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CT 73-07; LA COSTA SOUTH UNIT NO 3; HYDRAULIC CALCULATIONS; 1973-07-09
HYDRAULIC CALCULATION Lot 206 La Costa South unit No. 3 Prepared By: ~ick Engineering Company 509 Elm Avenue Carlsbad, California 92008 July 9, 1973 Job Number 4402 • " , :~~:'ri;1t4~~i::':~: :':,:,~~ ,-... ·.~;t~;:: ," ~. ". ~.I--'~-" -~ rl BASIC CRITERIA • .' , , -. ~ .... " ... ~~-~ -~: ;;:: "~.>' < • " . ~~.:~ ~ ;:. . ---::~': : .. ~ ~:~ Ca.lculations are based upon the following: ?:-':':''1-0££: Rational formula (Q -CIA) ",,':":.:::':;:_::.' :::':, c = 0.5 (D'rainage Area used in Calculation is adjusted for th~~ :;~~or):"~:;:'~~~~~~;L:< i = Per Peak Run-off. Rates on Sheet No .. 3 ~,:-:,,'. ", ","', ,,<,;..:i.:",;,:~,,::~.:,<' ,-, ... , .... : . . . .: :~ Pipe flow: } ..... -.... -:., Mannings, formula with n = 0.013 Pipes are sized for a 50:"year storm .' .. ..: ' .. . -.. " ' ."' .... Inlets: ?\OTE: Grate Inlets sized to carry 50-year run-off with a maximum of 3-1/2 II ' of ponding. Curb Opening Inlets Sized to carry 50-year run-orf with water ponded to top of curb. Loss Factor shown on the following'calculation sheets represents a fractional proportion of v2 in accordance with the following:, .. :' '~ " ' TITLE: JOB: For 90° bend in alignment For 45° bend in alignment For no bend in alignment (If the above bends are accomplished by a LOSS FACTOR 1.00 0.50 a substantial radius I use 1/2 of,the above Loss Factor) For entrance of sub lines to main lines Los s Factor on main line will be equivalent to ratio of Q's of sub line to main line (L.P. = Q'sub/Q main). 'SHEET NO. E Rick Engineering Co. JOB NO. DATE ------_.---.. -----. -. -_. =--::='-=-=-=-=--='-':...:'...::..' -::.-....' ~~,,,-,,-...... -=,-_-_ ...... --,~....;.~..:.o' ELEV. FACTon 0'-1500 lOO 1'300-3000 I. 2 5, 3000-4000 1.42 4000-5000 1.60 5 (I 00-GOOO 1.70 DESERT 1,25 To obtain correct intonsity, n'~lIip'y InfClnsi1y on chart b~ foclor, for design olevotion. 2 -·1 FI n ;:~ 0 (f), C; --c--I -l (') ...... " .. < ~\ c: I o "!j t.:) o ..,. .' <-c: 'YI r.1 ;.() (J) (f) » p' ::! ;e 0 » 0 2 ,-I lJ F1 .lJ G') '""(' P1 '0 ~J Z PI -. 0 0 c: ..... ,>< ,..1 lij 1:1 .--.1 (' .. n "~ ~J S> -";9 c_ "Tl J;l> r r ...... 3.0 o (!) ltl Cl 20:: 0.2 MIN UTE S DUn t\"f ION 10 20 . ---3() 40 50 .!H+HHliJlIlIIfI;ii!I-T;':'I~·Fri·l·T~l-r:l"I::rITn 1~:;:mlnnilr:1 t:I ~ nmr ..f.-,J I H ouns 2 3 4 5 6 7 (I 9 IQ -, ql~-I .'. --, jEt' + 1tW' 'I.' H'llitHf1illll' r' , Imt-OO, . !t'mlMl'; t ItH11~)lWlr·t·:s.''''lli· 'rff[ill~~--r-, ,ttu.mtt1lHlIlIlli' ': ---, -1-, -t" -' . .---. , , . +i-U' I" '. n---. j , ,-. ---tl:i±.r.rrrmllll.iJll1 . ----"" -'" "-, . --' .-'-" -. ',.... L' -; 'i", -::r '-,- 5 10 2"0 MINUTES .;,41 ''\ . 30 40 ~o I 2" 3 4 5 6 7 0 9 10 . 1 ':'l~~".: ~ i,' ,.,",j. ,"," . , 'DURAtiON i~ > ; • ~ I.', . ::':'-"." \ : ,~V:, ~,I '.';. ,' . • ~~ t.~ ,---t, .. • , Houns , ,,' " . , :(lJ '1 f:, :-.,. / . '--. "I \ -\ ", " , -. ~ ,or.' , :.. ..,.. -. .... '-. ~ .. \ -- ,,;... .. "- ~" _ ... -!' \ \} --.. .. 'f"-./",!--.... .,. :,>,.. ! -~ -EMrgy Gradient (E.G.) Hy '~"fH::--~--L.J 8a nd Loss {if ~ny} .:: ""';\H ' .. ' I'A .. ' ---L_ .. ~ -" . -' •... ----------~b~~~~~:JJr::::=: .. _ PiP.s 3 ., 3 5 34 • (3 1 S 2 • 3'6 5 4 S O. S ,5 1 T 8 3 0 S '''I ~ S i. of 38·7750 CO 12 J~~2~ nv O·OOGO AO 2'1'::00 :0 23"91 S ""I r ,.. ~ ?,.. "" ..J J ..; 'i \.....1 41" 'oJ .J..):...:.. '"\ V 3 • 3 . 5-6335 o • 2 s s s r <) : i) ,. .\ , 1 , . , " , ~ . ,. r-) S ~ (J J <'\ ; ~\ .J- I , ! i ,-- . :1..- i (T.C .. = /6 min.) :;c~· w. s. @. ® . ~~ ~ -: .. :-:.;\ ., HA ·(previous downstream...line) . "~ : ;~"'/ Bend.factor @ @ (O for'?-o bend~ 1 fo~ "9qo}) . ~~ Drainage Area (s .. £ .. ) ". :.::.:., :-.... : ...... ,. '._.' __ ~~::~" .:,.-:: Pipe size (inches) '. "--.' ~.' ,'. .._ R • ~. : -f· ••.. I Q (cis) V (ips) Bend loss~ if·any··, H. G. slope W.S. @.@ Length of line -. 'V.S. @ © HB (This line) • 0 , : _ '. _r o of •• ' __ 0.:' ", Flow tL.-ne (min.) ________ "--_ :. •• ~ ,. 0' ! i (T. C. = / ej·min. ) ! vr. S. @ (6) '., I· HA (Previou.'s downstre~ line) -. .... '. _ "', . Bend factor @ @ (0 for no bend, 1 for 900)' . . Drainage A-rea {s.f.} .Pipe S~ze (inches) Q (cis) V (ips) Bend loss, if any H. G. slope 'V. S. @@ Length of line W.S. @ © HB (This line) Flow time 'Cm.in. ) .. ' @ ~ .5 < ., ..J ~ 1 . ~ I 1 ~ j .( 1 ~ ~ 1 ~ ~ 1 1 ~ - ~ 1 .. , -. ~ -. Manhole or . 'Catch. Basin. ----- H' B. .. ;':-:-/:~~~:~~':~.' _ .... " -~i~';8:~:~~~:': ~ .::~: :~-~ Manhole-or . -~~~:~".:,~: ..... -', ''--, ":-~' :. Cafc h Ba8in··~·~.:~;"·.:'· .. ' , -"--.' >;--.- .send L •••. -6~~j~{> !; --_. __ ...l.; r=:~~~~~~~~~ ---'J:i~'-... ~:~::: -".'_:. . ::-~~~--~~~~~~~t~";~--. :~~~' :~~~~7': PiP.s .'. :(/i~~~L.~t.; . :.~: .. ' . 3 • 3 70 • 1-0 2 « 7 6 8 2' o • 5 1 3 s. s s. . $. s ." :'. -~ ~.-.. ' , -• ... • ;:: -: _' ..)Z _ .. --~. ..:-~. I ~:~:c@ ¥ 6~n., )-,::~-.:'~-; ~'-:~ffi--!~~.-·~~:·-:~::-·.,: .""'~-~~-~~*~ '~ . HA ·(previous downstrea.m::·1ine) -:-' :.~ ':$:/'Y;:{ .. ·' ~~.~ .i=k I Bend factor @.@ .(0 f~~·rio::b~.~d~·:'·l i6~i$0.~j'~i; .. ~~ I ~~:!":i~: ~~:~~:)f~) " "::'::~'>~6 ~!=:::1t!;~ . '" '.' '. : .. :.\:.;<.~ 1 ~3~~~f ~~~ I Q (cis) . "',ri:: ---:1i: :~~~S~:~e i£anT~ ":'-:}~rt!j:3~~t,~ w. s. @.@ ...... .~.;c. __ ..... ,' .~ Length of line . .. ·W.S. @ © HB (This line) Flow time (min.) ________ '--_ i (T. C. = ·min. ) 1 Yv.s. @ @, . .. HA (Previous' downstreaII?-' iuie) .>.: .. ;.> ..... ,.. ..- Bend. iactor @ ® (0 for no·bend~ 'I for'9qor'-~" Drainage Area (5. I. ) .'". . . .. , ',~-'R _ •• ~ .Pipe S~ze (inches).. . '.-.. I Q (cfs) ~ V (ips) .J l Bend loss. i£any. j H. G. slope ~. ·W.S. @ ® t wLensgth@o©fcline ~ . . . ! HB {This line} ~ FloW' time '(min.) ________ -'--__ t--------~--------------,_--~'----------~~~----~~--__1 ~ TIT l E: I PreporE'd' by.,. :.J05J..r::.~::;:.:::~~~-·~ SHE e T NO. t HYDRAULIC CALCULATIOKS 1/ RICK' ~--'''-, ., .. ~ JO B: Ii £nginHring.Compony -. . ~ ,i 509 Elm aven.ue-phone:' 7.f.9' 498T· L~ )1. _ Corfs~rt.~~'!"-'-92008 .' '. _. ----------- I ~ I ~ \ I I I I I I ,1 o ----"'---~-----,----.----~-,---.:.--,----:- PROFILE' SCALE" I-IOR IZ. :r /'':,40' VERT::II /"::8' ® "-.,:.: . ~:::; ;..::::.*t: ;k ':~ ~:.. .. :~",:,,:-::.. • • '.' • I' • • • • • • • • BENTON ENGINEERING. INC. APPLIED SOIL MECHANICS -FOUNDATIONS 6717 COt:'IVOY COURT SAN DIEGO, CALIFORNIA 92111 PHILIP HENKING BENTON PRESIDENT. CIVIL ENG'INEER November 6, 1973 1'El.EPHONE (714) 565.1955 La Cost(lde Marbella Associates 4924 Rebel Road San Diego, California 92117 Attenfi'on: Mr. Tony Busietta /-273 -26.23 Subject: Gentlemen: Proiect No. 73-7-18DF Slope Reconstruction Requirements La Costa de Marbell a Lot 206 La Costa South Unit No.3 Carl$bad, Cal ifornia This 'is .to report the r.ecomme.nded limits of soil removal and re.compacHon of the existing cut slope located on the southern side of the subject property iA,.Q.t~~_r.F~gk,Bqr~tl9..Q~l ' '!'!!~be l'f~and to reduce the possibility of fl,lture slope failure along the remainder of the slope. '!bP. r~fJP",qW>Jl! as contained in this report ~~~S,.~9!1,the recently proposed gra~i.p~·",~~~ Samuel WQ,cht Associat~s, AlA, undated, which shows an increase ''rlelevation~~ ofBuildings~A"" nro~~"'D';".J..,rn~~:A:~ In tbis regard the slope stability analyses were performed on a cross-se.cflon taken through the area of the slope where Bui Iding B is to ,be located with the front edge of the garage slab at Elevation 105 feet. In order to provide th-e necessary,engineering rec~mmendaHons for reconstruction of the slope" 'soil samples from the on-site' soHsin the existing slope and from two possible borrow sites were 'obta.ined for laboratory testing. For the convenience ofreferenc¢ th~ samples tested will ,be referred to as follows: Sample Designation A B C Orisin of Somple On-site .soils existin% in the cut slope. Borrow site located at Lots 196 and - 197 La Costa South Vl'lit No.2. Borrow site located at 'so\itneast , ' , corner of EI Camino Real and Encinitas Blvd. • • • • • • • • • • • Project No. 73-7-18DF • La Costc;l de Marbe II a Associ ates -2-'. November 6,1973 Since two samples were obtained from each of the two borrow sites, the designation of the samples from the same borrow site will be indicated by a numeri~al suffix such as Bl and B2 or Cl and C2. Laboratory Tests , Compaction tests were performed on the representative soil samples to establish compaction criteria. The soils were tested according to the A.S.T.M. D 1557-70 method of compaction which uses 25' bl'ows of a 10 pound rammer dropping ,]8 inches on each of 5 layers in a 4 inch diameter 1/30 cubic toot mold. Tne results of the tests are ,presented as follows: Maximum Optimum Mois- Soil Dry Density ,ture Content, Sample Description Ib/cu ft % dry wt A Yellow gray silty clay 108.1 16.4 B1 Brown silty clay 122.8 10.5 B2 light gray fine sandy clay, 122.6 10.6 C1 light yellow. gray silty fine sand 114.7 ,12.2' C2 Yellow brown silty fine sand 120.0 10.9 Dir~ct shear tests were performed on the selected soil samples, remolded to 90 percent of maximum dry densit~ that were all saturated and drained prior to testing. The results of these tests are presented below: Maximum Normal Shear Load in Load kips/sq ft kips/sq ft Sample A 0.5 0.74 1.0 0.80 2.0 1. 19 Sample B1 0.5 0.79 1.0 0.89 2.0 1. 18 Sample B2 0.5 0.68 1.0 0.85 2.0 1. 12 Sample C1 , 0.5 0.6'1 1.0 1.07 2.0 '1.98 Sample C2 0.5 0.65 1.0 1.04 2.0 1.84 * Arbitrarily reduced. BENTON ENGINEERiNG. INC. Angle of Internal Fri ction Degrees 20 15 16.5 40 * 38.5 Apparent Cohesion Ib/sq ft 430 650 545 160 250 • Proiect No. 73-7-18DF • La Costa de Marbella Assoc es Conclusions -3-• November 6, 1973 Based on the resut.ts of the laboratory tests a'nd slope stability analyses for a proposed slope • reconstruction with a slope ratio of 1.5 horizontal to 1 vertical, it is concluded that: • ,- • • '. • • • • • 1. If the slope is reconstructed entirely with the exisHng on-site soil, designated as Sample A, the slope will not be stabJe with an acleqiJote factor of safety. 2. 3. If the slope is reconstructed with certain limiting zones of on-site soils and select import soils, with both properry compacted to CIt least 90 percent of maximum dry de_nsity, the slope will be stable with an adequate factor of safety of at least J .5. The select import soil which win provide the required increased strength parameters necessary to insure a reconstructed slope with an adequate factor of safety should be obtained from the borrow site located at the southeast corner of EI Camino Real and ' Encinitas Boulevard, and can be either the type soil designated as Sample Cl or C2. ~ecommendcitions I.t is recommended that the entire existing cut 510pe located on fhe south side of the property ak'd having an approximate length of 425 feet as measured from the eastern prope .... y line be recon- structed. The reconstruction of the slope should entail the -removal of unsuitable existing soils and rebuilding the slope with a combination of the on-site soils ane:! select import soils aU recom- pacted tc? at least 90 percent of maximum dry density in accordance with A.S. T .M. Test Method D 1557-70. The limits of removal and replacement with properly compacted solis should extend down to a depth of at least 4 feet below the buildtng garage pad elevations beginning at the footing line at the back of the garage area. This depth of removal may be greater depending on the soil: conditions encountered in order that the rec,ompacted sc)iJ may be founded on firm natural ground. Clnd with a 20 feet width of compacted fill to form a shear key as part of buttressing the toe of the slope. From the back footing line at the garage level the removal should extend in towards the slope for a horizontal distance of at least 20 feet. From this point the temporarily exposed excavation may be carried up and back at a slope on the order of 1. 15 horizontal to 1 vertical to a point where a 15 feet wide horizontal distance is attained as measured between the face of the excavated slope and the face of the proposed outer slope Une to be reconstructed. From there the excavation may be allowed to daylight out at a slope which will safely stand during the construction phase. The zone of the recompacted slope which should be reconstructed with the select imported fill should include the bottom area of the "key" of the buttress fill and extend upward to a line horizontal with an elevation equal to the elevation of the patio area. The remainder of the r.ecompacted slope, including any required undercutting below the minimum 4 feet deep "key II , may be reconstructed with the existing on-site soils. . BENTON ENGINEERING, 'INC. • Proi~ct No. 73 ... 7-18DF • La Costa de Marbella Associates .... 4-• November 6, 1973 The attached Drawing No. 1A shows a typical cross-section view taken through Building Band .the slope behind indicating the general limits of removal and recompaction and the zone which should be reconstructed with select import soils and the zones which may be reconstructed with • existing on-site solis. • • • • • • • • • Any.portion of the existing bench and gunite-I ined brow ditch located on the slope whkh is removed dl,lring grading operations should be reconstructed to provide er9Sion protection. All of the slope reconstruction should be done in accor9ance with the attached Appendix AA, entitled "Standard Specifications for Placement of Compacted Filled Ground. II It is recom- .mended that continuous inspection and testing of the compacted fill be provided. It is also recommended that careful attention be given to the exposed cut slope during the slope removal operations t06bserve any adverse soil bedding planes or other conditions which might allow possible additional soil mass movement prior to the reconstruction of the slope. Respectfully submitted, BENTON ENGINEERING, INC. By8.r~- D.F. Leake, Civil Engineer Review.d~~ Philip H. Benton, Civil Engineer - Distr: (3) Addressee . (2) Olson Development Company Attention: Mr. Richard Chambers (2) Samuel Wacht & Associates, AlA Attention: Mr. Samuel Wacht BENTON ENGINEERING. INC. DFL/PHB/ew • • • • • • • • • • • • • BENTON ENGINEERING. INC. APPLIED SOIL MECHANICS -FOUNDATIONS 6717 CONVOY COURT SAN DIEGO, CALIFORNIA 92111 PHILIP HENKING BEN,TON PRESIDENT -CIVIL ENGINEER TELEPHONE (714) 565-191515 APPENDIX AA STANDARD SPECIFICATIONS FOR PLACEMENT OF COMPACTED FILLED GROUND 1. G~neral Description. The objective is to obtain uniformity and adequate internaJ strengt,h in filled ground by proven engineering procedures and tests so that the proposed struct\Jres may be safely supported. The procedures include the clearing and grubbing, remov'al of existing structures, preparation of land to be filled, fi lIing of the land', :the spreadi,ng, and compaction of the fi lied areas to conform with the I ines, grades, and slopes as 'shown on the accepted plans. ' The owt:Jer shall employ a qual ified soi Is engineer to inspect and test the Hired gro,und as 'placed to:verify the uniformity of compaction'of filled ground to the ,specified 90 percent 'ot maximum dry density. The soils engineer shall advise the owner and grading contractor immediately if any unsatisfactory conditions are observed to exist,and shall hove the authodty to re ject the compacted fi lied ground unti I such time that corrective measures are taken necessary to comply with the specifications. It shall be the sole responsibility of the grad ing contractor to achieve the specified degree of compaction. 