HomeMy WebLinkAboutCDP 2020-0018; FORESTER RESIDENCE; GEOTECHNICAL INVESTIGATION AND PRELIMINARY DESIGN RECOMMENDATIONS; 2019-12-31 ADVANCED GEOTECHNICAL SOLUTIONS, INC.
485 Corporate Drive, Suite B
Escondido, California 92029
Telephone: (619) 867-0487 Fax: (714) 409-3287
ORANGE AND L.A. COUNTIES INLAND EMPIRE SAN DIEGO AND IMPERIAL COUNTIES
(714) 786-5661 (619) 867-0487 (619) 867-0487
John Forester December 31, 2019
300 Carlsbad Village Drive, Suite 108a-335 P/W 1901-03
Carlsbad, California 92008 Report No. 1901-03-B-2
Attention: Mr. John Forester
Subject: Geotechnical Investigation and Preliminary Design Recommendations for Proposed
Single-Family Residence, 4464 Adams Street, Carlsbad, California
References: See Appendix A
Gentlemen:
Presented herein are the results of Advanced Geotechnical Solutions, Inc.’s, (AGS’s) geotechnical
investigation and preliminary design recommendations for the proposed single-family residence at 4464
Adams Street in the City of Carlsbad, California. The purpose of this geotechnical investigation is to
evaluate the proposed development relative to the near-site and on-site geologic and geotechnical
conditions, as well as to provide conclusions and recommendation to aid in the construction of the proposed
residential structure and improvements.
Advanced Geotechnical Solutions, Inc., appreciates the opportunity to provide you with geotechnical
consulting services and professional opinions. If you have any questions, please contact the undersigned
at (619) 867-0487.
Respectfully Submitted,
Advanced Geotechnical Solutions, Inc.
__________________________________
SHANE P. SMITH
Staff Engineer
___________________________________ _______________________________
ANDRES BERNAL, Sr. Geotechnical Engineer PAUL J. DERISI
RCE 62366/GE 2715, Reg. Exp. 9-30-21 CEG 2536, Reg. Exp. 5-31-21
Distribution: (1) Addressee (pdf)
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TABLE OF CONTENTS
Page
1.0 INTRODUCTION .............................................................................................................. 1
1.1. Scope of Work ................................................................................................................ 1
1.2. Geotechnical Study Limitations ...................................................................................... 1
2.0 SITE AND PROJECT DESCRIPTION.............................................................................. 2
3.0 FIELD AND LABORATORY INVESTIGATION ........................................................... 2
4.0 ENGINEERING GEOLOGY ............................................................................................. 2
4.1. Geologic Analysis ........................................................................................................... 2
4.1.1. Literature Review.................................................................................................... 2
4.1.2. Aerial Photograph and Historic U.S.G.S. Map Review .......................................... 2
4.1.3. Field Mapping ......................................................................................................... 2
4.2. Geologic and Geomorphic Setting .................................................................................. 2
4.3. Stratigraphy ..................................................................................................................... 3
4.3.1. Artificial Fill – Undocumented (Map symbol afu) ................................................. 3
4.3.2. Old Paralic Deposits (Map symbol Qop2-4) ............................................................ 3
4.4. Groundwater ................................................................................................................... 3
4.5. Non-seismic Geologic Hazards....................................................................................... 3
4.5.1. Mass Wasting and Debris Flows............................................................................. 3
4.5.2. Subsidence and Ground Fissuring .......................................................................... 4
4.5.3. Flooding .................................................................................................................. 4
4.6. Seismic Hazards .............................................................................................................. 4
4.6.1. Surface Fault Rupture ............................................................................................. 4
4.6.2. Seismic Design Parameters ..................................................................................... 4
4.6.3. Seismicity ................................................................................................................ 5
4.6.4. Liquefaction ............................................................................................................ 5
4.6.5. Dynamic Settlement ................................................................................................ 5
4.6.6. Seismically Induced Landsliding ............................................................................ 5
4.6.7. Tsunamis ................................................................................................................. 6
5.0 GEOTECHNICAL ENGINEERING .................................................................................. 6
5.1. Material Properties .......................................................................................................... 6
5.1.1. Excavation Characteristics ...................................................................................... 6
5.1.2. Compressibility ....................................................................................................... 6
5.1.3. Collapse Potential/Hydro-Consolidation ................................................................ 6
5.1.4. Expansion Potential ................................................................................................ 6
5.1.5. Chemical and Resistivity Test Results .................................................................... 7
5.1.6. Pavement Support Characteristics .......................................................................... 7
5.1.7. Shear Strength ......................................................................................................... 7
5.1.8. Earthwork Adjustments .......................................................................................... 7
5.2. Analytical Methods ......................................................................................................... 7
5.2.1. Bearing Capacity ..................................................................................................... 7
5.2.2. Lateral Earth Pressures ........................................................................................... 8
6.0 GRADING AND SHORING RECOMMENDATIONS .................................................... 8
6.1. Earthwork Recommendations ......................................................................................... 8
6.1.1. Site Preparation ....................................................................................................... 8
6.1.2. Removals................................................................................................................. 8
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6.2. Earthwork Considerations ............................................................................................... 8
6.2.1. Compaction Standards ............................................................................................ 8
6.2.2. Benching ................................................................................................................. 9
6.2.3. Mixing and Moisture Control ................................................................................. 9
6.2.4. Import Soils ............................................................................................................. 9
6.3. Temporary Excavations .................................................................................................. 9
6.4. Utility Trench Backfill .................................................................................................. 10
6.5. Flatwork Subgrade Preparation ..................................................................................... 10
7.0 CONCLUSIONS AND DESIGN RECOMMENDATIONS............................................ 10
7.1. Structural Design .......................................................................................................... 10
7.1.1. Foundation Design ................................................................................................ 10
7.1.2. Moisture and Vapor Barrier .................................................................................. 12
7.2. Conventional Retaining Walls ...................................................................................... 12
7.3. Concrete Design ............................................................................................................ 13
7.4. Corrosion....................................................................................................................... 14
7.5. Site Drainage ................................................................................................................. 14
7.6. Exterior Flatwork .......................................................................................................... 14
8.0 FUTURE STUDY NEEDS ............................................................................................... 14
8.1. Construction Plans ........................................................................................................ 14
8.2. Observation During Construction ................................................................................. 15
9.0 CLOSURE ........................................................................................................................ 15
ATTACHMENTS:
Figure 1 - Site Location Map
Figure 2 - Regional Geologic Map
Plate 1 - Geologic and Exploration Location Plan
Appendix A - References
Appendix B - Log of Exploratory Borings
Appendix C - Laboratory Test Results
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P/W 1901-03 Report No. 1901-03-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
GEOTECHNICAL INVESTIGATION AND
PRELIMINARY DESIGN RECOMMENDATIONS FOR
PROPOSED SINGLE-FAMILY RESIDENCE
4464 ADAMS STREET, CARLSBAD, CALIFORNIA
1.0 INTRODUCTION
Advanced Geotechnical Solutions, Inc., (AGS) has prepared this report which presents the results of our
geotechnical investigation onsite and provides specific recommendations for the design and construction
of the proposed single-family residence at 4464 Adams Street in Carlsbad, California.
1.1. Scope of Work
The scope of our study included the following tasks:
➢ Review of pertinent published and unpublished geologic and geotechnical literature, maps,
and aerial photographs readily available to this firm.
➢ Advance, log, and sample three (3) solid flight auger borings to depths of 21.5 feet below
ground surface on December 31, 2019 (B-1 through B-3). The boring logs are presented in
Appendix B.
