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Home My WebLink AboutCT 72-24; LA COSTA SOUTH UNIT 3; SOILS INVESTIGATION; 1973-04-11• • • • • • • • SOILS :INVESTIGAT'lON La Costa de MQrbelia . lot 206 La Costa South Unit No. 3 . :Carl~bad,. ,C'Glifornia La Costa d~ Marbel fa Associates , . i . Samuel Wacht AsSociates, A. I. A. Arch,fects, Engineers, PlanneJ'$ ProJect No. 73-3-1A >: . April 1.1, 1973 BENTON J;NGINEERING. INC. EIOIIEEII •• ~r 7c:2-) 'I ,. • • PHILIP HENKING BENTON PRE$IDENT-. CIVIL ENGINEER BENTON ENGINEERING, INC. APPLIEP s.61~ ME<;:HANICS -'-FOUNDATIONS 6717 CONVOY COURT SAN D.lEGO, ·CALIFORNIA 92~1t SOILSINV~STlGATION TELEPHONE (714) 565.1955 • Int.l'Qfiuction This is to present the results of a soils investigatIon conducted at the above site, to supplement an earlier investigation reported bY;I.u5 on January 16, 1973, and identified as •• our Project No.]2 ... 12-7A~ This supplemental inv~tigation was nece~itated by the fdct that certain grading and building location. changes had been adopted subsequent to our firstinvesH- • gation. These changes have raised some doubts as to the probable stability of certain proposed • • • • I • • cut slopes and building pads, and it was considered that the only way to de.termine the que$t.ion- able slope stabilities was to perform the supplemental investigdtion reported herein. In order to provide the desired additional information, three borings were drilled. Two of the~ borings: were drilled generally in the southwest com.et of Lot 206, and the other was drilled at the loeat- ion of a proposed cut slope in the easterly portion of the lot. Representative samples were obtained from each of the borings for labordtory testing • . Investigation The three borings were drilled, each to a diameter o.f 24 inches, with a truck-mounted rotary bucket-type drill rig at the approximate tocqtions shown on theaHached revised Drawing No.1, entitled, II Location of Test Borings.1I The borings were drilled to depths of 43.5 to 77.5 feet below the existing ground surface. A continuous log of the solis encountered in the borings was recorded at the time of drilling and Is. shown In detaU on Drawing Nos. 2 to 11, inclusive, each entitled, II Summary Sh~t. II La C~sta de MOrbe11a ... LQt 206 Protect No. 73-3-1A • -2- The solis were visually classified by field identification procedures in accordance with the Unified Soil Classification Chart. A simplified description of this classification system • is presented in the attached Appendix A at the end of this report. Undisturbed samples were obtained at frequent intelVcils below proposed cuts in the • soIls ahead of the drilling. The drop weight used for driving the sampling tube Into the soIl. • • '. • • ,. • • 'was J~jl:~":~fl~~ t~~U.L~~whlch weIghs 1623 pounds, and the average drop was 12 . ~.-- inches. The general procedures used In field sampling are descrthe'd under "Sampling" tn Appen- dix B,. Laboratory Tests Laboratory tests were perfonned on the malority of undisturbed samples of the soils in order to detennine the dry density and moisture content. The resul ts of these tests are presented on Drawing Nos. 2 to 11 ,Inclusive. In order to detennine the apparent cohesion and minimum angle of Interh:aJ friction of the solis, for use In slope )tabiltty analyses, selected samples were first saturated, <;rnd drained and then sheared by direct shear under varying nonnal loads. The results of the direct shear "; tests are presented as foIIQW$: Maximum . Angle of Normal Shear In hi rna I Apparent Load In load Friction Cohesion kiPVsq ft ktpVsq ft Deg.-a Ib/sq ft '\ Boring 1 I Sample 2 0.5 0.78 16.0 640 :' Depth: 22 Feet 1.0 1.29 2.0 1.57 Poring 1 , Sample 3 0.5 1.20 40.0* 450 . Depth: 27 Feet 1.0 2.04 2.0 3.27 BENTON ENGINEERING, INC. • • • • • • • • :. • La CQSta de' Marbella .... Lot 206 Pr9lect No. 73-3-1 A , ., ,I . Boring 1 , Sample .f ~pth: ,32 Feet Bor1ng 2 , Sample 1 Depth: 2 F.t Boring 2 , Sample 2 Depth: 6 Feet B9rlng 2 , Sample 3 Depth: 11 Feet Boring 2 " Sample 10 Depth; 36 Feet Boring 1 , Bag Sample 1** Depth: 8-10.Feet * -Arbitrarily Redu~ -3- Maximum Normal Shear Laod in Load kip';sq it kipt/sq ft 0~5 1.15 1.0 1.47 ' 2.0 2.28 .