2.' Clearing, Grubbing, and Preparing Areas to be Filled. (a) , (b) (c) All brush, vegetation and any rubbish shall be removed, piled, and 'burned or other'- wise disposed of so as to leave the areas to be filled free of vegetation and debris. Any soft, swampy or otherwise unsuitable areas shall be corrected by draining or removal, or both. The natural ground which is determined to be satisfactory for the support of the filled ground'shall then be plowed or scarified to a depth of at least six inches (6"), and untiJ the surface is free from ruts, hummocks,,' or other uneven features which would tend to prevent uniform compaction by the equipment to be used. Where fills are made on hillsides or exposed slope areas, g~eater than 10 percent, horizontal benches shall be cut into firm undisturbed natural ground in order tq provide both lateral and vertical stability. This is to provide a horizontal base so fhat each' layer is placed and compacted on a horizontal' plane. The initial bench at the toe of 'the fi II shall be at least 10 feet in width 'on firm undistvrbed natural ground at the e'leva- tion of the toe stake placed at the natural angle of repose or design slope. The soih engineer shall determine the width and frequency of all succeeding benches which will vary with the soil conditions and the steepness .6f slope. • • • • • • • • • • • • • APPENDIX AA -2- (d) After the natural ground has been prepared, it shall then be brought to the proper mois":' ture content and compacted to not less than ninety percent of ma~lmum density' in accordance with A.S. T.M. D-1557-70 method that uses 2~ blows of a 10 pound harrymer falling from 18 inches on each of 5 layers in a 4" diameter cylindrical mold of a 1/30th cubic foot volume. ' 3. Materials and Special Requirements. The fi II soils shall c~nsist of select materials so graded that at least 40 percent of the material passes a No.4 sieve. This may be obtained from the excavation of banks, borrow pits of any other approved sources and by mixing soils from one or more sources. The material uses shall be free from vegetable matter ,and other de'- leterious substances, and shall not contain rocks or lumps of g'reater than 6 inches in diameter. If excessive vegetation, rocks, or soils with inadequate strength 'or other unacceptable physical characteristics are encountered, these shall be disposed of in waste areas as shown onthe plans or as directed by the soils engineer. If during gra&ng operations, soils not encountered and tested in the preliminary investigation are found, tests on these soils sh911 be performed' to determine their physical characteristics. Any special treatment recommended in the preliminary or subsequent soil reports not covered herein shari become an addendum to these specifications. The testing and specifications for the compaction of subgrade,subbase, and base material's for roads, streets, highways, or other public property or rights-of-way shall be in accordance with those of the governmental agency having jurisdiction. 4. Placi ng I Spreading / and Compacti ng Fi II Materials. (a) The sui table fi II material shall be placed ·in layers whi ch, when compacted shall not exceed six inches (6"). Each layer shall be spread evenly and shall be thr:oughly mixed during the spreading to insure uniformity of material and moisture in each layer. (b) 'lVhen the moisture content of the fill material is b~low that specified by the soilsengi'neer, water shall be added until the moisture content is near optimum as specified by the (c) (d) soils engineer to assure thorough bonding during the compacting process. Vvhen the moisture content of the fi" materi<;ll is above that specified by the soi I~ engineer, the fill material shall be aerated by blading and scarifying or other satis- factory methods unti I the moisture content is near optimum as specified by the soJls engineer. After each layer has been placed, mixed and spread evenly, It shall, .be thoroughly compacted to not less than ninety· percent of maximum density in accordan.ce. with A. S. T.M. D-1557 -70 modified as described-in 2 (d) above. Compaction shart be accomplished with sheepsfoot rollers, multiple-wheel pneumatic-tired rollers, or other approved types of compaction equipment, such as vibratory equi.pment that is speciatry design~d for certain soil types. RoHers shall be of such design 'that they wi 1/ be able BENTON ENGINEERING. INC. • .' • • • • • • • • • • • APPENDIX AA - 3 - to compact the fi II material to the specified density. Roll ing shall be accompl,lshed while the fill mated-al is at the specified moisture content.' Rolling of each layer shall be continuous over Its entire area and the roller shall make sufficient ,trips to insure that the desired densi ty has been obtai ned. The entire areas to be filled shall be compacted. (e) Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compacting operations shall be continued until the slopes are stable but not too dens~ for planting and until there is no appreciable amount of loose soli on tbe slopes. Compacting of the slopes shall be accomplished by backrolling the slopes In increments, of 3 to 5 feet In elevation gain or by other methods producing, satisfactory results. (f) Field d~nsity tests shall be taken by the soils engineer for approximately each foot in elevation gain after compaction, but not to exceed two feet in vertical height between tests. Field density tests may be taken at intervals of 6 inches 1n elevation gain if required by the soils engineer. The location of the tests in plan shall be so spaced to , give the best possible coverage and shall be taken no farther apart than-100 feet. Tests shall be taken on corner and terrace lots for each two feet in elevation gain. The soils engineer may take additional tests as considered necessary to check on the uniformity of compaction. Where sheepsfoot rollers are used r the tests shall be taken in the com- pacted material below the disturbed surface. No additional layers of fill shall be'spread until the field density tests indicate that the specified density has been obtained. (g) The fill operation shall be continued in six inch (6 11) compacted layers, as specified ,above, untrl the fill has been brought to the finished slopes and grades as shown on. the accepted plans. ' 5. Inspection. Sufficient Inspection' by the soils engineer sheill be maintained during the' filling and compacting operations so that he'can certify-that the fill was constructed in ' accordance with the accepted specifications. 6'. Seasona( Limits. No fill material shall be placed, spread, or rolled if'weather conditlons increase the moisture content above permissible limits., When the work Is Interrupted by rain, fill operations shall not be resumed until field tests by the soils engineer' indicate that , ,'the moisture content and density of the fi II are as previously specified. 7. Linilting Values of Nonexpansive Soils. Those soils that expand 2.5 percent or less .From "air dry to saturation under a unit load of 500 pounds per square foot are considered to be ,nonexpansive. 8 •. All recommendations presented in the "Conclusions II section of the attached report are a parf of these specifications .. BENTON ENGINEERING, INC. • • • • • • • BENTON ENGINEERING. INC. PHILIP HENKING BENTON PRESIDENT ., CIVIL ENGINEI;R APPL1ED SOIL MECHANICS -FOUNDATIONS , 6717 CONVOY COURT SAN DIEGO, CALIFORNIA 92111 , August 29, 1973 La Costa de Marbella Associates 3883 Jewel Street· Suite G 103 San Diego, CaliJornia 92109 Attention: , Mr • Tony Busietta Subject: Gentlemen: Project No. 73-7-18DF Soil Removal and Recompaction Requirements La Costa de Marbella Lot 206 La Costa South Unit No.3 Carlsbad, California TELEPHONE (714) 565·1,955 This is to report the recommended limits of $oil removal and recompaction in the areas of the pro- posed Buildings Hand J of the subject development in order to r~~e !..~~~~ f~cl.AwJSlQ9.J;i and to allow shallow depth foundations for both Buildings Hand J. In ' addition, this is to report recommendations regarding fhe increased. structural design of shallow 'depth footings for ·those proposedbuildings which will be constructed in close proximity to the existing sewer and storm drain lines. Field Investigation Three exploration trenches were excavated on the site and then visually examined in order that the depths to competent soils could be determined. One trench was located in the southwestern ,. corner of the property in the area of a known previous landslide where Building H is to be con- structed. T'he other two trenches Were located along the western side of the property in fhe pro- posed ,area where .Building J is to be constructed • • l { / s • ~~~- r I ,..; Soil Conditions At the location of the trench in the area of Building H the upper $oiJs consisted of structurally unsu i tabJ.e_gLa,yAy~e..e ... sp"il$ and topso ils wh i ch had been s.b.2.aL.e ... <L.~~el ded !&as a .!!t'!J t .c;f. _~.M.eroeQJ..,. A competent sandy type soil w~ encountered in this trend, at a elev~tion of approximately 95.0 feet. "? . . ~ • • •• • • • • • • • P{plect No. 73-7-18DF • La Costa South Unit No.3 -2-• At the two trenches located along the area of Building J the upper 5 to 7 feet of soils encounter- ed consisted of structurally unsuitable soils which had previously been sheared and remolded due to soil mass movement. Competent soils were encountered below these upper unsl,Iitable soils. Conclusions It is concluded from the field investigation and the visual examination of the soil strata exposed in the exploratory trenches that in order to reduce the possibility of a slope failure in the area of Building H a buttress type compacted fill should be constructed h the slope behind that building. In addition, it is concluded that in order for Buildings Hand J to be supported by shallow depth footings, those unsuitable soils such as those found in the upper soil strata of the trenches should be removed and properly recompacted prior to excavating for fOl,lndaHons or placing addi tional compacted fill • Based on an analysis of .the location of existing sewer and storm drain lines relative to the adi~cent proposedbvilding locations, it is further concluded that certain portions of the foundations of auilding E, G, J and 5 should be structurally reinforced in order that any potential settlement which may occur due to consolidation within the previously placed questionable backfill soH placed over these utility lines may be tolerated. Recommendations I Removal and Compaction, : Area of Building H -It is recommended that the unsuitable soils In the area of the proposed location of-Building H and behind this building and up the existing slope be removed and properly recompacted. The limits of removal should extend to' a depth of e.ievation of 95.0 feet for the area in front of and back under the building to d point where the building pad steps up to the patio aral;!. At this point, the area of removal should be deepened by 2 feet for a total width of 1,5 feet as measured in toward the slope. This 2 feet additional undercutting will act as a key tor the buttress compacted fill. Behind this key, the existing soils should be ,excavated .on a slope as defined 'by a line running from the key into and up the slope to a point 15 feet measured horizontally j'nto the slope from the 131 feet contour on the final proposed grade and then from that point vertl~ally upward to intersect the existing ground surface. These HmHs of the recommended' removal and recompaction to at least 90 percent of maximum dry density for . Building Hare presented on the attached D.rawing No.1. It is further recommended that a 6. feet wide bench be constructed along the recompacted fill soils at approximately the 131 feet contour level. This bench should be graded slightly downward and into the slope and generally sloped down to one or both end~ of the bench. In addition, a gunite or concrete-lined ditcr should be constructed on the ir;tside· of the bench to, effectively intercept and carry off all surface water to existing or Proposed storm drainege systems. If poSsible, it is recommended that selective grading procedures be adopted whereby any nonexpansive soils encountered during the removal grading operations be stock-piled for later use tn the upper three feet below finishedgrede in the area under the build- ing. In this manner, the requirement for special foundation design consideration for potentially expansive soils would be eliminated. BENTON ENGINEERING, INC. • • • • • • • • • • • Prpi~c~ No. 73-7-1SDF • La Costa South Unit No _ 3 • -3- Area of Building J -It is recommended that for the area ·along the proposed location of Building J, the unsuitable upper natural soils be removed and be uniformly compacted to at least 90 percent of maximum dry density priQr to excavating for foundations or placing addition- al fill. The depth limits of this removal will vary with the qptual fieldc::onditions observed at the time of excavation and may extend to a depth of 5 feet(±) on the soufhern portion of the building and to a depth of 7 feet (:q on the northern portion of the building_ The limits of the width of the removal and ree6mpaction wi'll vary as a function of the building foundation area and whether new fill is to be placed on top of the existing natural ground. Two sections through the building, one at the northern portion and one at the southern portion, are presented on the attached Drawing No.2 and show the typical zones of removal and recompaction expected. ~ shown on Drawing No.2, it will be necessary to remove and rec.ompact some of the existing fill. ~ previously recommended for the grading of the area of Building H, 'it is again recommended that, if possible, ,!6lective-S1tpdi.n.9_~e ;!!lP..!.o.Xe~ in the area of Building J in order to allow non....e.xpaJ:lslv.e-solls....tD_ ·st in the up-er 3 feet oelow finish grade so that special design' consideration for potentially expansive 'soils could e errminated~ It should be noted that the. limits of removal as previously described and as shown on the aHached Drawing Nos •. 