant oxidation mottling
TRENCH TERMINATED AT 12 FEET
Groundwater not encountered
Backfilled on 06-30-2021
ML
SM
SM
TP2-1
TP2-2
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
Figure A-5,
Log of Test Pit TP 2, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
2
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)153'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
TOPSOIL
Firm dry, pale pinkish-brown to grayish brown, fine to medium Sandy SILT;
porous
ALLUVIUM (Qal)
Medium dense, moist, dark brown to reddish-brown, Clayey, fine to coarse
SAND; trace subrounded gravel
At 4 feet: subrounded gravel/cobble up to 4-inch in diameter
At 4 feet: abundant pin-hole porosity
At 6 feet: becomes dense, blocky texture with clay films on parting surfaces
SAN DIEGO FORMATION (Tsd)
Dense to very dense, damp, orangish-brown to pale yellowish-brown, very
fine Sandy SILT; some pinhole porosity
Dense, damp, whitish-gray, Silty, fine fine grained SANDSTONE; powdery
texture when excavated; micaceous
TRENCH TERMINATED AT 14 FEET
Groundwater not encountered
Backfilled on 06-30-2021
ML
SC
ML
SM
TP3-1
TP3-2
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
Figure A-6,
Log of Test Pit TP 3, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
3
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)165'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
TOPSOIL
Loose, dry, pale brown, Silty GRAVEL; rounded to subrounded gravel up to
6-inch diameter
TERRACE DEPOSITS (Qt)
Dense, dry to damp, pale yellowish-brown, fine to medium Sandy GRAVEL;
subrounded gravel and cobble up to 10-inch diameter
SAN DIEGO FORMATION (Tsd)
Dense, damp, light gray to pale yellowish-gray, Silty, very fine grained
SANDSTONE; micaceous, powdery texture, some gravel and cobble up to
6-inch diameter (subrounded)
TRENCH TERMINATED AT 10 FEET
Groundwater not encountered
Backfilled on 06-30-2021
GM
GP
SM
TP4-1
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
Figure A-7,
Log of Test Pit TP 4, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
4
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)185'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
TOPSOIL
Soft to firm, dry, pale pinkish-brown to brown, Sandy SILT; porous, abundant
rootlets
ALLUVIUM (Qal)
Loose to medium dense, dry to damp, Clayey, fine to medium SAND; blocky,
clay/manganese films on parting surfaces
At 4 feet: cobble layer, subrounded up to 12-inch diameter
SAN DIEGO FORMATION (Tsd)
Dense, dry to damp, orangish brown to yellowish gray, Silty, fine to medium
SAND; weakly cemented, bioturbated with few 1/8-inch open burrows, trace
caliche, oxidation, mottling, no gravel or cobble
At 7 feet: becomes yellowish orange, very dense
At 10 feet: shell fragments observed
TRENCH TERMINATED AT 12 FEET
Groundwater not encountered
Backfilled on 06-30-2021
ML
SC
SM
TP5-1
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
Figure A-8,
Log of Test Pit TP 5, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
5
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)173'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
TOPSOIL
Firm to stiff, dry, brown to grayish-brown, Silty SAND; strong blocky
structure, good ped development
SAN DIEGO FORMATION (Tsd)
Dense, dry, very pale yellowish-brown to whitish-gray, Sitly, very fine grained
SAND; powdery texture in places, massive, weakly, bioturbated, some
oxidation mottling
TRENCH TERMINATED AT 5 FEET
Groundwater not encountered
Backfilled on 06-30-2021
SM
SM
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
Figure A-9,
Log of Test Pit TP 6, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
6
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)178'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
TOPSOIL
Hard, dry, brown, Clayey SILT; trace gravel
ALLUVIUM (Qal)
Hard, moist, reddish-brown, fine to medium Sandy CLAY; trace gravel, some
caliche
SAN DIEGO FORMATION (Tsd)
Medium dense to dense, damp to moist, orangish-brown, Silty, fine to coarse
SAND; some caliche, weathered, trace clay
At 4.5 feet: becomes yellowish-brown, some cobble
Dense, damp, pale yellowish-brown, Sitly, very fine grained SAND; massive,
oxidation mottling
TRENCH TERMINATED AT 8 FEET
Groundwater not encountered
Backfilled on 06-30-2021
ML
CL
SM
SM
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-10,
Log of Test Pit TP 7, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