➢ Conduct laboratory testing on the collected soil samples to evaluate the engineering
properties of the subsurface materials. Laboratory results are presented in Appendix C.
➢ Conduct a geotechnical engineering and geologic hazard analysis of the site.
➢ Evaluate groundwater conditions and the potential effects on construction.
➢ Conduct a limited seismic hazards evaluation including research of readily available
published maps and reports.
➢ Determine preliminary design parameters for foundations.
➢ Provide a preliminary corrosivity evaluation of the onsite soils.
➢ Prepare this report with exhibits summarizing our findings. This report would be suitable
for design, construction, and regulatory review.
1.2. Geotechnical Study Limitations
The conclusions and recommendations in this report are professional opinions based on the data
developed during this investigation. The conclusions presented herein are based upon the current
design concept. Changes to the design concept would necessitate further review.
The materials immediately adjacent to or beneath those observed may have different characteristics
than those observed. No representations are made as to the quality or extent of materials not
observed. Any evaluation regarding the presence or absence of hazardous material is beyond the
scope of this firm’s services.
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2.0 SITE AND PROJECT DESCRIPTION
The roughly triangular shaped site encompasses approximately one-half acre and is generally located east
of the intersection of Adams Street and Highland Drive in Carlsbad, California (Figure 1). The site is
bounded by Highland Drive on the northwest, Adams Street on the southwest, and vacant undeveloped land
on the east. Topography at the site is generally sloping down to the south and west. Elevations across the
site range from approximately 105 feet above msl in the northeast corner of the site to 70 feet above msl in
the southeast corner of the site. The site is graded and currently supports a single-family residence and
associated improvements. The existing improvements will be razed to allow for new construction.
It is our understanding that the project will consist of a one- to two-story single-family residence with a
partially subterranean basement level. It is anticipated that the structure will be supported by conventional
spread and continuous footings and will consist of CMU or poured in place concrete construction for the
underground level with wood framing on the above ground levels. Access will be afforded from Highland
Drive along the northwesterly property boundary.
3.0 FIELD AND LABORATORY INVESTIGATION
AGS conducted a geotechnical investigation of the subject property in December 2019. As part of the
investigation three (3) solid flight auger soil borings were excavated onsite, logged, and sampled by a
representative of this firm. The borings were excavated to a maximum depth of 21.5 feet below ground
surface. Boring logs are presented in Appendix B with boring locations presented on Plate 1.
Representative bulk and “undisturbed” ring samples were transported to our laboratory for testing. Testing
included in-situ moisture content and density, shear strength, maximum density and optimum moisture
content, expansion potential and chemical/corrosivity analysis. Laboratory test results are presented in
Appendix C.
4.0 ENGINEERING GEOLOGY
4.1. Geologic Analysis
4.1.1. Literature Review
AGS has reviewed the referenced geologic documents (see Appendix A) in preparing this
study. Where deemed appropriate, this information has been included with this document.
4.1.2. Aerial Photograph and Historic U.S.G.S. Map Review
AGS has reviewed the aerial photographs available online and in our library as well as
historic U.S.G.S. quadrangle maps.
4.1.3. Field Mapping
A site reconnaissance was conducted at the site and its immediate vicinity.
4.2. Geologic and Geomorphic Setting
The subject site is situated within the Peninsular Ranges Geomorphic Province. The Peninsular
Ranges province occupies the southwestern portion of California and extends southward to the
southern tip of Baja California. In general the province consists of young, steeply sloped, northwest
FIGURE
1
DATE:
1/20
SITE LOCATION MAP
PROJECT NO.:
1901-03
N
NOTE: ALL DIMENSIONS, DIRECTIONS AND LOCATIONS ARE APPROXIMATE.SOURCE: USGS, THE NATIONAL MAP, 2020.
SITE
SINGLE FAMILY RESIDENCE
4464 ADAMS STREET
CARLSBAD, CALIFORNIA
Scale: 1:18,056
Zoom e11ef: 1 S
St.:it e
arks
Tr.:iilh ad
0.3m,
ii'
GS
Sanderling
l\laldorf
Sch
MAGNOLIA
Elem
VALLEY l111ld
Agua Hedionda
100
1
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P/W 1901-03 Report No. 1901-03-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
trending mountain ranges underlain by metamorphosed Late Jurassic to Early Cretaceous-aged
extrusive volcanic rock and Cretaceous-aged igneous plutonic rock of the Peninsular Ranges
Batholith. The westernmost portion of the province, where the subject site is located, is
predominantly underlain by younger marine and non-marine sedimentary rocks. The Peninsular
Ranges’ dominant structural feature is northwest-southeast trending crustal blocks bounded by
active faults of the San Andreas transform system.
4.3. Stratigraphy
The project site is mapped as being underlain by old paralic deposits (terrace deposits) overlying
Tertiary age Santiago Formation as shown in Figure 2, Regional Geologic Map. AGS encountered
materials considered to be associated with the old paralic deposits during our investigation at the
site. A description of the geologic units encountered is provided below. More detailed descriptions
of these materials are provided in the boring logs included in Appendix B.
4.3.1. Artificial Fill – Undocumented (Map symbol afu)
Undocumented artificial fill was encountered within borings B-1 through B-3 with an
approximate thickness of 2.5 to 5 feet. The fill material was observed to be silty fine- to
medium-grained sand with trace clay and occasional roots and debris that is dark gray
brown to dark yellow brown in a moist to very moist and loose condition. Additional
undocumented artificial fill deposits may be encountered throughout the site.
4.3.2. Old Paralic Deposits (Map symbol Qop2-4)
Pleistocene age old paralic deposits were encountered within all three borings excavated
onsite (B-1 through B-3) to the maximum depth explored. This unit was generally observed
to consist of yellow brown to gray brown to red brown, silty sand with clay in a slightly
moist to moist and medium dense to dense condition. Interbedded silt lenses were
encountered in boring B-1 below a depth of 15 feet.
4.4. Groundwater
Groundwater was not encountered in the recent exploratory excavations by AGS. No natural
groundwater condition is known to exist at the site that would impact the proposed site
development. However, it should be noted that localized perched groundwater may develop at a
later date, most likely at or near fill/bedrock contacts, due to fluctuations in precipitation, irrigation
practices, or factors not evident at the time of our field explorations. In general, all subterranean
portions of the proposed structures will require waterproofing and drainage.
4.5. Non-seismic Geologic Hazards
4.5.1. Mass Wasting and Debris Flows
No evidence of mass wasting or debris flows was observed onsite nor was any noted on
the reviewed maps.
FIGURE
2
DATE
1/20
PROJECT NO.
1901-03
REGIONAL GEOLOGIC MAP
NOTE: ALL DIMENSIONS, DIRECTIONS AND LOCATIONS ARE APPROXIMATE.
SINGLE FAMILY RESIDENCE
4464 ADAMS STREET
CARLSBAD, CALIFORNIA
LEGEND
N
SOURCE: GEOLOGIC MAP OF THE OCEANSIDE 30’ X 60’ QUADRANGLE, 2007.
SITE
Alluvial flood-plain deposits (late Holocene)
Old alluvial flood-plain deposits, undivided (late to middle
Pleistocene)
Old paralic deposits, undivided (late to middle Pleistocene)
I Qop2-4 I Units 2-4
~ Santiago Formation (middle Eocene)
GS
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ADVANCED GEOTECHNICAL SOLUTIONS, INC.