~ .. 0.5 1.01 1.0 1.30 2.0 2.25 0.5 0.6 1 .. 0 0.98 2.0 1.88 0.5 1.18 1.0 1.49 2.0 1.88 0.5 0.98 1.0 0.90 2.0 1.85 0.5 2.24 1.0 2.75 2.0 2.28 ** -Sample Remolded to 95, percent of MaxImum Dry Density Angle of Internal 'Appa~nt Friction Cohesion Degrees Ib/sq ft 37.0 750 37.0 650 40.0 200 :', 28.0 910 40.0* 0 16.5 2080 In that $Orne of the soils sampled at Borings 1 and 2 ~re naturally IIdlsturbed" as r.,ult'of prevtpusecuth movemtmts by slippage, selected samples were sublected to direct 'shear tests in which the same sampl~ were IlresheQred" under the ~m. normal loads. The n;sult$ of these "resheCir" tests are presented on .th4i followIng pag~. BENTON ENGINEERING, INC. • • • • • I. • -. • • • La CQ$ta ,~ Ma~lJa -Lot 206 Pro.jec;::t No. 73-3-1A Bortng 2 , Sample 4 _ .' Depth: 18 Feet :Bortng-a , Sample 2A " Depth: 11.5 Feet Boring 3 , Sample 28 Depth: 11.5 Feet ,Boring, 3 , Sample 2C Depth: n.5 Feet ,Boring 3, Somple 4A 'Oepth: 1~ feet Boring 3, Sample 4B Depth: 19 Feet ','Sorlng 3 I Sample 4C :,: QJpth: 19 Feet -4- Normal Loaer In klps/sqft 0.5 1.0 2.0 Tr.i,a[ l' 0.5 1..48 1.0 1.67 2.0 2.34 0.5 0.98 1.0 2.18 2.0 2.49 0.5 0.72 1.0 1.14 2.0 2.13 0.5 1.43 1.0 1.67 2.0 2.19 0.5 0.80 1.0 2.14 2.0 2.14 0.5 0.93 1.0 1.07 2.0 3.24 ~ Maximum , Angle of Shear Internal Apparent -Loqd Friction Cohesl,of}' 'klps/$q f,f , Degrees lb/~q rf' 1.00 37.0 620 1.46 2.24 Tdol: 2' ,Tr~aI3: .. 1 .'47' . .' 1 .26 22.0 620· 1.48 1.85 O.8,? , 16.0 480 2.19 2.02 2.23 ... 0.71 37.0 350' 1.12 1.98 1.88 1.30 1.12 24.0 -750 1.45 2~ 13 0.72 35.0 250 1.70 1.35 1.84 0.81 21.0 3~0 1.00 2.95 2.39 ' The,g~eral pro«qores: used for" th, Qbove laboratory ,I'e$ti al1S d8SCrl~d' brh'fly In i Appendix .B • • 1''6-;- In addltlon ~ t~· fQ~of~9 dfr~~t shear tests, frlaxlc:d compressIon hilts wer. perfOrmed ()h $elected s~~pl~ of thel sllck6rislded: clay soils found generally b,~n th. depths of 12.7:- and 31 .2 teet at BorIng 2. The results Qf these t.ts Indtcate that the Qngle of I'ntemal.frlcth;m BENTON ENGINEERING. INC. I • • • • • • • • • . La Costa de Marbella -Lot 206 Project No,. 7S",:3-1A -5- of thQSe soils varies from 25 to 33 degrees,qnd the cohealon varies from approxImately 1650 . to 3950 pounds ".r·squa~ foot. Compaction tests were performed on representative samples of the .soils to be excavated to establish .compaction crit.eria. The soils. wer~ tested accc;>rding to the A.S. T .M. 0 1557 -70 method of compaction which uses 25 blows of a 10 pound rammer dropping 18 Inches on·each:pf 5 layers in a 4 inch diameter 1/30 cubic foot mold. The results of the testsqre presented as follows: '. M9xtmum Qptimum Iy\ois- Boring Bag Depth Soil Dry Density ture Content No. Sample in Feet Description Ib/cu ft % dry wt ' 1 1 8-10 Clay 111.1 18.2 2 2 27.5-28.5 Clay t 12.5 15.5 3 3 24-25 Slightly Silty ~ 15.5 13.7 Fine Sand In order to classify more accurately some of the finer-grained soils, AUerberg LImit . Tests were performed pn selected samples. The results of these tests are presented as follows: ' Boring Bag Depth Liquid Plastic Plasticity Group '. ·No. Sample in Feet Limit limit Index SymbQl 1 1 8-10 55 24 " 31 ' CH 2 2 12.5-13.5 65 22 43 CH . DISCUSSIONS, CONCLUSIONS AND RECOMMENDATIONS Soil Strata The upper foot of ~iJs at Boring 1 consisted of medium soft clayey :fine to m~dium . sand. These soils were underlain to a depth of3.5 feet by medium firm flne to medtumsandy clay, and then to a depth of 5.0 feet by medium firm day. At 5.0 feet, theseUs merged to ':a • very firm clay; the solis In this stratum were very fractured and slickensIded, and appeared to be part of an olde~ creep/slump zone. 