HomeMy WebLinkAboutCDP 16-06; BAPTIE RESIDENCE; LIMITED GEOTECHNICAL INVESTIGATION-PRELIMINARY; 2016-07-26EAST COUNTY SOIL CONSULTATION
AND ENGINEERING, INC.
10925 HARTLEY ROAD, SUITE ''I"
SANTEE, CALIFORNIA 92071
(619) 258-7901
Fax 258-7902
Ken & Sandra Baptie
P. 0. Box 1221
Woodinville, Washington 98072
Subject: Limited Geotechnical Investigation (Preliminary)
Proposed Single-Family Residence
5070 Carlsbad Boulevard
Carlsbad. California 92008
CDP 16-06
Dear Mr. & Mrs. Baptie:
July 26, 2016
Project No. l 6-1126F2
In accordance with your request. we have performed a limited geotechnical investigation at the
subject site to discuss the geotechnical aspects of the project and provide recommendations for the
proposed development.
Our investigation has found that the proposed building pad is underlain by topsoil and slopewash to
a maximum depth of approximately 2.5 feet below existing grade. These soils were underlain by
dense terrace deposits to the explored depth of 10 feet. It is our opinion that the development of the
proposed residence is geotechnically feasible provided the recommendations herein are
implemented in the design and construction.
Should you have any questions with regard to the contents of this report. please do not hesitate to
contact our office.
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Mamadou Sal iou Diallo. P. E.
RCE 5407L GE 1704
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KEN & SANDRA BAPT/£1 CARLSBAD BOULEV4RD PROJECT/v'O. 16-l !16F2
TABLE OF CONTENTS
INTRODUCTION .............................................................................................................................................. 3
SCOPE OF SERVICES ...................................................................................................................................... 3
SITE DESCRIPTION AND PROPOSED CONSTRUCTION ........................................................................ 3
FIELD INVESTIGATION AND LABORATORY TESTING ........................................................................ 4
GEOLOGY ......................................................................................................................................................... 4
Geologic Setting .................................................................................................................................... 4
Site Stratigraphy .................................................................................................................................... 4
SEIS!'vtICITY ...................................................................................................................................................... 5
Regional Seismicity ............................................................................................................................... 5
Seismic Analysis ................................................................................................................................... 5
2013 CBC Seismic Design Criteria ...................................................................................................... 6
Geologic Hazard Assessment. ............................................................................................................... 6
GEOTECHNICAL EVALUATION .................................................................................................................. 7
Compressible Soils ................................................................................................................................ 7
Expansive Soils ...................................................................................................................................... 7
Groundwater .......................................................................................................................................... 8
CONCLUSIONS AND RECOMMENDATIONS ............................................................................................ 8
CLEARING AND GRUBBING ......................................................................................................................... 8
FOUNDATIONS AND SLABS ........................................................................................................................ 8
SElTLEMENT ................................................................................................................................................... 9
PRESATURATION OF SLAB SUBGRADE ................................................................................................... 9
RETAINING WALLS ........................................................................................................................................ 9
TEMPORARY SLOPES .................................................................................................................................. I 0
TRENCH BACKFILL ...................................................................................................................................... I 0
DRAINAGE ...................................................................................................................................................... 10
FOUNDATION PLAN REVIEW .................................................................................................................... 11
LIMITATIONS OF INVESTIGATION ......................................................................................................... I l
ADDITIONAL SERVICES ............................................................................................................................ 12
PLATES
Plate 1-Location of Exploratory Boreholes
Plate 2 -Summary Sheet (Exploration Boreholes and Boring)
Plate 3 -USCS Soil Classification Chart
PAGE L-1, LABORATORY TEST RESULTS .............................................................................................. 14
REFERENCES ................................................................................................................................................. 15
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KE.ti,/ & SANDRA BAPT/£r CARLSBAD BOULEVARD PROJECT NO. 16-J l 26F2
INTRODUCTION
This is to present the findings and conclusions of a limited geotechnical investigation for a
proposed two-story, single-family residence over a partial basement to be located at 5070 Carlsbad
Boulevard, in the City of Carlsbad, California.
