HomeMy WebLinkAboutSDP 2020-0006; AMAZON VEHICLE STORAGE; PRELIMINARY GEOTECHNICAL INVESTIGATION; 2020-09-29ALTA CALIFORNIA
GEOTECHNICAL INC.
GREYSTAR
444 South Cedros Avenue
Solana Beach, California 92075
Attention:
Subject:
Mr. Beau Brand
PRELIMINARY GEOTECHNICAL INVESTIGATION
5980 Eagle Drive
City of Carlsbad, California.
References: See Appendix A
Dear Mr. Brand:
170 North Maple Street, Suite 108
Corona, CA 92878
www.altageotechnical.com
September 29, 2020
Project No. 1·0346
Presented herein is Alta California Geotechnical, lnc.'s (Alta) preliminary geotechnical
investigation for the proposed parking lot, located at 5980 Eagle Drive, in the City of Carlsbad,
California. This report is based on a recent subsurface investigation conducted by Alta,
laboratory testing, review of the grading plans and a review of the referenced reports.
Alta's review of the data indicates that the proposed development is feasible, from a
geotechnical standpoint, provided that the recommendations presented in this report are
incorporated into the improvement plans and implemented during site development. Included
in this report are:
• Discussion of the site geotechnical conditions.
• Recommendations for remedial and site grading.
• Geotechnical site construction recommendations.
• Preliminary pavement design parameters:
Corona Office
Phone: 951.509. 7090
Project Number 1-0346
September 29, 2020
Page ii
If you have any questions or should you require any additional information, please contact the
undersigned at (951) 509-7090. Alta appreciates the opportunity to provide geotechnical
consulting services for your project.
Sincerely,
Alta California Geotechnical, Inc. Reviewed By:
FERNANDO RUIZ
Civil Engineering Associate
Engineering Geology Associate
Distribution: (1) Addressee
Reg.Exp.: 12-31-20 ___ __,
Registered Geotechnical Engineer
President
Reg. Exp.: 9-30
Certified Engineering Geologist
Vice President
SAG: TJC: FR: JC: 1-0346, September 29, 2020 (Preliminary Geotechnical Investigation, 5980 Eagle Drive,Carlsbad)
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
Page 1
1.0 INTRODUCTION ..........................................•....................................•.................................... 3
1.1 Purpose ......................................................•..•...........................................•.............. 3
1.2 Scope of Work ....................................•..........................................................•.......... 3
1.3 Report Limitations ................................................................................................... .3
2.0 PROJECT DESCRIPTION .........................................................................•.............................. .4
2.1 Site Location and Existing Conditions .........•........•.................................................. .4
2.2 Proposed Development ...............................................•...•..........•..............•............. 4
3.0 SITE INVESTIGATION ........................................................................................................... .4
3.1 Current Subsurface Investigation ........................................................................... .4
3.2 Infiltration Testing .................................................................................................... 5
4.0 GEOLOGIC CONDITIONS ........................•.............................................................................. 5
4.1 Geologic and Geomorphic Setting ........................•.................................................. 5
4.2 Stratigraphy .............................................•...•............................................................ 6
4.2.1 Artificial Fill-Undocumented (Map symbol afu) .................•........................ 6
4.3 Geologic Structure ........................................•...•...................................................... 6
4.3.1 Tectonic Framework ...........................................................................•...•.... 6
4.3.2 Regionally Mapped Active Faults .............................................................•... ?
4.3.3 Geologic Structure ....................................................................................... 7
4.4 Groundwater ..•..•.•..........................................................•......................................... ?
4.5 Earthquake Hazards ........................•........................................................................ 7
4.5.1 Local and Regional Faulting ......................................................................... 7
4.5.2 Surface Rupture ........•...........................................•...................................... 8
4.5.3 Liquefaction ................................................................................................. 8
5.0 ENGINEERING PROPERTIES AND ANALYSIS ......................................................................... 8
5.1 Materials Properties ..............................................................................•...............•. 8
5.1.1 Excavation Characteristics ........................................................................... 9
5.1.2 Compressibility ....................................................••....................................... 9
5.1.3 Expansion Potential ..................................................................................... 9
5.1.4 Chemical Analyses ................................•....................................................... 9
6.0 CONCLUSIONS AND RECOMMENDATIONS ........................................................................ 10
6.1 Remedial Grading Recommendations ................................................................... 1 O
6.1.1 Site Preparation ......................................................................................... 10
6.1.2 Unsuitable Soil Removals ...........•.........•.......................................•............. 10
6.2 General Earthwork Recommendations .................................................................. I I
6.2.1 Compaction Standards •.............................................................................. 11
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
Page 2
6.2.2 Groundwater/Seepage .............................................................................. 11
6.2.3 Documentation of Removals ...................................................................• .11
6.2.4 Treatment of Removal Bottoms ............................................................... .12
6.2.S Fill Placement .........•................................................................................... 12
6.2.6 Mixing ......................................................................................................... 12
6.2. 7 Import Soils ................................................................................................ 12
6.2.8 Utility Trenches .......................................................................................... 13
6.2.9 Backcut Stability .•.............................................................•......................... 14
6.3 Storm Water Infiltration Systems ........•.........................................................•...... .14
7.0 DESIGN CONSIDERATIONS ............•.......................................................................•............ 15
7.1 Structural Design .............................•...................................................................... 15
7.2 Block Walls .......................................................................•..................................... 16
7.3 Footing Excavations ..............................................................................................• 16
7.4 Exterior Slabs and Walkways ....................•......................................................•..... 16
7.4.1 Subgrade Compaction .............................................................•....•............. 16
7.4.2 Subgrade Moisture .................................................................................... 16
7.4.3 Concrete Slab Thickness ........................................................................... .16
7.4.4 Concrete Slab Reinforcement .................................................................... 17
7.4.S Control Joints ............................................................................................. 17
7 .5 Concrete Design ..................................................................................................... 17
7.6 Corrosion ..................•......................•..•................................................................... 17
7.7 Pavement Design .............................................•........................................• : ........... 18
8.0 FUTURE PLAN REVIEWS ..................................................................................................... 19
9.0 CLOSURE ....................................................................•........................................................ 19
9.1 Geotechnical Review .................................................................•..•......................... 19
9.2 Limitations ..........•.................................................•................................................. 20
APPENDIX A: REFERENCES
APPENDIX B: SUBSURFACE INVESTIGATION
APPENDIX C: LABORATORY TESTING
APPENDIX D: EARTHWORK SPECIFICATIONS
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
Page 3
1.0 INTRODUCTION
The following report presents Alta's findings, conclusions, and geotechnical
recommendations for the proposed parking lot, located at 5980 Eagle Drive, the City of
Carlsbad, California.
1.1 Purpose
1.2
1.3
The purpose of this report is to examine the existing onsite geotechnical
conditions and assess the impacts that the geotechnical conditions may have on
the proposed development. The property is depicted on the enclosed Plate 1.
This report is suitable for use in developing grading plans and engineer's cost
estimates.