1 and 2 are only estimates based oli the visuc;d ex- amination of the exploration t·renches. Actual depths of remova'I, except possibly for the zone of the buttress fill in the slope behind Building H, may vary and can only be determined by our field representative during grading operations. No great variance, however, is expected. All grading operations regarding the removal and recompaction of soils as presented in this report should be accomplished in accordance with the at·tached Appen- dix AA entifled, "Standard Specifications For Placement of Compacted Filled GrQund.1I Reinforcement of Building Foundations It is recommended that certain port'ions of Buildings E, G, J and S be structurally reinforced in order that potential settlements due to the consolidation of the lower questionable backfill pre- viously plq~ed over utility lines in the close proximity of these buildings will not result in structural distress to these buildings. The limits ot influence of the potential settlement in relation to the proposed building lo.cations are shown on the attached Drawing Nos. 3 and 4. It is recommended that all .reinforcing in the fOO.tings be carried beyond these limits as shown on these drawings in order that potential s'tre$Ses du~ to any settlement can be translated along and back to those $ecHons-of the footings which are not located In the area of influence. It is not possible to calculate a measured value of potentia, sett-Iements. Therefore, it is re- commended that within the I,imits of influence those footings be designed as continUous in- terconnected reinforced concrete grade beam type foundations that allow only that ~eflection which can be tolerated by the type of structure supported by those footings. BENTON ENGINEERING. INC. • • • • • • • •• • • P'Yl~ct No. 73 ... 7-18DF .- La Costa South Unit No. 3 -4-• If you should have any questions concerning the information presented in this report or desire additl.onal information please c/o not hesitate to contact our office. Respectfully submitted, BENTON ENGINE~RING/INC. ------/1t -.. ~ ~ ~o~/Z~FZ:= Reviewed b -. -. Distr: (3) Addressee (2) Olson· Development Company Attention: Mr. Richard Chambers (2) Samuel Wacht & Associates, A. J ~A. Attenfipn: Mr. Samuel Wacht DFL/PHB/m$9 BENTON ENGINEERING, IN~. • • • '. • • • • • • PROJECT NO .. 73-7-18DF \ " PROPOS£fJ fJUllOING J -Limits of Influence DRAWN LIMITS of INFLUENC E or POTENTIAL SETTLEMENT BUILDINGS J and S LA COSTA de MARBELLA LOT 206 LA COST A SOUTH UN IT NO.3 CARLSBAD, CALIFORNIA BENTON ENGINEERING, INC. BUILf)lNG S SCALE: 111=1 0' DRAWING NO. 3 • • • • • • • • • • PROPOSEO LJUILIJ/NG F '\ .; ... 1 II ... - PROPO.5EfJ BUILDING £ PllOPOSED BUILDIN6 t; PROPOSED BUILDING F -Limits of Influence PROJECT NO. 73-7-18DF LIMITS of INFLUENC E of POTENTIAL SETTLEMENT BUILDIN GS E, F, and G LA COSTA de MARBELLA LOT 206 LA COSTA SOUTH UN IT NO. 3 CARLSBAD, CA~JFORNIA BENTON eNGINEERING, INC. 1/ DRAWING NO. 4 • • • • • • • • • • • • • BENTON ENGINEERING. iNC~ APPLIED SOIL MECHANICS -FOUNDATIONS 6717 CONVOY COURT SAN DIEGO, CALIFORNI!,-92111 PHILIP HENKING BENTON PRESIDENT'. ciVIL ENGINEER TELEPHONE (714) 5,65·,1955 APPENDIX AA STANDARD SPECIFICATIONS FOR PLACEMENT OF COMPACTED FILLED GROUND 1. G~neral Description. The objective is to obtain uniformity andad~quate internalstrengt,h in filled ground by proven engineering procedures and tests so that the proposed structures may be safely supported. The procedures include the clearing and grubbingj removal of existing structures, preparation of land to be filled, filling of the land', t·he spreading, and compaction of the fi lied areas to conform with the I ines, grades, and slopes as shown on the, accepted plans. The owner shall employ. a qual ified soi Is engineer to inspect and test the Hlled ground as 'placed to'verify the uniformity of compaction of filled ground to the ,specified 90 percent of maximu,m dry density. The soils engineer shall advise the owner and grad'ing contractor immediately if any unsatisfactory conditions are observed to exisf.and shc;lll have the autho'rity to re ject the compacted fi lied ground until such time that corrective measures are taken necessary to comply with the specifications. J.t shall be the sole respo'nsibi litt of the grading contractor to achieve the specified degree of compaction. 2.' Clearing, Grubbing, and Preparing Areas to be Filled. (a) (b) (c) All brush, vegetation and any rubbish shall be removed, pried, and burned or ot,her- wise disposed of so as to leave the areas to be filled free of vegetation and debris. Any soft, swampy or otherwise unsuitable areas shall be corrected by draining or removal, or both. The natural ground which is determined to be satisfactory for the suppor!' of the filled ground shall then be plowed or scarified to a depth of at I~astsix inc;:hes (6"), and until the surface is free from ruts, hummocks, or other uneven features which would t~nd to prevent uniform compaction by the equipment to'be used. Where fills are made on hillsides or exposed slope areas, greater than 10 percent, horizontal benches shall be cut into firm und'isturbed natural ground in order tq provide both lateral and vertical stability. This.is to prav,ide a hor'izontal base so that each layer is pJ.aced and compacted on a horizontal plane. The initial bench at the toe of 'the fi" shall be at least J 0 feet in width on firm undisturbed natural ground at the e:Jeva- tion of the toe stake placed at the nat.ural angle of repose or design slope. The soi Is engineer shall determine the width and frequency of 0/1 succeeding benches which wi'/l vary with the soil conditions and the steepness of slope. • • • .1 • • • • • • APPENDIX AA -2- (d) After the natural ground has been prepared, it shall then be broughr to the proper mois- . ture content and compacted to not less than 90 percent of maximum ~ensity in accordance with A.S.T.M. D1557-66T method that uses 25 blows do 10 pound hammer fall ing from 18 inches on each of 5 I.ayers in a 4/1 diameter cyl indrical mold' of a 1/30th cubic foot volume. 3. Materials and Special Requirements. The fill soils shall consist ci select moterialsso graded that at least 40 percen,t CI the material posses a No.4 sieve. This may be obtained from 4. the excavation of bonks, barow pits of any other approved sources arid by mixing soils from one or-more sources. The material uses sholl be f.ree from vegetable matter, and other de- leterious substances, and shall not contain rocks a lumps of greater than 6 inches in diameter. If excessive vegetation, rocks, a soils with inadequate strength or other unac-' ceptab/.e physical characteristics are encountered, these shall be disposed of in waste areas as shown on thE! plans or as directed by the soils engineer. If during grading operations, soils not encountered and tested in the prel iminary investigation are found, tests on these soils shall be performed to determine their physical characteristics. Any special treatment recommended -in the preliminary or subsequent soil reports not covered herein shall become an addendum to these specifications. Th~ testing and specifications for the compaction of subgrade, subbase, and base materials for roods, streets, highways, or other public property or rights-of-way shall be in accordance with those of the governmental agency having ;urisdiction. Placing, Spreading, and Compacting Fill tv\;Jterials. (a) The suitable fill material shall be placed in layers which, when compacted; shall not exceed six inches (6"), Each layer shall be. spread evenly and shall be thoroughly mixed during the spreading to insure uniformity ci moterial and moisture in each layer. (b) When the moisture content of the fill material is below that specified by the soils engin- eer, water shall be added ontil the moisture content is near optimum as specified by the soils engineer to assure thorough bonding during the compacting process. (c) When the moisture content of the fill material is above that specified by the soils engineer, the fill materia.! shall be aerated by blading and scarifying or other satis- factory methods until the moisture content is near optimum as specified by the soils • engineer. • • (d) After each layer has been placed, mixed and spread evenly, it shall be thoroughly compacted to not less than "90 percent of maximum density in accordance with A. S. T.M. D1557-66T modified as described in 2 (d) above. Compaction shall be accomplished with sheepsfoot rollers, multiple-wheel pneumatic-tired r~lIers, or other approved types of compaction equipment, such as vibratory equipment that is specially designed for certain soil rypes. Rollers shall be of such design that they will be able a£NtoN ENqINEE"ING. INC. • • • • • • • • • APPENDIX AA - 3 - to compact the fi" material to the specified density. Rolling shall be accomplished . while the fill material is at the specified moisture content. Rolling of each layer shall be Gontinuous over Its e~tire area and the roller shall make suffi.cient trips to lnsure that the desired density has been obtained. The entire areas to be filled shall be compacted. (e) Fill slopes shall be compacted by means of sheepsfoot roners or other suitable eql)ipment. Compacting operations shall be continued until the slopes are stable but not too dense for planti re and unti I there is no appreciable amount of loose soli on the slopes. Compacting of the slopes shall be accomplished by backrolling the slopes in increments of 3 to 5 feet In elevation gain or by other methods producing satisfactory results. (f) Field density tests shall be taken by the soils engineer for approximately (;lach foot in elevation gain after compaction, but not to exceed two feet in vertical height between tests. Field density tests may be taken at intervals of 6 inches in elevation gain if required by the soils ereineer. The location of the tests in plan shall be so spaced to give the best possible coverage and shall be taken no farther apart than 100 feet. Tests shall be taken on corner and terrace lots for each two fee t f n elevation' gai n • The soi Is engineer may take additional tests as considered necessary to check on the uniformity of compaction. Where sheepsfoot rollers are used r the tests shall be taken in the Gom- pacted material below the disturbed surface. No additional layers offill shall be spread until the field density tests indicate that the specffied density has been obtained. (g) The fill operation shall be continued in six inch (6 11) compacted layers r as specified i;lbove, unHI the fill has been brought to the finished slopes and grades as shown on the accepted plans. 5. Inspection. Sufficient inspection by the soils engineer shall be maintained during the filli.ng and compacting operations so that he can certify that the fill was constructed in accordance with the accepted specifications. . 6. Seasonal Umits. No fill material shall be placed, spread, or rolled if weather conditions • increase the moisture content above permissible limits. When the work is. Interrupted by rain, fill operations shall not be resumed until field tests by the sons engineer indicate that the moisture content and density of the fill are as previously specified. 7. Limitire Values of Nonexpansive Soils.. Those solis that expand 2.5 percent or less from • air dry to saturation under a unit load of 500 pounds per square foot are considered to be nonexpansive. • • 8. All recommendations presented in the "Conclusions II sec.tion of the attached report are a part of these sped fi catf ons . BENTON ENGINEERING. INC. • • 'HILIP HENKING BENTON PRESIDENT· CIVIL EN.GINEER • • BENTON ENGINEERING. iNC. APPLIED SOIL MECHANICS -FOUNDATIONS 6717 CONVOY COURT SAN DIEGO. CALIFORNIA 92111 TELEPHONE (714) '565·1955· August 30, 1973 • .La Costa de Marbella Associates 3883 Jewel 'Street . • .' • • • • • SuiteG 103 Sqn Diego, California .92109 Attention: Mr. Tony Busletta SubJect.: . Proiect No. 73-7-H3DF Gentlemen: Landslide Conditions Westerly of ProP9sed Building J ~. CW' K awNtv' W'~i"'f"t¥ttv W?'HfIIt;Q "1$W~1"5j'l~iUia'aliJia:it=-~ La Costa de'Marbella . Lot 206 La Costa South Unit No .• 3 Carlsbad,. California RECEIVED FEB 14 1974 CITY OF CARLSBAD' . Engineering Department In accerd(1nce wi'th yo,ur request, we have cont,inued to make on-site field inspections of th~ grading .operations at the subJect site. During grading on August 28 and 29, 1973, westerly 'of the proposed Building J, .our field inspector observed what we beliewe is the northerly con- tinuation of the .landslide condition .. encountered in the area of p-roposed Building H ascdi~cussed in our report of Protect No •. 73-7-18DF, entitled "Soil Removal and Recompa~tion Requirements, La ·Costa ~, Mar~lIa, Lot 206, La Costa S~uth Unit No. 3, Carl~bad, Califomia," dated Aug- U$t 29, 1973. . . . This ne~J)! uncovered landslide_m~ slJ:e..P.~ds observed in the open north-south ope~ cut face westerly of Building J for a distance of approximately 50 feet and by profection it would continue on southe.asterly dnd downward to connect with the landslide sJie..e.lpne observed in .the area oLemM.~lJll.di.ngJ:L.gj;,.ge~imate)y elevation 95 feet. At a point about SO··feet 'northerlyo.f the sOuth end of prOPosid Building J .along the weste.m side of the building, the landsl idu!!e. elane was observed at an ~Ievation of about 106 feet which l!.s.t approximately the elevation of the p-rO~sed p-atio slab in back of proposed Building J. Since landsl ide planes tYPi~Yfu~-:m'~i;-e9Ufar sl,Jrface, several measurements of its inclination· were taken to arrive at a rep~ntative view of this undulating surface. These .measurements which fot·low, all jn~ dlcate on adverse and in our opinion a hazardo~s, e~t~r;t.!!9~Jl!.t9ble"P2n~!tio" ~~t!f!Uf .J.b~OO)erP.P&.SfL~u.i,lpiQ~ ... _Jhese slide plana measure~ents were founi to ~. dipging _do~ward out of slope in the following manner: 4.5 South 40 . to 4~ EaSt, 9 South 55 to 65 Ed$t, ana 13.SU South 6d' East. Other slide ... pJanesj>cmd small adjustment planes »:ere.,.a,tso_oJ?serves'r... but were not believed to be of as adverse a nature as the principal slide plane described above. ..... .e12'e'9'e,."...",....~, cwaz~lii!&iUla IAi:¥iaP . JI • • • • • • • • • • ProJect NQ. 73-7 -18DF • L~ Costa de Marbella -2- 'BY~~ /~ ,Wi 'am J. Elliott, Res.:;steree6ogist 1101 Dfstr; (3) (2) .(2) AddreJStile Olson DfWelopm$nt Compony AttentlQhl Mr. Richard Chambers Samuel Wacht &'AsSociat8s, A. J. Ai Attention: Mt. S(lJl1uel Wacht . .WJJ;/PHB/meg BENTON ENGINEERING. INC. • August 30, 1973 •• • • •• • • • • • • • • • BENTON ENGINEERING, INC. APPLIED SOIL MECHANICS -'-FOUNDATIONS 6717 CONVOY COURT SAN DIEGO. CALIFORNIA 92111 PHILIP HENKING BENTON PRESIDENT. CIVIL ENGINEER 1a Costa de MarbeUa Associates 4924 Rebe I Road . San Diego, California 92117 Subject: Project No. 73-7-18DF location of Foot i ngs La Costa de Marbella ~ot 206 La Costa South Unit No. 3 Corlsbad, California Genllemen: September 19, 1973 TELEPHONE (714) 565·1955 At the request of Mr. Dick Chambers, of Olson Development Company, this is to present recom- mendations regarding the location of certain footings of the subject development which will be ,placed neQr the top of existing compacted fill slope. The area of concern is the northern or downs tope footing line on each of the proposed buildings designated as L through S / inclusive .. , These footing. lines are shown as Section 1/S-3 on Sheet S.