HomeMy WebLinkAboutAMEND 2017-0012; LA COSTA TOWN SQUARE PARCEL 3 RESIDENTIAL; GEOTECHNICAL INVESTIGATION; 2017-02-28SDVOSB . DVB!;:
February 28, 2017
Mr. Thomas Fitzpatrick
Terramar Retail Centers
5973 Avenida Encinas, Suite 300
Carlsbad, California 92008
Subject: LIMITED GEOTECHNICAL INVESTIGATION
LA COSTA TOWN SQUARE MUL Tl-FAMILY HOUSING
LA COSTA BOULEVARD
CARLSBAD, CALIFORNIA
SCST, Inc.
Corporate Headquarters
6280 Riverdale Slreel
San Diego, CA 92120
877.215.4321
D 619.280.4321
f 619.280.4717
; www.scst.com
SCST No. 16051 SN
Report No. 1
RE CEIVE D
JUL 31 2017
CITY OF CARLSBAD
PLANNING DIVISION
References: 1.) SCS& T, (2012) "Geotechnical Investigation, La Costa Town Square, Office
Development, Carlsbad, California", dated July 31.
2.) SCS& T, (2013) "Interim As-Graded Geotechnical Report, La Costa Town Square,
Office Development, La Costa Avenue, Carlsbad, California ", Project No. C.T. 08-
07, dated December 23.
3.) Hunsaker & Associates, (2014), "Laterra Product Yield Study/Alt. 13, La Costa
Town Square Parcel 3, Carlsbad, California ", dated September 29.
Dear Mr. Fitzpatrick:
This report presents the findings and conclusions of a limited geotechnical investigation performed by
SCST, Inc. (SCST) at the subject site. SCST prepared a geotechnical report (SCS&T 2012,
Reference 1 above) for the subject project to provide grading recommendations prior to development.
SCS& T observed mass grading the pad to its existing grade and prepared an as-graded report to
summarize our observations and testing (SCS&T 2013, Reference 2 above). The purpose of the
subject investigation is to provide general updated geotechnical recommendations for future
development based on the existing mass graded conditions and the proposed development
(Hunsaker & Associates, 2014, Reference 3, above). Specific recommendations can be provided
when building details and final grades are established.
SCOPE OF WORK
The following tasks were performed for this updated report.
• Reviewed previously prepared reports
• Performed a site reconnaissance
G11olochnical tngineoring • tnvironmenlnl Science & tnginoering • Special lnspeclion & Malorials Tosling • ~acililies Consulting
Terramar Retail Centers
La Costa Town Square Mu/ti-Family Housing
Carlsbad, California
February 28, 2017
SCST No. 160518N-1
Page2
• Explored the subsurface conditions by excavating 18 test pits between about 3 to 6 feet deep
with a rubber tire backhoe (Appendix I)
• Performed laboratory testing consisting of expansion index and corrosivity testing on samples
collected during exploration (Appendix II)
• Conducted geotechnical analysis and prepared this report summarizing our findings,
conclusions, and recommendations.
SITE HISTORY AND SURFACE CONDITIONS
The site is located in Carlsbad on the north side of La Costa Avenue at the intersection with Calle
Timiteo. The site is a graded parcel that was part of the mass grading for the La Costa Towne Square
development (SCS&T 2013). Prior to grading, the site was undeveloped and characterized by a
north/south trending natural ridge line that sloped to the south.
PROPOSED DEVELOPMENT
The referenced plans (Hunsaker & Associates) indicate the proposed condominium development will
be constructed at approximately existing grade. Desilting basins in the southern half of the site will be
filled to finish grade. Cuts may be required at the intersection of the entrance road with Private Drive
"B". Excavations will be required for underground utilities.
SUBSURFACE CONDITIONS
Figure 1, Geologic Map presents the approximate distribution of the geologic materials at the site.
Metamorphic rock (Map Symbol Jmv) is exposed in the central portion of the site (Figure 2) and
underlies the remainder of the site at depth. The Delmar Formation (Map Symbol Td) overlies the
metamorphic rock and is exposed or buried by fill in the northern portion of the site (Figure 2). In the
western and eastern portion of the site, the metamorphic rock and Delmar Formation are covered with
compacted fill. Logs of test pits excavated in these materials are presented in Appendix I.
Fill
The fill was placed as part of the mass grading operations and is documented in the Interim As-
Graded Geotechnical Report (SCS&T, 2013). The fill encountered in the test pits and discussed in
as-graded reports consists primarily of clayey gravel, gravely clay, sandy gravel, silty gravel, sandy fat
clay and fat clay. As seen in the test pits (Appendix I), the more granular fill is found within 3 feet of
the current surface elevation. The fill exhibits a medium to high expansion potential and is non-to
moderately corrosive relative to sulfate exposure (Appendix II).
Terramar Retail Centers
La Costa Town Square Multi-Family Housing
Carlsbad, California
Delmar Formation
February 28, 2017
SCST No. 160518N-1
Page3
The Delmar Formation is comprised of poorly indurated very stiff to hard, sandy clay, and fat clay.
The Delmar Formation has a high to very high expansion potential and is non-to moderately corrosive
relative to sulfate exposure (Appendix I).