4.5.2. Subsidence and Ground Fissuring
Evidence of ground fissuring has not been identified on the site, and AGS is unaware of
ground fissuring the surrounding areas.
4.5.3. Flooding
According to available FEMA maps, the site is not in a FEMA identified flood hazard area.
4.6. Seismic Hazards
The site is located in the tectonically active Southern California area, and will therefore likely
experience shaking effects from earthquakes. The type and severity of seismic hazards affecting
the site are to a large degree dependent upon the distance to the causative fault, the intensity of the
seismic event, the direction of propagation of the seismic wave and the underlying soil
characteristics. The seismic hazard may be primary, such as surface rupture and/or ground shaking,
or secondary, such as liquefaction, seismically induced slope failure or dynamic settlement. The
following is a site-specific discussion of ground motion parameters, earthquake-induced landslide
hazards, settlement, and liquefaction. The purpose of this analysis is to identify potential seismic
hazards and propose mitigations, if necessary, to reduce the hazard to an acceptable level of risk.
The following seismic hazards discussion is guided by the California Building Code (2016),
CDMG (2008), and Martin and Lew (1998).
4.6.1. Surface Fault Rupture
There are no known active surface faults that transect or project into the subject site. The
nearest known active surface fault is the Rose Canyon fault zone which is approximately
2.1 miles west of the site. Accordingly, the potential for fault surface rupture on the subject
site is low. This conclusion is based on literature review and aerial photographic analysis.
4.6.2. Seismic Design Parameters
Based on our subsurface exploration, the site may be classified as Seismic Site Class D
consisting of a “stiff soil” profile with average NSPT blow count ranging between 15 to 50
blows/foot. Site coordinates of Latitude 32.7519° N and Longitude -117.2309° W were
utilized in conjunction with the SEAOC/OSHPD Seismic Design Maps web-based ground
motion calculator (https://seismicmaps.org/) to obtain the 2016 CBC seismic design
parameters presented in Table 4.6.3.
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ADVANCED GEOTECHNICAL SOLUTIONS, INC.
TABLE 4.6.3.
2016 CALIFORNIA BUILDING CODE DESIGN PARAMETERS
Seismic Site Class D
Mapped Spectral Acceleration Parameter at Period of 0.2-Second, Ss 1.195g
Mapped Spectral Acceleration Parameter at Period 1-Second, S1 0.457g
Site Coefficient, Fa 1.022
Site Coefficient, Fv 1.543
Adjusted MCER1 Spectral Response Acceleration Parameter at Short Period, SMS 1.221g
1-Second Period Adjusted MCER1 Spectral Response Acceleration Parameter, SM1 0.705g
Short Period Design Spectral Response Acceleration Parameter, SDS 0.814g
1-Second Period Design Spectral Response Acceleration Parameter, SD1 0.470g
Peak Ground Acceleration, PGAM2 0.524g
Seismic Design Category D
Note: 1 Targeted Maximum Considered Earthquake
2 Peak Ground Acceleration adjusted for site effects
4.6.3. Seismicity
As noted, the site is within the tectonically active southern California area, and is
approximately 2.1 miles from an active fault, the Oceanside section of the Newport-
Inglewood-Rose Canyon fault zone. The potential exists for strong ground motion that
may affect future improvements.
At this point in time, non-critical structures (commercial, residential, and industrial) are
usually designed according to the California Building Code (2016) and that of the
controlling local agency. However, liquefaction/seismic slope stability analyses, critical
structures, water tanks and unusual structural designs will likely require site specific
ground motion input.
4.6.4. Liquefaction
Due to the lack of loose saturated granular materials, and dense nature and age of the
underlying old paralic deposits, the potential for seismically induced liquefaction is
considered remote.
4.6.5. Dynamic Settlement
Dynamic settlement occurs in response to an earthquake event in loose sandy earth
materials. This potential of dynamic settlement at the subject site is considered very low
within the underlying formational materials.
4.6.6. Seismically Induced Landsliding
Evidence of landsliding at the site was not observed during our field explorations nor was
any geomorphic features indicative of landsliding noted during our review of aerial photos
and published geologic maps.
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4.6.7. Tsunamis
Our review of the 2009 Tsunami Inundation Map for Emergency Planning, Oceanside and
San Luis Rey Quadrangles, prepared by CalEMA, indicates the project site is not within a
potential inundation area. It is our opinion that tsunamis are not a significant risk at the
project site.
5.0 GEOTECHNICAL ENGINEERING
Presented herein is a general discussion of the geotechnical properties of the various soil types and the
analytic methods used in this report.
5.1. Material Properties
5.1.1. Excavation Characteristics
Based on our previous experience with similar projects near the subject site and the
information gathered in preparing this report, it is our opinion that the surficial soils and
old paralic deposits are readily excavatable with conventional grading equipment.
However, it should be anticipated that well cemented zones could be encountered within
the old paralic deposits that may be difficult to excavate. Specialized grading equipment
(large excavators, hoe rams, and/or bull dozers) may be necessary to efficiently excavate
these materials.
5.1.2. Compressibility
Surficial soils consisting of topsoil, fill and the upper highly weathered portion of old
paralic deposits are considered “moderately” compressible in their present condition. In
areas to receive settlement sensitive improvements these materials will require complete
removal prior to placement of fill, and where exposed at design grade. Compressibility of
the unweathered old paralic deposits is not a geotechnical design concern for the proposed
development.
5.1.3. Collapse Potential/Hydro-Consolidation
The hydro-consolidation process is a singular response to the introduction of water into
collapse-prone alluvial soils. Upon initial wetting, the soil structure and apparent strength
are altered, and a virtually immediate settlement response occurs. The unweathered old
paralic deposits are not considered prone to hydro-collapse.
5.1.4. Expansion Potential
Based on our laboratory testing and experience in the project area, it is anticipated that the
expansion potential of the onsite materials will generally vary from “very low” to
“medium” with the majority of onsite materials in the “very low to low” range. Post-
grading testing should be conducted to define as-graded expansive soil characteristics. The
results of those tests and the final as-graded conditions will govern design of foundations
and driveway sections.
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5.1.5. Chemical and Resistivity Test Results
The test results from a sample collected during the current investigation indicated a sulfate
concentration that corresponds to a negligible (S0 – not applicable) sulfate exposure when
classified in accordance with ACI 318. The onsite soils are expected to be corrosive to
ferrous metals.
5.1.6. Pavement Support Characteristics
Compacted fill derived from onsite soils is expected to possess moderate pavement support
characteristics. Pavement design recommendations should be based on the R-value of the
compacted subgrade soils and can be provided, if required.
5.1.7. Shear Strength
Shear strength testing was conducted by AGS (Appendix C). The shear strengths that were
used by AGS for design are presented in the following table.
TABLE 5.1.7
Shear Strengths Used for Design
Material Cohesion
(psf)
Friction Angle
(degrees)
Moist Density
(pcf)
Compacted Fill – afc 100 30 130
Old Paralic Deposits – Qop2-4 200 32 125
5.1.8. Earthwork Adjustments
The onsite soils are expected to undergo a volume change when excavated and utilized as
a fill material. In an effort to balance earthwork quantities, the following volume
adjustments can be utilized. These numbers are considered approximate and should be
refined during grading when actual conditions are better defined. Contingencies should be
made to adjust the earthwork balance during grading if these numbers are adjusted.