The objectives of the investigation were to evaluate the existing soils conditions and provide
recommendations for the proposed development.
SCOPE OF SERVICES
The following services were provided during this investigation:
0 Site reconnaissance and review of published geologic, seismological and geotechnical reports
and maps pertinent to the project area
0 Subsurface exploration consisting of three (3) boreholes within the limits of the proposed area
of development. The boreholes were logged by our Staff Geologist.
0 Collection of representative soil samples at selected depths. The obtained samples were sealed
in moisture-resistant containers and transported to the laboratory for subsequent analysis.
0 Laboratory testing of samples representative of the types of soils encountered during the field
investigation
0 Geologic and engineering analysis of the field and laboratory data. which provided the ba.;;is
for our conclusions and recommendations
0 Production of this report, which summarizes the results of the above analysis and presents our
findings and recommendations for the proposed development
SITE DESCRIPTION AND PROPOSED CONSTRUCTION
The subject site is a rectangular-shaped residential lot located on the east side of Carlsbad
Boulevard, in the City of Carlsbad, California. The property, which encompass an area of
approximately 6.600 square feet ( 11 o· X 60') is vacant with an approximately 8-foot high cut slope
descending to Carlsbad Boulevard. The building pad slopes gently to the west. Vegetation
consisted of grass and a few trees. Site boundaries include Carlsbad Boulevard to the west and
similar residential developments to the remaining directions.
The preliminary plans prepared by Wright Design of Carlsbad. California indicate the proposed
construction will include a single-family residence. The structure will be two-story. wood-framed
over a partial basement and founded on continuous footings with slab-on-grade t1oors.
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KEN & SANDRA BAPT/£1 CARLSBAD BOULEVARD PROJECT NO. !6-l /26F2
FIELD INVESTIGATION AND LABO RA TORY TESTING
On January 14, 2016, three (3) boreholes were excavated to a maximum depth of approximately 10
feet below existing grade with a hand auger. The approximate locations of the boreholes are shown
on the attached Plate No. 1, entitled "Location of Exploratory Boreholes". A continuous log of the
soils encountered was recorded at the time of excavation and is shown on Plate No. 2 entitled
"Summary Sheet". The soils were visually and texturally classified according to the filed
identification procedures set forth on Plate No. 3 entitled "LSCS Soil Classification·'.
Following the field exploration, laboratory testing was perfonned to evaluate the pertinent
engineering properties of the foundation materials. The laboratory-testing program included
moisture and density. particle size analysis and expansion index tests. These tests were perfonned
in general accordance with ASTM standards and other accepted methods. Page L-1 and Plate No. 2
provide a summary of the laboratory test results.
GEOLOGY
Geologic Setting
The subject site is located within the southern portion of what is known as the Peninsular Ranges
Geomorphic Province of California. The geologic map pertaining to the area (Reference No. 6)
indicates that the site is underlain by Pleistocene marine terrace deposits (Qt).
Site Stratigraphy
The subsurface descriptions provided are interpreted from conditions exposed during the field
investigation and/or inferred from the geologic literature. Detailed descriptions of the subsurface
materials encountered during the field investigation are presented on the exploration logs provided on
Plate No. 2. The following paragraphs provide general descriptions of the encountered soil types.
Topsoil
Topsoil is the surficial soil material that mantles the ground, usually containing roots and other organic
materials, which supports vegetation. Topsoil was observed in all boreholes with a thickness of
approximately 12 to 18 inches. It consisted of dark brown, silty sand that was moist, loose and porous
in consistency with some organics (roots and rootlets).
Slopewash (Qsw)
Slopewash was encountered under the topsoil with a thickness of approximately 12 inches. It
consisted of light bro\\n, silty sand that was dry to moist and loose in consistency.
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KEN & SANDRA BAPTIE! CARLSBAD BOULEVARD PROJECT.NO. 16-1 I 26F2
Marine Terrace Deposits (Qt)
Marine terrace deposits were observed below the topsoil layer. They generally consisted of reddish
brown. silty sand that was moist and medium dense to dense in consistency.