7
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)176'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
TOPSOIL
Soft to stiff, dry to moist, grayish-brown to dark reddish brown, Sandy
CLAY; trace gravel
ALLUVIUM (Qal)
Medium dense, damp to moist, reddish-brown to orangish-brown, Clayey, fine
to coarse SAND and Sandy CLAY; weathered
SAN DIEGO FORMATION (Tsd)
Dense to vern dense, damp, whitish-gray, Silty, very fine grained SAND;
powder texture, micaceous
TRENCH TERMINATED AT 9 FEET
Groundwater not encountered
Backfilled on 06-30-2021
CL
SC
SM
TP8-1
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-11,
Log of Test Pit TP 8, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
8
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)204'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
SAN DIEGO FORMATION (Tsd)
Very dense, dry to damp, pale yellowish-brown to gray, Silty, fine fine grained
SANDSTONE; massive
At 2 feet: subrounded gravel layer, 4-inch thick
At 5-7 feet: thin subvertical 1/4-inch, clay filled fractures
At 6.5 feet: subrounded pods of caliche
TRENCH TERMINATED AT 7 FEET
Groundwater not encountered
Backfilled on 06-30-2021
SM
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
Figure A-12,
Log of Test Pit TP 9, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
9
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)223'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
UNDOCUMENTED FILL (Qudf)
Loose to medium dense, dry to damp, brown to grayish-brown, Clayey, fine to
medium SAND; abundant cobble, fill place for perimeter berm
SAN DIEGO FORMATION (Tsd)
Very dense, damp, pale yellowish-brown to grayish-brown, Silty, very fine
grained SANDSTONE; trace gravel, massive, oxidation mottling throughout
TRENCH TERMINATED AT 8 FEET
Groundwater not encountered
Backfilled on 06-30-2021
SC
SM
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-13,
Log of Test Pit TP 10, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
10
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)205'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
UNDOCUMENTED FILL (Qudf)
Loose, dry, pale reddish-brown, fine Sandy SILT; abundant, cobbles and
chunks of the brownish black sandy clay topsoil
SAN DIEGO FORMATION (Tsd)
Very dense, damp, whitish-gray to yellowish-gray, Silty, very fine grained
SANDSTONE; massive
At 4.5 feet: 4-inch thick coarse grained, orangish-black sand bed; Bedding:
N20W/6ºW TRENCH
TERMINATED AT 6 FEET Groundwater
not encountered Backfilled
on 06-30-2021 ML
SM
DISTURBED
OR BAG SAMPLE GEOCON
DEPTH
IN
FEET
0
2
4
6
Figure
A-14,Log
of Test Pit TP 11, Page 1 of 1 DRY
DENSITY(P.C.
F.)... DRIVE SAMPLE (
UNDISTURBED)BACKHOE CAT 430F
PENETRATIONRESISTANCE(BLOWS/
FT.)TEST
PIT TP
11
CHUNK
SAMPLE
DATE COMPLETED
SAMPLING
UNSUCCESSFUL SOIL CLASS USCS)
GROUNDWATERR. ADAMS
CONTENT (%)SAMPLE
NO.06-30-
2021 SAMPLE SYMBOLS MOISTUREBY:
EQUIPMENTELEV. (
MSL.)213'G2762-
42-01.GPJ MATERIAL
DESCRIPTIONLITHOLOGY
STANDARD PENETRATION
TEST WATER TABLE OR ... SEEPAGE 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
SAN DIEGO FORMATION (Tsd)
Very dense, dry to damp, pale yellowish-brown, Silty, very fine grained
SANDSTONE
TRENCH TERMINATED AT 2 FEET
Groundwater not encountered
Backfilled on 06-30-2021
SM
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
Figure A-15,
Log of Test Pit TP 12, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
12
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)227'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
VERY OLD PARALIC DEPOSITS (Qvop)
Dense, dry to damp, brown to grayish-brown, medium coarse SAND with
cobble; cobble +/-30%, subrounded up to 10-inch diameter
SAN DIEGO FORMATION (Tsd)
Dense, damp to moist, yellowish-brown, Silty, fine to medium SANDSTONE
TRENCH TERMINATED AT 10 FEET
Groundwater not encountered
Backfilled on 06-30-2021
GP
SM
TP13-1
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
Figure A-16,
Log of Test Pit TP 13, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
13
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)231'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
TOPSOIL
Soft, dry, light brown, Clayey SAND; trace cobble
Stiff, moist, blackish-brown, Sandy CLAY; some gravel and cobble
ALLUVIUM (Qal)
Loose to medium dense, moist, brownish-black, Clayey SAND; some gravel