-3,of the construction plans. It is recommended that these foofings be placed so that the bottom of the foundation footing is no closer that 5 feet, measured horizontally, to the surface of the adjacent exposed slope. The attachecf drawing No. 1 shows this recommended location. Respe¢tfu/ly subtnit-ted, ,BE NTO N ENG INEERI NG, INC. BY~t~· David F. Leake, Civil Engineer RevIewed by (~ ~~ PhlJlp H.BtOn; c;lvil E~ D.tstr: (1) Addressee Attention: Mr • Tony Busietta (2) Samuel Wacht & Associates, A.I.A. Attention: Mr. Wally Wong (2)0Ison Development Company Attention: Mr. Dick Chambers DFL/PHB/mpm • • • FINAL GRADED SLOPE- • s~ MIN, /JOWIVSLOPE -rOOTINO L / N£ • • • • Date: 9-1 Drawn DW No • LOCATION OF FOOTINGS LA COSTA DE MARBELLA • LOT 206 ,LA COSTA SOUTH UNIT NO.3 CARLSBAD, CALIFORNIA PROJECT HO. DRAWING NO. • 73-7-1SDF BENTON ENGINEERING, INC. 1 • • PHILIP HENKING BENTON PRESIOf;NT • CIVIL 'ENGINEER • • BENTON ENGINE·ERING, INC. APPLIED SOIL MECHANICS -FOUNDATIONS 6717 CONVOY COURT SAN DIEGO. CALIFORNIA 92111 September 28, 1973 La Costa de Marbella A$$OCiates TELEPHONE (714.) &65·1955 • 4924 Rebel Road • • • • • • • San. DieQo, California 92117 Aftention: Mr. Tony Busietta Subject: Project No. 73-7-18DF ki.ewof rlan~1lN9 Co~2.itions~¥.t~ .s.t.er:ol2.os.e.drB.~~nd::;~ LaCostQde Marbella lot 206 La Costa South Unit No.3 Carlsbad, Calffornia '.~ Gentlelrien: . In accordance with your request, We have conti.nued to make on-site fie Id inspections of the gr.ading operations at the subject site westerly of proposed Buildings H and). During our field . inspection on September 25, 1973, we observed that the cut !ilQ~ gnd buttress_f.i..lLPlaced be- ' .. hind proposed Building H b.as..be~D..c9Jl§t.tuctedJn accorda~ce with the se.e~c.i.fLC.C#..i.QDLdS discussed in our report of Project No. 73-7-18DF, en~itled "Soil Removal and Recompactlon Requirements, La Costa de Marbella, Lot 206, La Costa South Unit No.3, Carlsbad, California," dated August 29, 1973. Although the qcutal placement of the buttress was not witne tbe.....vttile , our field inspector~ opinion that .the buttress was placed properly so as 0 miti epossibilityof future movement on the old landslide planes observed both at the groun . ng5--_ placed In the hillside behi.nd·'Prpposed Building H. . In our 'report .or Project No. 73-7-18DF, entitled "landslide. Conditions Westerly of proposed Building J, La Costa de Marbella,. LQt 206, La Costa South Unit No.3, Carlsbad, Caltfornia, II dated Aug!Jst 30, 1973, we reported on a laridslide condition behind proposed Buf/ding J and recommended that some remedial measures be taken to mitigate this PQtentlally damaging sit- uation. Two alternaitve solutions to the problem were suggested: 1) design a buttress fill behind PrQposed Building J similar to that recommended for the proposed Building H, or 2) to simply remove the entire slide mass and design new cut slopes in acc9rdance with standard specifications. In that no undercutting or no buttress fill has been constructed behind proposed Building J, it is .(J$sumed, th~ the plan selected WCtS essentially to "remove the entire sJide mass. " --- " • • • • • • • • • · ' • "., Septa,mber 28, 1973 " . ,. -2 - 5t!;ilting ~t'approximQte elevation'l06 f~et at about the mtddle~:oft.hewestem side Qf.proPQsed SOlld'ing J we observed the fol'l(,wing qpproximat,e sloPe profile;, ,:tt:2rl (horizontQl to'vertical) ffqt\l,approximate elevation l06 ,n.:;~t, to QPproximate ~nch el~:y~H6n 121 feet, thenc((3.2': 1 \(hQ.rfioritql to vertical) to apPr()ximclfe bench ~Ievatton 133, thenc;e, 1.5: 1 (horizontQt to vertical) to approximate bench eJevation 153 feefr then'ce 1.5:1 (horizontal to vertical) to'the top of the st~pe at approximate bench elevation, 180 feet. Eac'h behch appeared to be about' 6 feet wide and ,according to the grade checker, 'each'one slopes at about lpereent northerly for drciiriag.. , . .' . . <' ',I, ' .. " ~. '. '1 ' .. -;:' .:" ~: ".'!I>.:~.?;"·' " 1he"soils in the upper three SI,9~S '~ove the bench at :approxtniat..:,elevation121 fe~f:,w'~ '<moo: ,~,T-ved,to be white to light ,b~WfJ .'gi~muJQr soi Is consisting m:arnJ~:;Qf':$andy silt I stltY-;~il~ Qnd . ,~'I,ay.,y sqiid with a few int~r,~~(d(dlayey stlt. Bedding Qtttt~q~s't'aken Just above"t·ne bt.1i~h ,:di>QjJp~xhnate elevatfon, '1.a~if~~t~:~re varIable, but indi.d'Ote~: ij.;'~Jr;~;pf 4 degrees to. 8 degree,s: , dQ)Vnwdrd in ,anorthwester,IY';~t~~H#ry,. ' Alt~ugh small 'fai:lut~¥:\#t~,;~;~p-O«;!tt" aa:!.n2U!-!J!9~u.t... ~c'Ot.i~ of the highly fraet~~~: .. 'n~t~~, or theae soils, the'PQssJ~iJffty,:of such occVfrilig.:'~n'these upper three slQpes above' the;~~;n:~hdt :qpproximate e.levQtt~n"l~!;~[t~f-' appears' to b~remQte;i. The const,ruction of a concrete lin'ad brow dit.ch cit the top of the 'Cuf:slope and concrete Hned'inter- c:~j)t drainage ditches on E!Qq'aY~h~~~ 'de.signed to carry Qf",x~~$(wQter will ~lp"toJ·Vrth.Etr mi ... 'lig,gte po~sible failures bY.'CJ~Q~kslh~;:tke:'POssibil1ty'of all~';ii'ri.gtt~9~ificant moistur,:.9rQngt!ts to q¢'cor deep within the soil$':~~p'b$e~;,;jn the new cut slo~. ',:: ',,:~.'Ji,::::':, ' " ::' "."i -.i,·,.1:/:::::·.,:::~:....'· !,,' .. "'.:'.~./;:,::::" ;. ', • .': " ::':ill~ ~ils in the lower cut:st6~~;~~~fl ~proximqhteJ~~dtt~A.~~H~ti;;feet and 12l'fe~~~~~fe:'obs~Jrv~d 'b:di~: composed rargelyof-,9re~~'ht'" ,.'I>,fr 4.~~li£Is_I~~Itf~ wlth abvndan,rwhite cafi- !#ije;,veins. S·inc.e th~ eleV\:,tt ~Ji.'o·tlt~e! landslide slip·plantJ/:(;i$/~tta:..in OUr previous 'report, ;.$ at :~ute.levati¢n 106 feet iri'tlifiS:.,dre'a,;~behind proposed: ButldJ6g;dj~'Hfls our opiniQtr fhgt:Qf. lea$t some , "o'f:+~ h:;atidslidedebris obove;~fh(a''':slifi1p'la!'18 is ~tifl ,present',J~,J~~~-.;::~~wer cut slope. 'In:th,is regard, X!!.., dO' riot ,believe. that the eritire.';'sHd~':,mOss :has be.en re\'novediJ~:SU99(:jlited in our previOUS reB2rt. We do1"be1feve,~O~Mr,""fltirfhe,sj'f~~rtn:q,WW--nCtr:ii:~9"s.i9~~f.U~n'it =P~to . fhe ,excavation of the cut sJd~~-:tiave bQth unloCilecHJif,llfcle-fr~e and m~ frdtter .. : (3'.12: 1 hc?rJzohtal to vertlcaIX:$fQfJes h), thesnde.~r:one g~n',~l~.,\ , ~# : -<~ , , ,;',:.:.: " , ",~, -.;}."," '" ," , ,',">;'r,~,t~7' ~,: . ':;:',"\ ~~§;,S;in:~~,;~e::did not have the,;:C;;p~rt~~r~i,to ,make an~"xtel'i,stv:;:',~ ," ;~it<l~ation of the ~~~~~:$h'ape. Qnd , :~7J~~¥,rQn>Qf the critical sl~~r.;~t~r.~~1~d slide mass~e ca~~O.If.,I'!I\,;~~~~,~ased ypon.,~u,~r~~~rvations :;y';~~!,~,~i'4Qte:j.-' that fP~.b§..::i!.~~~~~'':';i.s",st .. iJ.I,."r,Q;..,,,Jgfbf.QJ~ n'l!~I~,~';:ellt slope 8"~~i1:iqtr?ro~~"&yU'!9 4~:,~\~S~~·~lthough the sjt~~qtiQQ~:is~,~'lleved to be consid~tij6!y '~§fe'i"now, than it o/qS;:b.~tOte· the :~j~~'C~QPt(was made, :shou!I?'::'YQ,~'~'4e:slr~ to further rectIfy thi,~:~!:t~~:t¢n, ~f!' tecommWt~Ya..t,~,~o;_ , );f,~;;r~cQtnp~fion of the J~~_~~c:aMIIJAogreen cl<:,~~~~;~f~f.i,.~eQ: Detwe8nptq~~i~~ildin9 'J. ",.:-;~' " . t~~out ':~fe~9tJ,<),J1'.' l~T feetana~~~m11.1-~f9tJQ,ri eif about 1 00' f¥~tq:'(:'rec:tte" ',~n?9,~k~y'and' buttress with 'a·,miii'~m~rrbVi~th at the top of'ab'ouf';'l)~f1"et 'against poS$ibJe;,rtilt~r.':,rJlo.ve,-' , , ,~nt' of fhe green clay. Thkis"tQ sqy;; in vIew of the p,"':s.nt:$jttiatiQn~ a cut and b\ltttess:simtlar . 'to ,fhat constructed behind .. pr<?po~d ,BuHdtng H ,would~d f~d~~~,',$afety to the exPQsed. $l9pe.:~hind propos-edB,uilding J. c,:' :, : , ' !:-:, ~J.: " .~.'.>,' '" :. ':, :·l~·"~':-' . " , . ',' . .' . . .,('~. ~ ,~. ::-. , .: ./: .(. ~ ,If YQu desire to leave tbe)tlj,lt):l9pe,s; 0$ they are beht,nd 'pr~~~~t}tul,ldjn9 J, w«',str9rt9:ly;recOmmend thc:afcis a minimum precaution, ,all beryches be concrete n"'~·"l<;lnct:.fhat Clconcr.te:Un~ brOw dItch be constructed to drain off all excess wafer' fo proper drainage factlttfescr Also', if planti!l9 is contem- plated on fhese slopes, the 'Yaterlos.e.r;ggrdllJ,.,sb,puld be ~.s.intained at a ve~,.!!llntFtl~m neS!!!9 .. 1j' to keep native~type plants and vegetat.ion aBve • .QD£~.!bLr:l,qJ.tve ... ':ie~~ati~~i.!!.!!!!!~l~!!!'~~ ~?l!,!o~ BENTON ENGINEERING. INC. I • • • • • •• • • • • • , .. Project No~ 73-7 ... 18Cf I La Costa de Marbella As iates - 3 -• September,2S, 1973 If you have ony questions after reviewing this letter, pleas$ do not hesitate to contact this office. T'his opportunity to be of service is sincerely appreciated. Sincerely! BENfON ENGINEERING I INC. By Vi«. ... ,... J. ~ Wiiliqm J. Elliott, Registered Geologist 1101 . ..--- Philip Ho enton, Civil Engineer D istr: (3) Addressee (2). Olson Development Company Atfention: Mr. Richard Chambers (2) Samuel Wacht & Associates, A.I.A. Attention: Mr. Samuel Wacht BENTON ENGINEERING. INC. W JE/PHB/mpm • • , ,. Bi::NTON J;NGINEERING. INC. APPUED SOIL MECHANICS -FOUNDATIONS 6717 CONVOY COUR1' SAN DIEGO. CALIFORNIA 92111 PHILIP HENKING BENTON PRESIDENT· CIVIL 'ENGINEER March 11, 1974 La Costa de Marbella Associates 4924 Rebel Road San Diego, California 92117 Attention: Subject: Gentlemen: Mr. Ted Muga Project No. 73-7-18DF Retaining Wall Design Recommendations and Proposed Supplementary Soils Investigation La Costa de Marbella Lot 206 La Costa South Unit No.3 Carlsbad, Cal·ifornia Flt-E CT73-? RECEIVED MAR 11 1974 CITY OF CARLSBAD Building Department TELEPHONE (714) 56H.1955 This is to present amplifying recommendations regarding the design of retaining walls for the ,subject site based on certain methods of backfilling behind these walls. In addition this is to -confirm themutualJ.y agreed intentions of proceeding with a supplementary soils investigation that will include at least one and possibly two test borings in the area of Buildings J and S in order that additional foundation design recommendations may be provided if found to be necessary relative to estimated settlements of the underlying soils in that area. Retaining Wall Design In our letter submitted under this same project number and dated March 4, 1974 it was recom- mended that certain active earth pressures be used in the design of the retaining walls depending primarily on the type of materials used in backfilling the walls and the slope of the soils being retained. . At present it is understood that those areas where retaining walls will be constructed have been cut back at a slope ratio of 3/4 horizontal to 1 vertical. It is further understood that the present de~ign of these retaining walls has utilized an eq,uivalent fluid pressure 55 pounds per gubi9 foot ? for a sloping backfill having a slope ratio of no greater than 1.5 horizontal to 1 vertical and 30 \ pounds per cllbtg, foot for a level backfill condition. ""(" , Consider1ng the present site conditions it is ouropinioh that fhe active earth pressure values used in the present design of the retaining walls are satisfactory provided cerfoin backfill requirements are met. In fhis regard it is recommended that a gravel be used in the lower 2.5 feet of backfil-I • ',,-, "." {Project No. 73-7-18DF e .~ -2-March 11, 1974 La Costa de Marbella Associates and that this gravel have a minimum thickness of 1 foot at the bottom. The remaining backfill should consist ofa granular type soil such as a silty sand, slightly clayey sand or sand. The l.imiting areas of these backfill materials are shown graphically on the attached Drawing No. 1 B. This method of backfilling and the resulting active earth pressures used in the destgn assume that provisions are made to prevent any hydrostatic pressures from developing behind the walls and that no sllrcharge loads are allowed on the soils being retained. Supplement~ry Soils Investigation In our report submttted under this same project number and dated August 29; 1973 it was recom- mended that certain portions of Buildings E, G, J and S be structurally reinforced in order that potent·iol settlements due to the consolidation of the lOWer questionable backfill placed over util ity lines and adjacent to possible loose topsoils in the close proximity of these buil"dings will not result in structural distress to the buildings. In order that the structural engineer may have definite values of estimated settlements with which to design the foundations of the buildings, it is mutually agreed to conduct a supple!'l1entary soils investigation. This soils investigation will consist of at least one and possibly two borings drilled to sufficient depths in order that undisturbed soil samples may be obtained for laboratory testing. Since the area of influence of these questionable subsur.face soils is the ,greatest in the area of Buildings J and S, the test borings will be located there. Based on the field investigation and the results of the laboratory tests, recommendations regarding estimated settlements will be presented in a report.;..-- Respectfully submitted, BENTON ENGINEERING, INC. (2) Addressee (3) Samuel' Wacht Associates, A.I.A. BYi{-;[~ D. F. Leake, Civil Engineer Distr: Attention: Mr. Wong (2) Paul Koshi & Assoc;:iates . ' Attention: Mr. Seyman ~ .~~(l) Olson Development Company . ~ ~ Attention: Mr. Chambers Reviewed by '/,." . > -- . Philip H. enton, Civil Engineer ' DFl!PHB!ew . BENTON ENGINEERING. INC. TYPICAL REl7I/NINe WALL (TO/? ACTUAL O£5IC# S££ STRfJCTIJ/fAL DRAWINGS) Date 3-11 .. 74 PROJECT NO. 73-7--18DF / n-----.--F-----+---~--__TJ~~,_ \ \\ ;0.. \~_\. \ (0:;; \0" IMPORTED CRANIJLAR SOIL BACf(FILL } ON-SIT£ CLAYEY SOILS GRAVEL BACf(FIL L Drawn; R.W. METHOD OF BACKFILLING BEHIND REfAINING WALLS LA COSTA de MARBELLA LOT 206 ~A COSTA SOUTH UN IT NO.3 BENTON ENGINEERING, INC. DRAWING NO. 1 ' ~. .'" "'II .. '~ -PAUL Y. KOSH!&ASSOCIATES. City of Carlsbad Dl3partment of Building 8: Safety 1200 Elm Avenue Carlsbad, CaliFornia 9200G Attention; Subject: Richard S. Osburn Director of Building and Housing La (os'-a de Marbella Condominium Proiect 2425 La Costa Avenue Carlsbad, CA 92117 Dear Mr. Osburn: 155 No San Vicente alvd. Belverly Hills, (A 90~11 RECEIVED MAR 11 1974 CIT.Y .OF CARLS'BAD BUlf<:hl1g Department This is to inform you that this office has all the copies of the soils report as follows: 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) .January 4, 1973, #72-12-7 A (Prel iminory) January 16, 1973, #72-12-7 A (Formal) Apr i I 11, 1973, #73-3-1 A (Addendum) August 29, 1973, #73-7-18DF (Addendum) August 30, 1973, #73-7-18DF (Addendum) September 19, 1973, 1173-7-18DF (Addendum) September 20, 1973, 1J73-7-18DF (Addendum) November 6, 1973, #73-7-18DF (Addendum) February 4, 1974, #73-7-18DF (Adderdlum) , March 4, 1974, #73-7-18DF (Latest Addendum) March 11, 197~ #73-7-18DF (Latest Addendum) 1('111. , , " We would I ike to inform you that all foundations and retaining walls have been ~esigned in conformance with the requireniel!ts and recommendations of all the enclosed Sqil report with the exception of the granular backfill and additional report required for the westerly portion over the existing sewer line (adJacent to Buildings j and ,S). If you have any other questions please call or write me. Very truly yours" PAUL Y. KOSHI & ASSOCIATES , /' ,. -/. /-, / /:C?C ,c<,,<'>./?