Scope of Work
Alta's Scope of Work for this geotechnical investigation included the following:
• Review ofthe referenced literature, maps, reports and aerial photos
(Appendix A).
• Site geologic mapping.
• Excavating, logging, and sampling twelve {12) backhoe test pits to a
maximum depth of 13-feet below the existing surface (Appendix B).
• Conducting laboratory testing on samples obtained during our
investigation (Appendix C).
• Performing an infiltration study to provide an assessment of the
infiltration characteristics of the onsite soils.
• Evaluating engineering geologic and geotechnical engineering data,
including laboratory data, to develop recommendations for site remedial
grading, import soil and pavement design recommendations
• Preparing this report and accompanying exhibits.
Report Limitations
The conclusions and recommendations presented In this report are based on the
field and laboratory information generated during this investigation, the
previous investigation, and a review ofthe referenced reports. The information
AL TA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
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contained in this report is intended to be used for development of grading plans
and preliminary construction cost estimates.
2.0 PROJECT DESCRIPTION
3.0
2.1
2.2
Site Location and Existing Conditions
The rectangular shaped, approximately 5.94-acre site is relatively flat and is
currently vacant. The site is located off located off the northeast corner of
Eagle Drive and Grey Hawk Court. The surrounding area is primarily
commercial/industrial developments. A review of aerial photos (Historic
Aerials, 2020) indicates that the site was graded by 2005 and has remained
relatively unchanged since then.
Proposed Development
Based on a review of the grading plans, it is our understanding that site will be
developed into a parking lot for the neighboring commercial/industrial
developments. Alta anticipates that conventional cut-and-fill grading techniques
will be used to develop the site to support the proposed parking lot. Significant
height slopes are not anticipated for the project.
SITE INVESTIGATION
3.1 Current Subsurface Investigation
Alta conducted a subsurface investigation on September 10, 2020 consisting of
the excavation, logging and select sampling oftwelve (12) backhoe test pits up to
a maximum depth of 13 feet below the existing ground surface. Three (3)
additional test pits were also excavated and utilized for infiltration testing. The
locations of the exploratory excavations are shown on Plate 1 and the test pit
logs are presented in Appendix B.
Laboratory testing was performed on a bulk sample obtained during the field
investigation. A brief description of the laboratory test procedures and the test
results are presented in Appendix C.
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
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4.0
3.2 Infiltration Testing
It is Alta's understanding that the project may utilize infiltration systems for storm
water disposal. Details of the system are not known at this time. Three
infiltration tests were conducted onsite using shallow percolation test methods in
general accordance with the County of San Diego standards. The tests were
conducted at the bottom of the test pits in an approximately 1-foot deep hand
dug boring. During the test, the hand-dug borings were filled with water and the
level was measured every 30 minutes until the readings stabilized.
The data was then adjusted to provide an infiltration rate utilizing the Porch et
Method. The resulting infiltration rates for PT-1 through PT-3 are presented in
Table 3-1. The results do not include a factor of safety. Recommendations for
infiltration BMP design are presented in Section 6.3.
Table 3-1-Summary of Infiltration Testing
(No Factor of Safety)
Test Designation PT-1 PT-2 PT-3
Approximate Depth of Test 6 ft 6 ft 6 ft
Time Interval 30 minutes 30 minutes 30 minutes
Radius of Test Hole 4inches 4inches 4 inches
Tested Infiltration Rate 0.36 (in/hr) 0.36 (in/hr) 0.36 (in/hr)
GEOLOGIC CONDITIONS
4.1 Geologic and Geomorphic Setting
Regionally, the subject site is located in the Peninsular Ranges geomorphic
province, which characterizes the southwest portion of southern California
where major right-lateral active fault zones predominately trend northwest-
southeast. The Peninsular Ranges province is composed of plutonic and
metamorphic rock, with lesser amounts of Tertiary volcanic and sedimentary
rock, Quaternary drainage in-fills and sedimentary veneers.
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Project Number 1-0346
September 29, 2020
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4.2 Stratigraphy
4.3
Based on Alta's review of geologic literature and our subsurface investigation,
the project site is underlain by undocumented artificial fill overlying the Santiago
Formation (Kennedy, 2007). The geologic unit encountered during our
investigation is briefly described below.
4.2.1 Artificial Fill-Undocumented (Map symbol afu)
The undocumented fill onsite primarily consists of orange tan to orange
brown, grayish brown, and dark brown, sandy clay and clayey sand in a
dry to slightly moist, dense/stiff to very dense/stiff condition. The unit
was logged to a maximum depth of 13 feet below the ground surface.
Geologic Structure
4.3.1 Tectonic Framework
Jennings (1985) defined eight structural provinces within California that
have been classified by predominant regional fault trends and similar fold
structure. These provinces are in turn divided into blocks and sub-blocks
that are defined by "major Quaternary faults." These blocks and sub-
blocks exhibit similar structural features. Within this framework the site
is located within Structural Province I, which is controlled by the
dominant northwest trend of the San Andreas Fault and is divided into
two blocks, the Coast Range Block and the Peninsular Range Block. The
Peninsular Range Block, on which the site is located, is characterized by a
series of parallel, northwest trending faults that exhibit right lateral dip-
slip movement. These faults are terminated by the Transverse Range
block to the north and extend southward to the Baja Peninsula. These
northwest trending faults divide the Peninsular Range block into eight
sub-blocks. The site is located on the Santa Ana sub-block, which is
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
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bound on the east by the Whittier-Elsinore fault zone and on the west by
Newport-Inglewood-Rose Canyon fault zone.
4.3.2 Regionally Mapped Active Faults
Several large, active fault systems, including the Rose Canyon, the
Whittier-Elsinore, the San Jacinto, and the San Andreas occur in the
region surrounding the site. These fault systems have been studied
extensively and in a large part control the geologic structure of southern
California.
4.3.3 Geologic Structure
The existing artificial fill is considered massive.
4.4 Groundwater
4.5
Groundwater was not encountered during our subsurface investigation. There
are no groundwater wells in the vicinity of the site, however it is anticipated that
groundwater is greater than 50 feet below the ground surface.
Earthquake Hazards
The subject site is located in southern California, which is a tectonically active
area. The type and magnitude of seismic hazards affecting a site are dependent
on the distance to the causative fault and the intensity and magnitude of the
seismic event. The seismic hazard may be primary, such as surface rupture
and/or ground shaking, or secondary, such as liquefaction and/or ground
lurching.
4.5.1 Local and Regional Faulting
The site is located on the Santa Ana sub-block, approximately 8.4 miles
east of the Newport Inglewood/Rose Canyon fault zone and 11.2 south
west of the Elsinore fault zone.
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
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4.5.2 Surface Rupture
Active faults are not known to exist within the project and a review of
Special Publication 42 indicates the site is not within a California State
designated earthquake fault zone. Accordingly, the potential for fault
surface rupture on the subject site is low.