and cobble, pin-hole porosity throughout
SAN DIEGO FORMATION (Tsd)
Medium dense, moist, pinkish-brown to yellowish brown, Clayey, fine to
medium SANDSTONE, mottled, weathered, manganese films on parting
surfaces
Dense, moist, pale yellowish-brown to yellowish-gray, Silty, very fine grained
SANDSTONE; massive, friable
TRENCH TERMINATED AT 9 FEET
Groundwater not encountered
Backfilled on 06-30-2021
SC
CL
SC
SC
SM
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-17,
Log of Test Pit TP 14, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
14
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)212'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
TOPSOIL
Loose, dry to damp, brown, Silty, fine SAND; some cobble
ALLUVIUM (Qal)
Stiff, moist, grayish-brown, Sandy CLAY; trace gravel and cobble; pinhole
porosity
VERY OLD PARALIC DEPOSITS (Qvop)
Dense, damp, reddish-brown to brown, medium to coarse SAND with gravel;
trace silt
SAN DIEGO FORMATION (Tsd)
Dense, damp, yellow to pale yellowish-gray, Silty, fine to medium
SANDSTONE
TRENCH TERMINATED AT 16 FEET
Groundwater not encountered
Backfilled on 06-30-2021
SM
CL
GP
SM
TP15-1
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
Figure A-18,
Log of Test Pit TP 15, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
15
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)215'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
TOPSOIL
Soft to firm, dry to damp, brown, Sandy CLAY; some gravel and cobble
VERY OLD PARALIC DEPOSITS (Qvop)
Dense, damp, orange brown, SAND with cobble; cobble subrounded up to
12-inch diameter
SAN DIEGO FORMATION (Tsd)
Dense, damp, pale, yellowish-brown to grayish brown, Silty, fine
SANDSTONE; massive, micaceous
TRENCH TERMINATED AT 9 FEET
Groundwater not encountered
Backfilled on 06-30-2021
CL
SW
SM
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-19,
Log of Test Pit TP 16, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
16
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)213'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
TOPSOIL
Loose, dry to damp, brown to pale reddish brown, fine to medium Sandy
SILT; trace gravel
SAN DIEGO FORMATION (Tsd)
Dense, damp, pale yellowish-brown to yellowish-orange, Silty, very fine
grained SANDSTONE; massive, mottled, weathered in upper 3 feet, trace
gravel, micaceous
TRENCH TERMINATED AT 8 FEET
Groundwater not encountered
Backfilled on 06-30-2021
ML
SM
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-20,
Log of Test Pit TP 17, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
17
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)198'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
TOPSOIL
Soft to stiff, dry to moist, light brown to reddish-brown, Silty CLAY; trace
sand, manganese coatings on parting surfaces
ALLUVIUM (Qal)
Medium dense to dense, moist, orange brown, Clayey, medium to coarse
SAND; few gravel and cobble
SAN DIEGO FORMATION (Tsd)
Dense, damp to moist, pale yellowish-brown to yellowish-gray, Silty, fine to
medium SANDSTONE; micaceous, mottled
TRENCH TERMINATED AT 8 FEET
Groundwater not encountered
Backfilled on 06-30-2021
CL
SC
SM
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-21,
Log of Test Pit TP 18, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
18
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)190'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
TOPSOIL
Soft, dry, pale reddish-brown, Sandy SILT; trace gravel
TERRACE DEPOSITS (Qt)
Dense, moist, yellow to yellowish-brown, Clayey, fine to medium SAND
with cobble; caliche stringers common, cobble is subrounded up to 10-inch
diameter
TRENCH TERMINATED AT 12 FEET
Groundwater not encountered
Backfilled on 06-30-2021
ML
SC
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
Figure A-22,
Log of Test Pit TP 19, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
19
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)173'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
TOPSOIL
Loose, dry, olive brown, Silty, very fine grained SAND; trace subrounded
gravel
SAN DIEGO FORMATION (Tsd)
Dense, damp, orangish-brown to whitish-gray, Silty, very fine grained
SANDSTONE; highly micaceous
TRENCH TERMINATED AT 7 FEET
Groundwater not encountered
Backfilled on 06-30-2021
SM
SM
DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
Figure A-23,
Log of Test Pit TP 20, Page 1 of 1
DRY DENSITY(P.