SEISMICITY
Regional Seismicitv
Generally, Seismicity within California can be attributed to the regional tectonic movement taking
place along the San Andreas Fault Zone, which includes the San Andreas Fault and most parallel
and subparallel faults within the state. The portion of southern California where the subject site is
located is considered seismically active. Seismic hazards are attributed to groundshaking from
earthquake events along nearby or more distant Quaternary faults. The primary factors in
evaluating the effect an earthquake has on a site are the magnitude of the event. the distance from
the epicenter to the site and the near surface soil profile.
According to the Fault-Rupture Hazard Zones Act of 1994 (revised Alquist-Priolo Special Studies
Zones Act), quaternary faults have been classified as ··active" faults, which show apparent surface
rupture during the last 11.000 years (i.e., Holocene time). ··Potentially-active" faults are those faults
with evidence of displacing Quaternary sediments between 11,000 to 16,000 years old.
Seismic Analysis
Based on our evaluation, the closest knov.rn .. active" fault is the Rose Canyon Fault located
approximately 4 miles (6.5 kilometers) to the east. The Rose Canyon Fault is the design fault of the
project due to the predicted credible fault magnitude and ground acceleration.
The Seismicity of the site was evaluated utilizing the 2008 National Seismic Hazard Maps from the
USGS website and Seed and Idriss methods for active Quaternary faults within the regional
vicinity. The site may be subjected to a Maximum Probable Earthquake of 6.9 Magnitude along
the Rose Canyon fault, with a corresponding Peak Ground Acceleration of 0.45g. The maximum
Probable Earthquake is defined as the maximum earthquake that is considered likely to occur
within a 100-year time period.
The effective ground acceleration at the site is associated with the part of significant ground
motion, which contains repetitive strong-energy shaking, and which may produce structural
deformation. As such, the effective or "free field" ground acceleration is referred to as the
Repeatable High Ground Acceleration (RHGA). It has been determined by Ploessel and Slosson
(1974) that the RHGA is approximately equal to 65 percent of the Peak Ground Acceleration for
earthquakes occurring within 20 miles of a site. Based on the above, the calculated Credible
RHGA at the site is 0.29g.
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KEN & SANDRA BAPT/£1 CARLSBAD BOULEVARD PROJECT NO. 16-1126F2
2013 CBC Seismic Design Criteria
A review of the active fault maps pertaining to the site indicates the location of the Rose Canyon
Fault Zone approximately 6.5 km to the east. Ground shaking from this fault or one of the major
active faults in the region is the most likely happening to affect the site. With respect to this
hazard, the site is comparable to others in the general area. The proposed residential structure
should be designed in accordance with seismic design requirements of the 2013 California Building
Code or the Structural Engineers Association of California using the following seismic design
parameters:
PARAMETER VALUE 1013 CBC aad ASCE 7 REFERENCES
Site Class D I Table 20.3-1/ ASCE 7, Chapter 20
Mapped Spectral Acceleration For Short Periods, 1.173g ! Figure 1613.3.1(1)
Ss I i
Mapped Spectral Acceleration For a I-Second I 0.45 lg j Figure 1613.3.1(2)
Period, S1
Site Coefficient, Fa I 1.031 Table 1613.3.3( 1)
Site Coefficient, F, I 1.549 Table 1613.3.3(2)
Adjusted Max. Considered Earthquake Spectral 1.209g Equation 16-37
Response Acceleration for Short Periods, SMs
Adjusted Max. Considered Earthquake Spectral 0.699g I Equation 16-38
Response Acceleration for I-Second Period, SM1 ! -5 Percent Damped Design Spectral Response 0.806g ' Equation 16-39
Acceleration for Short Periods, Sos r
s Percent Damped Design Spectral Response 0.466g 1 Equation 16-40
Acceleration for I-Second Period, S0 1
Geologic Hazard Assessment
Ground Rupture
Ground rupture due to active faulting is not considered likely due to the absence of known fault traces
within the vicinity of the project; however. this possibility cannot be completely ruled out. The
unlikely hazard of ground rupture should not preclude consideration of "flexible"' design for on-site
utility lines and connections.
Liquefaction
Liquefaction involves the substantial loss of shear strength in saturated soils, usually sandy soils with a
loose consistency when subjected to earthquake shaking. Based on the consistency of the underlying
terrace deposits, it is our opinion that the potential for liquefaction is very low.