TABLE 5.1.8
RECOMMENDED EARTHWORK ADJUSTMENTS
Geologic Unit Adjustment Factor
Topsoil and Artificial fill Shrink 5 – 15%
Old Paralic Deposits (Qop2-4) Bulk 0 – 3%
5.2. Analytical Methods
5.2.1. Bearing Capacity
Ultimate bearing capacity and shoring design values were obtained using the graphs and
formulas presented in NAVFAC DM-7.1. Allowable bearing was determined by applying
a factor of safety of at least three to the ultimate bearing capacity.
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5.2.2. Lateral Earth Pressures
Static lateral earth pressures were calculated using Rankine methods for active and passive
cases. If it is desired to use Coulomb forces, a separate analysis specific to the application
can be conducted.
6.0 GRADING AND SHORING RECOMMENDATIONS
Based on the information provided herein, the proposed project is considered feasible from a geotechnical
standpoint provided the conclusions and recommendations presented herein are incorporated into the design
and construction of the project.
6.1. Earthwork Recommendations
All grading should be accomplished under the observation and testing of the project soils engineer
and engineering geologist or their authorized representative in accordance with the
recommendations contained in the approved geotechnical reports, the Grading Specifications
contained in Appendix D, the project specifications, and the Building Code. Prior to fill placement,
the bottoms of all removal areas should be observed and approved by the engineering
geologist/soils engineer or their authorized representative.
6.1.1. Site Preparation
Existing vegetation, trash, debris, and other deleterious materials should be removed and
wasted from the site prior to commencing removal of unsuitable soils and placement of
compacted fill materials. Additionally, all pre-existing foundation elements and
underground improvements (e.g. utilities, storage tanks, etc.) should be removed and
wasted off-site. Abandoned utilities or storage tanks should be removed and/or abandoned
in accordance with local regulations.
6.1.2. Removals
Topsoil, artificial fill, and highly weathered old paralic deposits are considered to be
compressible in their current condition and should be removed in areas to receive fill and
where settlement sensitive improvements are planned. Detailed plans are not available at
this time and therefore the exact extent of required removals are unknown. In general, it is
anticipated that unsuitable soil removals will be on the order of 2 to 5 feet deep. Localized
areas may require deeper removals. The extent of removals can best be determined in the
field during grading when observation and evaluation can be performed by the soil engineer
and/or engineering geologist. Soils removed during remedial grading will be suitable for
reuse in compacted fills provided they are properly moisture conditioned and do not contain
deleterious materials.
6.2. Earthwork Considerations
6.2.1. Compaction Standards
All fills should be compacted to at least 90 percent of the maximum dry density as
determined by ASTM D1557. All loose and or deleterious soils should be removed to
expose firm native soils or bedrock. Prior to the placement of fill, the upper 6 to 8 inches
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should be ripped, moisture conditioned to optimum moisture or slightly above optimum,
and compacted to a minimum of 90 percent of the maximum dry density (ASTM D1557).
Fill should be placed in thin (6 to 8-inch) lifts, moisture conditioned to optimum moisture
or slightly above, and compacted to 90 percent of the maximum dry density (ASTM
D1557) until the desired grade is achieved.
6.2.2. Benching
Where the natural slope is steeper than 5-horizontal to 1-vertical and where determined by
the Geotechnical Consultant, compacted fill material shall be keyed and benched into
competent materials.
6.2.3. Mixing and Moisture Control
In order to prevent layering of different soil types and/or different moisture contents,
mixing and moisture control of materials will be necessary. The preparation of the earth
materials through mixing and moisture control should be accomplished prior to and as part
of the compaction of each fill lift. Water trucks or other water delivery means may be
necessary for moisture control. Discing may be required when either excessively dry or
wet materials are encountered.
6.2.4. Import Soils
Import soils, if required, 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. Import soils should be tested and approved by the Geotechnical Consultant prior
to importing. At least three working days should be allowed in order for the geotechnical
consultant to sample and test the potential import material.
6.3. Temporary Excavations
We anticipate that temporary, shallow excavations with vertical side slopes less than 4 feet high
will generally be stable. Deeper excavations should be sloped back at an inclination of 1.5:1
(horizontal: vertical). Personnel from AGS should observe the excavation so that any necessary
modifications based on variations in the encountered soil conditions can be made. All applicable
safety requirements and regulations, including CalOSHA requirements, should be met.
Where sloped excavations are created, the tops of the slopes should be barricaded so that vehicles
and storage loads do not encroach within 10 feet of the tops of the excavated slopes. A greater
setback may be necessary when considering heavy vehicles, such as concrete trucks and cranes.
AGS should be advised of such heavy vehicle loadings so that specific setback requirements can
be established. If the temporary construction slopes are to be maintained during the rainy season,
berms are recommended to be graded along the tops of the slopes in order to prevent runoff water
from entering the excavation and eroding the slope faces.
Vertical excavations greater than 4 feet high will require temporary shoring/shielding of the
subgrade soils. If temporary shoring becomes necessary, design recommendations can be provided
at that time.
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6.4. Utility Trench Backfill
Utility trench backfill should be compacted to at least 90 percent of maximum dry density (95
percent if below structural improvements) as determined by ASTM D1557. Onsite soils will not
be suitable for use as bedding material but will generally be suitable for use in backfill, provided
oversized and deleterious materials are removed. Compaction should be accomplished by
mechanical means. Jetting of native soils will not be acceptable.
6.5. Flatwork Subgrade Preparation
The upper one foot of subgrade below exterior slabs, sidewalks, patios, etc. should be compacted
to a minimum of 90 percent (95 percent below driveways) of the maximum dry density as
determined by ASTM D1557. The subgrade below exterior slabs, sidewalks, driveways, patios,
etc. should be moisture conditioned to a minimum of 110 percent of optimum moisture content
prior to concrete placement.
7.0 CONCLUSIONS AND DESIGN RECOMMENDATIONS
Construction of the proposed project is considered feasible, from a geotechnical standpoint, provided that
the conclusions and recommendations presented herein are incorporated into the design and construction
of the project. As with all projects, changes in observed conditions may result in alternative construction
techniques and/or possible delays. The contractor should be aware of these possibilities and provide
contingencies in his bids to account for them.
7.1. Structural Design
The site is mantled by a thin veneer of surficial soils which we anticipate will be removed to expose
formational materials that possess favorable geotechnical qualities. It is anticipated that the
majority of the onsite soils will generally vary from "Very Low" to "Medium" in expansion
potential when tested in general accordance with ASTM D 4829.
7.1.1. Foundation Design
The proposed single-family residential structure can be supported on conventional shallow
foundations and a slab-on-grade system bearing on competent formation materials or
compacted fill, as discussed above. The design of foundation systems should be based on
as-graded conditions as determined after grading completion. The following values may
be used in preliminary foundation design:
Allowable Bearing: 2500 psf.
Lateral Bearing: 250 lbs./sq.ft. at a depth of 12 inches plus
125 lbs./sq.ft. for each additional 12 inches
embedment to a maximum of 2500 lbs./sq.ft.
Sliding Coefficient: 0.35
Settlement: Total = 1 inch
Differential = 1/2 inch in 20 feet
December 31, 2019 Page 11
P/W 1901-03 Report No. 1901-03-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
The above values may be increased as allowed by Code to resist transient loads such as
wind or seismic. Based on anticipated preliminary expansion potential of “Very Low” to
“Medium” for the onsite soil and information supplied by the CBC-2016, additional
foundation design recommendations are provided in Table 7.1.1.