'This stratum WOJ continuous to a depth of 24.1 feet, except • BENTON ENGINEERING, INC. • • • • • La Costa Marbella -Lot 206 Project No. 73-3-1A -6- -for-a 3.0 fe.et thick layer be~ween 14.0 and 17.0 fee~ which had been llworked inll cis a pad for the drill ri9. The upper 14 fee~ of sorls were 109ged in an exposed bulidozeH3xcavtrted bank above the drIll ri9. Below the pad the clay strat!Jm was medium firm. Firm fine to medium sand was fptmd,between 24 • .1 and 24.7 .feet" and then firm clayey fine sand was found to a depth of 26.0 ~et. All of the ~i~s between 26.0 feet and the bQttom of the boring at a depth of 52.0 . ',"; feet·were v,ery firm .• These included 4.5 feet of fine to medium sand, containing a 1 1/2 inches . . , thttik'seam 0' clay, 6.1 fe'et of clay, '0.6 root of fine sandy silty, 5.S feet of verY fine sandy J' clay, arid 9.0 toot of silty fine sand • . At Boring 2, a one fOot thick layer of medium firm slightly clayey fine to medium sand was underlain .to a depth of 3.0 feet by medium firm very fine sandy clay and then to a ~epth of '.5.0 feet by flrmJitty flne·sand. Medium firm but bedded fine sandy clay was found between 5.0 . J' .' and 11.5 feet, and then medium firm fine to medium sand was found to a depth of 13.5 feet. • . From 13.5 fo 17.0 feet was medium firm·silty very fine to fine sand and then medtl:lm firm Jointed very fine sandy clay was found to a depth of 20.2 feet. The layer of joh1ted sandy clay was under- latn by a 5 inch thick seam of medium compact very fine to fine sand and then a Qne inch~fh:fdk • • sedm of medium. fIrm clay. Frpm 20.7 to 23.2 feet wt%$firm silty fine sand, and then alternattng -" - ·layel'$Qf flrm, clay' and silty fine sand were· found-to a :dep't.h of,26.2 feet .·Between 26.2 and 44.7 feet WO$ ,firm but slickensided and disturbed clay. The sot Is befween 44.7 and the bottom of the b9ring. at a depth of 77 .,5 feet were all very firm, and included 0.7 foot of clayey fine sand; '2.3 feet of slick-ensided clay, 4.5 feet of sil ty fine sand with some thin lenses of clay, 1. 9 feet of • fine to medium sand, 0.5 foot of clay, 4.5 f4tet of fine to medium sand wIth interbedded clay ~arM,l ~5 'et of slightly s',lty fine to medium sand, 1.0 foot of silt, 1.5 feet of slickensided • clay, 1.5· feet of fine sandy silt, 7.6 feet of clay, 1.7 feet of silty flne sand, 0.6 foot of fine sandy sUt/. and finally 2.7 feet of silty fine sand. BENTON ENGINEERING. INC. '. '. La Costa MarbeHa·-Lot 206 -7- ProJect No. 73-3-1A At Boring 3, a thiek IGYer of day thqt·wO$ ,sllek~nstded and Jointed into small 'llblocks" was found to a depth of 15.3 feet. Th,se clay s9!1swere medium firm to a d~pth of L5 feet, 'firm·between .1.5~(]nd lO.Ofeet and then, v~ry firm, and were underla.in to a depth of t6..6f~et'b.y"vlry ,firm ,sligntlY'silty fine' sana;.-: Ftom£'1~.6~t~h 1.9 .• 5 feetwp$ 'anothen'stratum ofvery , • . firm fointed, and slicken$tded .cJay that had cleqtly beetldistu·rbed by a previous earthrno.vel1'l.nt·. 'Between 19.5 and 29.5 feet were alternating iayers of very firm sandy soils. These includ.ed ' .. 1.5 feet, of sUty flne sand, 1.0 feet of fine sand and 5.5 feet of slightly flne tQ mediwn sand. • 'From 29 .. 5,tQ, 30.5 feet was. firm fine-to medium sand with some clay lenses, and tht*n very' firm '. • • • 'slightly silty ~~'ne to medium sand was foung fo, a depth of 32.3 feet. A layer of very ~rm fhie:'to medium sand was found between 32.3 and 33.3 feet, and then firm slickensided clay was found to : 34.3 feet,. From that depth tQ the bottom of the boring at 0 depth of 43.5 f~et the very firm soils ~n¢ountered included 2.2 feet of fine sandy stlt, and 6.5 feet of slightly silty fine sand. No ground water was encountered jn any of the,borings. (3eneral ,Discussion Thebosic reO$On for conducting the additional Jubsu.r:face Inv,stigotions report$d her,in was the fact that the general are~ investigated were known to be potentiQlly unstabl.e i'f the con- ditions which contribute the preseritstabillty of the areas in question were to ~ disrupted. It therefore was essentiaJ to onalyze the probable and possible disruption to these conditions by the proposed new SrQdtng and planned