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KEA. & SANDRA BAPT/£1 CARLSBAD BOULEVARD PROJECT NO. /6-/ 126F2
Landsliding
There is no indication that landslides or unstable slope conditions exist on or adjacent to the project
site. There are no obvious geologic hazards related to landsliding to the proposed development or
adjacent properties.
Tsunamis and Seiches
The site is not subject to inundation by tsunamis due to its elevation. The site is also not subject to
seiches (waves in confined bodies of water).
GEOTECHNICAL EVALUATION
Based on our investigation and evaluation of the collected information, we conclude that the proposed
construction is feasible from a geotechnical standpoint provided the recommendations provided herein
will be properly implemented during structural development.
In order to provide a uniform support for the proposed structure, footings should be excavated into the
dense terrace deposits. The new foundations may consist of reinforced continuous and/ or spread
footings with reinforced slabs. Recommendations and criteria for foundation design are provided in
the Foundation and Slab recommendations section of this report.
Compressible Soils
Our field observations and testing indicate low compressibility within the dense terrace deposits,
which underlie the site. However, loose topsoil and slopewash were encountered to a maximmn depth
of approximately 2.5 feet below surface grades. These soils are compressible. Due to the potential for
soil compression upon loading, remedial grading of these soils, including overexcavation and
recompaction will be required unless footings are extended to the dense terrace deposits.
Following implementation of the recommendations presented herein, the potential for soil
compression resulting from the new development has been estimated to be low. The low-settlement
assessment assumes a well-planned and maintained site drainage system.
Expansive Soils
An expansion index test was performed on a representative sample of the terrace deposits to
determine volumetric change characteristics with change in moisture content. An expansion index
of 5 was obtained which indicate a very low expansion potential for the foundation soils.
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KEN & SANDRA BAPTIJ:..1· CARLSBAD BOULEV4RD PROJECT NO. 16-l 126F2
Groundwater
Static groundwater was not encountered to the depths of the boreholes. The subject site is located
at an elevation of approximately 55 feet above Mean Sea Level. We do not expect groundwater to
affect the proposed construction. Recommendations to prevent or mitigate the effects of poor
surface drainage are presented in the Drainage section of this report.
CONCLUSIONS AND RECOMMENDATIONS
The following conclusions and recommendations are based upon the analysis of the data and
infonnation obtained from our soil investigation. This includes site reconnaissance; field
investigation; laboratory testing and our general knowledge of the soils native to the site. The site is
suitable for the proposed residential development provided the recommendations set forth are
implemented during construction.
CLEARING AND GRUBBING
The area of the proposed construction should be cleared of vegetation and deleterious materials.
Vegetation and debris from the clearing operation should be properly disposed of off-site. The area
should be thoroughly inspected for any possible buried objects, which need to be rerouted or removed
prior to construction. All holes, trenches, or pockets left by the removal of these objects should be
properly backfilled with compacted fill materials.
Our field investigation indicates that dense terrace deposits underlie the site at shallow depths.
These soils \\1ll be adequate for the support of the proposed structure without detrimental
settlement. However, for slab support in the main floor area, we recommend overexcavation and
recompaction of the upper 2 feet of subgrade. Foundation excavations should be observed by our
representative to verify competent bearing soils.
FOUNDATIONS AND SLABS
a. Continuous and spread footings are suitable for use and should extend to a minimum depth of 24
inches below the lowest adjacent grade for the proposed two-story structure over basement.
Continuous footings should be at least 18 inches in width and reinforced with a minimum of four
#4 steel bars; two bars placed near the top of the footings and the other two bars placed near the
bottom of the footings. Continuous footings for the main floor may be 18-inch deep and 15-inch
wide and reinforced as above. Isolated or spread footings should have a minimum width of 24
inches. Their reinforcement should consist of a minimum of #4 bars spaced 12 inches on center
(each way) and placed horizontally near the bottom. The minimum reinforcement recommended is
based on soil characteristics and is not intended to supersede the structural engineer requirements.