4.5.3 Liquefaction
Seismic agitation of relatively loose saturated sands, silty sands, and
some silts can result in a buildup of pore pressure. If the pore pressure
exceeds the overburden stresses, a temporary quick condition known as
liquefaction can occur. Liquefaction effects can manifest in several ways
including: 1) loss of bearing; 2) lateral spread; 3) dynamic settlement;
and 4) flow failure. Lateral spreading has typically been the most
damaging mode of failure.
Based on the anticipated depth to groundwater and the relatively dense
nature of the artificial fill, it is our opinion that the potential for
liquefaction to occur onsite is considered nil.
4.5.5 Dry Sand Settlement
Dry sand settlement is the process of non-uniform settlement of the
ground surface during a seismic event. Based on our subsurface
investigation the potential for dry sand settlement is anticipated to be
very low.
5.0 ENGINEERING PROPERTIES AND ANALYSIS
5.1 Materials Properties
Presented herein is a general discussion of the engineering properties of the
onsite materials that will be encountered during construction of the proposed
project. Descriptions of the soil (Unified Soil Classification System) and in-place
moisture/density results are presented on the test pit logs in Appendix B.
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
5.1.1 Excavation Characteristics
Page 9
Based on the data provided from the subsurface investigation, it is our
opinion that the majority of the onsite materials possess favorable
excavation characteristics such that conventional earth moving
equipment can be utilized.
5.1.2 Compressibility
The upper portions of the undocumented artificial fill are considered
compressible and unsuitable to support the proposed improvements.
Recommended removal depths are presented in Section 6.1.2.
5.1.3 Expansion Potential
Expansion index testing was performed on a sample taken during our
subsurface investigation. Based on the results, it is anticipated that the
majority of materials onsite are "medium" in expansion potential
(51SEIS90, Appendix C) when tested per ASTM D: 4829.
5.1.4 Chemical Analyses
Chemical testing was performed on a sample of material underlying the
proposed site. Soluble sulfate test results indicate that the soluble
sulfate concentrations of the soils tested are classified as negligible (Class
SO) per ACI 318-14.
Elevated chloride levels were detected in the on site soils, test pit T-S
(Appendix C). Resistivity testing conducted as part of this investigation,
indicates that the soils are "severely corrosive" to buried metals (per
Romanoff, 1989). Additional discussions on corrosion are presented in
Section 7.3. Corrosion tests results are presented in Appendix C.
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
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6.0 CONCLUSIONS AND RECOMMENDATIONS
Based on Alta's findings during our subsurface investigation, the laboratory test results,
our staff's previous experience in the area, it is Alta's opinion that the development of
the site is feasible from a geotechnical perspective. Presented below are
recommendations that should be incorporated into site development and construction
plans.
6.1 Remedial Grading Recommendations
All grading shall be accomplished under the observation and testing of the project
geotechnical consultant in accordance with the recommendations contained
herein and the City of Carlsbad criteria.
6.1.1 Site Preparation
Vegetation, construction debris, and other deleterious materials are
unsuitable as structural fill material and should be disposed of off-site
prior to commencing grading/construction. Any septic tanks, seepage
pits or wells should be abandoned as per the County of San Diego
Department of Health Services.
6.1.2 Unsuitable Soil Removals
The upper portions ofthe undocumented artificial fill are compressible,
and as such, are not suitable to support the proposed parking lot.
Therefore, it is anticipated that, on average, the upper two (2) feet of
existing soils will require removal and recompaction, although deeper
removals may be required if unsuitable soils are exposed at that depth.
For cuts greater than two (2) feet in parking areas, removals are not
required. For cuts less than two (2) feet, the artificial fill removal and
recompaction applies.
The Project Geotechnical Consultant should observe and approve the
removal bottom prior to the placement of compacted fill. Removal
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
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bottoms in the parking lot should be tested to determine that the
exposed soils have a minimum relative compaction of 8S% of the
laboratory maximum density (per ASTM test method D-1S57). Both
observations and tests must be accomplished to determine that suitable
bottoms have been exposed.
6.2 General Earthwork Recommendations
6.2.1 Compaction Standards
All fill and processed natural ground shall be compacted to a minimum
relative compaction of 90 percent, as determined by ASTM Test Method:
D-1557. Fill material should be moisture conditioned to optimum
moisture or above, and as generally discussed in Alta's Earthwork
Specification Section presented in Appendix D. Compaction shall be
achieved with the use of sheepsfoot rollers or similar kneading type
equipment.
6.2.2 Groundwater/Seepage
It is anticipated that groundwater will not be encountered during
construction. It is possible that perched water conditions could be
encountered depending on the time of year construction occurs.
6.2.3 Documentation of Removals
All removal/over-excavation bottoms should be observed and approved
by the project Geotechnical Consultant prior to fill placement.
Consideration should be given to surveying the removal bottoms and
undercuts after approval by the geotechnical consultant and prior to the
placement of fill. Staking should be provided in order to verify undercut
locations and depths.
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
6.2.4 Treatment of Removal Bottoms
Page 12
At the completion of removals/over-excavation, the exposed removal
bottom should be ripped to a minimum depth of eight (8) inches,
moisture-conditioned to above optimum moisture content and
compacted in-place to the project standards.
6.2.5 Fill Placement
After removals, scarification, and compaction of in-place materials are
completed, additional fill may be placed. Fill should be placed in eight-
inch bulk maximum lifts, moisture conditioned to optimum moisture
content or above, compacted and tested as grading/construction
progresses until final grades are attained.
6.2.6 Mixing
Mixing of materials may be necessary to prevent layering of different soil
types and/or different moisture contents. The mixing should be
accomplished prior to and as part of the compaction of each fill lift.
6.2. 7 Import Soils
Import soils, if necessary, should consist of clean, structural quality,
compactable materials similar to the on-site soils and should be free of
trash, debris or other objectionable materials. The project Geotechnical
Consultant should be notified not less than 72 hours in advance of the
locations of any soils proposed for import. Import sources should be
sampled, tested, and approved by the project Geotechnical Consultant at
the source prior to the importation of the soils to the site. The project
Civil Engineer should include these requirements on plans and
specifications for the project.
AL TA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
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6.2.8 Utility Trenches
6.2.8.1
6.8.2.2
Excavation
Utility trenches should be supported, either by laying back
excavations or shoring, in accordance with applicable OSHA
standards. In general, existing site soils are classified as Soil
Type "B" per OSHA standards. Upon completion ofthe
recommended removals and recompaction, the artificial fill
will be classified as Soil Type "B". The Project Geotechnical
Consulting should be consulted if geologic conditions vary
from what is presented in this report.
Backfill
Trench backfill should be compacted to at least 90 percent of
maximum dry density as determined by ASTM D-1557.
Onsite soils will not be suitable for use as bedding material
but will be suitable for use in backfill provided oversized
materials are removed. No surcharge loads should be
imposed above excavations. This includes spoil piles, lumber,
concrete trucks, or other construction materials and
equipment. Drainage above excavations should be directed
away from the banks. Care should be taken to avoid
saturation of the soils. Compaction should be accomplished
by mechanical means. Jetting of native soils will not be
acceptable.
Under-slab trenches should also be compacted to project
specifications. If select granular backfill (SE > 30) is used,
compaction by flooding will be acceptable.