constructton. Ouropproach to this problem was to perform a Rumber or~lope stability analyses for the proposed new grading and construoti~o, using the soU • property parameters derived from the field inv.tJgatlons and the laboratory testing_ • BENTO,,! ENGINEERING. II''!C: • • • La Costa de Marbella Project No, 73-3-1A Conclusions -8- It is concluded from the above analyses that the proposed grading and new construction wtll be stable with a factor of safety of not less than 1.285, provided the recommendations in the following paragraphs of this report are complied with. RecommendaUons 1. It is recommended that we be called upon to inspect the new cut slopes 'during gradihg, to verify that there are no unfavorable s'lippage planes dipping out of Quts,.attd/or·to make appro- • ' pirate re~Qmmendati~ns for butress fills if these are needed, ,grid inspect the proper remQval arid • i r~pldcetnent of compacted filled ground as may be required • . 2,. With reference to an Irregular area in the westerly portion of the site shOwn on .' Drawing No. 1 of our report of Proiect No. '70-4-160 0$ 11 Not Recommended For BuJlding Sites, II : thcitparticular recommendation was made becau$8 the' fill.soils within that area had notall~n • satisfa(:tori.ly compacted due to the installation of sewer lines~ It Is therefore recommended that, • • . ~ , ... , :' wherever proposed newcon~ruction is planned withIn the area presently not recommended f6r~ \ .'. building sites, the present ·unsatisfactory fill sotIs be removed and replaced as properly compacted fiU, Qr that those buIldings (or portions of buildings) within the area be supported by grade beams .spanning to drille.dand cast-tn-place piers tha.t penetrate through the uns~tJsfactory fiJI. SQiI.· .. lnto und~tlyln9 firm nQtural soils. IF the first of these two recommendations Is adopted; the "are'a -0.£ re- -., rriovaland recornpQction $hould extend to rtnes not l.ess than 5 feet oul'sJde of fOQtings and Ol,J~ward . and d_ownward on a 1 horizontoJ to l v.ertical slope to intersectw.HhAirm natural grQund. DrQwing I. .·No·. 1 of Proiect No. 70-4-160 is j·ncluded for reference, following Appendix B gfthe end of'this report. • Respectfully submftted, BENTON ENGJJ* . lNG, INC. By;;' ~~ .. -~ Reviewed· -m;-.-~- Engmeer Olitr: (8) Addressee • MVP/PHB/meg BENTON ENGINEERING, INC. • .. ' .. • • • '. • w ~ Z III Sl • ... w w II; -~ ... lI,; w 0 n. .... 1- - ~. - 3:-. - . ~, - ~ - 6-- -,.. 7-. SUMMARY SHEET . BORING No.,_...!.l __ ELEVATION ]09,0' * · .... · .. " .. • •• e',. · .. _.' . ·to. ..... .. ....... -.... -.......... . " .' . ~ . . .......... . Brown, Moist, Medium Soft, Much Organic Material Light Gray and Light Gray--': ' ,brown, Moist, Medium Firm, Rootlets ~=3 Light Green-gray and Red-brown t:"' __ "\1001 Motst, Medium Firm, Rootlets ... ,-......j Dark Green-gray, SI Ightl y t::=:1 Moist, Very Firm, Very ..... -......j Slickensided, Very Fractured t·:, :::3' In 1/2 - 2 Inch Pieces, CLAYEY FINE TO· MEDIUM SAND FINE TOMEDIUM SANDY CLAY EI::=:3 Occasional Decomposing Cobble 8= With Dark Brown Silty Fine to _ t::~ Medium Sand SurrOllndtng It CLAY 9-[!] iii··-· ...... ~ -~ .: .10- " .~ 11 ..... " · , .-.'. 12"", -" 13- "'" 14:'" , -Continued on Drawing No.3 - '-,' ... - .,.,. o -IndiCQtes Loose Bag Sample - -, o -Indicates Undisturbed Drive Sample > >. W· c,,' W~ ...... u'" a:'" O§ -II. a:ZII. . w.!:!:. ~. Z0 cCd w!!:: .., .... > w;:) ,winS!! W'0a: O~ w~ \LO O >fa ~ iiUf' >. _ ... .~ lit w-. a: II. ~ ... a:'li!( 0 ,. --* -Elevations shown were obtained by interpolation between . contour lines on Samuel Wacht Associates ..... - - .:... DRAWING NO. 2 PROJECT NO. 73-3-1A BENTON ENGINEERING, INC • • • • '. • z 0 ~-A SUMMARY SHEET . -Au O a-Ill BORING NO. 1 (Cont.) en"'~ 15"': - - 18- - -> ~en ~ u Dark Green-gray With Red- 1---1 brown, Slightly Moist, Very .. E~~~-3 Slickensided, Many Gypsum' r: Veins, Many Rootlets, I 20- ......--4 Fractured to 1/2 to 2 Inch r==3 Pieces, Occasional Partially 1--.... Decomposed Cobble to 4 Inche$ I - 21-..., fBt;, .