Metamorphic Rock
The metamorphic rock is comprised of metamorphosed and un-metamorphosed volcanic and
sedimentary rock. Exposures in the central portion of the site expose massive, moderately to intensely
weathered, moderately fractured rock. In the exploration trenches, the rock is decomposed to clay.
Where moderately weathered, the rock will likely need to be blasted or broken with rock breakers.
The decomposed metamorphic rock we tested has a high expansion potential and is non-corrosive
relative to sulfate exposure (Appendix I). Both moderately weathered and decomposed rock have
been differentiated on the Geotechnical Map, Figure 2.
LABORATORY TESTING
The laboratory testing program consisted of expansion index and corrosivity tests. The results of the
laboratory tests, and brief explanations of test procedures, are provided in Appendix II.
UPDATED CALIFORNIA BUILDING CODE SEISMIC DESIGN PARAMETERS
The site coefficients and adjusted maximum considered earthquake spectral response accelerations
in accordance with the 2016 California Building Code are presented below:
Site Coordinates: Latitude 33.080459°
Longitude -117.232470°
Site Class: C
Mapped Spectral Response Acceleration at Short Periods, Ss = 1.029g
Mapped Spectral Response Acceleration at 1-Second Period, S1 = 0.399g
SMs=FaSs = 1.029g
SM1=FvS1 = 0.559g
Sos=½ SMs = 0.686g
S01=½ SM1 = 0.373g
PGAM = 0. 398g
CONCLUSIONS
The main geotechnical considerations affecting the future development at the site are:
• Difficult excavation conditions in areas underlain by moderately weathered rock
• Expansive soil
• Locally corrosive soil
• Cut/fill transitions below the building pads
Terramar Retail Centers
La Costa Town Square Multi-Family Housing
Carlsbad, California
RECOMMENDATIONS
February 28, 2017
SCST No. 160518N-1
Page4
The following recommendations are general and preliminary since building details and finish grades
will need to be finalized.
REMEDIAL GRADING
Remedial grading will generally include the following activities:
• Excavation of metamorphic rock to a depth of approximately 5 feet below finished pad grade.
Excavations should be backfilled with material having an expansion index of 50 or less.
• Excavation of formational materials at lots with cut/fill transitions. The cut portion of the pads
typically should be excavated 3 feet below planned bottom of footing elevation. Excavations
should be backfilled with material having an expansion index of 50 or less
• Excavation of highly expansive material to a depth of approximately 5 feet below finished pad
grade. Excavations should be backfilled with material having an expansion index of 50 or less.
• Remedial grading excavations in excess of 2 feet deep should not encroach within at least 7
feet from the existing MSE wall on the north side of the site without special grading techniques
reviewed by the geotechnical engineer.
EXCAVATION CHARACTERISTICS
It appears that most excavations can be ripped and excavated to a depth of at least 5 feet below
existing grade. Excavations within about 100 feet of the intersection of the entrance and Private Drive
"B" may encounter moderately weathered rock. Grading or trenching in these locations may be
difficult and rock breakers and blasting may be required for trenching. In addition, oversized, buried
hard rock requiring special handling should be anticipated.
Conventional heavy equipment in good working order is expected to be able to excavate the fill
materials, Delmar Formation and decomposed metamorphic rock on-site. Contract documents should
specify that the contractor mobilize equipment capable of excavating and breaking the metamorphic
rock.
OVERSIZED MATERIAL
Excavations into metamorphic rock may generate oversized material. Oversized material is defined as
rocks or cemented clasts greater than 6 inches in largest dimension. Oversized material should be
broken down to no greater than 6 inches in largest dimension for use in fill. Oversized material may
be used in fills in excess of about 5 feet. Oversize material that cannot be used may need to be
disposed off-site.
Terramar Retail Centers
La Costa Town Square Multi-Family Housing
Carlsbad, California
EXPANSIVE SOIL
February 28, 2017
SCST No. 160518N-1
Page 5
The existing on-site materials that we tested have a medium to very high expansion potential in
accordance with ASTM D 4829. Soil with an expansion index greater than 50, such as material from
the Delmar Formation should be kept at least 5 feet below the planned final pad grade elevation, at
least 2 feet below hardscape subgrade, and at least 10 feet from the face of all fill slopes and
retaining walls, or exported from the site.
As an alternative to exporting or burying highly expansive soil, the excavated soils can be mixed with
cement or lime to reduce their expansion potential. Typically, 5% cement or lime by dry unit weight
can be assumed for estimating purposes. The material to be stabilized should not contain rocks or
clods larger than 2½ inches in any dimension. Additional testing will need to be performed if this
alternative is selected.
BULK AND SHRINK ESTIMATES
Fills should not be expected to bulk during compaction. Lime treated fills may bulk up to 3%. Delmar
Formation and decomposed rock will likely bulk 3 to 5 percent where recompacted or lime treated.
Weathered rock will likely bulk 10-15 percent as a fill but will depend on crushing or disposal methods.
These estimates are based on our experience on this and other mass grading projects. The actual
volume changes will vary due to grading methods and soil changes. The estimates should be verified
by testing during grading.
CORROSIVE SOIL
Representative samples of the current finish grade soils were tested to evaluate corrosion potential
and were found to be non-to moderately corrosive relative to sulfate exposure. The test results are
presented in Appendix II. The project design engineer can use the sulfate results in conjunction with
ACI 318 to specify the water/cement ratio, compressive strength and cementitious material types for
concrete exposed to soil. A corrosion engineer should be contacted to provide specific corrosion
control recommendations.