C.F.)... DRIVE
SAMPLE (UNDISTURBED)BACKHOE CAT
430F PENETRATIONRESISTANCE(
BLOWS/FT.)
TEST PIT
TP
20
CHUNK
SAMPLE DATE
COMPLETED
SAMPLING UNSUCCESSFUL SOIL CLASS
USCS)GROUNDWATERR.
ADAMSCONTENT (%)
SAMPLE NO.06-
30-2021 SAMPLE SYMBOLS
MOISTUREBY:EQUIPMENT
ELEV. (MSL.)160'
G2762-42-01.GPJ
MATERIAL
DESCRIPTIONLITHOLOGY STANDARD
PENETRATION TEST WATER TABLE OR ... SEEPAGE 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
APPENDIX B
Geocon Project No. G2762-42-01 July 28, 2021
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 samples were tested
for in-situ dry density and moisture content, maximum dry density and optimum moisture content,
expansion potential, consolidation potential, gradation, soluble sulfate content, chloride content, p.H. and
resistivity, and shear strength. The results of these tests are summarized on the following tables and
figures. The in-place dry density and moisture content of the samples tested are presented on the boring
logs in Appendix A.
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D 1557-02
Sample No. Description Maximum Dry
Density (pcf)
Optimum
Moisture Content
dry wt.)
T1-1 Brown clayey fine to medium SAND 123.3 12.1
T1-2 Brown silty SAND with gravel 121.3 12.7
T3-2 Dark yellow Silty fine SAND 103.2 16.5
SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS
ASTM D 4829-03
Sample
No.
Moisture Content Dry
Density (pcf)
Expansion
IndexBeforeTest (%) After Test (%)
T1-1 10.9 22.0 107.3 46
T1-2 10.8 18.0 107.3 16
T3-1 8.3 13.8 116.8 0
T3-2 14.4 26.7 94.1 0
T8-1 11.7 28.0 103.8 99
Geocon Project No. G2762-42-01 July 28, 2021
SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULTS
CALIFORNIA TEST NO. 417
Sample No. Water-Soluble Sulfate Sulfate Exposure
T1-1 0.020 S0
T3-2 0.001 S0
SUMMARY OF LABORATORY WATER-SOLUBLE CHLORIDE ION CONTENT TEST RESULTS
AASHTO TEST NO. T 291
Sample No. Chloride Ion Content ppm (%)
T1-1 380 (0.038)
T3-2 71 (0.007)
SUMMARY OF LABORATORY POTENTIAL OF HYDROGEN (PH) AND
RESISTIVITY TEST RESULTS
CALIFORNIA TEST METHOD 643
Sample No. Geologic Unit pH Minimum Resistivity
ohm-centimeters)
T1-1 Qal 8.92 700
SUMMARY OF LABORATORY ATTERBERG LIMITS TEST RESULTS
ASTM D 4318
Sample
No.
Liquid Limit Plastic Limit Plasticity
Index
T1-1 42 20 22
T1-2 30 22 8
T3-2 Non Plastic Non Plastic Non Plastic
SAMPLE
NO.
GEOLOGIC
UNIT
LIQUID
LIMIT
PLASTIC
LIMIT
PLASTICITY
INDEX
SOIL TYPE
T1-1 Qal 42 20 22 CL
NUM! #DIV/0! #NUM! #NUM!
NUM! #DIV/0! #NUM! #NUM!
NUM! #DIV/0! #NUM! #NUM!
NUM! #DIV/0! #NUM! #NUM!
ML-OL
MH-OH High-Plasticity Silt to High-Plasticity, Organic Silt
CL-ML
High-Plasticity Clay
Low-Plasticity Clay
Low-Plasticity Silt
TEST RESULTS
SOIL TYPE DESCRIPTION
CH
CL
ML
Low-Plasticity Clay to Low-Plasticity Silt
Low-Plasticity Silt to Low-Plasticity, Organic Silt
PLASTICITY INDEX - ASTM D 4318
SHINOHARA
PROJECT NO.: G2762-42-01
0
10
20
30
40
50
60
70
80
0 10 20 30 40 50 60 70 80 90 100 110120PLASTICITY
INDEXLIQUID LIMIT
T1-1
CH
MH-OH
ML-OL
CL
ML
CL-ML
HIGHPLASTICITYLOWPLASTICITY
SAMPLE
NO.