=::::1 Light Gr~en-gray With Red 22-_ 32 .. ':, And Yellow-brown, Contact . ...... ..... Dips 180 N 60° W . 23- 24- CLAY > CJ' >. ·w • a: I-w~ 1-1-ul-w~ Qa: iii '" . z'" zen -Ai=!> z' a: c( • w!!: w:::l ~I-g Wena: Q~ W~ ii:i~ :I:.en ->. >la 'cnu;~ -I-!S-A w-a:'" . a:~. Q 4.9 4~9 20.3 102.5 _ ~~:::::.:.:<.:, Light Gray and Red-brown, FINE TO MEDIUM 25-. .:: : : : : \Sl1ghtI Y'Moist, Firm, Contact SAND .' .. /J---+--r--f-.,.----f--~ . :. .... ,00';s SO -S 850' F.. . . --..... . .26-tB. .,:::.. Light Gre..~n-gray With Red-CLAYEY FINE' . • .g ... ~: >.: 4 \brown, i~tig~tly Moist, Firm SAND' I . <3 :.27,... 3 \...--..,... .. +,::.;-------+--------.1 .. 16.2 7.0 106.6 '. • . :', '_ LIght G~'with Red-brown, . :28:.... Slightly Moist, Very Firm, _ Pocket of Dark Brown Sil ty 29-. \ Fine to Medium Sand - FINE TO MEDIUM SAND ' 30-1 1/2 Inch· Seam of Light Gra~!" . ,~, ,:.:': <,~ , , ,,, brown Film CIC!)' Dips 5° S 40 'W .: ~,·3·t ~W' ; ~reen-gr~; With Red-brown, ) 32-8) C,·. . Slightly ,Moist, Very Firm, ~_ ... Contact ~tps 40 S 650 W ' -CLAY 33-. - w 34 .... ~ c( -Z III 35-° ... Continued on' Drawing No. 4 PROJ!,:CT NO. 73-3-1A BENTON ENGINEERING, INC. 11 .4 21.4 1 01 .8 DRAWING NO. 3 •• • • • • • • • • o - w :E cs: z SUMMARY SHEET' BORING NO. 1 (Cont.~) _ Green-gray With Red-brown, 36-Slightly Moist, Very Firm CLAY -VAtt'-. 37-®~ Light Gray, Slightly MoIst, FINE SANDY ) . 'O~',,' "Verv Firm SILT .... ./ -., ' .' " 0' 38-::'.:',:: :": Light Green-gray With Red-· _ ',', '::': :~: brown, Slightly Moist, Very 39-::~ :":::.-, Firm . ," .~ ... ',. .'v _ ·,{'::t ..... '1_~'." .40-.. ,. ~ .. ' ... " ., .'"':".~ • I, ... ~.~ ' ... ' ' .. - - FINE SANDY . CLAY SILTY FINE SAND al -o .., PROJECT NO. 73-3-1A BENTON ENGINEERING, INC. ,> o· a:: I-w!!:: zen w!!: w~ >. -I-a::1L. Q 35.4 33.3 41.6 DRAWING NO. 4 '. • • • • • • • • • -~ > >. W' o· Q~~ 1-1-(.)1- SUMMARY SHEET a: I--II. zu.. w~ ~::j a: « . , zen ...I;:» « a BORING NO. 2 w2: wlna: w(J ~ ~.In!!! w~ Q ..... l' ii:oQ >!a enu;~ ELEVATION 132 O· >. :iill! w--I-lS...I a:~ a: II. Q ~lIGHTL Y CLAYEY · ,. , ... -· .... · .... 1- Brown, Moist, Medium Soft, Rootlets FINE TOMEO IUM . .J-_+-----l:----+---+-----,-I SAND / 0 -.! t5 ~ ~ 0_ .... 8 u .9 W ~ z - - 3- .,.. 4-' - 5- - 6- - 7- ,- 10-- 11- - .' ....... . .... :.:: ;;::: Light Gray With Red-brown, :::.,: ::::: Slightly Moist, Medium Firm I.::,:~ Light Gray, Slightly Moist, :"~ 'Firm, Fractured, Occasional ::,:',··/t Pockets of Brown Silty Fine to ":.~ .... :. '.: Medium Sand .' " :':.:.::'.:: Light Yellow-gray And Light ':.:::::.:2. Brown-gray, Slightly Moist, :',:.::'::"::. Medium Firm, 1/4 to 1/2 Inch '.::::'::. :'. Bedding Planes Dipping 530 ........... N ISO E . ,.: ..... . .. ' ...... ' .. ~-........... . ·0·· .. :· • ••• '0 •• ~ ' •• FINE SANDY CLAY SILTY FINE SAND FINE SANDY CLAY 12-;?\/:.{ Dark Brown, Slightly Moist, FINE TO MEDIUM _ :;'::~,;.::.:.:.:) Medium Firm, Calcium Cemented SAND 13-, :':;::.:::::.,;;: Many Sea Shells -:::':'::::'.:::.:-. 14-I:'::' ...... :~ Light Gray, light Brown-gray, _ _II~I:'\" .':: And Yellow~bro~, Slightly 15-Sj .... ': . .;: Moist, MedIum Firm, "~.' ... ,. Occasional Roots - 1 '. " . ' 16-:.:",~,,: I~ ~ Pocket of Dark Brown Topsoil 18-':::::;:::: ~ With Sea Shells. _ .::.:::.::~ ~ight Red-brown, Slightly 19-~ '.: ::.::~'.:,: .. ~~tl:t Mpt'HII", Firm @ ........... LIght Gray-green, Gray-red, 2; ':::::::::: And Brown SILTY FINE SAND FINE 'SANDY CLAY -Continued on Drawing No.6 ) III -~ PROJECT NO. 73-3-1A BENTON ENGINEERING, INC. 3.2 14.6 97.2 4.9 ,]9.3 90.8 DRAWING NO. 5 • • • • • • • • • w ~ ~ z III 0 .., • SUMMARY SHEET BORING NO. 2 (Cont. r -' . ~.::::'>'\: Light Brown, Slightly Moist; VERY FI NE TO >-c). a:t: ·w_ ztn w!!: 'w~ >. -.-a: I&. Q 21"'" I~':~~ ,\MediumComDact·· . FINE SAND ....., ~ 1 Inch Seam ()f Green~edlum ./ •. 22;... ~; Firm Clay , 2;'· ~ Light Green-gray and Red-brown SILTY FINE _ : ',:"':' Slightly Moist, Firm SAND I 24-. , ' , . J-----+-+---+--.--+-----t _ ®~'.