CUT/FILL TRANSITIONS BENEATH BUILDINGS
Some of the planned building pads span a cut/fill transition with a fill differential ranging between
about 5 and 15 feet. The cut portion of the pads typically should be excavated 3 feet below planned
bottom of footing elevation. The bottoms of the excavation and subgrades beneath fill areas should
be sloped toward the street or fill portion of the lot, and away from its center. Subdrains may be
needed at the bottom of the excavated areas. Specific recommendations should be made on a case
by case basis and will depend on the building details, location, and finish grade elevations.
Terramar Retail Centers
La Costa Town Square Multi-Family Housing
Carlsbad, California
FOUNDATIONS
February 28, 2017
SCST No. 160518N-1
Page6
Foundation design will depend on the final as-graded conditions and should be reviewed by the
geotechnical consultant during fine grading. Either conventional shallow foundations with special slab
designs or post tension slab foundations may be used for foundation materials that have a low
expansion index.
Conventional Shallow Foundations
Shallow spread footings with bottom levels on compacted fill having a low expansion potential should
extend at least 18 inches below lowest adjacent finished grade.
Post-Tension Slab Foundations
One and two story structures can generally be supported on post-tensioned slab foundations with
bottom levels on compacted fill having a low expansion index. The slab should be designed by a
structural engineer familiar with the design criteria presented in the Post-Tensioning Institutes (PTI},
as required by the 2013 California Building Code.
Geotechnical parameters for design of post-tension slabs can be provided based on the final as-
graded conditions and laboratory testing.
PLAN REVIEW
Fine grading plans should be reviewed by SCST to see that the recommendations in this update
report have been considered. Additional sampling or exploration may be recommended.
CLOSURE
SCST should be advised of any changes in the project scope so that the recommendations contained
in this report can be evaluated with respect to the revised plans. The findings in this report are valid
as of the date of this report. Changes in the condition of the street can occur with time. In addition,
changes in the standards of practice and government regulations can occur. Thus, the findings in this
report may be invalidated wholly or in part by changes beyond our control. This report should not be
relied upon after a period of two years without a review by us verifying the suitability of the conclusions
and recommendations to site conditions at that time.
In the performance of our professional services, we comply with that level of care and skill ordinarily
exercised by members of our profession currently practicing under similar conditions and in the same
locality. Subsurface conditions can vary from those encountered at the boring locations, and our data,
interpretations, and recommendations are based solely on the information obtained by us. We will be
responsible for those data, interpretations, and recommendations, but will not be responsible for
Terramar Retail Centers
La Costa Town Square Multi-Family Housing
Carlsbad, California
February 28, 2017
SCST No. 160518N-1
Page 7
interpretations by others of the information developed. Our services consist of professional
consultation and observation only, and no warranty of any kind whatsoever, express or implied, is
made or intended in connection with the work performed or to be performed by us, or by our proposal
for consulting or other services, or by our furnishing of oral or written reports or findings.
This opportunity to be of professional service is sincerely appreciated.
Respectfully S
SCST, INC.
Principal Engineering Geologist
WLV/ER:aw
Attachments:
Figures
Figure 1 -Site Vicinity Map
Figure 2 -Geotechnical Map
Appendices
Appendix I -Field Investigation
Appendix II -Laboratory Testing
(1) Addressee via e-mail at tfitzpatrick@trcretail.com
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La Costa Town Square Multi-Family Housing
Carlsbad, California
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Approximate Location of Test Pit
Approximate Geologic Contact
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Approximate Buried Geolog ic Contact
Delmar Formation, Circled Where
Buried By Compacted Fill
~ Decomposed Metamorphic Rock,
~ Circled Where Buried By
Compacted Fill
J mv d Decomposed Metamorphic Rock
J mvm Metamorphic Rock, Moderately
Weathered
Date: March, 2017 Figure:
By: MAW
Job No.: 160518N 2
APPENDIX I
FIELD EXPLORATION
APPENDIX I
Our field investigation consisted of logging 18 backhoe test pits to depths of between about 3 and 6
feet below the ground surface. An SCST geologist visually logged test pits. Selected samples of the
exposed soil in the test pits were collected for laboratory testing. The soils are classified in
accordance with the Unified Soil Classification System as illustrated on Figure 1-1, and the Caltrans
Soil and Rock Logging, Classification, and Presentation Manual, 2010 Edition. Logs of the test pits
are presented on Figures 1-2 through 1-19.
SUBSURFACE EXPLORATION LEGEND
UNIFIED SOIL CLASSIFICATION CHART
SOIL DESCRIPTION GROUP TYPICAL NAMEl2 SYMBOL
I. COARSE GRAINED, more than 50% of material is larger than No. 200 sieve size.
GRAVELS CLEAN GRAVELS GW Well graded gravels, gravel-sand mixtures, little or no fines More than half of
coarse fraction is GP Poorly graded gravels, gravel sand mixtures, little or no fines. larger than No. 4
sieve size but GRAVELS WITH FINES GM Silty gravels, poorly graded gravel-sand-silt mixtures. smaller than 3". (Appreciable amount of
fines) GC Clayey gravels, poorly graded gravel-sand, clay mixtures.