TABLE 7.1.1
FOUNDATION DESIGN RECOMMENDATIONS
Expansion Potential Very Low to Low (Cat. I) Medium (Cat. II)
Footing Depth Below Lowest Adjacent Finish Grade
One-Story 12 inches 18 inches
Two-Story 18 inches 18 inches
Footing Width
One-Story 12 inches 12 inches
Two-Story 15 inches 15 inches
Footing Reinforcement
One-Story No. 4 rebar, one (1) on top and one
(1) on bottom
No. 4 rebar, two (2) on top and two
(2) on bottom or No. 5 rebar one (1)
on top and one (1) on bottom
Two-Story No. 4 rebar, one (1) on top and one
(1) on bottom
No. 4 rebar, two (2) on top and two
(2) on bottom or No. 5 rebar one (1)
on top and one (1) on bottom
Slab Thickness 5 inches (actual) 5 inches (actual)
Slab Reinforcement No. 3 rebar spaced 15 inches on
center, each way
No. 3 rebar spaced 12 inches on
center, each way
Slab Subgrade
Moisture
Minimum of optimum moisture
prior to placing concrete.
Minimum of 120% of optimum
moisture 24 hours prior to placing
concrete.
Footing Embedment Next to Swales and Slopes
If exterior footings adjacent to drainage swales are to exist within five (5) feet horizontally of the swale, the
footing should be embedded sufficiently to assure embedment below the swale bottom is maintained.
Footings adjacent to slopes should be embedded such that a least seven (7) feet are provided horizontally from
edge of the footing to the face of the slope.
Garages
A grade beam reinforced continuously with the garage footings shall be constructed across the garage
entrance, tying together the ends of the perimeter footings and between individual spread footings. This grade
beam should be embedded at the same depth as the adjacent perimeter footings. A thickened slab, separated
by a cold joint from the garage beam, should be provided at the garage entrance. Minimum dimensions of
the thickened edge shall be six (6) inches deep. Footing depth, width and reinforcement should be the same
as the structure. Slab thickness, reinforcement and underslab treatment should be the same as the structure.
Isolated Spread Footings
Isolated spread footings should be embedded a minimum of 18 inches below lowest adjacent finish grade and
should at least 24 inches wide. A grade beam should also be constructed for interior and exterior spread
footings and should be tied into the structure in two orthogonal directions, footing dimensions and
reinforcement should be similar to the aforementioned continuous footing recommendations. Final depth,
width and reinforcement should be determined by the structural engineer
I I I I
I I I I
December 31, 2019 Page 12
P/W 1901-03 Report No. 1901-03-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
7.1.2. Moisture and Vapor Barrier
A moisture and vapor retarding system should be placed below the slabs-on-grade in
portions of the structure considered to be moisture sensitive. The retarder should be of
suitable composition, thickness, strength and low permeance to effectively prevent the
migration of water and reduce the transmission of water vapor to acceptable levels.
Historically, a 10-mil plastic membrane, such as Visqueen, placed between one to four
inches of clean sand, has been used for this purpose. More recently Stego® Wrap or similar
underlayments have been used to lower permeance to effectively prevent the migration of
water and reduce the transmission of water vapor to acceptable levels. The use of this
system or other systems, materials or techniques can be considered, at the discretion of the
designer, provided the system reduces the vapor transmission rates to acceptable levels.
7.2. Conventional Retaining Walls
The following earth pressures are recommended for the design of proposed retaining basement
walls onsite. Earth pressures for both compacted fill and the Old Paralic Deposits are provided
below:
Static Case
Compacted Fill (phi = 30°, unit wt. = 130 pcf)
Rankine Equivalent Fluid
Level Backfill Coefficients Pressure (psf/lin.ft.)
Coefficient of Active Pressure: Ka = 0.33 43
Coefficient of Passive Pressure: Kp = 3.00 390
Coefficient of at Rest Pressure: Ko = 0.50 65
Rankine Equivalent Fluid
2 : 1 Backfill Coefficients Pressure (psf/lin.ft.)
Coefficient of Active Pressure: Ka = 0.54 70
Coefficient of At Rest Pressure: Ko = 0.90 118
Old Paralic Deposits (phi = 32°, unit wt. = 125pcf)
Rankine Equivalent Fluid
Level Backfill Coefficients Pressure (psf/lin.ft.)
Coefficient of Active Pressure: Ka = 0.31 38
Coefficient of Passive Pressure: Kp = 3.25 407
Coefficient of at Rest Pressure: Ko = 0.47 59
Rankine Equivalent Fluid
2 : 1 Backfill Coefficients Pressure (psf/lin.ft.)
Coefficient of Active Pressure: Ka = 0.47 59
Coefficient of At Rest Pressure: Ko = 0.85 106
December 31, 2019 Page 13
P/W 1901-03 Report No. 1901-03-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
Seismic Case
In addition to the above static pressures, unrestrained retaining walls located should be designed to
resist seismic loading as required by the 2016 CBC. The seismic load can be modeled as a thrust
load applied at a point 0.6H above the base of the wall, where H is equal to the height of the wall.
This seismic load (in pounds per lineal foot of wall) is represented by the following equation:
Pe = ⅜ *γ*H2 *kh
Where: Pe = Seismic thrust load
H = Height of the wall (feet)
γ = soil density = 125 pounds per cubic foot (pcf)
kh = seismic pseudostatic coefficient = 0.5 * peak horizontal
ground acceleration (PGAm)
Walls should be designed to resist the combined effects of static pressures and the above seismic
thrust load.
A bearing value of 2500 psf may be used for design of retaining walls bearing on compacted fill or
competent formational mateirals. A value of 0.35 may be used to model the frictional between the
soil and concrete. For sliding passive pressure both passive and friction can be combined to a
maximum of 2/3 the total.
Retaining wall footings should be designed to resist the lateral forces by passive soil resistance
and/or base friction as recommended for foundation lateral resistance. To relieve the potential for
hydrostatic pressure wall backfill should consist of a free draining backfill (sand equivalent “SE”
>20) and a heel drain should be constructed. The heel drain should be place at the heel of the wall
and should consist of a 4-inch diameter perforated pipe (SDR35 or SCHD 40) surrounded by 1
cubic foot of crushed rock (3/4-inch) per lineal foot, wrapped in filter fabric (Mirafi® 140N or
equivalent).
Proper drainage devices should be installed along the top of the wall backfill, which should be
properly sloped to prevent surface water ponding adjacent to the wall. In addition to the wall
drainage system, for building perimeter walls extending below the finished grade, the wall should
be waterproofed and/or damp-proofed to effectively seal the wall from moisture infiltration through
the wall section to the interior wall face.
The wall should be backfilled with granular soils placed in loose lifts no greater than 8-inches thick,
at or near optimum moisture content, and mechanically compacted to a minimum 90 percent
relative compaction as determined by ASTM Test Method D1557. Flooding or jetting of backfill
materials generally do not result in the required degree and uniformity of compaction and,
therefore, is not recommended. The soils engineer or his representative should observe the retaining
wall footings, backdrain installation and be present during placement of the wall backfill to confirm
that the walls are properly backfilled and compacted.
7.3. Concrete Design
Testing by AGS indicated that the onsite soils have low concentrations of soluble sulfate,
corresponding to an S0 exposure class when classified in accordance with ACI 318. Final
December 31, 2019 Page 14
P/W 1901-03 Report No. 1901-03-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
determination will be based upon testing of near surface soils obtained at the conclusion of grading.
Some fertilizers have been known to leach sulfates into soils otherwise containing "negligible"
sulfate concentrations, therefore Type II/V cement is recommended for concrete in contact with
soil.