~~ray-li9ht Brown, Slightly CLAY MIXED 8.1 10.3 94.9 25""-~ MOis.t, Firm, Gypsum Crystals, WITH SILTY FIN1 _ m Vertical Seams, Contact Dips SAND ....... _-1-_+--_+-_-1-_-1 26-. ~1~8_o~.s~3~~~E __________ ~ ________ ~ , '"-(1) Gray-green, And Yellow-11.4 14.0 110.~ 27;...llJ brown With Black, Slightly SILTY FINE _ ,:' . Moist, ,Firm, Sea Shells, SAND 28""'7 :: Calcium Cemented, Contact \ DiDS 180 S lOoW 29=CV: Black arid Dark Green, SI ightl~ .... @) ;' Moist, Firm, Many Sea Shells 30,-Ir:::', =::1 ,. ~t==::J Green With Yellow-brown, J: " ., Sit ckensided - 34-r:i\jIiool." \ ==I -0~ ...... -~ 3'5- - 36-- 37-S - 38 ..... ., 40-. . - ,. Green-gray CLAY 41-C~~tinued on Drawing No. 7 .PROJECT NO. 73-3-1A BENTON ENGINEERING, INC. ·13.0 16.5 109.9 9.7 16.7~08.3 30.8, 17.0 ~08.8 DRAWING NO. 6 • • • • • • • w ~ < z en' o .., z I-0 w wa: i=..I SUMMARY SHEET w ..I~O ..Iw IL a. en _Uen .... x ~~ OU::~ BORING NO. 2 (Cont.) m-> I-<;:) a. mz ~m w < 0 ..I 41 u -' Green-gray, 'Slightly Moist, 42-" , Finn - 43_ , - 44-0,' -; 45-..... Light Yellow-brown, Slightly -.-' .... -,' .... -Motst, Very Finn 46- -Gray-green, 51 ightly Moist, 47-Very Finn, Slickensided -48-';',~,-~ , [ill'~~ Dark Gray With Gray-brown 49= ® I':~ And Yellow-brown, Slightly '~ ,Moist, Very Finn, Slight Clay 50: ~~ Binder, Occasional Thin Lens , ~~: §& of Clay, 51= :-\~~~"::':~' Light Gray, Red-brown, And _ ~" '.:' Brown-gray, 'Contact Dips 90 S 52-~~'" Soo~E~ ______ -.....---1 CLAY (Merges) CLAYEY FINE SAND CLAY SILTY FINE SAND / '_ ~ ..... -P~ket of Organic Material " ' 53-<\:',:>:' Light Gray With Red-brown, FINE TO MEDIUM . ~ @ 2%1 :::::~t~:e:::MY' SAND 55-~.~,\.::.':~::/.: \S1i9ht1 Y Moist, Very Finn, ' -:::;.::::::; Some Gypsum Seams, Contact 56-:~)::~::: Dips 11 0 S 300 W -':::,:::~~: 57-.:::::/:: .. ;';~ Light Gray, SHghtly Moist, ~'. '.::;','::::: \. VerY Comcact ' , -.... " sa-4 :::?\:/:/' 2 Inch Gray-brown, Very Firm, FINE TOMEDIUM 12 ::.:.::::.':': Clay Seam With Some Gypsum SAND ..,. ':.:;':':':"::'.'::: \ Dips SO S 300 W ' 59-.... -: ... -:;::>:':'. CLAY I 60- > CJ' >. w " a: I-w...: ... 1-ul-' w!!: cg;~ inlL ZIL, zm z· a:~ .' w!!: ..1,1->' W';:) <1-0 wma: c~ Wmm w:W: iLoc x-Cii >. >~ mma. -I-~~ w-a: ,..I a::W: a:IL C' c lS.3 16.4 111.( 35.S 19.9 10S.4 37.5 ~~~ \3 Inch Brown-gray Finn Cigy I ~ Layer Wi th Gypsum Dips 9' ~: " 5 300 W, ,{Merges} J.-.-_.L--..iL.-----'--L--t - 61-Red-brown, Slightly Moist, SLIGHTLY SILTY \ Very Finn , ,FINE TO MED'IUM SAND - - Continued on Drawing No. S DRAWING NO. 7 PROJECT NO. 73-3-1A BENTON ENGINEERING, INC. , 1 :, • ) '. • • • '. '.' W • :IE < z • m o ., SUMMARY SHE!=T BORING NO. 2 (Cont.) 61_0 ~ Dark 'Gray, Sli9h~y Moist, 62-~ IVArv Firm. DillS 5' S 300 W _ Green-gr.ay, Slightly Moist, .63-Very Finn, Slickensided 6; (.;;\~ ~~~':,>,.<." ':ray, Slightly Moist, Very W ~Q.i' Finn ...;. 'g-.:) 65-,,' .".. Green-gray With Red-brown, 66= Slightly Moist, Very ·Finn - 67- - 68- - 69-@1o!-,_ .... . - 70- - 71- - 72- - SILT , (Meroes) CLAY (Merges) ,FINE SANDY SILT (Merges) CLAY (Merges) 73-,~<.\-/.:.;-::.: Light Yellow-gray, SUghtly SILTY FINE _ ":,:/i:'\':/ Moist, Very Finn SAND > > ., CJ' w"'; 1::[ W' a:'" u'" w!!:. o~:~ ~, ZIL zll) 0::< ' w!!:: ""' .... > w::l < ... 0 WII)a: o~ WII)~ w!Ii:: U:'OO >11) ~c;;~ >' _ ... :IE~ a:lD w- a:1L 0"'" a: !Ii:: 0 38.2 47.8 , 74-q§)' ..,.,:..:::~r:;.,r..:·<.r:·· _.....,.....:..-------+-------+ -VM Green-gray, Slightly Moist, FINE SANDY 1-- 53 _.-I- tf _--+-_-+-_-+--....... 75-/::/:';:~::>I\ Very Firm SILT (Merges) / 76= ' /(L/:) ~'-e-,-,ow....----g-ra ...... y---bro ......... w-n-, -S-IJ-gh-t-,y--+-S-'-L T"';y-. -F"';I N;"'E-...J -::::::>~ .. ::::.:":' Moist, Very Finn SAND 77-C\ ::::-:.:::::.:--~ .::.:: . .':.::::;:: '. 78- - , - -' - - - - PROJEtT NO, 73-3-1A BENTON ENGINEERING, INC. 43.0 DRAWING NO, S • • • • • • • •• • • o ....I w :E « z co o ., t-w w u.. ....... :t Ii: w o 0- - 1- - - 3- - SUMMARY SHEET BORING NO. 3 ELEVATION 139.0' 1--_-1 Dark Gray-green With Red and ..... _ ..... Yellow-brown Streaks, Moist, Medium Firm, Rootlets ..... __ -1 Slightly Moist, Firm, ..... _-1 Slickensided But Smaller Pieces 4-[18 - 5- - 6- - 7- - 8"- - 9- ~=::1 Very "Blockyll, Large Long r==::1 Slickensided Surfaces 10= CDE .. 