GEOLOGIC
UNIT
LIQUID
LIMIT
PLASTIC
LIMIT
PLASTICITY
INDEX
SOIL TYPE
T1-2 Qal 30 22 8 CL
NUM! #DIV/0! #NUM! #NUM!
NUM! #DIV/0! #NUM! #NUM!
NUM! #DIV/0! #NUM! #NUM!
NUM! #DIV/0! #NUM! #NUM!
ML-OL
MH-OH High-Plasticity Silt to High-Plasticity, Organic Silt
CL-ML
High-Plasticity Clay
Low-Plasticity Clay
Low-Plasticity Silt
TEST RESULTS
SOIL TYPE DESCRIPTION
CH
CL
ML
Low-Plasticity Clay to Low-Plasticity Silt
Low-Plasticity Silt to Low-Plasticity, Organic Silt
PLASTICITY INDEX - ASTM D 4318
SHINOHARA
PROJECT NO.: G2762-42-01
0
10
20
30
40
50
60
70
80
0 10 20 30 40 50 60 70 80 90 100 110120PLASTICITY
INDEXLIQUID LIMIT
T1-2
CH
MH-OH
ML-OL
CL
ML
CL-ML
HIGHPLASTICITYLOWPLASTICITY
Qal
D10 (mm)D30 (mm)D60 (mm)
0.016 0.048 0.105
SIEVE ANALYSES - ASTM D 135
SHINOHARA
PROJECT NO.:
U.S. STANDARD SIEVE SIZE
G2762-42-01
SAMPLE NO.:T1-1 GEOLOGIC UNIT:
SAMPLE DEPTH (FT.):2'-4'
Cc
1.4
TEST DATA
SOIL DESCRIPTION
SC - ClayeySAND6.6
Cu6"5"
4"
3"
2"
1-
1/
2"
1"
3/
4"
1/
2"3/8"#
4#8#10#
16#20#30#
40#
50#
Qal
D10 (mm)D30 (mm)D60 (mm)
0.023 0.068 0.132
SIEVE ANALYSES - ASTM D 135
SHINOHARA
PROJECT NO.:
U.S. STANDARD SIEVE SIZE
G2762-42-01
SAMPLE NO.:T1-2 GEOLOGIC UNIT:
SAMPLE DEPTH (FT.):10'-12'
Cc
1.5
TEST DATA
SOIL DESCRIPTION
SM - Silty SAND withgravel5.9
Cu6"5"
4"
3"
2"
1-
1/
2"
1"
3/
4"
1/
2"3/8"#
4#8#10#
16#20#30#
40#
50#
Tsd
D10 (mm)D30 (mm)D60 (mm)
0.047 0.089 0.121
SIEVE ANALYSES - ASTM D 135
SHINOHARA
PROJECT NO.:
U.S. STANDARD SIEVE SIZE
G2762-42-01
SAMPLE NO.:T3-2 GEOLOGIC UNIT:
SAMPLE DEPTH (FT.):10'-12'
Cc
1.4
TEST DATA
SOIL DESCRIPTION
SM - SiltySAND2.6
Cu6"5"
4"
3"
2"
1-
1/
2"
1"
3/
4"
1/
2"3/8"#
4#8#10#
16#20#30#
40#
50#
1 K 2 K 4 K AVERAGE
1000 2000 4000 --
13.0 13.2 12.2 12.8
100.7 108.8 104.5 104.7
1 K 2 K 4 K AVERAGE
28.7 25.9 26.1 26.9
1125 1599 3046 --
1004 1602 3046 --
400
33
280
34
INITIAL CONDITIONS
FRICTION ANGLE (DEGREES)
ULTIMATE
COHESION, C (PSF)
FRICTION ANGLE (DEGREES)
NORMAL STRESS TEST LOAD
ACTUAL NORMAL STRESS (PSF):
WATER CONTENT (%):
AFTER TEST CONDITIONS
Tsd
N
SAMPLE NO.:
SAMPLE DEPTH (FT):
LB1-1
10'-11'
GEOLOGIC UNIT:
NATURAL/REMOLDED:
DRY DENSITY (PCF):
517 SHINOHARA
G2762-42-01
DIRECT SHEAR - ASTM D 3080
NORMAL STRESS TEST LOAD
WATER CONTENT (%):
PEAK SHEAR STRESS (PSF):
ULT.-E.O.T. SHEAR STRESS (PSF):
RESULTS
PEAK
COHESION, C (PSF)
PROJECT NO.:
0
500
1000
1500
2000
2500
3000
3500
4000
0 0.05 0.1 0.15 0.2 0.25 0.3SHEAR
STRESS (PSF)HORIZONTAL
DEFORMATION (IN)1 K 2 K
4 K 1 K PEAK 2 K PEAK 4
K PEAK 1 K ULTIMATE 2 K ULTIMATE 4
K ULTIMATE
4 K
2 K
1
K
0
1000
2000
3000
4000