7.4. Corrosion
The onsite soils are expected to be corrosive to buried metallic materials. AGS recommends
minimally that the current standard of care be employed for protection of metallic construction
materials in contact with onsite soils and consultation with a corrosion engineer to determine
specifications for protection of construction materials. Steel reinforcement in contact with onsite
soils should be protected with an epoxy coating, adequate concrete cover, or other approved
methods as detailed by the structural engineer.
7.5. Site Drainage
Final site grading should assure positive drainage away from structures. Planter areas should be
provided with area drains to transmit irrigation and rainwater away from structures. The use of
gutters and down spouts to carry roof drainage well away from structures is recommended. Raised
planters should be provided with a positive means to remove water through the face of the
containment wall.
7.6. Exterior Flatwork
Concrete flatwork not subject to vehicular traffic loading should be designed utilizing 4-inch
minimum thickness. Consideration should be given to construct a thickened edge (scoop footing)
at the perimeter of slabs and walkways adjacent to landscape areas to minimize moisture variation
below these improvements. The thickened edge (scoop footing) should extend approximately 8
inches below concrete slabs and should be a minimum of 6 inches wide.
Weakened plane joints should be installed on walkways at intervals of approximately 6 to 8 feet.
Exterior slabs should be designed to withstand shrinkage of the concrete. Consideration should be
given to reinforcing any exterior flatwork.
8.0 FUTURE STUDY NEEDS
8.1. Construction Plans
Grading and construction plans have not yet been developed. The recommendations provided
herein are considered preliminary and subject to change based on the actual design. When
available, the geotechnical engineer should review detailed construction plans. The following plans
should be reviewed:
• Precise grading and utility plans
• Structural plans including foundation plans and retaining wall plans and
calculations.
December 31, 2019 Page 15
P/W 1901-03 Report No. 1901-03-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
8.2. Observation During Construction
Continuous geologic and geotechnical observations, testing, and mapping should be provided
throughout site development. Additional near-surface samples should be collected by the
geotechnical consultant during grading and subjected to laboratory testing. Final design
recommendations should be provided in a grading report based on the observation and test results
collected during grading.
9.0 CLOSURE
The findings and recommendations in this report are based on the specific excavations, observations, and
tests results obtained during this investigation. The findings are based on the review and interpretation of
the field and laboratory data combined with an interpolation and extrapolation of conditions between and
beyond the exploratory excavations. Services performed by AGS have been conducted in a manner
consistent with that level of care and skill ordinarily exercised by members of the 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 geotechnical engineers and engineering geologists who are 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. If the project description varies from what is
described in this report, AGS must be consulted regarding the applicability of, and the necessity for, any
revisions to the recommendations presented herein. AGS accepts no liability for use of its recommendations
if AGS is not consulted regarding any project changes.
The data, opinions, and recommendations of this report are applicable to the specific design of this 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 AGS.
AGS has no responsibility for construction means, methods, techniques, sequences, or procedures, or for
safety precautions or programs in connection with the construction, for the acts or omissions of the
CONTRACTOR, or any other person performing any of the construction, or for failure of any of them to
carry out the construction in accordance with the final design drawings and specifications.
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
APPENDIX A
REFERENCES
December 31, 2019 Page A-1
P/W 1909-11 Report No. 1909-11-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
REFERENCES
American Concrete Institute, 2014, Building Code Requirements for Structural Concrete (ACI318M-14)
and Commentary (ACI 318RM-11), ACI International, Farmington Hills, Michigan.
American Society for Testing and Materials (2018), Annual Book of ASTM Standards, Section 4,
Construction, Volume 04.08, Soil and Rock (I), ASTM International, West Conshohocken,
Pennsylvania.
California Building Standards Commission, 2016, California Building Code, Title 24, Part 2, Volumes 1
and 2.
City of San Diego, 2008, Seismic Safety Study, Sheet 20.
Jennings, C.W., 1994, Fault Activity Map of California and Adjacent Areas: California Geological Survey,
California Geologic Data Map No. 6, Scale 1:750,000.
Kennedy, M.P., and Tan, S.S., 2007, Geologic Map of the Oceanside 30' x 60' Quadrangle, California,
California Geological Survey, Preliminary Geologic Maps, Scale 1:100,000.
SEAOC/OSHPD, 2019, ASCE 7-10 Seismic Design Maps, https://seismicmaps.org/
United States Geological Survey, 2019, Unified Hazards Tool,
https://earthquake.usgs.gov/hazards/interactive/
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
APPENDIX B
BORING LOGS
Artificial Fill - Undocumented (afu)
Silty fine- to medium-grained SAND with trace Clay, darkbrown to dark yellow brown, slightly moist, loose; occasionalroots
Old Paralic Deposits (Qop)Silty fine- to coarse-grained SAND, dark gray brown, dry to
slightly moist, dense; slightly micaceous
@ 5.0 ft., very dense; minor iron oxide staining
@ 7.5., Silty fine-grained SAND with trace Clay, light gray
brown to olive, slightly moist, very dense; abundant iron oxide staining, occasional manganese oxide nodules
@ 10.0 ft., mostly fine-grained with some coarse-grained,
increased Clay content, yellow brown to gray brown to olive brown; rock fragments in sample, gravel to cobble lense
@ 15.0 ft., increased Silt content, dark yellow brown to orange brown
@ 20.0 ft., Sandy SILT to Silty SAND, fine-grained, light yellow brown, slightly moist to moist, stiff to medium dense
Total depth = 21.5 feetNo groundwater encountered
Backfilled with bentonite and cement grout
7-13-21
(34)
17-26-40(66)
11-24-35
(59)
50
15-21-24
(45)
10-12-15
(27)
BU
MC
MC
MC
MC
SPT
SPT
111
129
118
3.0
5.6
6.1
3.4
15
49
39
SM
SM
EI,CHEM
SHEAR
NOTES
GROUND ELEVATION 81.8 ft
LOGGED BY SS
DRILLING METHOD Hollow Stem Auger
HOLE SIZE 8
DRILLING CONTRACTOR Baja Exploration GROUND WATER LEVELS:
CHECKED BY PJD
DATE STARTED 12/31/19 COMPLETED 12/31/19
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
MATERIAL DESCRIPTION
BL
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BORING NUMBER B-1
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CLIENT John Forester
PROJECT NUMBER 1901-03
PROJECT NAME 4464 Adams Street
PROJECT LOCATION Carlsbad, CA
:. :. ·.: .• -:_:_·,_._.
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Artificial Fill - Undocumented (afu)
Silty fine- to medium-grained SAND, dark brown to darkgray brown, moist, loose; occasional roots, piece of wood
Old Paralic Deposits (Qop)Silty fine- to coarse-grained SAND trace Clay, dark graybrown to dark red brown, moist, dense; slightly micaceous
@ 9.0 ft., yellow brown to red brown; micaceous
Total depth = 21.5 feetNo groundwater encountered
Backfilled with bentonite and cement grout
6-6-12
(18)
6-10-15(25)
10-12-18
(30)
8-15-16(31)
7-16-19
(35)
9-13-17
(30)
BU
MC
MC
MC
SPT
MC
SPT
108
117
114
113
3.8
4.9
3.8
4.3
18
30
21
24
SM
SM
MAX,REMOLD
SHEAR
NOTES
GROUND ELEVATION 82.5 ft
LOGGED BY SS
DRILLING METHOD Hollow Stem Auger
HOLE SIZE 8
DRILLING CONTRACTOR Baja Exploration GROUND WATER LEVELS:
CHECKED BY PJD
DATE STARTED 12/31/19 COMPLETED 12/31/19
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
MATERIAL DESCRIPTION
BL
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BORING NUMBER B-2
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CLIENT John Forester
PROJECT NUMBER 1901-03
PROJECT NAME 4464 Adams Street
PROJECT LOCATION Carlsbad, CA
... : .