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Project Number 1-0346
September 29, 2020
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6.3
6.2.9 Backcut Stability
Temporary backcuts, if required during unsuitable soil removals, should
be made no steeper than 1:1 without review and approval of the
geotechnical consultant. Flatter backcuts may be necessary where
geologic conditions dictate and where minimum width dimensions are to
be maintained.
Care should be taken during remedial grading operations in order to
minimize risk of failure. Should failure occur, complete removal of the
disturbed material will be required.
In consideration of the inherent instability created by temporary
construction backcuts for removals, it is imperative that grading
schedules are coordinated to minimize the unsupported exposure time of
these excavations. Once started, these excavations and subsequent fill
operations should be maintained to completion without intervening
delays imposed by avoidable circumstances. In cases where five-day
workweeks comprise a normal schedule, grading should be planned to
avoid exposing at-grade or near-grade excavations through a non-work
weekend. Where improvements may be affected by temporary
instability, either on or offsite, further restrictions such as slot cutting,
extending work days, implementing weekend schedules, and/or other
requirements considered critical to serving specific circumstances may be
imposed.
Storm Water Infiltration Systems
From a geotechnical perspective, allowing storm water to infiltrate the onsite soil
in concentrated areas increases the potential for settlement, liquefaction, and
water-related damage to structures/improvements, such as wet slabs or pumping
subgrade, and should be avoided where possible. If infiltration systems are
ALTA CALIFORNIA GEOTECHNICAL, INC.
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September 29, 2020
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required on this site, care should be taken in designing systems that control the
storm water as much as possible.
Infiltration testing was conducted at the site as part of this investigation, and the
methodology is discussed in 3.2. The resulting infiltration rate for PT-1 through
PT-3 were calculated to be 0.36 inches per hour at approximately 6-feet below
the existing ground surface. The results do not include a factor of safety.
Groundwater was not encountered during our subsurface investigation and is
anticipated to be greater than SO feet below the ground surface.
Given the very low infiltration rates and the presence of artificial fill, infiltration-
type WQMP systems may not be feasible at the subject site at the depths tested.
The Project Geotechnical Consultant should review the final WQMP design prior
to construction.
7.0 DESIGN CONSIDERATIONS
7.1 Structural Design
It is anticipated that screen walls will be constructed onsite. Foundations may be
designed based on the values presented in Table 7-1 below. Footings near slopes
shall be embedded sufficiently to provide a minimum of five (S) feet of horizontal
distance between the bottom of the footing and the slope face.
Table 7-1
Foundation Design Parameters*
Allowable Bearing 1500 lbs/ft2 (assuming a minimum embedmentdepth and
width of 12 inches)
Lateral Bearing 200 lbs/ft' at a depth of 12 inches plus 200 lbs/ft' for each
additional 12 inches of embedment to a maximum of 2000
lbs/ft'.
Sliding Coefficient 0.30
*These values may be increased as allowed by Code to resist transient loads such as wind or
seismic. Building code and structural design considerations may govern depth and reinforcement
requirements and should be evaluated.
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
7.2 Block Walls
Page 16
Block walls, if used, should be embedded a minimum of 2 feet below the lowest
adjacent grade. Construction joints (not more than 20 feet apart) should be
included in the block wall construction.
7 .3 Footing Excavations
Soils from the footing excavations should not be placed in slab-on-grade areas
unless properly compacted and tested. The excavations should be cleaned of all
loose/sloughed materials and be neatly trimmed at the time of concrete
placement. The Project Geotechnical Consultant should observe the footing
excavations prior to the placement of concrete to determine that the excavations
are founded in suitably compacted material.
7.4 Exterior Slabs and Walkways
Exterior concrete slabs and walkways should be designed and constructed in
consideration of the following recommendations.
7 .4.1 Subgrade Compaction
The subgrade below exterior concrete slabs should be compacted to a
minimum of 90 percent relative compaction as determined by ASTM Test
Method: D 1557.
7.4.2 Subgrade Moisture
The subgrade below concrete slabs should be moisture conditioned to a
minimum of 120 percent of optimum moisture prior to concrete
placement.
7.4.3 Concrete Slab Thickness
Concrete flatwork should be designed utilizing four-inch minimum
thickness. Concrete driveways should be designed utilizing six-inch
minimum thickness.
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Project Number 1-0346
September 29, 2020
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7.5
7.6
7.4.4 Concrete Slab Reinforcement
The majority of the soils onsite are classified as medium in expansion
potential. Consideration should be given to reinforcing flatwork with
irregular (non-square/rectangular) shapes or flatwork underlain by
medium expansive soils. Reinforcement may consist of 6x6 W.14/Wl.4
welded wire mesh or an equivalent section of rebar.
7.4.5 Control Joints
Weakened plane joints should be installed on walkways at intervals of
approximately eight feet (maximum) or less. Exterior slabs should be
designed to withstand shrinkage of the concrete.
Concrete Design
As stated in Section 5.1.6, negligible concentrations of sulfates were detected in
the on site soils. Therefore, the use of sulfate resistant concrete is not required
per ACI 318-14 at this time. Post-grading conditions should be evaluated, and
final recommendations made at that time.
Corrosion
Based on preliminary testing, elevated chloride levels were detected onsite (690
ppm). This condition should be monitored during grading. If consistent elevated
levels of chlorides are detected near finished grade, additional corrosion
protection mitigations may be necessary. The onsite soils are severely corrosive
to buried metal objects. Buried ferrous metals should be protected against the
effects of corrosive soils in accordance with the manufacturer's
recommendations. Typical measures may include using non-corrosive backfill,
protective coatings, wrapping, plastic pipes, or a combination ofthese methods.
A corrosion engineer should be consulted if specific design recommendations are
required by the improvement designer.
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September 29, 2020
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7.7
Per ACI 318-14, an exposure class of Cl would be applicable to metals encased in
concrete (rebar in footings) due to being exposed to moisture from surrounding
soils. Per Table 19.3.2.1 of ACI 318-14, the requirements for concrete with an
exposure class of Cl are a minimum compressive strength of 2500 psi and a
maximum water-soluble chloride ion content in concrete of 0.30 (percent by
weight of cement).
Pavement Design
Pavement sections for the proposed parking lot shall be designed based on
laboratory testing conducted on samples taken from the soil subgrade.
Preliminarily, based on a tested R-Value of 24, the pavement may be designed
utilizing the sections presented in Table 7-1. These sections should be verified
upon the completion of grading, based on R-Value testing.
Table 7-1
Preliminary Pavement Sections
Traffic Pavement Section Options
Index OR
5.0 3·inch AC on 6.5-inch AB I 4-inch AC on 4.5-inch AB
AC-Asphalt Concrete
AB-Caltrans Class II Base
Prior to the placement of base material, the subgrade should be suitably
moisture conditioned, processed and compacted to a minimum 95 percent of
the laboratory maximum density (ASTM: D 1557) to at least twelve (12) inches
below subgrade. After subgrade compaction, the exposed grade should then be
"proof"-rolled with heavy equipment to ensure the grade does not "pump" and
is verified as non-yielding. Aggregate base material should be placed on the
compacted subgrade and compacted in-place to a minimum 95 percent of the
laboratory standard obtained per ASTM: D 1557.