SANDS CLEAN SANDS SW Well graded sand, gravelly sands, little or no fines. More than half of
coarse fraction is SP Poorly graded sands, gravelly sands, little or no fines. smaller than No.
4 sieve size. SM Silty sands, poorly graded sand and silty mixtures.
SC Clayey sands, poorly graded sand and clay mixtures.
II. FINE GRAINED, more than 50% of material is smaller than No. 200 sieve size.
SILTS AND CLAYS ML Inorganic silts and very fine sands, rock flour, sandy silt or clayey-
(Liquid Limit less silt-sand mixtures with slight plasticity.
than 50) CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty
clays, lean clays.
OL Organic silts and organic silty clays or low plasticity.
SILTS AND CLAYS MH Inorganic silts, micaceous or diatomaceous fine sandy or silty soils,
(Liquid Limit elastic silts.
greater than 50) CH Inorganic clays of high plasticity, fat clays.
OH Organic clays of medium to high plasticity.
Ill. HIGHLY ORGANIC SOILS PT Peat and other highly organic soils.
SAMPLE SYMBOLS LABORATORY TEST SYMBOLS z -Bulk Sample AL -Atterberg Limits
CAL -Modified California sampler CON -Consolidation -CK -Undisturbed Chunk sample COR -Corrosivity Tests
MS -Maximum Size of Particle (Resistivity, pH, Chloride, Sulfate) -ST -Shelby Tube OS -Direct Shear -SPT -Standard Penetration Test sampler El -Expansion Index -MAX -Maximum Density
GROUNDWATER SYMBOLS RV -R-Value
'¥ -Water level at time of excavation or as indicated SA -Sieve Analysis
UC -Unconfined Compression
~~ -Water seepage at time of excavation or as indicated RW -Response to Wetting
m ■ LA COSTA TOWN SQUARE MUL Tl-FAMILY HOUSING
SCST, Inc. Carlsbad, California
■ii By: WLV I Date: February, 2017
Job Number: 160518N !Figure: 1-1
Date Drilled: 12/7/2016
Equipment: Backhoe
LOG OF TEST PIT TP-1
Logged by: WL V
Project Manager: DS
Elevation (ft): Approximately 294 Groundwater Depth (ft): Not Encountered
SAMPLES ~ '5' e..... -9: I-z I-
g w :I: I-(!) en z ~ ::r: (.) SUMMARY OF SUBSURFACE CONDITIONS z ~ 0 I-en w (.) c.. :::> ~ ...J w :::> w I-Cl ll: ID ll: z Cl :::> I-::> en >-5 a::: ~ Cl
GC FILL (Qfl -CLAYEY GRAVEL with SAND, moderate brown, moist, low plasticity. -
-1 -GP POORLY GRADED GRAVEL with SAND, gray, moist. --GC CLAYEY GRAVEL, moderate brown, moist, low plasticity. -
-2
-
-3 -CL LEAN SANDY CLAY, greenish gray, moist, medium plasticity. -
-
-5
-
,-6
,-
-7
-
-8
-
-9
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-10,..___....._ __________________________ __._ _ __._ _ __._ _ _._ _ __. _ ___.
SCST, Inc. By:
Job Number:
La Costa Town Square Multi-Family Housing
Carlsbad, California
MAN Date: February, 2017
160518N Figure: 1-2
LOG OF TEST PIT TP-2
Date Drilled: 12n/2016 Logged by: WL V
Equipment: Backhoe Project Manager: OS
Elevation (ft): Approximately 293 Groundwater Depth (ft): Not Encountered
SAMPLES -'6 ~ en ~ .e I-I-en z I-w
g w :c I-I-(!) >-U) z jjJ ::c (.) SUMMARY OF SUBSURFACE CONDITIONS z 0 0:::
I-U) w ~ (.) ~ 0 ll. > ...J ~ w ::::> ii:: ::::> w I-C IJl 0::: z C ::::> 0:::
I-::> 0 U) ~ co 0 :5 :i: Cl
GC FILL (Qf) -CLAYEY GRAVEL with SAND, moderate brown, moist, medium plasticity.
-
-1
-
-2 -------------------------------------------CH GRAVELY FAT CLAY grayish green, moist, high plasticity.
--------------------------------------------GM SIL TY GRAVEL with SAND, moderate brown, moist.
-3
-
-4
-
-5 TD 5 FEET
-
-6
>-
>-7
>-
>-8
>-
.... 9
>-
-10
'1 ■! La Costa Town Square Multi-Family Housing
SCST, Inc. Carlsbad, California
■ii~ By: MAN Date: February, 2017
Job Number: 160518N Figure: 1-3
Date Drilled: 12/7/2016
Equipment: Backhoe
LOG OF TEST PIT TP-3
Logged by: WLV
Project Manager: DS
Elevation (ft): Approximately 292 Groundwater Depth (ft): Not Encountered
SAMPLES ~ '6' :,I?. e.... s I-z I-
g w I I-CD en z w J: (.) SUMMARY OF SUBSURFACE CONDITIONS z 0 I-en w ~ (.) s D.. > ...J w ::, a:: ::, w I-Cl co 0::: z Cl ::,
I-:::, en & 5 :!!: 0
CH FILL (Qf)-GRAVELY CLAY, greenish gray, moist, high plasticity.