<-"/ ------ II' .... Paul Y. Roshi Structural Engineer i .. -==±J '. • l'f:.!; '·t, • . - . ' ·e. • • * '. i '. • SOILS JNVESTIGAllON La Costa de Ma~lla , Lot 206 . La Costa South Unit NQ. 3 . , ,:Caris.bad,. CcdifGrnia La CCi)s~a de Marbelfa Associates . . Samuel Wacht Associates, A. I" A. Arc~ltects,En9ineers, Plc;mnen Proiect No. 73-3-'lA April 1.1, 1973 BENTON ENGINEERING, INC. • RECEIVED FEB 14 1974 CITY OF CARLSBAD. Engineering Department II II 1: • pHILIP HENKING BENTON PRESIDENT· CIVIL ENGINEER • • BENTON ENGINEERING, INC. APPLIED SOIL MECHANICS -FOUNDATIONS 6717 CONVOY COURT SAN DIEGO, CALIFORNIA 92111 SOILS INVESTIGATION TEL-EPHONE(714) 565·1955 • Introduction • 1 .. This is to present the results of a soils investigation conducted at the above sHe, to' supplement an earlier investigation reported by;/us on January 16, 1973, and identified a~ .--- our Proiect No. 72-12-7 A. This supplemental investigation was necessitated by the fact that certain grading and building location changes had been adopted subsequ-ent to our first investi- • gation. These changes have raised some doubts as to the probable stabi I~ ty of certain proeesed "". ___ _ 't - • .' • • cut slopes and build1.l2g_p-ca9!,~ and it was considered that the only way to determine ,the question- . I . able slope stabilities was to perform the supplemental investigation reported herein. In order .to provide the dESSired additional information, three borings were drilled. Two of these borings were drilled generally in the southwest comer of Lot 206, and the other was drilled at the locat- ion of a proposed cut slope in the easterly portion of the lot. Repr~ntQtive samples were obtained from each of the borings for laboratory testing • Investigation The three borings were drilled, each to a diameter of 24 inches, with a truck-mounted rotary .bucket-type drill rig at the approximate locations shown on the attached 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 soUs encountered in the borings was recorded at the time of drilling and Is shown in detail on Drawing Nos. 2 to 11, inclusive, .; each entltl:ed, IISummary Sheet. II • • • La Costa de MarbeUa -Lote Protect No. 73-3-1A -2-• The soIls were visually classified by field identification procedures in accordance with the Unified Soli 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 intervals below,proposed cuts in the • soils ahead of the drilling. The drop weight used for driving the Sampling tobe Into the soils - was .tbWY!~ij\~!~,~f th!1tItUl rt\i'twhich weighs 1623 pounds, and the avera~e drop was 12 ~ ".-~ . , -. • • • • • • • Inches. The general procedures used in field sampling are described under "Samplingll in Appen- dix B. , Laborgtory Tests Laboratory tests were performed on the maiority of undisturbed samples of t~e soils in o~der to determine the dry density and moisture cOntent. The results of these tests are presented on Drawing Nos. 2 to 11, inclusive. In order to determine the apparent cohesion and minimum angle of internal friction of the soils, for use In slope ,tability analyses, selected samples were first saturated and drained and then sheared QY direct shegr under varying normal loads. The results of the direct shear tests are presented as follows: ,Boring 1 , Sample 2 , .'Depth: 22 Feet BorIng 1 , Sample 3 Oopth: 27 Feet ,Maximum Normal Shear Load In Load kips/sq ft kiwsq ft 0.5 0.78 '1.0 1.29 2.0 1.57' 0.5 1.20 1.0 2.04 2.0 3.27 BENTON ENGINEERING, INC. Angle of ' Internal Friction Degrees Apparent Coheston Ib/sq ft 16.0 640 40.0* 450 • • • • • " -• • • • • • L~ Costa de Marbeila -.06 ProJect No. 73-3-1A ~ Boring 1 , Sample .f Depth: 32 Feet Boring 2 , Sample 1 Depth: 2 Feet Boring 2 , Sample 2 Depth:-6 Feet BorIng 2 . , Sample 3 Depth: 11 Feet Boring 2· , Sample 10 Depth: 36 Feet Poring 1 , Bag Sample 1 ** Depth: 8-10 Feet * -Arbltrarily Reduced ~3-• Maximum Angle of Normal Shear Internal Laod in Load Friction kIp:Vsq it klps/sq ft Degrees 0.5 1.15 37.0 1.0 1.47 2.0 2.28 . - 0.5 1.01 37.0 1.0 1.30 2.0 2.25 -0.5 0.6 40.0 1.0 0.98. 2.0 1.88 0.5 1.18 28.0 1.0 1.49 2.0 1.88 0.5 0.98 . 40.0* 1.0 0.90 2.0 1.85 0.5 2.24 16.5 1.0 2.75 2.0 2.28 *'!t ... Sample Remolded to 95 percent of MaxImum Dry Density Apparent Cohesion Ib/sq ft 750 650 200 910 0 2080' In that some or the soils sampled at Borings 1 and 2 we", naturally i1dIsturbecfll as result or pr$vtou5 earth mQvements by slippage, selected samples were sub Iected to direct sh~ar tests In whIch the same samples were "resheared" under the ~me normal loads. The results of, these II reshearll tests are presented on .the following page. BENTON ENGINEERING, INC. • • • • • • • • • • • L~ Cp~ta ,dfj MctrbeHa -. Lot. ' Pro.j~c:t NQ. 73-3-1A Boring 2 , Sample 4 , 'Depth:, 13 Feet "Borlng ,3 " Sample 2A :, 'D~pth: 11.5 Feet Boring 3 , Sample 28 .Depth: 11.5 Feet , ,BOring 3 I SQmple 2C Depth: 11.5 Feet Boring 3, Sample 4A Depth: 19rFeet BorIng 3, sample 4B Depth: 19 Feet BQrtng 3 , Sample 4C " D.pth: 19 Feet -4- Normal Load In klps/sq .ft 0.5 1.0 2.0 Td.al: 1 0.5 1.48 l.0 1.67 2.0 2.34 0.5 0 .. 98 1.0 2.18 2.0 2.49 0.5 0 .. 72 1.0 1.14 2.0 2.13 0.5 1.43 1..0 1.67 2.0 2.19 0.5 0.80 1.0 2.14 2.0 2.14 0.5 0.93 1.0 1.07 2.0 3.24 • Maximum . Anglelof Shear Internal Apparent Load Friction Coh$Ston" . ktps/sq ft Degrees Ib/sq' ft 1.00 37.0 620 1.46 2.24 . Trial: 2: .Trial 3: .. , 1 At . 1.26, 22.0 620 1.48 1.85 0.8~ 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 21.0 320 1.00 ... 2.95 2.39 The SOlteral procecfures used, for th. above laboratory tests are described brl.,flxin' ' :Appendlx B. .. In addition to the foregoing dlr,ct shear tests, tri~xlal compression tests were performed on selected sampl~ of the slickensided clay soils found generally between the depths o'f 12.7 and 31 .2 feet at BorIng 2. The results of these tests indicate that the angle of internal friction BENTON ENGINEERING. INC. • • ,- La Costa de Marbella -Lot 2. Proiect No. 73-3-1A -5-• of these soils vciries.,from 25 to 33 degrees, and the cohesion varies from approximately 1650 , to 3950 pounds per square foot. Compact-ion tests were performed on representCiltlve samples of the .soils to be excavated to establish compaction criteria. The soils we.re tested accord'ing to the A.S.T.M. D 1557 -70 • ' method of cpmpactlon which uses 25 blows of a 10 pound rammer dropping 18 inches oneac;h of :. • • • • • • • 5 layers in ci 4 inch diameter 1/30 cubic foot mold. The results of the tests are presented as ' follows: Maximum Optimum Mois- Boring Bag Depth Soil Dry Density ture Content No. Sample in Feet Des.criptlon Ib/cu ft % dry wt . 1 1 8-10 Clay 111.1 18.2 2 2 27.5-28.5 Clay 112~5 15.5 3 3 24-25 Slightly Silty 115.5 13.7 Fine Sand In order to classify more accurately some of the finer-grained soils, AUerberg Limit -\ Tests were performed on selected samples. The results of these tests are presented as follows:' Boring 8'ag· Depfh Liquid Plastic Plasticity Group 'No. Sample in Feet Limit limit Index Symbol 1 1 8-10 55 ,24 31 . CH' 2 2 12.5-13.5· 65 22 43 CH '. DISCUSSIONS, CONCLUSIONS AND RECOMMENDATIONS Soil StrQta The upper foot of sotls at ,Boring 1 consisted of medium soft clayey' fine to m,dium sand. These soils were-underlain to a depth of 3.5 feet by medium firm fine to medium sandy .clay, and then to a depth of 5.0 feet by medium firm clay. At 5.0 feet, the soils merged to a very firm clay; the soils In this stratum were very fractured and. slickensIded, and appeared to be -,- A,cu:t..o.£.:an..o1der .. cr.e.eJUslume zone. This stratum was continuous to a depth of 24,.1 feet, except BENTON ENGINEERING. INC. • • • • • La Costa Marbe·lla .. Lot 206 Proi~ct No. 73-3-1A • -6-•• 'fc>-r a 3.0 feet :thicklayer b~twee-n 14.0 and 17.0 feet which had been IIworked in" as a pad . for the drill riS. The upper 14 feet of soils were logged in an exposed bulldozer-excavat.,d bank above the drill rig. Below the pad the clay stratum was medium firm. Firm fine to medium sand was found ,between 24.·1 and 24.7 .feet". and then firm clayey fine sand was found to a depth Qf 26.0 feet. All of the SClIils between 26.0 feet and the bottom'of the boring at a depth of 52.0 , , feet were v~ty firm. These included 4.5 feet of fine to medium sand., containing a 1 1/2 inches '. thick ~am of clay, 6.1 feet of clay, 0.6 root of fine sandy sitty, 5.8 feet of very fine sandy . day, and 9.0 root of silty fine sand. Ataortng 2, a one foot thick layer of medium firm slightly clayey fine to medium sand WQS underlain to a depth of 3.0 feet by medium firm very fine sandy clay and then toa ~epth of .5.0 feat by fJrmsil:ty fine sand. Medium firm but bedded fine sandy clay was found between 5.0 y . .. and 11.5 feet, and then medium firm fine to medium sand was found to a depth of 13 •. 5 feet. •. From '13.5 to 17.0 feet was medium firm-silty very fine to fine sand and then medium firm Jointed • • very fine sandy clay was found to a depth of 20.2 feet. The layer of jointed sandy clay was under-. 'Iain by a 5 Inch thick seam of medium compact very fine to fine sand and then a one inch :thh:ik seam of medium. firm clay. Ft:om .20.7 to '23.2 feet was firm siHy fine sand, and then alternating layers of n.rm clay and silty fine sand we·re· fou~d. t¢ a.:dep't.h of26.2 feet. Between 26.2.pnq44.L . . f!!t ~fltm~t..!!i~kensided and disturbed c1c:l: The soi Is between 44.7 and the bottom of the b(>rfng at a depth of 77.5 feet were all very firm, and included 0.7 foot of clayey fine sand, 2.3 feet of slickensided clay, 4.5 feet of silty fine sand with sOme thin lenses of clay, 1.9 feet of efine to medium sand; 0.5 foot of clay, 4.5 feet of fine to medium sand with interbedded clay. • . . -,"''t. o ~." .-"'1 : '.,,' .: ....... -.' .. :! : ."~ i __ ._;"'i *" ..... ~-. seams, 1 .. 5 feet ofsHghtly silty fine to medium scmd, 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 fIne sand, 0.6 foot of fine sandy sflt, and finally 2.7 feet of silty fine sand. BENTON ENGINEERING, INC. • • La Costa Marbella -Lot 206 • Pro iect No. 73-3-1 A -7-• At BOring 3, a thi(:k .1<"Yer of ,elay that was ~ltckensided"ar)d,:,i~~L. "blocks" was ·found to a'depthof 15.3 feet. Th,se <:1'0)' 5011$ were medium ftrm to a d~pth of b\ < ..... .. 1.5 feet, 'flrm between 1.$ ~Ild 10.0 feet and then very firm, and were underlain to a depth of 16.6 F~et'by,>'i'e;ry ·fitrrislightly·silty fine'sarie!",. Ftom",l~.·6-. tOl. 1.9.5 feet was "another,stratum of very , • firm tointed and illck~:td~,,~ .. clar. ~h~t ~adM~b:..q,~e~. qi!!.2~g~k,.2..er..t!YL9.,~b...m~m!.DL. • • • • •• Between 19 • .sand 29.5 feet were alternating layers of very firm sandy soils. These included 1.5' feet of silty flne $and, 1.0 feet of fine sand and 5 .o5.feet of slightly flne to mediu.m sand. From 29.5 to 30.5 feet was firm flne to medium sand with some clay lenses, and then very firm slightly silty ~rne to medt~m sand was found to a depth of 32.3 feet. A layer of very nrm flne to . . . ~ medium sand WIlS found between 32.3 and 33.3 feet, and then firm slickensided clay w~ found to .. 34.3 feet. From that depth to the bottom of the boring at a depth of 43.5 feet the very firm soils encountered. included 2 .• 2 feet of fine sandy slit, and 6.5 feet o·f slightly silty fine sand. General Discussion The basic reason for conducting the additlon~d subsurface investigations reported herein WQ$ the .fact that the general areQS investigated were .known to be ~tentlall)' undable i'f the con- ditions which contribute the present stability of the areas in question' were to be disrupted. It therefore was essential to analyze the probable and possible disrllpt.ion to these conditions by the proposed new gradIng and planned constructlen. Our approach to this problem was to perform a Rumber of slope stability analyses for the proposed new grqding and construction, using th~ soil • property parameters derived from the field jnv.tJgattons and the laboratory t_ting. • • BENTON ENGINEERING, INC. • '. • • • La Cosfade Marbella Project No. 73-3-1A Conclusions • -8-• If i-s concluded from fhe above analyses that thLprol2osed grading and new construcnon r·wtllJ:a:.tg,l?,te 'fIith 0 fqctor ?~~af~tx.otJlot.l,~ss than 1,.?85!. provide.d the recomm~ndcitions in the following paragraphs of this report are complied with. Recommendations . . 1. It is recommended that we be coiled upon to inspect the new cut slopes during grading, f6 verify that there a~ no unfavorable slippage pfanes dipping 'out of cuts" Clnd/or to make appro- priate re~ommendations for buttess fills if these are needed, .arid inspect the proper removal Qrid rf3pl'(Jcemeht of compacted filled ground as may be required. 2. With· reference to an irregular area in the wester:ly portion of the sHe shown on . Drawing No. 1 of our report of ProJect No. 70-4-16~ as 11 Not Recommended For .Building Sites, II ... fhcit parficulQr recommendation was made because the fill soils within that area had not all ~n • . satisfa<:tortly compacted due to the installatIon of sewer lines. It Js therefore recommended that, • , :-' • '.' wherever proposed new construcfion is planned within the area presently hot recommended for, :: building sites., the present unsatisfactory fill soils be removed and replaced as properly compacttKf ", fill, or that those buildings (or portions of buildings) wt.thin the grea be supported by grade be.ams ,. spanning'to drilled and cast-in-place piers that penetrate through the unsati~factory'fill soils in'to .. underlying firm natural soils. If the firsf of these two recom~endQttons Is adoph~d, the ai'e~ of re- -. movaland ~compactton -should extend to lines not less than 5 feet outside oJ fOQtings and ou~ward , and downward on a 1 horizontaJ to 1 vertical slope to intersec.t w.ith firm Ratural ground. Drqwing • No.1 of Project No. 70-4-160 is j.ncluded for ~eference, following Appendix B afthe erid of this report. Respectfully submitted, • BENTON ENGI lNG, INC. By» Reviewed Engineer Olsti': (8) Addressee • . MVP/PHB/tneg . BENTON ENGINEERING, INC. .' • • • • • • • • ~ "" w :i: « z - l-- 2- - 3- - 4- - 5-- - 6- - r_ - 8- - SUMMARY SHEET BORING No.,_..:..l_.,... ELEVATION 109 ,01 * ... ' .. ',' . . ' Brown, Moist, Medium Soft, Much Org~"ic tildt".-ial r=:~ Light Gray and Ught Gray--" ' '~;~iEtd brown, Moist, Medium Firm, fZ Rootlets Light Green-gray and ~ ... ..: -!.."","' Moist, Medium Firm, Rootlets Dqrk Green-gray, 51 ightl Y Moist, Very Firm, Very E:=a Slickensided, Very Fractured ~=~ In 1/2 - 2 Inch Pieces, ~I:~::J Occos'ional Decomposing Cobble I: ,With Dark Brown Silty Fine to t::::=:1 Medium Sand Surrounding It CLAYEY FINE TO MEDIUM SAND FINE rOMEDIUM SANDY CLAY CLAY 9-OJ t:' =::I -ro- -, 11- - 12- ,.... 13- '..., 14:... -... .... ... - - - -- - ..., - - Continued on Drawing No.3 D -Indicates loose Bag Sample o -Indicates Undisturbed Drive Sample * -Elevations shown were obtained by interpolation between contour ',ines 00 Samuel Wacht Associates PROJECT NO. 73-3-1A DRAWING NO. BENTON ENGINEERING, INC. 2 I , .' • • • • 2 ' •. 8 u \ . .. j " \ " .)' ' I " • • • o .-J w ::a c( z CD o ., "'" ~ > >. CI": W' w ~.J SUMMARY SHEET o~~ "'""'" u"'" w wa: a:u. ii)~ zu. u. .Jut .J 0 w_ ~.c(d -Go CD -CD 1 (Cont.) zen .Jj:!