b. Interior concrete floor slabs should be a minimum 4 inches thick. Reinforcement should consist
of #3 bars placed at 16 inches on center each way within the middle third of the slabs by supporting
the steel on chairs or concrete blocks "dobies". The slabs should be underlain by 2 inches of clean
sand over a 10-mil visqueen moisture barrier. The effect of concrete shrinkage will result in cracks
in virtually all-concrete slabs. To reduce the extent of shrinkage, the concrete should be placed at a
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maximum of 4-inch slump. The minimum steel recommended is not intended to prevent shrinkage
cracks. Actual slab thickness and reinforcement may be designed by the project structural engineer
using a coefficient of subgrade reaction of 250 pci.
c. Where moisture sensitive floor coverings are anticipated over the slabs, the 10-mil plastic
moisture barrier should be underlain by a capillary break at least 2 inches thick. consisting of
coarse sand, gravel or crushed rock not exceeding 3/4 inch in size with no more than 5 percent
passing the #200 sieve.
d. An allowable soil bearing value of 2,000 pounds per square foot may be used for the design of
continuous and spread footings at least 12 inches wide and founded a minimum of 12 inches into
the dense terrace deposits as recommended in the 2013 California Building Code, Table 1806.2. This
value may be increased by 400 psf for each additional foot of depth or \\<1dth to a maximum value
of 6,000 lb/ft2.
e. Lateral resistance to horizontal movement may be provided by the soil passive pressure and the
friction of concrete to soil. An allowable passive pressure of 250 pounds per square foot per foot
of depth may be used. A coetlicient of friction of 0.35 is recommended. The soils passive pressure
as well as the bearing value may be increased by 1/3 for wind and seismic loading.
SETTLEMENT
Since footings for the proposed structure are anticipated to be supported by the dense terrace
deposits, total and differential settlement should be within acceptable limits.
PRESA TURA TION OF SLAB SUBGRADE
Because of the granular characteristics of the subgrade soils, presoaking of subgrade prior to
concrete pour is not required. However. subgrade soils in areas receiving concrete should be
watered prior to concrete placement to mitigate any drying shrinkage, which may occur following
foundation excavation.
RETAINING WALLS
Cantilevered retaining walls should be designed for an "active'' lateral earth pressure of 35 psf/ft (35
pcf EFP) for approved granular backfill and level backfill conditions. Cantilever walls subject to
uniform surcharge loads should be designed for an additional uniform lateral pressure equal to one-
third (I /3) the anticipated surcharge pressure.
Restrained walls such as basement walls should be designed utilizing an "at-rest" earth pressure of 60
psf/ft (60 pcf EFP) for approved granular and level backfill. Restrained walls subject to uniform
surcharge loads should be designed for an additional uniform lateral pressure equal to one-half (1/2)
the anticipated surcharge.
For earthquake motions, additional lateral pressures of 26 and 39 pcf (EFP) may be applied for non
restrained and restrained conditions respectively using an inverted triangular distribution if required.
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·,_. """" KE\' & SANDRA BAPT/£1 CARLSBAD BOULEVARD PROJECT NO 16-1 l 26F2
Soil design criteria, such as bearing capacity. passive earth pressure and sliding resistance as
recommended under the Foundation and Slab recommendations section, may be incorporated into the
retaining wall design.
Footings should be reinforced as recommended by the structural engineer and appropriate back
drainage provided to avoid excessive hydrostatic wall pressures. As a minimum we recommend a
fabric-wrapped crushed rock and perforated pipe system. At least 2 cubic feet per linear foot of free-
drainage crushed rock should be provided.
The remaining wall backfill should consist of approved granular material. This fill material should
be compacted to a minimum relative compaction of 90 percent as determined by ASTM D-1557
test method. Flooding or jetting of backfill should not be permitted. Granular backfill should be
capped with 18 inches (minimum) of relatively impervious fill to seal the backfill and prevent
saturation. It should be noted that the use of heavy compaction equipment in close proximity to
retaining structures can result in wall pressures exceeding design values and corresponding ,vall
movement greater than that associated with active or at-rest conditions. In this regard, the
contractor should take appropriate precautions during the backfill placement.