5000
6000 7000 0 1000 2000 30004000
5000 6000SHEAR STRESS (
PSF)
NORMAL
STRESS (
PSF)
0
1000
2000
3000
4000 5000 6000 7000 0 10002000
3000 4000 5000
1 K 2 K 4 K AVERAGE
1000 2000 4000 --
4.0 4.8 4.1 4.3
95.3 97.4 100.8 97.8
1 K 2 K 4 K AVERAGE
23.1 21.5 19.5 21.4
1118 1687 3348 --
1112 1693 3046 --
290
37
440
33
DRY DENSITY (PCF):
SHINOHARA
G2762-42-01
DIRECT SHEAR - ASTM D 3080
NORMAL STRESS TEST LOAD
WATER CONTENT (%):
PEAK SHEAR STRESS (PSF):
ULT.-E.O.T. SHEAR STRESS (PSF):
RESULTS
PEAK
COHESION, C (PSF)
PROJECT NO.:
Tsd
N
SAMPLE NO.:
SAMPLE DEPTH (FT):
LB 1-2
20'
GEOLOGIC UNIT:
NATURAL/REMOLDED:
INITIAL CONDITIONS
FRICTION ANGLE (DEGREES)
ULTIMATE
COHESION, C (PSF)
FRICTION ANGLE (DEGREES)
NORMAL STRESS TEST LOAD
ACTUAL NORMAL STRESS (PSF):
WATER CONTENT (%):
AFTER TEST CONDITIONS
500
0
500
1000
1500
2000
2500
3000
3500
4000
0.05 0 0.05 0.1 0.15 0.2 0.25 0.3SHEAR
STRESS (PSF)HORIZONTAL
DEFORMATION (IN)1 K 2 K
4 K 1 K PEAK 2 K PEAK 4
K PEAK 1 K ULTIMATE 2 K ULTIMATE 4
K ULTIMATE
4 K
2 K
1
K
0
1000
2000
3000
4000
5000
6000 7000 0 1000 2000 30004000
5000 6000SHEAR STRESS (
PSF)
NORMAL
STRESS (
PSF)
0
1000
2000
3000
4000 5000 6000 7000 0 10002000
3000 4000 5000
1 K 2 K 4 K AVERAGE
1000 2000 4000 --
5.2 5.4 6.4 5.7
94.5 81.3 86.3 87.3
1 K 2 K 4 K AVERAGE
28.3 37.5 35.1 33.6
1086 1586 3338 --
793 1563 3361 --
210
37
0
39
DRY DENSITY (PCF):
517 SHINOHARA
G2762-42-01
DIRECT SHEAR - ASTM D 3080
NORMAL STRESS TEST LOAD
WATER CONTENT (%):
PEAK SHEAR STRESS (PSF):
ULT.-E.O.T. SHEAR STRESS (PSF):
RESULTS
PEAK COHESION, C (PSF)
PROJECT NO.:
Tsd
N
SAMPLE NO.:
SAMPLE DEPTH (FT):
LB 1-4
40'
GEOLOGIC UNIT:
NATURAL/REMOLDED:
INITIAL CONDITIONS
FRICTION ANGLE (DEGREES)
ULTIMATE COHESION, C (PSF)
FRICTION ANGLE (DEGREES)
NORMAL STRESS TEST LOAD
ACTUAL NORMAL STRESS (PSF):
WATER CONTENT (%):
AFTER TEST CONDITIONS
0
500
1000
1500
2000
2500
3000
3500
4000
0.05 0 0.05 0.1 0.15 0.2 0.25 0.3SHEAR
STRESS PSF)HORIZONTAL
DEFORMATION IN)1 K 2 K
4 K 1 K PEAK 2 K PEAK 4
K PEAK 1 K ULTIMATE 2 K ULTIMATE 4
K ULTIMATE
4 K
2 K
1
K
0
1000
2000
3000
4000
5000
6000 7000 0 1000 2000 30004000
5000 6000SHEAR STRESS
PSF)
NORMAL
STRESS
PSF)
0
1000
2000
3000
4000 5000 6000 7000 0 10002000
3000 4000 5000
SAMPLE NO.:GEOLOGIC UNIT:
SAMPLE DEPTH (FT):NATURAL/REMOLDED:
1 K 2 K 4 K AVERAGE
890 2030 4300 --
13.1 10.7 11.5 11.8
109.6 113.3 112.6 111.8
1 K 2 K 4 K AVERAGE
19.0 16.8 18.0 17.9
1141 1904 2866 --
1103 1904 2866 --
780
26
750
27
COHESION, C (PSF)
DRY DENSITY (PCF):
AFTER TEST CONDITIONS
T1-1
G2762-42-01
SHINOHARA