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
Page 19
8.0 FUTURE PLAN REVIEWS
This report represents a geotechnical review of the site. As the project design for the
project progresses, site specific geologic and geotechnical issues should be considered in
the design and construction of the project. Consequently, future plan reviews may be
necessary. These reviews may include reviews of:
► Grading Plans
► Utility Plans
These plans should be forwarded to the project Geotechnical Consultant for review.
9.0 CLOSURE
9.1 Geotechnical Review
For the purposes of this report, multiple working hypotheses were established for
the project, utilizing the available data and the most probable model is used for
the analysis. Future information collected during the proposed grading
operations is intended to evaluate the hypothesis and as such, some of the
assumptions summarized in this report may need to be changed. Some
modifications of the grading recommendations may become necessary, should
the conditions encountered in the field differ from the conditions hypothesized in
this report.
Plans and sections of the project specifications should be reviewed by Alta to
evaluate conformance with the intent of the recommendations contained in this
report. If the project description or final design varies from that described herein,
Alta must be consulted regarding the applicability of the recommendations
contained herein and whether any changes are required. Alta accepts no liability
for any use of its recommendations if the project description or final design varies
and Alta is not consulted regarding the alterations.
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
9.2 Limitations
Page 20
This report is based on the following: 1) the project as presented on the attached
plan; 2) the information obtained from Alta's laboratory testing included herein;
and 3) from the information presented in the referenced reports. The findings
and recommendations are based on the results ofthe subsurface investigation,
laboratory testing, and office analysis combined with an interpolation and
extrapolation of conditions between and beyond the subsurface excavation
locations. However, the materials adjacent to or beneath those observed may
have different characteristics than those observed, and no precise
representations are made as to the quality or extent of the materials not
observed. The results reflect an interpretation of the direct evidence obtained.
Work performed by Alta has been conducted in a manner consistent with the
level of care and skill ordinarily exercised by members of the geotechnical
profession currently practicing in the same locality under similar conditions. No
other representation, either expressed or implied, and no warranty or guarantee
is included or intended.
The recommendations presented in this report are based on the assumption that
an appropriate level of field review will be provided by a geotechnical consultant
who is familiar with the design and site geologic conditions. That field review
shall be sufficient to confirm that geotechnical and geologic conditions exposed
during grading are consistent with the geologic representations and
corresponding recommendations presented in this report.
The conclusions and recommendations included in this report are applicable to
the specific design ofthis project as discussed in this report. They have no
applicability to any other project or to any other location and any and all
subsequent users accept any and all liability resulting from any use or reuse of the
data, opinions, and recommendations without the prior written consent of Alta.
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
Page 21
Alta has no responsibility for construction means, methods, techniques,
sequences, procedures, safety precautions, programs in connection with the
construction, acts or omissions of the CONTRACTOR or any other person
performing any of the construction, or for the failure of any of them to carry out
the construction in accordance with the final design drawings and specifications.
ALTA CALIFORNIA GEOTECHNICAL, INC.
APPENDIX A
REFERENCES
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
APPENDIX A
References
Page A-1
Bryant, W.A., Hart, E.W., 2007, Fault Rupture Hazard Zones in California, Alquist-Priolo
Earthquake Zoning Act with index to Earthquake Fault Zones Maps, Special Publication 42,
interim revision, California Department of Conservation, California Geological Survey.
California Code of Regulations, 2019, California Building Code, Title 24, Part 2, Volume 2, Based
on the 2018 International Building Code, Effective Date January 1, 2020.
California Department of Water Resources, online information:
http://www.water.ca.gov/waterdatalibrary/index.cfm.
California Geological Survey, 2008, Guidelines for Evaluating and Mitigating Seismic Hazards in
California, Special Publication 117 A.
California Geological Survey, 2018, Earthquake Fault Zones, A Guide for Government Agencies,
Property Owners/Developers, and Geoscience Practitioners for Assessing Fault Rupture
Hazards in California, Special Publication 42, revised 2018.
Historic Aerials, 2020, www.historicaerials.com, by NETROnline, Copyright 2019, accessed
March 2020, online review of vintage air photos from 1947, 1953, 1964, 1967, 1981, 1989,
1990,1994,1995,1996,1997,1998,1999,2002,2003,2005,2009,2010,2012,2014and
2016.
Jennings, C. W., 1985, An explanatory text to accompany the 1:750,000 scale fault and geologic
maps of California: California Division of Mines and Geology, Bulletin 201, 197 p.
Jennings, C.W., and Bryant, W.A., 2010, Fault Activity Map of California: California Geological
Survey Geologic Data Map No. 6, map scale 1:750,000.
Jennings, C. W., and Bryant, W.A., 2010, An explanatory text to accompany the Fault Activity
Map of California: California Department of Conservation, California Geological Survey.
Kennedy, M.P., Tan, S.S., Bovard, K.R., Alvarez, R.M., Watson, M.J. and Gutierrez, C.I., 2007,
Geologic map ofthe Oceanside 30x60-minute quadrangle, California: California Geological
Survey Regional Geologic Map No. 2, scale 1:100.000
Romanoff, Melvin, 1989, Underground Corrosion, NBS Circular 579, Reprinted by NACE,
Houston, TX, 1989
ALTA CALIFORNIA GEOTECHNICAL, INC.
APPENDIX B
Subsurface Investigation
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1-0346
September 29, 2020
APPENDIX B
Subsurface Investigation
Page B-1
Alta's subsurface investigation consisted of excavating, logging, and sampling twelve {12)
backhoe test pits. Details of the subsurface investigation are presented in Table B. The
approximate locations of the exploratory excavations are shown on Plate 1 and the
Geotechnical Logs are attached.
TABLEB
SURFACE INVESTIGATION DETAILS
Equipment Range of Sampling Methods Sample Locations
Depths
Backhoe Up to 13 feet 1. Bulk Samples 1. Bulk-Select Depths
ALTA CALIFORNIA GEOTECHNICAL, INC.
Test Pit No. Depth (ft.)
T-1 0.0-9.0
Project No. 1-0346
Date Excavated September 10th, 2020 ---'-----'------Logged by JC
Equipment JD 310
TABLE I
LOG OF TEST PITS
uses
SC
Description
ARTIFICIAL FILL-UNDOCUMENTED (afu): CLAYEY
SAND, fine to coarse grained, tan, dry, dense,
trace fine gravel <3/4", with roots.
@l.Oft. alternating 3" layers of yellowish tan and
brownish tan
SC @S.Oft. CLAYEY SAND/SANDY CLAY, very fine to
fine grained, slightly orangish brown, slightly
moist, dense/stiff.
@7.0ft. dark brown, very fine to medium grained.
SM @7.Sft. SILTY SAND with CLAY, fine grained, tan,
dry, dense.
