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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 '1 ■ ■ii ~ C) z ii: w w iii 0 SCST, Inc. fl la Costa Countr,y ,, Club Son Marcos Creek ' Orchard wood Road l.1s()\aS(.QUrt SITE VICINITY MAP 510 La Costa Town Square Multi Family Housing Carlsbad, California Date: By: Job No.: , , ,' ' ' I --,.,., March, 2017 MAW 160518N ' ... ,,. P: A.venida Pantera c.of'ecastiUo Figure: 1 ,-----· I I I I I I ' ' ' I I I I I I I I I I I I I I p' : i: • I ' I • I g-! ~ --------7 t .. _, ... ------- 'Ill ',_ .. -~·---~-,-, " TP-1 ~ "fl"".'.:..i~,: ~!'f..~-1 " . ,, J•.' "i ' '. ' l,L , . ' --~ I_; . ,-,,,1;f l _ ·1· __.,,,,,,.-----:;r:,·, :~, . ~ \ -,{' \ ,,~--!~~1;. ~~ 1/ -:p~ -~ ./ J ' -,:., --' ~/-. ,,,,,,,. ~ ---/ / .. ,. -~ ~;. ;._ •--•-... ~-' ~•:'>"~-< • '():, ,~· -',J lil // /// __.,,,,,,-, • ~--.. . Iii/ TD-4-3/ -/ ~ -,~.. tJ ..1---r-1 / ,-, ·."Ji r~ I 1 -(J _!-41-/ ~-, --\__ ta--\ / !-, --~_<, -Jmvtt 1 -\ --<-\,. ,, i' r::a ~.<'g _,, '-,,.,,. I , 1 -~ TP-4 Td-L ~ · .. / -1:-~ ~ -· -~ . . ... , ..... .,, '-• \ I ~ I . , , •<l' • • r,..( Tt\t RtC , ; ' ~ , .. TP-5 I . Jmv Jmvm I I ."] ~ .. • • • ARf.A \ ~ ....... _ .:;_ _ _J~~ ., d \ \' ' • •· ' I~ { , . . ·.' .', \ ~ ."): ' ;, . • ,p \ •. _ ~ \ _ _. _ . ; :~, 5~t iJ \ 't \ • ..?: , • , \ @ · .;,•~ · ~ TP-3 .. -.. --r ~ ~.\ •'{: ,-.· .. '. 1 \ \ Td \ 0 . _,.." "~ '\.:X , \ ' ) ~ ' •• \. . --~ QI' ---\ .......,_ ....__ \ \ \, "',-~ \ \ A . . .. \ \ \·~ l." , .. ~. ~ '-,\ ,, . i ' ' ) \\ . • -S-/ '-'\ . ', . I \ ~ - ,, y /. ,. I j ,, --, /\ :\_ --/ \ ---, __ / \ ~( ~-;J'·. JQ8 I • ,. ~ __ .... / -. I • • .. . / /' \ \ ) ACTIVE RII AR[ I s 7' I I I I Td - \ \ Td \ ~-~-'.-;_..,~-/' --~~~ ·"'. ~ .,- ..... S •,·· .. C> ' ' z ~ w w iii -'t>t· ~ SCST, Inc. -:::-, . ' --~-~..,7 t . '-. )(). , -r ·r,~, l· 1 ' ., .. ~~ .... J .J ~ ..... \:-'--::...,,.';;,., 1 __ __... I \- \ \ ""' i:< ' -.. ~--.... ~ .. -~· ·• ,;.- o 60' 120' R Scale 0 GEOTECHNICAL MAP La Costa Town Square Multi-Family Housing Carlsbad, California TP-18 wl ' \ ' ...---r-~:, '\ =::--..-y~ .. t,l' fl--_ _::•_-1 --' t !: I , <,V ~~ \ '\~ / ;,-' ~ I ,. ® SCST LEGEND: Approximate Location of Test Pit Approximate Geologic Contact ). • • • • ® 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 - (/) I-(/) LU I- >-a::: 0 ~ a::: 0 cc :5 El, COR -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