COHESION, C (PSF)
FRICTION ANGLE (DEGREES)
DIRECT SHEAR - ASTM D 3080
PROJECT NO.:
FRICTION ANGLE (DEGREES)
NORMAL STRESS TEST LOAD
ACTUAL NORMAL STRESS (PSF):
WATER CONTENT (%):
ULTIMATE
RESULTS
PEAK
Qal
2'-4'
NORMAL STRESS TEST LOAD
WATER CONTENT (%):
PEAK SHEAR STRESS (PSF):
ULT.-E.O.T. SHEAR STRESS (PSF):
INITIAL CONDITIONS
R
0
500
1000
1500
2000
2500
3000
3500
0.000 0.050 0.100 0.150 0.200 0.250 0.300SHEAR
STRESS (PSF)HORIZONTAL
DEFORMATION (IN)1 K 2 K
4 K 1 K PEAK 2 K PEAK 4
K PEAK 1 K ULTIMATE 2 K ULTIMATE 4
K ULTIMATE
4 K
2 K
1
K
0
1000
2000
3000
4000
5000
6000 7000 0 1000 2000 30004000
5000 6000SHEAR STRESS (
1 K 2 K 4 K AVERAGE
1000 2000 4000 --
13.6 12.8 13.3 13.2
109.0 109.3 109.2 109.2
1 K 2 K 4 K AVERAGE
17.5 16.9 21.6 18.7
1219 2012 3530 --
1160 2012 3530 --
460
38
400
38
INITIAL CONDITIONS
FRICTION ANGLE (DEGREES)
ULTIMATE
COHESION, C (PSF)
FRICTION ANGLE (DEGREES)
NORMAL STRESS TEST LOAD
ACTUAL NORMAL STRESS (PSF):
WATER CONTENT (%):
AFTER TEST CONDITIONS
Qal
R
SAMPLE NO.:
SAMPLE DEPTH (FT):
T1-2
10'-12'
GEOLOGIC UNIT:
NATURAL/REMOLDED:
DRY DENSITY (PCF):
SHINOHARA
G2762-42-01
DIRECT SHEAR - ASTM D 3080
NORMAL STRESS TEST LOAD
WATER CONTENT (%):
PEAK SHEAR STRESS (PSF):
ULT.-E.O.T. SHEAR STRESS (PSF):
RESULTS
PEAK
COHESION, C (PSF)
PROJECT NO.:
0
500
1000
1500
2000
2500
3000
3500
4000
0 0.05 0.1 0.15 0.2 0.25 0.3SHEAR
STRESS (PSF)HORIZONTAL
DEFORMATION (IN)1 K 2 K
4 K 1 K PEAK 2 K PEAK 4
K PEAK 1 K ULTIMATE 2 K ULTIMATE 4
K ULTIMATE
4 K
2 K
1
K
0
1000
2000
3000
4000
5000
6000 7000 0 1000 2000 30004000
5000 6000SHEAR STRESS (
PSF)
NORMAL
STRESS (
PSF)
0
1000
2000
3000
4000 5000 6000 7000 0 10002000
3000 4000 5000
SAMPLE NO.:GEOLOGIC UNIT:
SAMPLE DEPTH (FT):NATURAL/REMOLDED:
1 K 2 K 4 K AVERAGE
890 2030 4300 --
18.5 16.8 18.3 17.9
90.9 92.8 91.2 91.6
1 K 2 K 4 K AVERAGE
32.7 29.7 31.1 31.2
886 1518 2904 --
886 1461 2866 --
340
31
330
30
COHESION, C (PSF)
DRY DENSITY (PCF):
AFTER TEST CONDITIONS
T3-2
G2762-42-01
SHINOHARA
COHESION, C (PSF)
FRICTION ANGLE (DEGREES)
DIRECT SHEAR - ASTM D 3080
PROJECT NO.:
FRICTION ANGLE (DEGREES)
NORMAL STRESS TEST LOAD
ACTUAL NORMAL STRESS (PSF):
WATER CONTENT (%):
ULTIMATE
RESULTS
PEAK
Tsd
10'-12'
NORMAL STRESS TEST LOAD
WATER CONTENT (%):
PEAK SHEAR STRESS (PSF):
ULT.-E.O.T. SHEAR STRESS (PSF):
INITIAL CONDITIONS
R
0
500
1000
1500
2000
2500
3000
3500
0.000 0.050 0.100 0.150 0.200 0.250 0.300SHEAR
STRESS (PSF)HORIZONTAL
DEFORMATION (IN)1 K 2 K
4 K 1 K PEAK 2 K PEAK 4
K PEAK 1 K ULTIMATE 2 K ULTIMATE 4
K ULTIMATE
4 K
2 K
1
K
0
1000
2000
3000