SC @8.0ft. CLAYEY SAND/SANDY CLAY, very fine to
medium grained, orange brown, slightly moist,
SM dense/stiff.
@8.Sft. SILTY SAND with CLAY, fine grained, tan,
dry, dense.
TOTAL DEPTH 9.0 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
Test Pit No. Depth (ft.)
T-2 0.0-11.0
uses
SC
Description
ARTIFICIAL FILL-UNDOCUMENTED (afu): CLAYEY
SAND, fine to coarse grained, tan, dry, dense,
trace fine gravel <3/4", with roots.
@5.0ft. alternating 4" layers of tan and orangish
brown.
CL @8.0ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @8.Sft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense.
CL @9.0ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @9.Sft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense.
CL @10.0ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @10.Sft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense.
TOTAL DEPTH 11.0 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
Test Pit No. Depth (ft.)
T-3 0.0-8.5
uses
SC
Description
ARTIFICIAL FILL-UNDOCUMENTED (afu): CLAYEY
SAND, fine to coarse grained, tan, dry, dense,
trace fine gravel <3/4", with roots.
@l.0ft. yellowish tan.
@l.5ft. grayish tan, few fine gravel <3/4".
@2.0ft. brown with mottled orangish tan
CL @4.0ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @4.5ft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense.
CL @5.0ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @5.5ft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense.
CL @6.0ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @6.5ft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense.
CL @7.0ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SM @7.5ft. SILTY SAND, very fine to fine grained,
orangish brown, dry, dense, trace clay.
TOTAL DEPTH 8.5 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
Test Pit No. Depth (ft.) uses Description
T-4 0.0-10.5 SC ARTIFICIAL FILL-UNDOCUMENTED (afu): CLAYEY
SAND, fine to coarse grained, tan, dry, dense,
trace fine gravel <3/4", with roots.
CL @3.0ft. SANDY CLAY, very fine to fine grained,
brownish tan, slightly moist, stiff.
SC @6.0ft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense.
CL @6.5ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @7.0ft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense.
CL @7.5ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @8.0ft. CLAVEY SAND, fine grained, orangish
brown, slightly moist, dense.
@8.5ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
@9.0ft. trace roots
TOTAL DEPTH 10.5 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
Test Pit No. Depth (ft.) uses Description
T-5 0.0-11.0 SM ARTIFICIAL FILL-UNDOCUMENTED (afu): SILTY
SAND with CLAY, fine to coarse grained, tan, dry,
dense, trace fine gravel <3/4", with roots.
@3.5ft. orangish tan
CL @6.0ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @6.5ft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense.
CL @7.0ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SM @7.5ft. SILTY SAND, very fine to fine grained,
orangish brown, dry, dense, trace clay.
TOTAL DEPTH 11.0 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
Test Pit No. Depth (ft.)
T-6 0.0-12.0
uses
SC
Description
ARTIFICIAL FILL-UNDOCUMENTED (aful: CLAYEY
SAND, fine to coarse grained, tan, dry, dense,
trace fine gravel <3/4", with roots.
@3.Sft. orangish tan
@5.Sft. fine grained, orangish brown, slightly
moist, dense.
CL @6.0ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @6.Sft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense.
CL @7.0ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SM @7.Sft. SILTY SAND, very fine to fine grained,
orangish brown, dry, dense, trace clay.
TOTAL DEPTH 12.0 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
Test Pit No. Depth (ft.) uses Description
T•7 0.0-13.0 SC ARTIFICIAL FILL-UNDOCUMENTED {afu): CLAYEY
SAND, fine to coarse grained, tan, dry, dense,
trace fine gravel <3/4", With roots.
@3.0ft. orangish tan
@4.3ft. plastic debris.
@4.5ft. alternating 4" layers of yellowish tan and
orangish tan.
@8.0ft. fine grained, orangish brown, slightly
moist, dense.
CL @8.5ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @9.4ft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense.
CL @10.2ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @10.Sft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense, few fine gravel
<3/4".
TOTAL DEPTH 13.0 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
Test Pit No. Depth (ft.) uses Description
T-8 0.0-10.5 SC ARTIFICIAL FILL-UNDOCUMENTED {afu): CLAYEY
SAND, fine to coarse grained, tan, dry, dense,
trace fine gravel <3/4", with roots.
@4.0ft. alternating 4" layers of yellowish tan and
orangish tan.
CL @7.5ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @8.0ft. SILTY SAND, very fine to fine grained,
orangish brown, dry, dense, trace clay.
CL @8.5ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @9.0ft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense.
TOTAL DEPTH 10.5 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
Test Pit No. Depth (ft.)
T-9 0.0-8.0
Test Pit No. Depth (ft.)
T-10 0.0-9.0
uses
SC
Description
ARTIFICIAL FILL-UNDOCUMENTED (afu): CLAYEY
SAND, fine to coarse grained, tan, dry, dense,
trace fine gravel <3/4", with roots.
@3.Sft .. alternating 4" layers of yellowish tan
and orangish tan.
@5.0ft. plastic debris.
@6.Sft. fine grained, orangish brown, slightly
moist, dense.
CL @7.0ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @7.Sft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense, few fine gravel
<3/4".
uses
SC
TOTAL DEPTH 8.0 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
Description
ARTIFICIAL FILL-UNDOCUMENTED (afu): CLAYEY
SAND, fine to coarse grained, tan, dry, dense,
trace fine gravel <3/4", with roots.
@3.0ft. orangish tan
@6.Sft. fine grained, orangish brown, slightly
moist, dense.
CL @7.0ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @7.Sft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense, few fine gravel
<3/4".
@8.0ft. trace roots.
TOTAL DEPTH 9.0 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
Test Pit No. Depth (ft.)
T-11 0.0-8.S
Test Pit No. Depth (ft.)
T-12 0.0-8.0
uses
SC
Description
ARTIFICIAL FILL-UNDOCUMENTED (afu): CLAYEY
SAND, fine to coarse grained, tan, dry, dense,
trace fine gravel <3/4", with roots.
@2.0ft. orangish tan
CL @3.0ft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @4.0ft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense, few fine gravel
<3/4".
uses
SC
@7.0ft. alternating 4" layers of dark brown and
grayish tan.
TOTAL DEPTH 8.5 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
Description
ARTIFICIAL FILL-UNDOCUMENTED (afu): CLAYEY
SAND, fine to coarse grained, tan, dry, dense,
trace fine gravel <3/4", with roots.
@2.Sft. orangish tan
@5.0ft. fine grained, orangish brown, slightly
moist, dense.
CL @5.Sft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @6.0ft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense.
CL @6.Sft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
SC @7.0ft. CLAYEY SAND, fine grained, orangish
brown, slightly moist, dense.
CL @7.Sft. SANDY CLAY, very fine to fine grained,
dark brown, slightly moist, stiff.
TOTAL DEPTH 8.0 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
Test Pit No. Depth (ft.) uses Description
PT-1 0.0-5.0 SC ARTIFICIAL FILL-UNDOCUMENTED (afu): CLAYEY
SAND, fine to coarse grained, tan, dry, dense,
trace fine gravel <3/4", with roots.