TEMPORARY SLOPES
For the excavation of the basement, foundations and utility trenches, temporary vertical cuts to a
maximum height of 4 feet may be constructed in natural soils. Any temporary cuts beyond the above
height constraints should be shored or further laid back follo~ing a 1 : 1 (horizontal to vertical) slope
ratio. OSHA guidelines for trench excavation safety should be implemented during construction.
Based on the consistency of the bedrock material and setbacks to adjacent residences, it is our
opinion that the proposed development will not have an adverse effect on the off-site frontage area
and adjacent properties provided temporary slopes are excavated in accordance with OSHA
guidelines.
TRENCH BACKFILL
Excavations for utility lines, which extend under structural areas should be properly backfilled and
compacted. Utilities should be bedded and backfilled with clean sand or approved granular soil to
a depth of at least one foot over the pipe. This backfill should be uniformly watered and
compacted to a firm condition for pipe support. The remainder of the backfill should be on-site
soils or non-expansive imported soils, which should be placed in thin lifts, moisture-conditioned
and compacted to at least 90% relative compaction.
DRAINAGE
Adequate measures should be undertaken after the structure and other improvements are in place,
such that the drainage water within the site and adjacent properties is directed away from the
foundations, footings, floor slabs and the tops of slopes via rain gutters, do~nspouts, surface swales
and subsurface drains towards the natural drainage for this area. A minimum gradient of 2 percent
is recommended in hardscape areas. In earth areas, a minimum gradient of 5 percent away from the
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KE.\' & SANDRA BAPTIE/ CARLSBAD BOULfi~4RD PROJECT NO. 16-l l 26F2
structure for a distance of at least IO feet should be provided. If this requirement cannot be met due
to site limitations, drainage can be done through a swale in accordance with Section 1804.3 of the
2013 California Building Code. Earth swales should have a minimum gradient of 2 percent.
Drainage should be directed to approved drainage facilities. Proper surface and subsurface
drainage will be required to minimize the potential of water seeking the level of the bearing soils
under the foundations. footings and floor slabs, which may otherwise result in undermining and
differential settlement of the structure and other improvements.
FOUNDATION PLAN REVIEW
Our firm should review the foundation plans during the design phase to assure conformance with the
intent of this report. During construction. foundation excavations should be observed by our
representative prior to the placement of forms, reinforcement or concrete for confom1ance with the
plans and specifications.
LIMIT A TIO NS OF INVESTIGATION
Our investigation was performed using the skill and degree of care ordinarily exercised, under similar
circumstances, by reputable soils engineers and geologists practicing in this or similar localities. No
other warranty, expressed or implied. is made as to the conclusions and professional advice included in
this report. This report is prepared for the sole use of our client and may not be assigned to others
without the 'Written consent of the client and ECSC&E, Inc.
The samples collected and used for testing, and the observations made, are believed representative of
site conditions; however, soil and geologic conditions can vary si&>nificantly between exploration
trenches, boreholes and surface exposures. As in most major projects, conditions revealed by
construction excavations may vary with preliminary findings. If this occurs, the changed conditions
must be evaluated by a representative of ECSC&E and designs adjusted as required or alternate
designs recommended.
This report is issued with the understanding that it is the responsibility of the O\\ner, or of his
representative to ensure that the information and recommendations contained herein are brought to the
attention of the project architect and engineer. Appropriate recommendations should be incorporated
into the structural plans. The necessary steps should be taken to see that the contractor and
subcontractors carry out such recommendations in the field.
The findings of this report are valid as of this present date. However, changes in the conditions of a
property can occur with the passage of time, whether they are due to natural processes or the works of
man on this or adjacent properties. In addition, changes in applicable or appropriate standards may
occur from legislation or the broadening of knowledge. Accordingly, the findings of this report may
be invalidated wholly or partially by changes outside of our control. Therefore. this report is subject to
review and should be updated after a period of two years.
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KEA' & SANDRA BA.PT/El CARLSBAD BOULEVARD PROJECT NO. 16-J J26F2
ADDITIONAL SERVICES
The review of plans and specifications, field observations and testing under our direction are integral
parts of the recommendations made in this report. If East County Soil Consultation and Engineering,
Inc. is not retained for these services, the client agrees to assume our responsibility for any potential
claims that may arise during construction. Observation and testing are additional services, which are
provided by our firm. and should be budgeted within the cost of development.