> z:;) , ::t: ~~ ~~~ BORING NO. w!:!: wena: Wu wt;se, "'" c(:;) en > wllt ii:i~ 0..., ~ii)1f Go enz .;: en >. >~ w 0 -"'" fS.J w- e: a:u. a:~ A 0 1'"1' LIght Brown and Light Green-- 15-gray, Moist, Medium Firm -(Soil Worked In For Drill Rig 16-'~ Pad To 17 Feet) - ,-4.9 -Dark Green-gray With Red- 18-' brown; Slightly Moist, Very -Slickensided, Many Gypsum ,-Veins, Many R09tlets, Fractured to 1/2 to 2 Inch CLAY - 20-Pieces, Occasional Par,tiall.y . ' ; Decomposed Cobble to 4 Inches - 21--Light Green-gray With Red -~ 22-""" And Yellow-brown, Contact 4.9 20.3 102.5 Co Dips 180 N 600 W - 23- '- 24-_ ;,':: ,:'.: -::' Llght'Gray and Red-broWn, 25-. ... SJightly:0oist, Firm, Contact •. , ,DtDS,:;Q,~ 850' E -., FINE TO MEDIUM SAND .. /J---+.:.--+----+---.f--.,........,..-.-I 1 .. 26-tB ... Light Green-gray With Red-' '\ /, _ 4-~ brown, .IS~.ig~tly Moist, 'Fi~ I: ':"'" 3· .. CLAYEY FINE SAND / 16.2 7.0 106.6 ,', _ LIght G..qy,.with Red-brqwn, , ':28:'-Slightly Moist, Very Firm, . _ 1\ Pocket of. Dark Brown Sil ty 29-1 \ Fine to Medium Sand -'30-1 1/2 Inch Seam of Light Gray- ",\l.. brown· Firm Clay Dips SO S 400 W .3 32 '_= ffi45 '~3!\. ' . E~=~ Green-gray With Red-brown, C Slightly Moist, Very Firm, E=~' COntact ~tps 4°' S 650 W ,- 33- - 34 .... - FINE TO MEDIUM SAND J CLAY 35-Continued on Drawing No. 4 PROJECT NO. 73 ... 3-1A BENTON ENGINeERING, INC. 11.4 21.4 101.8 DRAWING NO. 3 • • • • • • • • j .. w :!l « z .... w w u. -l: .... ·fh Q Ill:! SUMMARY SHEET' BORING NO. . 1 (Cont .• ) _ Green!""gray With Red-brown, 36-Slightly Moist, Very Firm CLAY ,> 0' a:t: w ... zen w!!: w~ >. _ .... a:u. Q > . ....... -u. ~::) wo Q~ >!a ~..I 3; 0~~ight Gray, Slightiy Moist, FINE SANDY ,.. ,~V'~e~~F~:irm~ ____ ~ ______ ~~_S_I_lT ____ --J/A---~--+---~--~~ 38-Light Green-gray With Red- _ brown, S Iightl y Moist, Very 39-Firm - 40--1°, ,.. :; :cc - 43'- _ ~ Dark Gray, Slightly Moist, 44-~~~ Very Firm ,.. ~'\:~~ 45~ ~ -~ \-IL,\ ~ Light Brown and Green-gray, ,.. r::\ Contact Dips 140 S 300 W 47'"" \l.J -~ 48-~'\0 -I~"; 49-&-;,.,~ I~~ ,.. . 50..,. I~ . -I~~~$ FINE SANDY CLAY (Merges) SILTY FINE SAND 33.3 41.6 i1-I~~S I~x~ ~ 52=Ci)~I~~~~~~~x0~~ __________________ -L __________ ---L~41~.~6~--~--~--~--1 -- -- - . - - In . -o ., PROJECT NO • 73-3-1A BENTON ENGINEERING, INC. o DRAWING NO. 4 • • • • • • • • • • • ..9 :8 b ~ Q) 0 .2 8 u ..9 w ~ « ;z en o -. z ~ 0 j:~ W wa: w I£, ..Iw, . ~~? ..... Q.en -0 ~ ::t: ~,~ Ii: «:::l en~ Q w enZ ~ n ~c: v ., -.. .. " 1- - ,2- - 3-.~ - 4-~~ .... § -~ 5- .:0. - 6- -'> .,..:. ;' - a- I PAl - 9"-, ........... ' ;'c ,'.' . :" -:'-~, 10-',' .... 1-' 11-'", ;\":' '., - 12-[', ,," -:'~', :.:i{@& - t3-. ,., ':.:.:' :;' '::::. - 14-~ ~ - 15-1& - 16- - 11-I~ - lS-;,' ,', -, :; 19-10 ~' - 2()- -- PROJECT NO. 73-3-1A > >. o· Q~~ ...... W' a: .... u'" SUMMARY SHEET -I£, zu. w!:!:: ~ . , zen ..I~> a: « • w2:: w:::l « ... 0 BORING NO. 2 Wena: Q~ Wenen I w~ ii:oQ ::t:-~ >fg en en ELEVATION 132.0' ~''': ~~ w-, a: I£, !i..l a:~ Q Brown, Moist, Medium Soft, ~UGHTL Y CLAYEY Rootlets FINE TO MEDIUM SAND. / Light Gray With Red-brown, FINE SANDY' Slighfly Moist, Medium Firm CLAY Light Gray, SI ightly M~ist, SILTY FINE Firm, Fractured, Occasional SAND Pockets of Brown Silty Fine to Medium Sand Light Yellow-gray And Light Brown-gray, Slightly Moist, Medium Firm, 1/4 to 1/2 Inch Bedding Planes Dipping 530 N 150 E FINE SANDY CLAY - Dark Brown, Slightly Moist, FINE TO MEDIUM Medium Firm, Calcium r, ritt,u SAND Many Sea' Shells . Light Gray, Ught Brown-gray, And Yellow-brown, Slightly Motst, Medium Firm, SILTY FINE, Occasional Roots .SAND 3.2 14.6 97.2 Pocket of Dark Brown Topsoil I'\. With Sea Shells .J Light ~ ... ..Il fVVf~~iISli9htIY FINE SANDY I'"U ... t_" MAdlum' irm cLAY Light GrUl-~'~~ G.-ay-red, 4.9 19.3 90.8 And Brown '. Continued on Drawing No. 6 DRAWING NO. , B~NTON ENGINEERING, INC. 5 • • • • • .' • w ::E « z iii 0 ., • SUMMARY SHEET BORING NO. 2 (Cont. r '~\T_ ;:: ~: i.< Light BrOwn, SI ightly Moist, ~':..:.,,~ ,\MediurTI Com..,u~t VERY FI NE TO :1-- 22-~~.....".,,~"'''''i, '1 Inch Seam of Green Medium FINE SAND I ' ~ Firm Clay , ~ ~ -~~~ L~I-h--G------~-d-D--.~-L---+----~~--~ 23-~)...~ 9 treen-gray an ... -....... , SILTY FINE _ SI ightly Moist, Firm SAND / 24-,-I fn'\"!\ ' ~--+---+----+----I ""1\.V~x.~~l\:raY-1i9ht Brown, Slightly CLAY MIXED 18•1' 10.3 94.9 25-Moist, Firm, Gypsum Crystals, WITH SILTY FINE _ ~ Vert} cal Seams, Contact Dips SAND 26-' 18 ,5 3SO E ' '. .,. (1) Gray-green, And Yellow-11.4 14.0 110.~ ,_ [D brown With Black, Slightly SILTY FINE 29= ~,t""~f'!-=-:::I' Black and Dark Green, Slightly _ ~~~I\\ Molst,-·Firm, Sea Shells, SAND '28-Cal cium Cemented, Contact \ DIDS 18° S 100 W _ 6 Moist, Firm, Many Sea Shells 301-' - 31- - 32- - 36- - '-- 38- ..,. 39-® - 40-' - ~~~ Green With Yellow-brown, I: E ",§§ Slickensided t=:::I Green-gray "' CLAY 41-C~,:,tinued on Drawing No. 7 PRO~ECT NO. , 73.i.3-1A BENTON ENGINEERING, INC. ", , 13.0 16.51109.~ 9.7 16.7 108.3 30.8 17.0 ~08.8 DRAWING NO • 6 • • • • • • • • W ::E c{ 2 III o .., 2 > S~ffi .J~ ~ SUMMARY SHEET 'ffi~ ~.~ ~t: !:!:: Q. III _ (.) ( 2 til Q =>1'~. 2 ::; X '::E::E OU::: BORING NO. 2Cont.) wQ. iil!n WQg. Q~ ~i .. tIl~~ -~: U::o ~~ . ~ a:1l. ::E~. Q.J. 4~1-t--1===~~--------~~~~----~----------~~Q~r---+---+---4---4 _ 1----1 Green-gray, 51 ig.htly Moist, 42-"'---1 Firm . -CLAY 43 .... - lS.3 16.4 l11.C ~ ~\t:::::::i~ -\V (M~,·ge~) 45-'~~7~~.~rl. ~L~ig~h-t'~~e~lI-ow-4~row-.-n-,~S71i-g~ht~ly--4-C-LA~Y~EY~F~1N-E--~--~--~~~~~--~ '.'. . -: 46- .... 47- Moist, Very Firm SAND ~~~ __ ~ ______________ ~ __ ~ __ ~-JI 1::":=3 Gray-green, SI ightly Moist, 1-_ .... Very Firm, Slickensided CLAY ~~I,~~~ ________________ ~ ________ ~~~~--J-~--~ 48-[~. ~~~ Dark Gray With Gray-brown An_-'_ ~ ,,~,,~ And Yellow-brown, Slightly £1'7-L':"''"'''''~'~'-'''''' Moist, Very Firm, Slight Clay Binder, Occasional Thin Lens 50-of Clay - 51- _ :o~~-gray, Contact Dips 90 S :--Pocket of Organic Material -53-::::,::::. Light Gray With Red-brown, _ :::::2.\.. Slightly Moist, Very Firm ~!Qi) 62/: Gray-brown, And Dark Gray, SILTY FINE SAND FI NE TO MED IUM . SAND 55-.;.;.:: .. :~.::~ .. ,~;SIt9htIY Moist, Very Firm, CLAY I t:!.L -"::.:.-"::::: Some Gypso' um oSeams, Contact . ;x;>-:~)::) Dips 11 530 W .,.. :;:-':.>.:. '---________ ,..----If---_------I ,_ ::::\x·;: . Light Gray, SI ightly Moist, FINE TOMEDIUM 35.S 19.9 10S.4 5.0 108.8 IE!] :.:.:.:::.: I\. Very rr-. 58=!@.I::":; 1\ 2 i,:~ S:=0':th"~~eg;:' SAND 37.5 59= :""/i(/:\ 1\ Dips SO S 30 0 W ' - 60-~ 1\:3 Inch Brown-gray Firm 'Clay _ &,,~~')( Lar~~ With Gypsum Dips 90 61-~"""'\ 5 ~u-W ' (Merges) 1~_..L.-_..L.-___ ..1.---'-----1 1\ Red-brown, Slightly Moist, Very f·irm -SLIGHTLY SILTY FINE'TO MEDIUM SAND Contjnued on Drawing No.8 PROJECT NO. 73-3-1A BENTON ENGINEERING, INC. DRAWING NO. 7 • • z > I-0 >. j:..J '. (!)~ w..: 1-1-w· w 01- w w'o:: SUMMARY SHEET a:u. ea:~ iiiU. zu. u. ..Jw ..J<to w_ z' . a: <t . ....... g,CQ o~CQ 2 (Cont.) z-fI) ..J'I=!> w;:) <to g,' ::t :t:t fl)u.:t BORING NO. w_ Wfl)a: 'e~ w!;;~ I-et;:) -> ~ -u::oe ~iii!f -g, fl)z ~fI) W >fI) >. W -I-:tCl"! a:CQ w- e a:u. e..J a:~' 61 rl e fI] ~ Dark Gray, SI~~~JY~ Moi SILT - 62-Nerv Firm. Dios S 300 W (~A_ ..... """i) Green-gray, Slightly Moist, CLAY - 63"': Very Finn, SIi<;:kensided (Merges) • -~ FINE5ANDY 64-@ Gray, Slightly Moist, Very Finn . SILT 38.2 . -(~A ....,) 65--Green-gray With Red-brown, • -SI Jghtly Moist, Very Finn 66- - 67.., - 68- • - 69-@ CLAY -47.8 70- - • 71- -, 72-(Merges) - • • 73--: ~:.:,~.:.>:.:. Light Yellow-gray, Slightly SILTY FINE -::///!{'}: Moist, V ~ry Finn SAND '4-QW '::::".:.:~. ...... . , 53.0 -V~ Green-gray, Slightly Moist, FINE SANDY 7fr I: ... :. 1\ Very Finn SIL T (~A rges) / {}"ii!; - IYlel 76-Yellow-gray-brown, Slightly SILTY FINE -Moist, Very Firm SAND 77-Q '.:::.::::: . 43.0 - 78- • - - - - - • - -- • PROJECT NO. DRAWING NO. 73-3-1A BENTON ENGINEERING, INC. 8 • • • • • • • • • • • w ~. Z III o ... t-W W II. ..... :I: Ii: w Q 0-- 1- ....; 2'-- - 5- - 6- - ,..-:. - 8- - - 13- - 14--..... SUMMARY SHEET BORING NO. 3 ELEVATION 139.0' Dark Gray-green With Red and ..... -..... Yellow-brown Streaks, Moist, Medium Firm, Rootlets ..... _ ... Slightly Moist, Firm, .... _ ... Slickensided But Smaller Pieces Very "Blocky", Large Long Slickensided Surfaces 1==:1 Becomes Less "Blocky" CLAY :5-(g""~,,,,;) 6 • S 18.9 107.9 14.6 17.0 111.8 ---~ Light Green-gray, Slightly SLIGHTLY SILTY 16--Moist, Very Firm FINE SAND '"7= 0 ~~":--:-=--'-':"'_-:-:-::--:::-:-:-_+-~ V.l./~\II:'I~~"''';1-'}-----I) -16.2 12.6 116. 2. " V~ 16.7 113.8 _ .-_ ... Dark Gray-green Wity Yellow 18~ ..... --..... And Red-brown Streaks, r.-~ Slightly Moist, Very Firm, n= 0 Slickensided "Blocky" -Loosely '7-Jointed - 20- - '~ Light Green-gray, 51 ightly ~~ Moist, Very Firm, Contact ~ Dips SO N'SSo W .cLAY ) ,: ~ \ t SILTY FINE SAND 21-Continued on Drawing No. 10 BENTON ENGINEERING, INC. PROJECT No. 73-3-1A 1lA 20",11108.S DRAWING NO. 9 • • ,. • • • • • • • w ::IE « z al o .., SUMMARY SHEET BORING NO. 3 (Cont.) Light Brown, SI ightly Moist, . V Cemented Light Gray With Red-brown And Gray Brown, Slightly .... "' ..... .,. ...... , LX,-,;:.""."''''''l Moist, Very Finn 1~~~~'X'Xl Light Brown end Light Gray, Slightly Moist, Very Firm Dark Green-grey and Yellow-- Slightly Moist, Finn, FINE SAND SLIGHTLY SILTY FINE SAND SLIGHTLY SILTY FINE TO MEDIUM SAND FINE TO MEDI SAND SLIGHTLY SILTY > >. 0' W' a:'" . o§~ ...... u'" w~ ii)1L ZIL zm z· a: <t • w2: -I ... > w;j ~ ... o wma: o~ Wmm w~ ii:(50 l:-~ >. >m mm _ ... ::IE~ a:al w-a:1L 0-1 a:~ 0 35.4 11.2 120. 39.0 9.1 l3. , ....................... '" Light Brown end light Gray, Slightly Moist, Vety Firm FINE TO MEDIUM 63.2 8.8 112. Gray, Slightly Moist, Very Firm, C.emented 1---'" Red-brown, Slightly Moist to Moist, Firm, Slickensided, Some Gypsum Gray, Slightly Moist, Very Firm . K~~",""~""" Gray, Slightly Moist, Very Firm . SAND FINE TO MEDI SAND CLAY FINE SANDY SILt SLIGHTLY SILTY FINE SAND Continued on Drawing No. 1--1 'PROJECT NO. 73-3-1A BENTON ENGINEERING, INC. 19. 10. 54.5 11.3 112 . DRAWING NO. 10 • • • • .' • • • • • • ., ~-, ~ ., ~ CI.) 0 .E 'S u ., .... w ::e et z III o ., ... w w' I&. -:r: ... Q. w e 4' - 42- - ~ - 44- -,- - - - - ~- - .,.. - - .,- - - - - - - .,.. .:... ,... .,- - - ~ - ~ - - - -- .,.. .,.. - - z 0 j:..J wa: ..Jw ..Jeto Q.1Il -UIIl ::e::e Oii:::e et::> en~ ~ en Z' ~ ~ ~ ~~ ~ i~ ~ i..:"s I~ ~~ PROJECT NO. 73-3 ... 1A > CJ~ > . w' SUMMARY SHEET e~~ ...... u'" a:~1&. -I&. zl&. w_ ~" a: C( " 3 (Cont.) zen ..J~~ w::> et ... o BORING NO"~ w!!: wI;; e~ w en~en w~ U::o :r:-cn >" >:g enenQ. _ ... ::e~ ~..J w-a: I&. a:~ e Gray, Slightly Moist, Very Firm SLIGHTLY SILTY FINE SAND Becpmes More Firm and r'\. Cem~nted I' - < < < . DRAWING NO. BENTON ENGINEERING, INC. 11 • • • • • • • • • • • • • BENTON ENGINEERING, INC. APPLIED SOIL MECHANICS -FOUNDATIONS 6717 CONVOY COURT SAN DIEGO, CALIFORNIA 92111 PHILIP HENKING BENTON Pltl!SIOI:NT • CIVIL ENGINEER APPENDIX A , TELEPHONE (714) 868·1988 Unified Soil Classification Chart* SOIL DESCRIPTION I. COARSE GRAI NED, More than half of material is larger than No. 200 sieve size. ** GRAVELS MOre than h'a!f of coarse fraction is larger than No.4 C LEAN GRAVE LS sieve size but smaller GRAVE LS WITH FINE S than 3 inches (Appreciable amount , of fines) SANDS C LEAN SANDS More than half of coarse fraction is sma lie r 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 GROUP SYMBOL GW GP GM GC SW SP SM SC ML CL OL MH CH OH PT TYPICAL NAMES Well graded gravels, gravel-sand mixtures, little or no fines. . Poorly grdded gravels, gravel-sand mixtures, little or no fi'nes. Silty gravels, poorly graded gravel- sand-silt. mixtures. Clayey gravels, poorly graded gravel- sand-c I'ay 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 flo1,Jr, sandy silt or clayey-silt-sand. mixtures with sl ight pla~ticity. Inorganic clays of low to medium plas- ·ticity, gravelly 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 soils, elastic silts. Inorganic clays of high plasticity, fat clays. Organic clays of medium to high '.' plasticity Peat and other highly organic soils~. .A~opted by the Corps of Engineers and Bureau of Reclamation in January, 1952. ''/r .All sieve sizes on this chart are U. S. Standard. . . '/r* • • • • • • • • • • • PHILIP HENKING BENTON PlllEaIDENT· CIVIL ENGINEER Sampling • BENTON ENGINEERING. INC. APPLIED SOIL MECHANICS -FOUNDATIONS 6717 CONVOY COURT SAN DIEGO, CALIFORNIA 92111 APPENDIX B • TELEPHONE (714) S81S.191S1S ' The undisturbed soil samples are obtained 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 rat'e of deformation is approximately 0.05 inch per minute. The machine is so designed that f:he tests are madl? without removing the samples from the brass liner ring~ 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 se~eral increments to the upper , surface of the test specimen and the resulting deformations are recorded at selected time intervals for each increment. 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 expa~sion 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 until downward movement stops. The dial reading is recorded .and expansion' is recorded until the rate of upward movement is less tha~ ,1/10000 inch per.hour. ' '. • PHILIP HENKING BENTON PRESIDENT. CIVI!-ENGiNEER La Costa de Marbella Assoc BENTON ENGINEERING, INC. APPl.IED SOIl. MECHANICS -FOUNDATIONS 6717 CONVOY COURT SAN DIEGO. CAl.IFORNIA 921H January 4, 1973 TELEPHONE (714) 565·1955 ~. 3862 Jewel Street Suite Gl03 • • • / • • San Diego, California 92109 Attention:' Mr. Ted Muga RECEIVED ~ubieet: Gentle'men: Proiect No. 72-12-7A Advance Report on Soils Investigation La Costa de Marbella La Costa, San Diego County 'California FEB 1,4 1974 CITY OF CARLSBAD' Engineering Oepartment , ' , In accord<;lnce with your t~quest we are forwarding preliminary information in'advance of the basic soils investigation report for the subject site. The information desired is as follows: " . . a) b) An allowable safe bearing value for foundation footings placed .in the existing compaeteq filled ground for a 1 foot wide continuous footing locoted 1 foot into this soil is 1510 pounds per square foot. This value may'be incr¢ased by 800 pounds per square foot for each foot increase in depth of footing as measured from the lowest adiacent ground elevation and .may also b~ increased by 290 pounds per square foot for each foot ' increase in 'f90ting Width for a maximum final allowable bearing value of ~500 poun~per square foot. " An allowable safe bearing valu,e for foundation fOQtings placed in the existing natural ~iI for 1 foot wide continuous footings located 1 foot tnto this soil is 2000pouncls per square foot. This v(llue may be Increased by 400 pouri~S per square foot for each foot increase in depth of footing' as measured" from the lowest adJacent ground elevation and may also be increa$ed by 120 p.ounds per sq~are foot for each' foot inqrease in footing width for a 'maximum final allowable bearing value of 3000 pounds per squQr~ f09t~ , , : The bearing valuesl,i$ted 9bove are for dead plus live loads and maybe increased by one-third for combined dead, live qnd seismic loads. ' • • • • • • • • • • Project No. 72-12-7 A • La Cosl'Q de Marbelld -2-• January 4, 1973 , ' , , , From the architectural prints provided this office It appears that the easterly 4 II All ty~ unIts $ltUatedon the southerly area of the .site and the one 118/1, type unit situated at the northeasterly comer of the site will hQV8 ~tfngs 'located in noNral ground. The remainder of the proposed unIts -will have footings located basIcally: in th~ ext_ting compaeted filled ground excepf for the IIAII type ,units situated in the JOuthwesterly area of the stte which will have footings located in both compacted fill and natural ground. ' - The depths of tho$e footings located til the qrea of the sJoping ground surface on the northerly sid. of the site should be placed at a depth so that the bottom of the footings are no closer than 7 feet as meqsured horizontally inward from the -exposed sutface of the ,existing slopes. , ,eo.t~g.tialtl.,"::,e_};SI?