... :. ·.: .• -:_:_·,_._ . ... : .
... :. ·.: .• -:_:_·,_._ . ... : .
... :. ·.: .• -:_:_·,_._ . ... : .
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-·.:: ... :. ·.: .• -:_:_·,_._ . ... : .
... :. ·.: .• -:_:_·,_._ . ... :.
Artificial Fill - Undocumented (afu)
Silty fine- to medium-grained SAND with trace Clay, darkgray brown, moist to very moist, loose
Old Paralic Deposits (Qop)Silty fine- to coarse-grained SAND, dark gray brown to dark
yellow brown, dry to slightly moist, dense
@ 5.0 ft., fine- to medium grained, dense; micaceous
@ 10.0 ft., yellow brown to orange brown
@ 20.0 ft., light yellow brown
Total depth = 21.5 feetNo groundwater encountered
Backfilled with bentonite and cement grout
13-23-24(47)
9-18-22(40)
11-24-31
(55)
10-16-20
(36)
MC
SPT
MC
SPT
111
4.3
3.3 17
SM
SM
NOTES
GROUND ELEVATION 94 ft
LOGGED BY SS
DRILLING METHOD Hollow Stem Auger
HOLE SIZE 8
DRILLING CONTRACTOR Baja Exploration GROUND WATER LEVELS:
CHECKED BY PJD
DATE STARTED 12/31/19 COMPLETED 12/31/19
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
MATERIAL DESCRIPTION
BL
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BORING NUMBER B-3
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CLIENT John Forester
PROJECT NUMBER 1901-03
PROJECT NAME 4464 Adams Street
PROJECT LOCATION Carlsbad, CA
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ADVANCED GEOTECHNICAL SOLUTIONS, INC.
APPENDIX C
LABORATORY TEST RESULTS
December 31, 2019 Page C-1
P/W 1909-11 Report No. 1909-11-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
APPENDIX C
LABORATORY TESTING
Classification
Soils were visually and texturally classified in accordance with the Unified Soil Classification System
(USCS) in general accordance with ASTM D2488. Soil classifications are indicated on the boring logs
in Appendix B.
Expansion Index Test
The expansion index of selected materials was evaluated in general accordance with ASTM D 4829.
Specimens were molded under a specified compactive energy at approximately 50 percent saturation
(plus or minus 1 percent). The prepared 1 inch thick by 4-inch diameter specimens were loaded with a
surcharge of 144 pounds per square foot and were inundated with tap water. Readings of volumetric
swell were made for a period of 24 hours. The results of these tests are presented on Figure C-1.
Modified Proctor Density
The maximum dry density and optimum moisture content of a selected representative soil sample was
evaluated using the Modified Proctor method in general accordance with ASTM D1557. The results
of these tests are summarized on Figure C-2.
Direct Shear
Direct shear tests were performed on undisturbed and remolded samples in general accordance with
ASTM D3080 to evaluate the shear strength characteristics of selected materials. The samples were
inundated during shearing to represent adverse field conditions. The results are shown on Figures C-3
though C-5.
Soil Corrosivity
Soil pH, and resistivity testing was performed on a selected sample in general accordance with
California Test (CT)643. The chloride content of a selected sample was evaluated in general
accordance with CT422. The sulfate content of a selected sample was evaluated in general accordance
with CT417. The test results are presented on Figure C-6.
EXPANSION INDEX - ASTM D4829 AGS FORM E-6
Project Name: 4465 Adams St Excavation/Tract: B-1
Location: Carlsbad Depth/Lot: 0 - 2.5'
P/W: 1901-03 Description: Drk Brn SM
Date: 1/6/20 Tested by: JR
Checked by: FV
Expansion Index - ASTM D4829
Initial Dry Density (pcf): 119.5
Initial Moisture Content (%): 7.6
Initial Saturation (%): 49.8
Final Dry Density (pcf): 119.6
Final Moisture Content (%): 14.2
Final Saturation (%):93.8
Expansion Index: 0
Potential Expansion: Very Low
ASTM D4829 - Table 5.3
Expansion Index
0 - 20
21 - 50
51 - 90
91 - 130
>130 Very High
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
Potential Expansion
Very Low
Low
Medium
High
1901-03_EI_B-1_0.0-2.5 ft_01-06-2020_JR FIGURE C-1
MAXIMUM DENSITY - ASTM D1557 AGS FORM E-8
Project Name: 4464 Adams St Excavation: B-2
Location: Carlsbad Depth: 0 - 3 ft.
P/W No.: 1901-03 Soil Type: Dark Brn. SC-SM
Date:Tested by: JR
Checked by: PJ
Method: A Oversize Retained: 0 %
Point No.1234
Dry Density (pcf)124.2 129.0 131.5 126.9
Moisture Content (%)5.7 7.7 9.5 11.7
Corrected Max. Dry Density 131.5 pcf Corrected Moisture 9.5 %
Max. Dry Density 131.5 pcf Optimum Moisture 9.5 %
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
01-2020
100.0
105.0
110.0
115.0
120.0
125.0
130.0
135.0
140.0
0.0 5.0 10.0 15.0 20.0 25.0 30.0
DR
Y
D
E
N
S
I
T
Y
(
p
c
f
)
MOISTURE (%)
MAXIMUM DENSITY CURVE
Test Curve
Zero Air Voids Curves
SG=2.6
SG=2.7
SG=2.8
FIGURE C-2
I ,_ I..----~
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~ ,
•
'---,_.__ -, ,_.__
" .. '
1, ' I,. ',t-,'""'\: t~ 1. '\
Project Name: 4464 Adams St Excavation: B-2
Location: Carlsbad Depth: 0-3 ft
Project No.: 1901-03 Tested by: FV
Date:Reviewed by:
Samples Tested 123 Soil Type: Dark Brn SC-SM
Intial Moisture (%) 9.5 9.5 9.5 Test: Remolded 90%
Initial Dry Density (pcf) 118.3 118.3 118.3 Method: Drained
Normal Stress (psf) 1000 2000 4000 Consolidation: Yes
Peak Shear Stress (psf) 912 1452 2700 Saturation: Yes
Ult. Shear Stress (psf) 696 1332 2472 Shear Rate (in/min):0.01
Strength Parameters Peak Ultimate
Friction Angle, phi (deg)31 30
Cohesion (psf)288 126
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
DIRECT SHEAR - ASTM D3080
1/21/2020
‐0.02
‐0.01
0.00
0.01
0.02
0.03
0.04
0.05
0.00 0.10 0.20 0.30
Ve
r
t
i
c
a
l
De
f
o
r
m
a
t
i
o
n
(i
n
)
Displacement (in)
Vertical Deformation v. Displacement
4000
2000
10000
500
1000
1500
2000
2500
3000
0.00 0.10 0.20 0.30
Sh
e
a
r
St
r
e
s
s
(p
s
f
)
Displacement (in)
Shear Stress v. Displacement
4000
2000
1000
0
500
1000
1500
2000
2500
3000
0 500 1000 1500 2000 2500 3000 3500 4000 4500
Sh
e
a
r
St
r
e
s
s
(p
s
f
)
Normal Stress (psf)
Peak
Peak
Ultimate
Ultimate
FIGURE C-3
-
1-I I 7 -
~
I_ I I I _J c====----t-t-1
.... ····· ..