-
-1
-GC SIL TY to CLAYEY GRAVEL with SAND, moderate brown, moist, medium plasticity. -
-2
-3
-
en I-en w I->-c:::
0 ~ c::: 0 co ::s
-4~~-------------------------~-~-~-~-~-~ TD 5 FEET
-
-5
-
-6
-
-7
-
-9
-
-10 L-...L.-_________________________ __._ _ __._ _ _._ _ _.__...L.-_ __,
SCST, Inc. By:
Job Number:
La Costa Town Square Multi-Family Housing
Carlsbad, California
MAN Date: February, 2017
160518N Figure: 1-4
LOG OF TEST PIT TP-4
Date Drilled: 12/7/2016 Logged by: WLV
Equipment: Backhoe Project Manager: OS
Elevation (ft): Approximately 293 Groundwater Depth (ft): Not Encountered
SAMPLES ~ n ;:R. Cl) !:!..., .9, I-I-Cl) z I-w
g w I I-I-(!) >-en z w I (.) SUMMARY OF SUBSURFACE CONDITIONS z 0 0::
I-w ~ (.) ~ 0 c.. en > ....I !;j: w :::) ii:: :::) w I-Cl cc 0::: z Cl :::) 0::
I-:::) 0 en >-cc 5 0:: ::s ~ 0
GM FILL (Qf) -SIL TY GRAVEL.moderate brown, moist, little fine-grained SAND, medium
-plasticity.
-1 CH DELMAR FORMATION (Td) -FAT CLAY, greenish gray, moist, high plasticity,
-moderately indurated.
-2
-
-3
-
-4 TD4FEET
-
-5
-
-6
-
._ 7
-
._ 8
-
-9
-
-10 ~-La Costa Town Square Multi-Family Housing
SCST, Inc. Carlsbad, California
■ii By: MAN Date: February, 2017
Job Number: 160518N Figure: 1-5
LOG OF TEST PIT TP-5
Date Drilled: 12/7/2016 Logged by: WLV
Equipment: Backhoe Project Manager: DS
Elevation (ft): Approximately 292 Groundwater Depth (ft): Not Encountered
SAMPLES ~ 13 ~ Cl) !:'..... .e I-I-Cl) z I-w
g w :::c I-I-(!) >-en z i J: (.) SUMMARY OF SUBSURFACE CONDITIONS z 0 c:::
I-en w lil:: (.) 0 a. > ...J ~ w ::> 0:: ::> w I-0 Ill It: z 0 ::> c:::
I-::::) 0 en >-a:i 5 c::: ::s ~ 0
GC FILL (Qf) -CLAYEY GRAVEL with SAND, moderate brown, moist, medium plasticity.
-
-1 CH DELMAR FORMATION (Td) -FAT CLAY, greenish gray, moist, high plasticity,
-fissured, moderately indurated.
f-2
f-
-3
-
-4 TD4 FEET
~
f-5
f-
-6
-
-7
-
-8
-
-9
-
-10 ~-j La Costa Town Square Multi-Family Housing
SCST, Inc. Carlsbad, California
■iii By: MAN Date: February, 2017
Job Number: 160518N Figure: 1-6
LOG OF TEST PIT TP-6
Date Drilled: 12/7/2016 Logged by: WLV
Equipment: Backhoe Project Manager: DS
Elevation (ft): Approximately 293 Groundwater Depth (ft): Not Encountered
SAMPLES ~ 'fi' :,5! en ~ a. I-I----en z I-w
g w :::c I-I-(.9 >-en z w I (.) SUMMARY OF SUBSURFACE CONDITIONS z 0 a::: I-w ~ (.) s 0 ll. en > ....I
w ::::, a:: ::::, w I-~ 0 Ill 0:: z 0 ::::, a::: I-::, 0 en >-al 5 a::: ~ ::!1: 0
GM FILL (Qfl -SIL TY GRAVEL with SAND, moderate brown, moist, non-plastic.
-
-1
-
-2
-
-3 CH DELMAR FORMATION (Td)-FAT CLAY, greenish gray, moist, high plasticity.
-
-4
-TD4½ FEET
-5
-
-6
I-
I-7
-
I-8
-
-9
-
-10
~■I La Costa Town Square Multi-Family Housing
SCST, Inc. Carlsbad, California
■iii By: MAN Date: February, 2017
Job Number: 160518N Figure: 1-7
LOG OF TEST PIT TP-7
Date Drilled: 12/7/2016 Logged by: WLV
Equipment: Backhoe Project Manager: DS
Elevation (ft): Approximately 292 Groundwater Depth (ft): Not Encountered
SAMPLES ~ 't3 ~ Cl) ~ 8 I-I-Cl) z I-w
g w I I-I-(!) >-en z ~ :r: (.) SUMMARY OF SUBSURFACE CONDITIONS z ::.::: 0 0::: I-en w (.) 0 a. ~ ...J ~ w :::> :::> w I-0 0::: ID 0::: z 0 :::> 0:::
I-::J 0 en >-al 5 0::: ::i :a: 0
CL DELMAR FORMATION (Td)-FAT CLAY, greenish gray, moist, high plasticity.