$InsJ.Y.~ ... clqm~so.ll!.. were encountered'in both the natural and compacted fill soil ~ Therefore,' in order to reduce possIble stlVctoral damage due to these potentially expansive soils, special destgn and precautionary meCJ$u~~ mus,t be taken. These specific recommlilndations wm ~'provided in the basie report. . - It should be noted that the hifonnation provided in this advance report is prel iminaryln nature and issubJec:t ,to revision when all laboratory work is completed and the final report is drafted. However, the basic type of information as provided herein wi II be made a part of the final report. ' , If you ~ave any questions concernins the information contaIned in this advance ~port please do not hesistate to confClct thIs office. ' ~~ctfully submitted, ' SENTON ENGINEERING, INC. BY&1Jt~ MoL. ~/ Reviewed by t1. ~~--------------~~----M. V. Pothter I Civil· Engineer Distr: (2) Add~. BENTON ENGINEERING, INC. DFL/MVP/ew • • • • • • • • • • • SOILS INVESTIGATION La Costa de Marbella Lot 206 La Costa South Un i t No. 3 San Diego County, California La Costa de· Marbella Associates Samuel Waeht Associates, A.I.A. Architects, Engineers, Planners Pro lect No ~ 72:'12-7 A January 16, 1973 BENTON ENGINEERING, INC. • • • • • , PHII..IP,HENKING BENTON PRESIDENT •. CIVi'L ENGINEER (ntroduction • .' BENTON ENGINEERING, INC. APPI..IED 5011.. MECHANICS -FOUNDATIONS 6717 CONVOY COURT SAN DIEGO, CAI..IFORNIA 92.111 TELEPHONE (714) 565.1955 SOILS INVESTIGATION This is to present the results of a soils investigation conducted at the site of the proPQsed La Costa de M.arbella; the site is Lot 206 of La Costa South Unit No.3, in San Diego County, California. It Is our understanding, from prel'iminary drawings provided by Samuel D. Wacht, '. Architect, that the proposed residential units will include some type A units of two-level !lving • areas over grade parking and some Type B units of two-level I iving areas with adjacent grade parking. Some of the proposed buildings are to be located in existing compacted filled ground, some in natural soils, and some 'Qn both. • The obJectives of tbis -investigation were to determine the existing soil conditions at the site, and to determine some of the major physical properties of these soils, so that recommendations '. . could be presented for the safe and economical support of the proposed buildings and for the aceom~ • • plishment of some minor grading. In order to accomplish these obJectives, borings were drilled at four selected locations, and undisturbed bag samples were obtained from the, borings for laboratory testing. ':': ---- Field Inyestig<;ltion , All of the borings were drilled, each to a diameter of 24 inches, with a truck-mounted ',rotary bucket-type drill rig at the approximate locations shown on the attached Drawing No.1, , - enHt,led "Location of Test Borings. II The borings were drilled to depths of 1.5 to 26 feet below the • existing ground surface. A continuous log of the soils encountered in the borings was recorded at the time of drming and is shown in detail on Drawing Nos. 2 'to 6, inclusive, each ~ntitled JlSummary Sh~et. II • • '. -2~ • The sotls were visually classIfied by field Identiflcatlon procedures In accordance with the Uni·fied Soli Classification Chart. A $implifled description of this classification syste":t is • presented in the attached Appendix A at the end of this r.pc;rt. • • Undfsturbed $ample~ were obtained at frequent IntelVals in the soils ahead of the drilling. The drop weight used for driving the sampling tvbe 1nto the soils was the II Kelly"bar of the drill rig which weighs 1623 pounds, and the average drop was 12 inches. Thea.neral proc,dures used . in field s,ampling are described under IISampUngll in Appendix B. Laboratory tests were performed on all undisturbed samples of ,the soils in order to determine the dry >~ensity, moisture content I and shearing strength. The results of these tests are. presented • on D~w.ing Nos. 2 to 6, inclusive. Con$Olidatlon tests wereperfQrmed on representative $Qmpl8$ ,in order to de'termine the load""Settlement characterist.ics of the solis and the results of these tests • are prestlnted grqphically on ,Drawing No.7, entftJed·IIConsolidatlon,CurYes.1I In addition to the above laboratory te$ts, ~xpansiQn tests wt,ne performec,lon some of the clayey soils encountered to determine their volumetric change chqractorlstics with chang!l ip • moisture content. The record,d expansions of the samples are ptQ,Sented as follows': • • • • Percent ExpanslQn ' . Bortng No. Sample NQ. Depth' of Sampl$, in Feet Soil Description Under Unit Load of 150 Pounds ~r Square Foo t from Ai r Dry . to Saturation . 1 2 3 2 2 2 6.0 5.0 5.0 Silty clay Fine sandy clay Clay I silty clay and fine sandy clay (fill mixture) 8.26 * 2.12 * 6.11 * The general procedu.-used for the laboratory tests are de$crlbed briefly in Appendix B. -It In the interesl'$ of meeting a deadUne, th. expansloh tests were termInated before total expansions had occur ... d. However, It Is. evident that the silty clay at Boring 1 Qnd the mixture of clay, silty clay and fine sandy clay fill at Boring 3 are crrtrcally expansi.ve. It is our opinion-that th& fine sandy clay Qt Boring 2 would also be ·clQ$Stft.c:J as critically expansive. ' BENTON ENGINEERING. INC. -. • • • • • DlSCUSSION, CONCLUSIONS AND RECOMMENDATIONS Sari Stl'C1ta At Boring 1, firm to very firm fine to medium sandy clay was found to a depth o,f 1. 0 foot, and was underlain to a depth of 9.,0 feet by very firm silty clay. Very firm silty nne sgnd was then found to a depth of 9.8 feet. From 9.8 to 1405 feet was a' stratum of very compact s'llght Iy sflty nne to medium SCllnd, and from 14~5 feet to the bottom of the boring at a depth of 16'.0 feet was very compact fine to medium sand. The, upper 7.Q feet of soils af Boring 2 consisted of firm to very-firm fine sandy clay. Very firm slightly clayey fine to medium sand was then found to a depth of 805 feet, and was underlain to the bottom of the boring at a depth of 15.0 feet by very firm clay; this stratum was sUghtly • sltcke~lided to a depth of 11 05 feet. All of the soils at Borlhg 3 were fill SOill, consisting of a mixture of clay, silty clay and fine sandy clay. These flU soils were very firm to a depth of 7.5 feet, ftrm with a few thin layers • of clayey and slightly clayey fine to medium sand between 7.5 an<l11.5 feet, and then agclin very firm. ":"" • Fill sol,ll were also found ot Boring 4, to a depth of 17.0 .feet. These 59ill were a mixture of fine sandy.clay, nne to medium sandy clay and cIQY; the mixture was firm to a depth of 6 inches and then very firm. Underlying the fHI to the bottom of the boring at a depth of 26.0 feet was • very firm fine to medium sandy clay. No ground water was encountered In any of the borings. Conclusions • It is concluded from the fteld investigation and the results of the laboratory testing that the - on-slte~Hs, both natural and compacted fill soils, ate suitable for use as load-bearing soils, • provided due consideration is given to the,potential exeansiveness of these soils. It is also con- cluded that the~istJng. natural solis mer be safel~ cut at a sloperatic of 1 1/2' ho.ti,!ontal to L • BENTON ENGINEERING. INC. • • -4-• at a slope ratio of 1 1/2 ho~izontal to 1 vertical for heights up to 18 feet.. RecommendatJons (Ht& .... *~jH:f"""'S"('W' )\.., ~~~~~~~.-oo,~S::*,,!fflI~:.lit~~~.~;~ F*lf~5:@f;;i!{j~ .... ~~~ • based on these conclusions are.as follows. • • ReCc)mmendations 1. General In "rder to preclude the likelihood of damage that could be cQl,Ised by diffe~tiQI se.ttle- ments, H is .recommended that no footings be placed partially on natural Qround ang partly on compacted fl.lled grol.!nd. It is alsO recommended that no. footings be founded in filled ground unless the thickness of filled ground below the footing is at least equal to the width of the footing. Wherever potentially expansive clay soils a.te ~und to exist within 3.~ feet below finish • grade, suitable design precautions should be adopted, in order to minimize harmful effects to • • • • • • footings and slabs due to So if expc;rnsion. Our recommendc;rtions for such design precautions are as follows: . 2 •. 3. Use continuous interconnected reinforced footings throughout, and place these at a minimum depth of two feet below the lowest adJacemt exterior final ground surface. Rtsinrorce dnd interconnect continuously with steel bars all interior and exterior footings with a minimum of one 115 bar at 3 inches above the bottom of all footings and one #5 bar placed 1 .1/2 inches below the top of the' stems of the footings. Reinforce all concrete slabs with a minimum of 6 x 6 -10/10 welded wlre fQbric (lnd provide a'bo~ layer of at least 4 inch. of crushed rock beneath all ~.ncn~te ·slabs. A moisture barrier should be provIded above the. ~ru5h.d r'Qek and then 2 Inches of sand should be placed over the moisture barrier and below the bottom of the slab. BENTON ENGINEERIN·G. INC. • . ' • • •• • • -5-• 4. Separahf"garage ,slabs, when tlie~ are $8parate from living areas, fi'Qm 5. . . . perime~r footlngs by· 1/2 Inch thickness of construction feltor equivalent, to allow ·i~d.pendent movement of garaQ8 slabs·relative to perimeter footings • Assure complete separation by extending fha consttuctlon felt over the full depth of the front thickened edge of the garage slab. Cut off garage dOor stops at leaSt 1/2 inch above the garage slob. Provide positive drainage away from all perimeter footings to a horizontal distanoe of ~ least 5 feet outside the house walls. 6,. Exercise ,every effort to assure theit the soil under thefoundaHons and slabs, has a uniform moisture content at leaSt 1 to 3 percent greater than optimum throughout ·the top 3 feet below finished grade at the time of placing the foundations' and slabs. 2. Grading . Prior to p·ldcing any compacted fill, tt is recommended that any existing soft· or loose solis in' qreas· that are to rec$lve fill be excavated from those areas that are to receIve fi II, that the • exposed natural soils be scarified to a depth of 6 Inches and then be uniformly compacted to at I.~t 9Qpercent of maximum dry density In accordanc-e with A.S. T .M. Df#$lgnatlon D 1557-70, fhat uses 25 blows of a 10 pound rammer fall ing from a heigM of 18 inches ·on each of 5 layers In i'· . 'Q 4 .Inch diameter 1/30 cubic foot mold. Thereafter approved fill material may be placed and '. compact,d to at least 90 percent of maximum dry density. It is also recommended that_allgradl,ng_ .. be ~he under engineering ins~ction, and be tn accordance with th. applicable portions of the rwrt!t<itf tn?·*c;. ... G?"''"-'i7E""~ ... r... t;;;r:::'C7S"$"in-S--R'C"\'iiZ%~ . \.", ·attached Appendtx AA, entitled IIStandard Speciflc(jtlons 'for Placement of Compact~d Filled • i"Ground • II· I . : • ~-::::.. ....... " ... '"'-.~. '--'. Cal'culattons .. ba$ed on the relul ti ·of-the determined angle of int,mQlfriction and apparent Q9h8$ion of both natural and flU toll$ Jnd"cQte that the existIng natural soUs may be cut at a $lope '. BENTON ENGINe:ERING. INC. • - • -6-• ratio of 1 1/2 h9rizontal to 1 vertical for heights up to 35 feet with an adequate factor of safety, , and that the existing compacted fill soils may be cut at the same ~Iope ratio for heights up to 18 • ftlet· with ,an adequate factor .of safety. It wilt of course be necessary to comp,ly with applicable • • • • grading ordinances in this regc;rrd. 3. Footings a) Natural Sotls An allowable safe 'bearing, value for fOundation N:>otlngs ,placed In theexfstlng natural soil for 1 foot wide continuous footings located 1 foot Into this soli is 2000 pounds per squate foot. This value may be Increased by 400 pounds per ·,sql,lare foot for eac;:h foot ·increase fn depth of footing Q$m~asured from the lowest adjacent ground elevation <lnd may also be tncrec;rsed by 120 pounds per square foot for each foot incJ1jdSe in footing width for a maximum ftllQl aHowable bearing value . of 3000 pouncb per square foot. -kI allowable safe bearing value for foundation footingS placed In the exl$tli1Q~m'" poeted filled gro,un'd for a 1 foot-wide continuous foofinglocated 1 foot into thti soil is -1510 pound$ 'per sqU~:II-e' fQot. thIs vQlue may be incrp,ed by 800 pounds per ',q!J"'" j i· foot for each foot increase'in depth of fOot'ns Qs measured from the ,Iowest.adi~ent. ground ehtvation l!1.ntJ may also 'be tncre~ by 290 pounds-per sq"QTe foot for ,ach foot increase In foottns width for a maxImum fIpal allowable ~rlng value of 2500 j • " pounds per squQr~ foot • :Settl,ments Based on the results of the load-consolidation testsl' the total settlements of a one foot ,wide foot- • ,ihg deSigned ,Qnd locbted in'ocoQrciance with ,our recornmendq,ti(m,Jn .natural' sotls,' qnd lo<K'Jed t¢> 2000 poundS per square foot",. ts esttmated' to be, on .:th, ord.~,of, 1/8 . Inch·. The total sett,.m.nt of a one • BENTON ENGINEERING •. INC. • • ':'7-• foot wide simil~rly designed and located footing in pro"rly compacted filled ground, and IO(lcJed to 1510 pounc;lsper squa ... ' foot I is also .esttmated to be 9n the order of 1/8 inch. • Respec:tfu II:y 5ubmlU,q, ~&ENTONENGINEERING, INC. • By ----~-------------------M. V. Pothi~r, Civil Engineer • • Distr: (2) Addressee (3) Samuel Wacht Associates, A.I.A. Architects, Engineers, Planners • • • • • MVP/ew • BENTON ENGINEERING. INC. r . l' . r , t! • • • • w :E ~ Z 10 o .., PROJECT NO . . 72-12-7A SILTY CLAY 39.0 13.6 21. 5.68' O' Indicates Undisturbed Drive Sample * ** ElevatIons Shown Were Obtained By Interpolcitton Between Contour Lines on· a grading plan provided by.La Costa de Morbella Assoc .. , and identified as County of .san Diego GradIng Perma No. L-5731 • Shear strength of soils exceeded limits of testing apparatus. BENTON ENGINEERING, INC. O.RAWING NO. 2 ., • • • • • •• ". • • • ..2 -.e ~ G) ." 