Plates No. 1 through 3, Page L-1 and References are parts of this report.
12
EAST COUNTY SOIL CONSULTATION
& ENGINEERING, INC.
I 0925 HAR1l.BY RD •• SUITE I, SANTEE. CA .92071
_(6!9) 2SB·?~I Fu C619) 258-7902
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DEPTH
Surface
1.0'
1.5
2.0'
2.5'
3.0'
3.5'
5.0'
DEPTH
Surface
1.5
2.5'
3.0'
5.0'
DEPTH
Surface
1.5
2.5'
3.0'
10.0'
KEN & SANDRA BAPT/£1 CARLSBAD BOULEVARD PROJECT NO. /6-I I 26F2
PLATEN0.2
SUMMARY SHEET
BOREHOLE NO. 1
SOIL DESCRIPTION
TOPSOIL
dark brown, moist. loose, porous. silty sand with rootlets
" U u H
SLOPEWASH (Qsw)
light brown. dry to moist, loose, silty sand
" " u " u
TERRACE DEPOSITS (Qt)
reddish brown. moist, medium dense, silty sand
becomes dense ..
bottom of borehole. no caving, no groundwater
borehole backfilled I /J 4/ 16
BOREHOLE NO. 2
SOIL DESCRIPTION
TOPSOIL
dark brown, moist. loose. porous. silty sand with rootlets
SLOPEWASH (Qsw)
light brown, moist, loose. silty sand
TERRACE DEPOSITS (Qt)
reddish brown. moist, medium dense. silty sand
becomes dense
bottom of borehole, no caving, no groundwater
bore ho le backfi lied I /14/16
BOREHOLE NO. 3
SOIL DESCRIPTION
TOPSOIL
dark brown, moist, loose, porous, silty sand with rootlets
SLOPEW ASH (Qsw)
light brown, moist, loose, silty sand
TERRACE DEPOSITS (Qt)
reddish brown. moist, medium dense, silty sand
becomes dense
bottom of borehole, no caving, no groundwater
borehole backfilled I /14/ I 6
y
y
111.3
122.2
y
Y = DRY DENSITY IN PCF M = MOISTURE CONTENT IN %
13
M
8.4
4.8
4.2
M
7.2
5.3
M
KEN & SANDRA BAPTIIYCARLSBAD BOULEVARD PROJECT NO./6-1126F2
INITIAL
MOlSTURE
CONTENT(%)
8.8
U.S. Standard
Sieve Sia
l"
1 /2"
3/8"
#4
#8
#16
#30
#50
#100
#200
uses
PAGEL-1
LABO RA TORY TEST RESULTS
EXP ANSI ON INDEX TEST (ASTM D4829)
SATURATED
MOISTURE
CONTENT(%)
15.9
INITIAL DRY
DENSITY EXP ANSI ON
(PCF) INDEX
110.1 5
PARTICLE SIZE ANALYSIS (ASTM D422)
Percent Passing Percent Passing
BH-1@ 1.0' '· BH-1@2.0'
Toosoil Slooewash
--
--
--
100 -
99 -
99 100
91 91
44 41
20 20
13 14
SM SM
14
LOCATION
BH-1@3.5'
Perceat~
BH-1@.)~•
~ -•., -errace I
-
-
-
--
100
93
44
19
13
SM
-KEN & SA:VDRA BAPTIEI CARLSBAD BOULEVARD PROJECT NO. 16-1126F2
REFERENCES
I. "2013 California Building Code. California Code of Regulations, Title 24, Part 2, Volume 2 of2'',
Published by International Code Council.
2. "Geologic Map of the San Diego 30' x 60' Quadrangle, California", by Michael P. Kennedy and
Siang S. Tan, 2008.
3. ·'Geotechnical and Foundation Engineering: Design and Construction", by Robert W. Day, 1999.
4. ''1997 Unifonn Building Code, Volume 2, Structural Engineering Design Provisions'', Published by
International Conference of Building Officials.
5. ·'Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada to
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