-
-1
-
-2
-
-3
-TD 3½ FEET
-4
-
-5
-
-6
--7
--8
-
-9 -
-10
~-! La Costa Town Square Multi-Family Housing
SCST, Inc. Carlsbad, California
■iii By: MAN Date: February, 2017
Job Number: 160518N Figure: 1-8
LOG OF TEST PIT TP-8
Date Drilled: 12/7/2016 Logged by: MAN
Equipment: Backhoe Project Manager: DS
Elevation (ft): Approximately 291 Groundwater Depth (ft): Not Encountered
SAMPLES ~ 13 ~ en e.... -3, I-I-en z I-w
g w I I-I-(!) >-en z ~ :c (.) SUMMARY OF SUBSURFACE CONDITIONS z ~ 0 a:: I-en w (.) 0 a.. ;::: ...J ~ w ::i ::i w I-0 a::: al a::: z 0 ::i a::
I-::> 0 en >-co 5 a:: ::s :z 0
GC FILL (Qfl -CLAYEY GRAVEL with SAND, moderate brown, moist, medium plasticity. --1
-
.... 2 CH DELMAR FORMATION (Td) -FAT CLAY, greenish gray, moist, high plasticity .
....
-3
....
.... 4 TD4 FEET
....
.... 5
....
-6 -
-7 -
-8
-
-9
-
-10
~■I La Costa Town Square Multi-Family Housing
SCST, Inc. Carlsbad, California
■iii By: MAN Date: February, 2017
Job Number: 160518N Figure: 1-9
LOG OF TEST PIT TP-9
Date Drilled: 12/7/2016 Logged by: MAN
Equipment: Backhoe Project Manager: OS
Elevation (ft): Approximately 291 Groundwater Depth (ft): Not Encountered
SAMPLES ~ '6' CJ) e_. -9, I-I-CJ) z I-LU
g w :c I-I-C) >-Cl) z jjj :::c: (.) SUMMARY OF SUBSURFACE CONDITIONS z 0 a::
I-Cl) w ~ (.) s 0 a. > ...J ~ w :::, 0:: :::, w I-0 ID 0::: z 0 :::, I-::, 0 Cl) >-cc 5 a:: ~ :i: 0
GC FILL (Qfl-CLAYEY GRAVEL with SAND, green and orange, moist, medium
-plasticity.
-1
--CH DELMAR FORMATION (Td) -FAT CLAY, moderate brown, moist, high plasticity.
X -2 El,
COR
-
-3 TD 3 FEET
-
-4
-
-5
-
..... 6
.....
..... 7
-
..... 8
-
-9
-
-10
~■I La Costa Town Square Multi-Family Housing
SCST, Inc. Carlsbad, California
■iii By: MAN Date: February, 2017
Job Number: 160518N Figure: 1-10
LOG OF TEST PIT TP-10
Date Drilled: 12/7/2016 Logged by: MAN
Equipment: Backhoe Project Manager: OS
Elevation (ft): Approximately 292 Groundwater Depth (ft): Not Encountered
SAMPLES ~ '6' ::,g Cl) ~ -9: I-I-Cl) z I-w g w I I-I-(!) >-Cl) z ~ I (.) SUMMARY OF SUBSURFACE CONDITIONS z ~ 0 0:::
I-Cl) w (.) 0 a.. ::> ;::: ...J ~ w ::> w I-Cl a::: CD a::: z Cl ::> 0:::
I-=> 0 Cl) >-al 0 0::: ~ ~ Cl
CH DELMAR FORMATION (Td) -FAT CLAY, moderate brown and greenish gray, moist, -high plasticity, poorly indurated.
-1
-
-2 METAMORPHIC ROCK {Jmv): Intensely weathered rock, light brown, non-plastic
I-
-3
-
-4
-TD4½ FEET
I-5
I-
-6
-
-7
-
-8
-
-9
-
-10 ~-La Costa Town Square Multi-Family Housing
SCST, Inc. Carlsbad, California
■ii By: MAN Date: February, 2017
Job Number: 160518N Figure: 1-11
LOG OF TEST PIT TP-11
Date Drilled: 12/7/2016 Logged by: MAN
Equipment: Backhoe Project Manager: DS
Elevation (ft): Approximately 292 Groundwater Depth (ft): Not Encountered
SAMPLES 'E' ~ Cl) .e, I-I-Cl) z I-UJ g w :c I-I-(.9 ~ en z w J: (.) SUMMARY OF SUBSURFACE CONDITIONS z 0 I-en w ~ (.) ~ 0 a. ::::, > ...J ~ w ii: ::::, w I-0 ID a::: z 0 ::::, a:::
I-::, 0 en >-co 5 a::: ~ :i: 0
CH DELMAR FORMATION (Td) -FAT CLAY, greenish gray, moist, high plasticity, poorly
--indurated.
.... 1
-
-2
-
-3
-
.... 4
....
TD4½ FEET -5
-
--6
--
--7
-
.... 8
-
,-9
I-
-10
~-! La Costa Town Square Multi-Family Housing
SCST, Inc. Carlsbad, California
■iii By: MAN Date: February, 2017
Job Number: 160518N Figure: 1-12
Date Drilled: 12/7/2016
Equipment: Backhoe
LOG OF TEST PIT TP-12
Logged by: MAN
Project Manager: OS
Elevation (ft): Approximately 293 Groundwater Depth (ft): Not Encountered
g
:c I-a. w Cl
....