@l.5ft. yellowish tan
@4.0ft. orangish tan, few fine to coarse gravel
<3".
TOTAL DEPTH 5.0 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
Test Pit No. Depth (ft.) uses Description
PT-2 0.0-5.0 SC ARTIFICIAL FILL-UNDOCUMENTED (afu): CLAYEY
SAND, fine to coarse grained, tan, dry, dense,
trace fine gravel <3/4", with roots.
@3.0ft. alternating 2" layers of orangish tan and
tan.
@4.0ft. orangish tan, few fine to coarse gravel
<3".
TOTAL DEPTH 5.0 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
Test Pit No. Depth (ft.) uses Description
PT-3 0.0-5.0 SC ARTIFICIAL FILL-UNDOCUMENTED (afu): CLAYEY
SAND, fine to coarse grained, tan, dry, dense,
trace fine gravel <3/4", with roots.
@2.5ft. alternating 4" layers of orangish tan and
tan.
TOTAL DEPTH 5.0 FEET
NO GROUNDWATER ENCOUNTERED
NO CAVING OBSERVED
APPENDIXC
Laboratory Testing
ALTA CALIFORNIA GEOTECHNICAL, INC.
Project Number 1·0346
September 29, 2020
LABORATORY TESTING
Page C-1
The following laboratory tests were performed on a representative sample in accordance with
the applicable latest standards or methods from the ASTM, California Building Code (CBC) and
California Department of Transportation.
Classification
Soils were classified with respect to the Unified Soil Classification System (USCS) in accordance
with ASTM D-2487 and D-2488.
Particle Size Analysis
Modified hydrometer testing was conducted to aid in classification of the soil. The results of
the particle size analysis are presented in Table C.
Expansion Index Tests
One (1) expansion index test was performed to evaluate the expansion potential of typical on-
site soil. Testing was carried out in general conformance with ASTM Test Method D-4829. The
results are presented in Table C.
Chemical Analyses
Chemical testing was performed on one select sample by Alta. The results of these tests
(sulfate content, resistivity, chloride content and pH) are presented on Table C.
R-value
R-value testing was performed on one select sample by Labelle Marvin, Inc. The results of this
test are presented on Plate C-1.
ALTA CALIFORNIA GEOTECHNICAL, INC.
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LI\A R-VALUE
LaBeUe Marvin
PROJECT No. 46443
DATE: 9/24/2020
BORING NO. ..;;T..:;-5;..;@,:...::3-".0'-' _______ _
P.N.1-0246
DATA SHEET
SAMPLE DESCRIPTION:. ____ .;;;Br;..;;occw:.::n;..;;S;;;;an:.::dc,V:..:S:.::11.:..t ___________ _
.....................................................................
Mold ID Number
Water added, grams
Initial Test Water,%
Comnact Gage Pressure.psi
Exudation Pressure, psi
Height Sample, Inches
Gross Weight Mold, grams
Tare Welnht Mol-f, grams
Samnle Wet Weight, grams
Expansion, Inches x lOexp-4
Stability 2,000 lbs 1160nsll
Turns Dlsnlacement
R-Value Uncorrected
R-Value Corrected
Dry Density, pcf
Traffic Index
G.E. by Stablllty
G. E. bv Exnanslon
Equilibrium R-Value
Gf =
R-VALUE TESTING DATA J CA TEST 301
SPECIMEN ID
a b
10 11
/':, !l':J
14,l 16.1
90 so
526 218
2.54 2.66
3064 3092
1946 1951
1118 1141
56 16
37 I 87 43 / 104
3.93 4.91
35 22
35 24
116.9 112.0
DESIGN CALCULATION DATA
Assumed: 4.0
1.25
0.67
1.87
24
by
EXPANSION
4.0
0.78
0.53
Examined & Checked:
0.1% Retained on the
REMARKS: 3/4" Sieve.
C
12
bU
12.6
145
665
2.49
3056
1946
1110
103
32 I 70
3.70
46
46
120.0
4.0
o.ss
3.43
9 /24/ 20
The data above Is based upon processing and testing samples as received from the field. Test procedures in
accordance with latest revisions to Department of Transportation, State of California, Materials & Research Test
Method No. 301. PLATE C-1
APPENDIX D
Earthwork Specifications
ALTA CALIFORNIA GEOTECHNICAL, INC.
ALTA CALIFORNIA GEOTECHNICAL, INC.
EARTHWORK SPECIFICATIONS
These specifications present the generally accepted standards and minimum earthwork
requirements for the development of the project. These specifications shall be the project
guidelines for earthwork except where specifically superseded in preliminary geology and soils
reports, grading plan review reports or by the prevailing grading codes or ordinances of the
controlling agency.
A. GENERAL
1. The Contractor shall be responsible for the satisfactory completion of all
earthwork in accordance with the project plans and specifications.
2. The project Geotechnical Engineer and Engineering Geologist, or their
representatives, shall provide observation and testing services, and Geotechnical
consultation for the duration of the project.
3. All clearing, grubbing, stripping and site preparation for the project shall be
accomplished by the Contractor to the satisfaction of the Geotechnical
Engineer/Engineering Geologist.
4. It is the Contractor's responsibility to prepare the ground surface to receive fill to
the satisfaction of the Geotechnical Engineer and to place, spread, mix, moisture
condition, and compact the fill in accordance with the job specifications and as
required by the Geotechnical Engineer. The Contractor shall also remove all
material considered by the Geotechnical Engineer to be unsuitable for use in the
construction of engineered fills.
5. The Contractor shall have suitable and sufficient equipment in operation to
handle the amount of fill being placed. When necessary, equipment will be shut
down temporarily in order to permit the proper preparation of fills.
B. PREPARATION OF FILL AREAS
1. Excessive vegetation and all deleterious material should be disposed of offsite as
required by the Geotechnical Engineer.
Existing fill, soil, alluvium or rock materials determined by the Geotechnical
Engineer as being unsuitable for placement in compacted fills shall be removed
and hauled from the site. Where applicable, the Contractor may obtain the
AL TA CALIFORNIA GEOTECHNICAL, INC,
Earthwork Specifications
Page 2
approval of the Soils Engineer and the controlling authorities for the project to
dispose of the above described materials, or a portion thereof, in designated
areas onsite.
After removal of the deleterious materials have been accomplished, earth
materials deemed unsuitable in their natural, in-place condition, shall be
removed as recommended by the Geotechnical Engineer/Engineering Geologist.
2. Upon achieving a suitable bottom for fill placement, the exposed removal
bottom shall be disced or bladed by the Contractor to the satisfaction of the
Geotechnical Engineer. The prepared ground surfaces shall then be brought to
the specified moisture content mixed as required, and compacted and tested as
specified. In localities where it is necessary to obtain the approval of the
controlling agency prior to placing fill, it will be the Contractor's responsibility to
contact the proper authorities to visit the site.
3. Any underground structure such as cesspools, cisterns, mining shafts, tunnels,
septic tanks, wells, pipelines or other structures not located prior to grading are
to be removed or treated in a manner prescribed by the Geotechnical Engineer
and/or the controlling agency for the project.