3:-:---::----' .--~ ..... -... Very Firm '11=~1~·', -0= 12-~=I - 13- - : 14- 15- CLAY 6.5 18.9107.9 14.6 17.0 111.8 ,(Merges) . w" uli: " a:~ • «"'0 wt-CI)CI) :t -Cl)cnK! w-a:lII:: .. 16= ~~:~~:~:;;7;:' Slightly S~:~~~YN~LTY "17= (i)1=~:::~::!"'=':-.~. '--___________ .--J~~(JM~e!.!JrQ~.e~s)~----'/ 16.2" ~~:~ ~!~:~ _ t---... Dark Gray-green WHy Yellow 1S"': ..... ---1 And Red-brown Streaks, t--.... Slightly Moist, Very Firm, , 19= 0, Slickensided "Blocky" -Loosely Jointed - 20-light Green-gray, Slightly Moist, Very Firm, Contact Dips 50 N 550 W " \ CLAY SILTY FINE SAND 21-Continued on Drawing No. 10 PROJECT NO. 73-3-1 A BENTON ENGINEERING, INc. 11.4 20 .. 1 108.5 DRAWING NO. 9 • • • • • • • B. • • • Z I-0 > >. ltl ' ~ ffi. ..I ~ 5 SUMMARY SHEET ffi~ c ~ ~ z~ ~ ~ Q.m _Om zen ..I1-:J> :J l: :i!:':i!: OU:::i!: BORING NO. 3 (Cont.) w!!: Wena: ~g Ii: <:J enii.i> --wlII: U::o-c . w enz en en > . >fg c ~ a:t: :i!:~ 15,0.1 21-r--T:::~o~~~~~--~~~~~--~~--~--------~c~~--~~~---+--~ ~:::\\r.~. light Brown, Slightly Moist, FINE SAND 27 28 2 30 3 :36 41 ::':::':':'<:~ Ver Finn. Cemented Light Gray With Red-brown And Gray Brown, Slightly Moist, Very Fi rm Light Brown and Light Gray., Slightly Moist, Very Firm Dark Green-gray and Yellow- ~;.",;.,;,.~ brown, Slightly Moist, Finn, L n light Brown and light Grc;ty, Slightly Moist, Very Firm Gray, Slightly Moist, Very Firm, C.emented 1==:1\ Red-brown, Slightly Moist to Moist" Firm, Slickensided, Some Gypsum Gray,Slightly Moist, Very Firm SLIGHTLY SILTY FINE SAND (Merges) SLIGHTLY SILTY FINE TO MEDIUM SAND FINE TO MEDIUM SAND. SLIGHTLY SILTY 35.4 11.2 120.2 39.0 9.1 113.4 FINE TO MEDIUM 63.2 S.S 112.2 SAND FINE TO MEDIUM SAND CLAY . FINE SANDY SILT (Mer ~s) SLIGHTLY SILTY FINE SAND 19.1 H). 54.511.3112.7 Continued on Drawing No. H DRAWING NO • 10 PROJECT NO. 73-3-1A BENTON ENGINEERING, INC. • • • • • • • • • • • ..£ ~ c :E (1) 0 .E 8 c ....J W ::E <t Z m o .., z 1-' 0 i=..J ,W W Wct ..J<to I£. ..Jw ..... ~m _CJm X <t::E OU::::E I-" en-> Q. en;:) !a en W Z 0 <t ..J 4' CJ -, I~~~ 42-I -..... ~. '-, : .. . '" 43-I~~~~~ - 44- - ..;., - - - - - ..;; -- - - ~ - - -... - - - - -' - - ..,.. -' .... - .... - - - ..,.' ..,.. ' - - PROJECT NO. 73-3-1A > 0' >. W' W~ 1-1-(,,)1- SUMMARY SHEET ctl--I£. w!:!:: oct ~ . zu. zen ct <t • 3 (Cont.) ..J~> W;:) <tl-0 BORING NO. w!!::, W'enct o~ wense wlIi: U::Oo X-en ~.,.: >~ enenQ. ::E~ w-ct·u. ~..J ctlli: 0 Gray, Slightly Moist, Very Firm SLIGHTLY SILTY FINE SAND Becomes More Firm and '" Cemented . DRAWING NO. BENTON ENGINEERING, INC. 11 • • • • • • • • ., I I • • BENTON ENGINEERI~G. INC. APPLIED SOIL MECHANICS ---' FOUNDATIONS -PHILIP HENKING BENTON ""EB/DENT -CIVIL ENGINEER 6717 CONVOY COURT SAN DIEGO. CALIFORNIA 92111 APPENDIX A TELEPHONE (714) 15615-191515 Unified Soil Classification Chart* SOIL DESCRIPTION GROUP I. COARSE GRAINED, More than half of material is larger than No. 200 sieve size. ** GRAVELS MOre than half of coarse fraction is I arger than No. 4 CLEAN GRAVE LS sieve size but smaller GRAVELS WITH FINES than 3 inches (Appreciable amount of fines) SANDS CLEAN SANDS . More than half of coarse fraction is smaller than No.4 sieve size SANDS WITH FINES (Appreciable amount of fines) II. FINE GRAINED, More than half of material is smaller than No. 200 sieve size.