4000
5000
6000 7000 0 1000 2000 30004000
5000 6000SHEAR STRESS (
SAMPLE NO.:Qal
SAMPLE DEPTH (FT):
B1-3
7.5'
GEOLOGIC UNIT:
TEST INFORMATION
120.0
PROJECT NO.: G2762-42-01
8.3%
INITIAL DRY DENSITY (PCF):
INITIAL WATER CONTENT (%):
SAMPLE SATURATED AT (KSF):
INITIAL SATURATION (%):
4.0
57.4%
CONSOLIDATION CURVE - ASTM D 2435
SHINOHARA
2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.10 1.00 10.00VERTICAL
STRAIN (%)APPLIED PRESSURE (
SAMPLE NO.:Qal
SAMPLE DEPTH (FT):
B1-4
10'
GEOLOGIC UNIT:
TEST INFORMATION
117.7
PROJECT NO.: G2762-42-01
8.1%
INITIAL DRY DENSITY (PCF):
INITIAL WATER CONTENT (%):
SAMPLE SATURATED AT (KSF):
INITIAL SATURATION (%):
4.0
52.7%
CONSOLIDATION CURVE - ASTM D 2435
SHINOHARA
2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.10 1.00 10.00VERTICAL
STRAIN (%)APPLIED PRESSURE (
SAMPLE NO.:Qal
SAMPLE DEPTH (FT):
B1-5
15'
GEOLOGIC UNIT:
TEST INFORMATION
120.0
PROJECT NO.: G2762-42-01
9.5%
INITIAL DRY DENSITY (PCF):
INITIAL WATER CONTENT (%):
SAMPLE SATURATED AT (KSF):
INITIAL SATURATION (%):
4.0
65.9%
CONSOLIDATION CURVE - ASTM D 2435
SHINOHARA
2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.10 1.00 10.00VERTICAL
STRAIN (%)APPLIED PRESSURE (
APPENDIX C
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
FOR
517 SHINOHARA LANE
INDUSTRIAL BUILDING
SAN DIEGO, CALIFORNIA
PROJECT NO. G2762-42-01
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.
GI rev. 07/2015
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, Division 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), or
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 wide 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, should
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.
Geocon Project No. G2762-42-01 July 28, 2020
LIST OF REFERENCES
1. FEMA (2012), Flood Map Service Center, FEMA website, https://msc.fema.gov/portal/home,
flood map numbers 06073C2156G and 06073C2157G, effective May 16, 2012, accessed July
16, 2021;
2. Kennedy, M. P., and S. S. Tan, 2007, Geologic Map of the Oceanside 30’x60’ Quadrangle,
California, USGS Regional Map Series Map No. 1, Scale 1:100,000.
3. SEAOC (2019), OSHPD Seismic Design Maps: Structural Engineers Association of
California website, http://seismicmaps.org/, accessed July 19, 2021;
4. USGS (2019), Quaternary Fault and Fold Database of the United States: U.S. Geological
Survey website, https://www.usgs.gov/natural-hazards/earthquake-hazards/faults, accessed
July 19, 2021;
5. Unpublished reports and maps on file with Geocon Incorporated.