C. ENGINEERED FILLS
1. Any material Imported or excavated on the property may be utilized as fill,
provided the material has been determined to be suitable by the Geotechnical
Engineer. Deleterious materials shall be removed from the fill as directed by the
Geotechnical Engineer.
2. Rock or rock fragments less than twelve inches in the largest dimension may be
utilized in the fill, provided they are not placed in concentrated pockets and the
distribution of the rocks is approved by the Geotechnical Engineer.
3. Rocks greater than twelve inches in the largest dimension shall be taken offsite,
or placed in accordance with the recommendations of the Geotechnical Engineer
in areas designated as suitable for rock disposal.
4. All materials to be used as fill, shall be tested in the laboratory by the
Geotechnical Engineer. Proposed import materials shall be approved by the
Geotechnical Engineer 48 hours prior to importation.
5. The fill materials shall be placed by the Contractor in lifts, that when compacted,
shall not exceed six inches. Each lift shall be spread evenly and shall be
ALTA CALIFORNIA GEOTECHNICAL, INC.
Earthwork Specifications
Page3
thoroughly mixed to achieve a near uniform moisture condition and a uniform
blend of materials.
All compaction shall be achieved at or above the optimum moisture content, as
determined by the applicable laboratory standard. The Contractor will be
notified if the fill materials are too wet or too dry to achieve the required
compaction standard.
6. When the moisture content of the fill material is below the limit specified by the
Geotechnlcal Engineer, water shall be added and the materials shall be blended
until a uniform moisture content, within specified limits, Is achieved. When the
moisture content of the fill material ls above the limits specified by the
Geotechnical Engineer, the fill materials shall be aerated by discing, blading,
mixed with dryer fill materials, or other satisfactory methods until the moisture
content Is within the specified limits.
7. Each fill lift shall be compacted to the minimum project standards, in compliance
with the testing methods specified by the controlling governmental agency, and
In accordance with recommendations of the Geotechnlcal Engineer.
In the absence of specific recommendations by the Geotechnical Engineer to the
contrary, the compaction standard shall be the most recent version of ASTM :D
1557.
8. Where a slope receiving fill exceeds a ratio of five-horizontal to one-vertical, the
fill shall be keyed and benched through all unsuitable materials into sound
bedrock or firm material, in accordance with the recommendations and approval
of the Geotechnical Engineer.
9. Side hill fills shall have a minimum key width of 15 feet into bedrock or firm
materials, unless otherwise specified In the soil report and approved by the
Geotechnical Engineer in the field.
10. Drainage terraces and subdrainage devices shall be constructed in compliance
with the ordinances of the controlling governmental agency and/or with the
recommendations of the Geotechnical Engineer and Engineering Geologist.
11. The Contractor shall be required to maintain the specified minimum relative
compaction out to the finish slope face of fill slopes, buttresses, and stabilization
fills as directed by the Geotechnical Engineer and/or the governing agency for
the project. This may be achieved by either overbuilding the slope and cutting
ALTA CALIFORNIA GEoTEcHNICAL, INC.
Earthwork Specifications
Page4
back to the compacted core; by direct compaction of the slope face with suitable
equipment; or by any other procedure which produces the required result.
12. The fill portion of fill-over-cut slopes shall be properly keyed Into rock or firm
material; and the fill area shall be stripped of all soil or unsuitable materials prior
to placing fill.
The design cut portion of the slope should be made first and evaluated for
suitability by the Engineering Geologist prior to placement of fill In the keyway
above the cut slope.
13. Pad areas in cut or natural ground shall be approved by the Geotechnlcal
Engineer. Finished surfaces of these pads may require scarification and
recompaction, or over excavation as determined by the Geotechnical Engineer.
D. CUT SLOPES
1. The Engineering Geologist shall observe all cut slopes and shall be notified by the
Contractor when cut slopes are to be started.
2. If, during the course of grading, unforeseen adverse or potentially adverse
geologic conditions are encountered, the Engineering Geologist and Soll Engineer
shall Investigate, analyze and make recommendations to remedlate these
problems.
3. Non-erodible interceptor swales shall be placed at the top of cut slopes that face
the same direction as the superjacent, prevailing drainage.
4. Unless otherwise specified in specific geotechnlcal reports, no cut slopes shall be
excavated higher or steeper than that allowed by the ordinances of controlling
governmental agencies.
5. Drainage terraces shall be constructed In compliance with the ordinances of the
controlling governmental agencies, and/or in accordance with the
recommendations of the Geotechnical Engineer or Engineering Geologist.
E. GRADING CONTROL
1. Fill placement shall be observed and tested by the Geotechnlcal Engineer and/or
his representative during grading.
Field density tests shall be made by the Geotechnlcal Engineer and/or his
representative to evaluate the compaction and moisture compliance of each fill
lift. Density tests shall be conducted at intervals not to exceed two feet of fill
ALTA CALIFORNIA GeotECHNICAL, INC.
Earthwork Specifications
Pages
height. Where sheepsfoot rollers are used, the fill may be disturbed to a depth
of several inches. Density determinations shall be taken in the compacted
material below the disturbed surface at a depth determined by the Geotechnical
Engineer or his representative.
2. Where tests indicate that the density of any layer of fill, or portion thereof, is
below the required relative compaction, or improper moisture content is in
evidence, that particular layer or portion thereof shall be reworked until the
required density and/or moisture content has been attained. Additional fills shall
not be placed over an area until the previous lift of fill has been tested and found
to meet the density and moisture requirements for the project and the previous
lift is approved by the Geotechnical Engineer.
3. When grading activities are Interrupted by heavy rains, fill operations shall not be
resumed until field observations and tests by the Geotechnlcal Engineer indicate
the moisture content and density of the fill are within the specified limits.
4. During construction, the Contractor shall properly grade all surfaces to maintain
good drainage and prevent the ponding of water. The Contractor shall take
remedial action to control surface water and to prevent erosion of graded areas
until such time as a permanent drainage and erosion devices have been installed.
5. Observation and testing by the Geotechnlcal Engineer and/or his representative
shall be conducted during filling and compacting operations in order that he will
be able to state In his opinion that all cut and filled areas are graded in
accordance with the approved specifications.
6. Upon the completion of grading activities and after the Geotechnlcal Engineer
and Engineering Geologist have finished their observations of the work, final
reports shall be submitted. No further excavation or fill placement shall be
undertaken without prior notification of the Geotechnical Engineer and/or
Engineering Geologist.
F. FINISHED SLOPES
All finished cut and fill slopes shall be planted and irrigated and/or protected from
erosion In accordance with the project specifications, governing agencies, and/or as
recommended by a landscape architect.
ALTA CALIFORNIA GEOlECHNICAL, INC.
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ALTACALIFORNIAGEOTECHNICAL, INC .
170 N. MAPLE STREET, STE 108,CORONA, CA 92880
TELEPHONE: (951)509-7090
PROJECT NUMBER: 1-0346 DATE:9-29-20
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