** SILTS AND CLAYS Liquid limit Less than 50 SILTS AND CLAYS Liquid limit Greater than 50 III'. HIGHLY ORGANIC SOILS SYMBOL GW GP GM GC SW SP SM SC ML CL OL MH CH OH, PT TYPICAL NAMES Well graded gravels, gravel-sand mixtures, I ittle or no fines. . Poorly grdded gravels, gravel-sand mixtures, little or no ffries. Silty gravels, poorly graded gravel- sand-silt, mixtures. Clayey gravels, poorly graded gravel- sand-c lay mixtures. Well graded sand, gravelly sands" little, or no fines. Poorly graded sands, grav'elly sands, little or no fines. Silty sands, poorly graded sand-silt mixtures. :Clayey sands, poorly graded sand-clay mixtures. InorganiC silts and very fine sands, rock flour, sandy silt or clayey-silt-sand, mixtures with sl ight pla~ticity. Inorganic .clays of low to medium plas- 'ticHy, gravel'ly clays, sandy clays, silty clays, lean clays • Organic silts and organic silty",:,clays of low plasticity. Inorganic silts, micaceous or diatomaceous fine sandy or silty soi Is, elastic silts. Inorgan'ic clays of high plasticity, fat -, clays. Organic clays of medium to high',- plasticity 'Peat and other highly or.ganic soils., ,Adopted by the Corps of Engineers and Bureau of Reclamation.in January, 1952. '* All sieve sizes on this chart are U. 5., St~:mdard. ,'_ ** P-------------------------------------------------------------------------~--------- • • • • • • • • • • • PHILIP HENKING BENTON PltlEalDENT • CIVIL ENGINEER Sampl ing BENTON ENGINEERING. INC. APPLIED SOIL MECHANICS -FOUNDATIONS 6717 CONVOY COURT SAN DIEGO. CALIFORNIA 92111 TELEPHONE (714) 5615.19155 APPENDIX B The undisturbed soil samples are obtaine'd by forcing a special sampling tube into the undisturbed soils at the bottom of the boring, at frequent intervals below the ground surface. ' 'The sampling tube consists of a steel barrel 3.0 inches outside diameter, with a special cutting' tip on one end and a double ball valve on the other, and with a lining of twelve thin brass rings, each one inch long by 2.42 inches inside diameter. The sampler, connected to a twelve inch long waste barrel, is either pushed or driven approximately 18 inches into the soil and a six inch section of the center portion of the sample is taken for laboratory tests, the soi I being' still confined in the brass rings, after extraction from the sampler tube. The samples are taken to the laboratory in close fitting waterproof containers in order to retain the fie'ld~ moisture until completion of the tests. The driving energy is calculated as the average energy in foot-kips required to force the sampling tube through one foot of soil at the depth at which the sample is obtained. Shear Tests The shear tests are run using a direct shear machine of the strain control type in which' the rate of deformation is approximately 0.05 inch per minute. The machine 'is so designed that t.he tests are madl? without removing the samples from the brass liner rings in which they are secured. Each sample is sheared under a normal load equivalent to the weight of ,the soil above the point of sampl ing. In some instances, samples are sheared under various normal loads in order to obtain the internal angle of friction and cohesion,. Where considered necessary, samples are saturated and drained before shearing in order to simulate extreme field moisture conditions. Consolidation Tests The apparatus used for the consolidation tests is designed to receive one of. the 'one inch high rings of soil as it comes from the field. Loads are applied in several increments to. the upper , surface of the test specimen and the resulting deformations are recorded at selected time intervals for each fncrement. Generally, each increment of load is maintained on the sample unti I the rate of deformation is equal to or less than 1/10000 inch per hour. Porous stones are placed in contact with the top and bottom of each specimen to permit the ready addition or release of water. Expansion Tests One inch high samples confined In the brass rings are permitted to 'air dry at 105° F for at least 48 hours prior to placing into the expansion apparatus. A unit load of 500 pounds per .square foot is then applied to the upper porous stone in contact with the top of each'sample·. Water ,Is permitted to contact both the top and bottom of each sample through porous stones. Continuous" observations are made unti I downward movement stops. The d.ial reading is recorded .and expansion' is recorded until the rate of upward movement is less tha~ :1/10000 inch per' ho.ur. .