,_ 1
,_
.... 2
....
.... 3
....
.... 4
.__
.... 5
....
-
,_ 7
,_
-8
-
-9
-
en (.) SUMMARY OF SUBSURFACE CONDITIONS en ::::,
CH FILL (Qf) -FAT CLAY with SAND, medium brown, moist, high plasticity .
CH DELMAR FORMATION (Tdl -FAT CLAY, greenish gray, moist, high plasticity, poorly
indurated .
SAMPLES ~ 13 ~ ~ .e I-z I-w :c I-(!) z w z 0 w ~ (.) s > ...J
a:: ::::, w I-co a::: z Cl ::::, I-:, en ~ 5 :i: □
CJ)
I-CJ) w I->-0:: 0 ~ 0:: 0 co ~
-10L----'------------------------------'-----'----'--........L---L-----'
SCST, Inc. By:
Job Number:
La Costa Town Square Multi-Family Housing
Carlsbad, California
MAN Date: February, 2017
160518N Figure: 1-13
LOG OF TEST PIT TP-13
Date Drilled: 12n/2016 Logged by: MAN
Equipment: Backhoe Project Manager: OS
Elevation (ft): Approximately 292 Groundwater Depth (ft): Not Encountered
SAMPLES ~ 13' ~ en e.., .e I-I-en z I-w g w :::c I-I-(9 >-en z w :c (.) SUMMARY OF SUBSURFACE CONDITIONS z lil:: 0 0:: I-en w (.) ~ 0 a.. => > ...J ~ w i:i:: => w I-Cl co 0:: z Cl => 0::
I-::> 0 en & Ill 5 ::s ~ 0
CH DELMAR FORMATION (Td) -FAT CLAY, greenish gray, moist, high plasticity, poorly
indurated. -
-1
-
-2
-
-3
-
-4 TD4 FEET
,_
,_ 5
,_
-6
-
-7
-
-8
-
-9
-
-10
'1 ■ La Costa Town Square Multi-Family Housing
SCST, Inc. Carlsbad, California
■ii By: MAN Date: February, 2017
Job Number: 160518N Figure: 1-14
LOG OF TEST PIT TP-14
Date Drilled: 12/7/2016 Logged by: MAN
Equipment: Backhoe Project Manager: DS
Elevation (ft): Approximately 294 Groundwater Depth (ft): Not Encountered
SAMPLES ~ 13 ~ Cl) ~ -9, I-I-Cl) z I-LU g w :c I-I-C) >-en z w ::c (.) SUMMARY OF SUBSURFACE CONDITIONS z 0 c::: I-en w ~ (.) s: 0 a.. ::J > ....I ~ w ii: ::J w I-co 0:: Cl Cl ::J z c::: I-::::> 0 en & CD 5 ::s ::a: Cl
CH METAMORPHIC ROCK (Jmv) -light brown, decomposed rock.
-
-1
-
-2
-
-3
-
-4
-
-5
-TD 5½ FEET
-6
-
-7
-
-8
-
-9 -
-10 ~-La Costa Town Square Multi-Family Housing
SCST, Inc. Carlsbad, California
■ii By: MAN Date: February, 2017
Job Number: 160518N Figure: 1-15
LOG OF TEST PIT TP-15
Date Drilled: 12/7/2016 Logged by: MAN
Equipment: Backhoe Project Manager: OS
Elevation (ft): Approximately 294 Groundwater Depth (ft): Not Encountered
SAMPLES ;;-u en ~ ,9, I-I-en z I-w
g w :::c I-I-(!) >-en z ~ ::c (..) SUMMARY OF SUBSURFACE CONDITIONS z 0 c::
I-en w ~ (..) 0 a. > ....I ~ w :::::, a: :::::, w I-Cl Ill 0:: z Cl :::::, c::
I-:::> 0 en >-CD 0 c:: :5 :E 0
GC FILL (Qfl -CLAYEY GRAVEL with SAND, moderate brown, moist, low plasticity. -
-1
-CH DELMAR FORMATION (Td) -FAT CLAY with SAND, greenish gray, moist, high
X -2 plasticity, poorly indurated.
El,
COR -
-3 -
-
-4
-
-5
-TD 5½ FEET
-6
-
-7
-
-8 -
-9
,-.
-10 ~-La Costa Town Square Multi-Family Housing
SCST, Inc. Carlsbad, California
■ii By: MAN Date: February, 2017
Job Number: 160518N Figure: 1-16
LOG OF TEST PIT TP-16
Date Drilled: 12/7/2016 Logged by: MAN
Equipment: Backhoe Project Manager: OS
Elevation (ft): Approximately 295 Groundwater Depth (ft): Not Encountered
SAMPLES ~ '5' ~ Cl) !:...--9, I-I-Cl) z I-UJ g w :r: I-I-(.'.) >-Cl) z w J: u SUMMARY OF SUBSURFACE CONDITIONS z 0 0:: I-Cl) w ~ u s 0 a. > ....I ~ w ::::> i:2 ::::> w I-0 Ill 0:: z 0 ::::> 0::
I-=> 0 Cl) >-co 5 0:: ::s :ii: 0
CH FILL (Qf) -FAT CLAY with SAND, brown and greenish gray, moist, low to medium
-plasticity.