--------
Project Name: 4464 Adams ST Excavation: B-1
Location: Carlsbad Depth: 8.5-9.0 ft
Project No.: 1901-03 Tested by: FV
Date:Reviewed by:
Samples Tested 123 Soil Type: Qop
Intial Moisture (%) 6.1 6.1 6.1 Test: Undisturbed
Initial Dry Density (pcf) 116.6 118.0 122.5 Method: Drained
Normal Stress (psf) 1000 2000 4000 Consolidation: Yes
Peak Shear Stress (psf) 1080 1692 3456 Saturation: Yes
Ult. Shear Stress (psf) 744 1416 3084 Shear Rate (in/min):0.01
Strength Parameters Peak Ultimate
Friction Angle, phi (deg)39 36
Cohesion (psf)198 0
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
DIRECT SHEAR - ASTM D3080
1/7/2020
‐0.02
‐0.01
0.00
0.01
0.02
0.03
0.04
0.05
0.00 0.10 0.20 0.30
Ve
r
t
i
c
a
l
De
f
o
r
m
a
t
i
o
n
(i
n
)
Displacement (in)
Vertical Deformation v. Displacement
4000
2000
10000
500
1000
1500
2000
2500
3000
3500
4000
0.00 0.10 0.20 0.30
Sh
e
a
r
St
r
e
s
s
(p
s
f
)
Displacement (in)
Shear Stress v. Displacement
4000
2000
1000
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 500 1000 1500 2000 2500 3000 3500 4000 4500
Sh
e
a
r
St
r
e
s
s
(p
s
f
)
Normal Stress (psf)
Peak
Peak
Ultimate
Ultimate
FIGURE C-4
••••• ••••••••••• ····••o,,, ················
------
------j,1/ ----7
;r 1-----I
Project Name: 4464 Adams St Excavation: B-2
Location: Carlsbad Depth: 10-10.5 ft
Project No.: 1901-03 Tested by: FV
Date:Reviewed by:
Samples Tested 123 Soil Type: Qop
Intial Moisture (%) 3.8 3.8 3.8 Test: Undisturbed
Initial Dry Density (pcf) 110.7 113.8 110.0 Method: Drained
Normal Stress (psf) 1000 2000 4000 Consolidation: Yes
Peak Shear Stress (psf) 840 1548 2724 Saturation: Yes
Ult. Shear Stress (psf) 672 1272 2484 Shear Rate (in/min):0.01
Strength Parameters Peak Ultimate
Friction Angle, phi (deg)32 31
Cohesion (psf)252 66
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
DIRECT SHEAR - ASTM D3080
1/21/2020
‐0.02
‐0.01
0.00
0.01
0.02
0.03
0.04
0.05
0.00 0.10 0.20 0.30
Ve
r
t
i
c
a
l
De
f
o
r
m
a
t
i
o
n
(i
n
)
Displacement (in)
Vertical Deformation v. Displacement
4000
2000
10000
500
1000
1500
2000
2500
3000
0.00 0.10 0.20 0.30
Sh
e
a
r
St
r
e
s
s
(p
s
f
)
Displacement (in)
Shear Stress v. Displacement
4000
2000
1000
0
500
1000
1500
2000
2500
3000
0 500 1000 1500 2000 2500 3000 3500 4000 4500
Sh
e
a
r
St
r
e
s
s
(p
s
f
)
Normal Stress (psf)
Peak
Peak
Ultimate
Ultimate
FIGURE C-5
··········· ··············
' f ,, ' , ! ,
--... -... __ _.,,,,,.v--.,.----------
/'---~------------------------------------------
II J
ANAHEIM TEST LAB, INC
196 Technology Drive, Unit D
Irvine, CA 92618 Phone (949)336-6544
DATE: 01/10/2020 Advanced Geotechnical Solutions, Inc. 485 Corporate Ave., Suite B P.O. NO.: Chain of Custody Escondido, CA 92029 LAB NO.: C-3479
SPECIFICATION: CTM-417/422/643
MATERIAL: Soil
Project No.: 1901-03
Project: 4464 Adams Street Date sampled: 01/06/2020
Location: B-1 @ 0’-2.5’
ANALYTICAL REPORT
CORROSION SERIES
SUMMARY OF DATA
pH SOLUBLE SULFATES SOLUBLE CHLORIDES MIN. RESISTIVITY
per CT. 417 per CT. 422 per CT. 643
ppm ppm ohm-cm
7.7 240 92 1,500
RESPECTFULLY SUBMITTED
________________________________
WES BRIDGER, LAB MANAGER
FIGURE C-6
Project:
P/W 1901-03
Report:Date:
Jan. 2020
PLATE 1
Geologic and Exploration Location Plan
1901-03-B-2
LEGEND:
Approximate location of exploratory
borings ( , 2017)AGS
B-3
afu Artificial Fill - Undocumented
Old Paralic Deposits
(Bracketed where buried)
Santiago Formation
(Bracketed where buried)
Existing Grade/Structures
Proposed Grade/Structures
Approximate Location of Geologic
Contacts (Queried were uncertain)
Approximate location of geologic
cross sections
A A’
Qop
Tsa
B-1
B-2
B-3
?
?
?
afu
(Qop)
((Tsa))
Qop
(Tsa)
PROJECT
SITE 4
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CNC!NfTAS
VICINITY MAP
NOT TO SCALE
W'LY PR. S'LY S'LY l{y R/W R/W
R/W~I :_ _______ ___!5~5'._' --------,1--r!-PROJECT
I 25• 5• 25'
VARIES
~10'
VARIES
~20' 5• R/W DEDICATION ONLY
NO FRONTAGE IMPROVEMENTS
2% -
HIGHLAND DRIVE
NOT TO SCALE RESIDENTIAL STREET
EX. PR. W'LY E.'L Y E.'LY
W'LY R/W R/W
R/CLW=======~~==========~55~•========~~~3;;:o"--·=======ii=;;r-PROJECT 25' 5' R/W DED1CA T10N 25' VAR/£ VARIES
2%
ADAMS STREET
17'
SAW CUT
LINE
8'
3'
NOT TO SCALE RESIDENTIAL STREET
PROPOSED MINOR ROAD WIDENING ,
WDE NEW CURB & GUTTER 17
/=~BM C/L W/ 3' GRADED BENCH
-----
---
206-180-38
EXISTING 8' VCP
f'NER-,MAIN--Pt.l?-1<'1STING B' P,VC n 117: L
DWG' 937-4 WATER MAIN R u ;u
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PREPARED BY:
Fusion Eng Tech
4231 Balboa Ave #619
San Diego CA
(619) 736-2800
0 20 40 ----
SCALE 1 " -20'
APN:
206-192-08
60
LEGAL DESCRIPTION: MAP 2152 LOT 13 PER SUBDIVISON
EARTHWORK QUANTITIES:
C.Y. CUT -C.Y. FILL -C.Y. IMPORT -C.Y. EXPORT
-C.Y. REMEDIAL
DMA CALCS:
EXISTING ROOF=1,290 S.F.
EXISTING HARDSCAPE=?,734 S.F.
PROPOSED ROOF=B,436 S.F.
PROPOSED HARDSCAPE=3,965 S.F.
NET INCREASE 3,377 S.F.
PRELIMINARY SITE PLAN
FORESTER RESIDENCE
4464 ADAMS STREET
CITY OF CARLSBAD, CALIFORNIA
MAP
1
OF I
'1 1
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