-1 -
-El,
-2 COR
-
-3 -
-
-4
-
-5 TD 5 FEET
-
-6
-
-7
-
-8
-
-9
-
~ 10
'1 ■! La Costa Town Square Multi-Family Housing
SCST, Inc. Carlsbad, California
■iii By: MAN Date: February, 2017
Job Number: 160518N Figure: 1-17
Date Drilled: 12/7/2016
Equipment: Backhoe
LOG OF TEST PIT TP-17
Logged by: MAN
Project Manager: DS
Elevation (ft): Approximately 296 Groundwater Depth (ft): Not Encountered
g
:I: I-ll. w 0
-
-1
-
..... 2
-
..... 3
-
-4
-
-5
-
(/)
t) SUMMARY OF SUBSURFACE CONDITIONS (/)
:::)
GP FILL (Qfl -POORLY-GRADED GRAVEL with SAND, moderate brown, moist, non-
plastic.
METAMORPHIC ROCK (Jmv) -light brown, intensely weathered rock.
SAMPLES -'§' ~ e..., ,9; I-z I-w :r: I-C) z ~ z 0 w ~ t) > ....I
ii: :::) w I-co a::: z 0 :::)
I-::> (/) >-6 a:::: :i: 0
X -
rn I-rn LU I->-a::::
0 ~ a:::: 0 CD ::S
El,
COR
-6~~-------------------------~-~-~-~-~-~ TD6 FEET
-7
..... 8
.....
..... 9
-10 L-__.__ _________________________ _._ _ _.__ _ ___._ _ _,__......_ _ __.
SCST, Inc. By:
Job Number:
La Costa Town Square Multi-Family Housing
Carlsbad, California
MAN Date: February, 2017
160518N Figure: 1-18
LOG OF TEST PIT TP-18
Date Drilled: 12/7/2016 Logged by: MAN
Equipment: Backhoe Project Manager: OS
Elevation (ft): Approximately 296 Groundwater Depth (ft): Not Encountered
SAMPLES ~ '6' ::,e en e..... ,9, I-I-en z I-UJ g w I I-I-(!) >-en z w I u SUMMARY OF SUBSURFACE CONDITIONS z 0 0:: I-en w ~ u ~ 0 a. > ....I w :::) ~ :::) w I-~ 0 ID 0::: z 0 :::) 0::
I-::, 0 en ~ cc 5 ::i ~ Cl
CH DELMAR FORMATION (Tdl -FAT CLAY, greenish gray, moist, high plasticity.
-
-1
-
-2
-
-3
-
-4 TD4FEET
-
-5
-
-6
-
-7
-
-8
-
-9
-
~ 10
'1 ■1 La Costa Town Square Multi-Family Housing
SCST, Inc. Carlsbad, California
■iii By: MAN Date: February, 2017
Job Number: 160518N Figure: 1-19
APPENDIX II
LABORATORY TESTING
SUMMARY
APPENDIX II
Laboratory tests were performed to provide geotechnical parameters for engineering analyses. The
following tests were conducted:
• EXPANSION INDEX: The expansion index of three samples was determined in accordance
with ASTM D4829. Figure 11-1 presents the test results.
• CORROSIVITY: Corrosivity tests were performed on five samples. The pH and minimum
resistivity were determined in general accordance with California Test 643. The soluble
sulfate content was determined in accordance with California Test 417. The tota I chloride
ion content was determined in accordance with California Test 422. Figure 11-1 presents the
test results.
EXPANSION INDEX
ASTM D2489
SAMPLE DESCRIPTION EXPANSION INDEX
TP-1 FILL: LEAN SANDY CLAY, greenish gray 51
TP-9 DELMAR FORMATION: FAT CLAY, moderate brown 104
TP-15 DELMAR FORMATION: FAT CLAY, greenish gray 108
TP-16 FILL: FAT SANDY CLAY, greenish gray 116
TP-17 METAMORPHIC ROCK SANDY CLAY, liaht brown, decomposed 110
CLASS/FICA TION OF EXPANSIVE SOIL 1
EXPANSION INDEX POTENTIAL EXPANSION
1 -20 Very Low
21 -50 Low
51 -90 Medium
91 -130 High
Above 130 Very High
1 . ASTM -D4829
RESISTIVITY, pH, SOLUBLE CHLORIDE and SOLUBLE SULFATE
SAMPLE RESISTIVITY (O-cm) pH CHLORIDE (%) SULFATE(%)
TP-1 288 7.28 0.066 0.171
TP-9 189 6.09 0.022 0.141
TP-15 149 7.27 0.049 0.144
TP-16 290 6.9 0.006 0.020
TP-17 179 6.82 0.001 0.016
SULFATE EXPOSURE CLASSES 2
Class Severity Water-Soluble Sulfate (SO4) in Soil, Percent by Mass
so Not applicable SO4 < 0.10
S1 Moderate 0.10 s SO4 < 0.20
S2 Severe 0.20 s SO4 ::s; 2.00
S3 Very Severe SO4 > 2.00
2. ACI 318, Table 4.2.1
~ ■ SCST, INC.
La Costa Town Square Multi-Family Housing
Carlsbad, California
■ii By: WLV Date: February, 2017
b Number: 160518N Figure: 11-1