0 -s u· .3 w :E c( Z 10 o ., Z I-0 w wa: · ~..I W ..Iw ..1.(,)0 SUMMARY SHEET U. .... Q.'IO (5_10 J: :E:E fl)u..:E I-ct::::l -> Q. fI).Z ~fI) W ct . BORING ,NO. 2 ELEVATION -~9":-1-.5-':- 0 ..I (J :,~ , t:S,$; lfght Green-srcty, Slightly r.;.;. .. : Moist, Firm , hifio!~"'" ...: 1- 2= CD I'. ~~:ioI!I •• ....;. 3- - 4- .-f2\ ,"; 5 -'-.::J ~':'-'=:I - 6- - 7- ,- S"'" - 9"- - 10- - 1'1- - 12 .... - 13- - 14-- 15 - -, '-- :- '- - '-- - '--, - CV (D 0" fo-'--'--'---'--"JRed-brown, Slightly Moist, ~~4Ve,ry Firm. .. " . '. · ',' · .. · .. " Dark Green-gray, Slightly Moist, V~ry Firm, Slightly ~ I Ickensided and Occasional Caliche Seams and Occasional Rootlets to 11.$ Feet FINe SANDY CLAY ISLIGHTLY CLA'lEY J:JNE TO MEDIUM SAND CLAY PROJECT NO. 72-12 .. 7A BENTON ENGINEERING, INC. > o· a: I-w!:!::. zfI) w2: wllli: >. -I-a:,u. o >. 1-1--u. ~ . w::::l o~ >!a :5..1 6.517.7 102 .• 5 1.10 13.0 12.8 111..2 1.83 13. 0 17.3 109. 1-2.50 ' 17.8 17.9 1110.1 4.46 DRAWING NO. 3 .' Z > >. , ' ... , 0 C!I' w" ~..1 " a:'" o~~ ...... (')Ii: w wa: SUMMARY SHEET f~ w' w!!: a:Z ~ ..Iw ..1(,)0 zen ..I:;» 'c(c(d -a. III S-Ill 3 w!!: wlna: w:;) wt;~ :t ~,:Il en~:Il BORING NO. w~ o~ ... -> ii:SQ ~:g, ~u;!e a. eni ~en 'ELEVATION 81.5' >. :Il~ w-,w _ ... a:~ 0 :s a:~ 0..1 Q ,il (,) • ~~ Light and Dark Green-gray, -~ 1-Slightly Moist, Very F'irm -ICD 9.7 2-15.9 115.4 1.46 -• 3- - '4- .' -<V 2.7 16.7 1107.6 2.59 ~- - ~ ... ,.. '- -• 8-Wi,th light Brown, Firm, -Occasional Thin ~ayers of '9,... Clayey and Slightly Clayey • -® FIne to Medium Sand to 11.5 6.5 16.7 1110.3 2.00 , 10-Feet CLAY" SILTY -' ...... -' -~ .'x., CLAY AND -LI- 11-" ..... FINE SANDY ... "-CLAY .,.. " 12-~ IVery Firm I (Mixed) " " -~ • 1'3:-:"': ,,,, -, , , "g, '-, ~ L- ~ • ~' " -0 ~ 9.7 18.,3 1106.0 3.84 ~ts-~ .. : -. 0 it; ,0 0 1:6- -.9, 1,7- '-,', • " "18~- - 1'9- -, • 20- , ,-I@ 1.9.2 1109 .8 5.63 Ir ,2l-13.0 DRAWING NO. • PROJECT NO. 72-'12-7A BENTON ENGINEERING, INC. 4 • • • • • • • .;.2 -~. ~. • .,. -0 .e 8 u .3 • •. W :E « Z • III o ... ,', z I-0 i= .... W wa: W' .... w .... «0 II. Q.1Il _(Jill --:t: :e:e Oii::e I-«::J en-> Q. enZ '~en W « 0 ~ n. ... -' 1-~::.. -;·C·. 2-:.~ -CD :..:. 3- ~" . <- , - 4-,'.' ,~'-'-' -.... ....: 5--' ;7,;'.: -(V 6-.,"': ;0-..... .... :< 7-.~ ~ -. ~ . ...': 8-;-;- -'.'", _ 9-;'-.: :,:~, ,'-'" -CV :': ,.1'$',,;, . ' - 11-.... .''': -['::" 12 -.: ... ;-;: "- 13- -® 14"-''-'. -7: 15-. ' .,.. '" 16-t··, [., -= -r;~ . ,.' '.: 1.7- _I- 16-., -' 19-'.'. -0;' ;-', 20-"- - 21.-;': :.:; ',: PROJECT NO. 72-12-7A /' , . > > • ". ~~; 1-.1-W' SUMMARY SHEET a: I-(JI- wI:!: Ci.iu. zu. zen Z::) a: « • 4 .... 1-«1-0 BORING NO. w!!: Wen w(J w'enen w~ ii::o 0 ..... :t-~ 77.2' :!t-l >en en en ELEVATION :eClt a:: III w-a:: II. 0 .... a:~ Q Green-grqy, G-ray. and 1Jght , 8rown-groy, S lightly Mold, Firm \. ' . 9.7 19.3 107.2 2.04. FINE SANDY 8. 1 16.5 !:102.7 1.83 CLAY, FINE TO MEDIUM SANDY CLAY AND .... CLAY .... -LL. . (Mixed) . ' . 6.5 19.2 ~05.2 2~9'8 .' 14.6 20.0 105.7 5.20 .. , DClrk Brown, Slightly Moist, very Firm, Rootlets FINE TO MEDIUM SANDY CLAY 11.4 14.1 11 06.2 6.S6 Continued' on Drawing No.6 DRAWING NO. BENTON ENGINEERING, INC. 5 .' / i / ,/ I I • • • • : Z t-0 >', ~. ~ffi .J~5 SUMMARY SHEET .,~ . ..= ~U'~"= ~..= ...... 0.113 (,)113 w!:!: u;u. u. ~ :iE"'" Cl)ou::"", ' ' 4 ~C) zCl) z-: a:~. ..-ct"" "" BORING NO. onto 0. -' ct ... o ,tt cni iZ~ -:~ ~g wlnCl) o ~ , ,~,,: ?c~ ~ffl~ 2'1_~ __ ~::~(,)::rc~ki~~~~~~~jri~ __ r-________ ~ __ ~~~~u.~----~o~.J~~a:~~~--~ _ -r;-Dark Brown, sfi9htTy Moist, ~;~,:~ Very Firm, Rootlets 22- - 23- - 24- .".. 25-,.' FINE TO MEDIUM SANDY CLAY "'L-t(;\E5E:a ~~i~r-~ ______ ~~ ______ ~ ____ ~~J215~.~O~1~4.~6~1~~.7~4~.8~71-~ - - -- ..;.. - - - -- - - • 0, - • I • j - - .- - - -.s ---- '---- - - - '113 --o ... DRAWING NO. ' 6 PROJECT NO. 72-12-7A BENTON ENGINEERING, INC.. • .' • • • • • • • • ..2 ..8 a.. 0 ~ Q) -0 0 ... 8 u .3 .., • C ,K • o ") 0 1 2 0 1 ., ., 1&1 :2 2 :z: ~ 3 1&1 ... L 2 =4 ... 0 .,.5 z 1&1 U ffio L Z 2 1 ,~ Q :J S2 ! u PROJECT NO. 72-12-7A CONSOLIDATION CURVES LOAD IN KIPS, PER SQUARE FOOT o INDICATES PERCENT CONS01.IDATIONAT FIELD MOiSTURE • INDICATES PERCENT CONSOLIDATION AFTER SATURAT,ION BENTON ENGINEERING. INC. DRAWING NO. 7 • • • • • • • • • • • • • BENTON ENGINEERING, INC. APPLIED SOIL MECHANICS -FOUNDATIONS 6717 CONVOY COURT SAN DIEGO, CALIFORNIA: 92111 PHILIP HENKING BENTON PRESIDENT. CIVIL ENGINEER TELEPHONE: (714) 5615·191515 APPENDIX AA STANDARD SPECIFICATIONS FOR PLACEMENT OF COMPACTED FILLED GROUND 1. General Description. The objective is to obtain uniformity and adequate internal strength in Hlled ground by proven engineering procedures and tests so that the proposed structures may be safely supported. The procedures include the clearing and grubbing, removal of existing structures, preparation of land to be filled, filling of the land, the spreading, and compaction of the filled areas to conform with the lines, grades, and slopes as shown on the accepted plans. 2. The owner shall employ a qualified soils engineer to inspect and test the fill.ed grol:Jnd as p laced to verify the un iformity of compaction of fi I fed ground to the specifi ed' 90 percent" of maximum dry density. The soi Is eng ineer shall advise the owner and grading contractor immediately if any unsatisfactory conditions are observed to exist and shafl have the authority to reject the compacted filled ground until such time that corrective measures are taken ~ecessary to comply with the specifications. It shaH be the sole responsibi lity of-the grading contractor to achieve the specified degree of compaction. . Clearing, Gr'ubbing r and Preparing Areas to be Filled. (a) All brush, vegetation and any rubbish shall be removed, piled, and burned or other- wise disposed of so as to leave the areas to be filled free of vegetation and debris. Any soft, swampy or otherwise unsuitable areas shall be corrected by draining or removal, or both. - (b) The natural ground which is determined to be satisfactory for the support of the filled ground shall then be plowed or scarified to a depth of at least six inches (6 11), and until the surface is free from ruts, hummocks, or other uneven features which would tend to prevent uniform compaction by the equipment to be used. (c) Where fi lis are made on hi I Is ides or exposed slope areas, greater than 10 percent, horizontal benches shall be cut into firm undisturbed natural ground in order to provide both lateral and vertical stability. This is to provide a horizontal base so that each layer is placed and compacted on a horizohtal plane. The initial bench at the toe of the fill shall be at least 10 feet in width on firm undisturbed natural ground ,at the eleva~ Hon of the toe stake placed at the natural angle of repose or design slope. The soils engineer shall determine the width and frequency of all succeeding benches which will vary with the soil conditions and the steepness of slope. • • • APPENDIX AA -2- (d) After the natural ground has been prepared, it shall then be brought to the proper mois- • ture content and compacted to not less than ninety percent of maximum density in accordance with A.S. T.M. D-1557-70 method that uses 25 blows of a 10 pound hammer falling from 18 inches on each of 5 layers in a 411 diameter cylindrical mold of aI/30th cubic foot volume. • • • 3. Materials and Special Requirements. The fi II soils shall cpnsist of select materials so graded that at least 40 percent of the material passes a No.4 sieve. This may be obtained from the excavation of banks, borrow pits of any other approved sources and by mixing soils from one or more sources. The materiar uses shall be free from vegetable matter, and other de- leterious substances, and shall not contain rocks or lumps of greater than 6 inches in diameter. I(excessive vegetation, rocks, or soils with inadequate strength or other unacceptable physical characteristi cs are encountered, these shall be disposed of in waste areas as shown on the plans or as directed by the soils engineer. If during grading operations, soils not encountered c;md tested in the preliminary investigation are found, tests on these soils shall be performed to determine their"physical characteristics. Any special treatment recommended in the preliminary or subsequent soil reports not covered herein shall become an addendum to these ~pecifications. The testing and specifications for the compaction of subgrade,subbase, and base materials for roads, streets, highways, or other public property or rights-of-way shall be in accordance with those of the governmental agency having jurisdiction. • 4. Placing, Spreading, and Compacting Fill Materials .. • • • • • (a) The suitable fill material shall be placed in layers which, when compacted shall not exceed six inches (6 11). Each layer shall be spread evenly and shall be throug"hly mixed during the spreading to insure uniformity of material and moisture in each layer. (b) VYhen the moisture content of the fill material is below that specified by the soils engineer, water shall be added until the moisture content is near optimum as specified by the soils engineer to assure thorough bonding during the compacting process. " (c) 'lvhen the moisture content of the fi II material is above that specified by the soils engineer, the fill material shall be aerated by blading and scarifying or other satis- factory methods until the moisture content is near optimum as specified by the soils engineer . . (d) After each layer has been placed, mixed and spread evenly, it shall be "thoroughly compacted to not less than ninety percent of maximum density in accordance with A.S.T.M. D-1557-70 modified as described in 2 (d) above. Compaction shall be accomplished with sheepsfoot rollers, multiple-wheel pneumatic-tired rollers, or other approved types of compacti on equipment, such as vibratory equipment that is specially designed for certain soil types. Rollers shall be of such design that they wi II be able BENTON ENGINEERING. INC. • • • • • .' • ., • • • • • APPENDIX AA - 3 - to'compact' the fi" material to the specified density. Rolling shall be accomplished while the fill materi.cs! is at the specified moisture content.' Rolli~ of each layer shall be continuous over Its entire area and the roller shall make sufficient.trips to insure that the desired density has been obtained. The entire areas to be filled shall be ·compacted . (e) Fill slopes shall be compacted by means 'of sheepsfoot rollers or other suitable equlp~ent. Compacting operations shall be continued unti I the slopes are stable but not too de.nse for planti ~ and unti I there is no appreciable amount of loose soil c;m tne· slopes. Compacting of the slopes shall be accomplished by backrolling the slopes In increments .. of 3 to 5 feet In elevation gain or by other methods produci~. satisfactory results. (f) Field d~:msity tests shall be taken by the soils engineer for approximately each foot·i.n elevation gain after compaction, but not to exceed two feet in vertical height between tests. Field density tests may be taken at intervals of 6 inches in elevati6n gain if required by the soils e~ineer. The location of the tests in plan shall be so spaced to give the best possible coverage and shall be taken no farther apart than~ 100 feet. Te~ts shall be taken on corner and terrace lots for each two feet In elevation gain • The sons e~ineer may take additional tests as considered necessary to check on the uniformity (g) of compaction. Where sheepsfoot rollers are used r the tests shall be taken in the .com- pacted material below the disturbed surface. No additional layers of fill shall be·spread . until the field density tests indicate that the specified density has been obtained. . . The fill operation shall be continued in six inch (6") compacted layers I as specified .above, until the fill has been brought to the finished slopes and grades as shown on the accepted pI ans . 5 .. InspectioJ"). Sufficient Inspection' by the soils e~ineer shall be maintained during the ' fillj~ and compacting operations so that he'can certify-that the fill was constructed in accordance wi th the accepted speci fi cati ons . , 6'. Seasonal Limits. No fill material shall be placed, spread, or rolled iF-weather conditions j~crease the moisture content above permissible limits .. When the work Is Interrupted by' . 'rain, fill operations shall not be resumed until field tests by the soils engineer' indicate that 'the moistUre content and density of the fill are as previously specified. 7. limiting Values of Nonexpanslve Soils. Those soils that expand 2.5 percent'or less ,From . 'air dry to saturation under a unit load of 500 pounds per square foot are considered to be ,nonexpansive. ' 8. All recommendations presented in the "Concluslons II section of the attached report are a parf of these spe,elfi cations. B~NTON ENGINE~RING~ INC. • • • • • • • • • • • • • BENTON ENGINEERING. INC. APPLIED SOIL MECHANICS -FOUNDATIONS 6717 CONVOY COURT SAN DIEGO. CALIFORNIA 92111 PHILIP HENKING BENTON "REBID.NT • CIVIL ENGINEER APPENDIX A TELEPHONE (714) !SG!S.19SS Unified Soil Classification Chart* SOIL DESCRIPTION I. COARSE GRAI NED, More than half of material is larger than No. 200 sieve size. ** GRAVELS More than h'a!f of coarse fraction is larger than No. 4 C LEAN GRAVE LS sieve size' but smaller GRAVELS WITH FINES than 3 inches (Appreciable amount of fines) SANDS C LEAN SANDS More than half of , coarse fraction is smaller than No.4 sieve size SANDS WITH FINES (Appreciable amount of fines) II. F!NE 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 GROUP 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 gr~deq gravels, gravel-sand mixtures, little or no fines. Silty gravels, poorly graded gravel- sand-silt, mixtures. Clayey gravels, poorly graded gravel- sand -c lay m ixtu res. Well graded sand, gravelly sands, little or no fines. Poorly graded salids, gravelly sands, little or no fines. Silty sands, poorly graded sand-silt mixtures. :Clayey sands, poorly graded sand-clay mixtures. InorganiC: si Its and very fine 'sands, rock flour, sandy silt or clayey-silt-sand mixtures with sl ight plasticity. , Inorganic clays of low to medium plas- ticity, gravel'ly clays, sandy clays, silty c lays, lean clays. Organic silts and organic si.lty-clays of low plasticity. Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts. I,norganic clays of high plasticity, fat clays. Organic clays of medium to high ',' plasticity Peat and other highly organic soils. , * A~opted by the Corps of Engineers cind Bureau ,of Reciamation in January" 1952. ** All s'ieve sizes on this chart are U. S. St~ndard. " , • • • • • • • • • • • PHILIP HENKING BENTON P"E8IDI!NT • CIVIL ENGINEER Sampling • BENTON ENGINEERING, INC. APPLIED SOIL MECHANICS -FOUNDATIONS 6717 CONVOY COURT SAN DIEGO. CALIFORNIA 92111 APPENDIX B • TELEPHONE (714) 15615.191515 ' The undisturbed soil samples are obtained by forcing a special sampling tube into the undisturbed soi Is 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 approximate Iy 18 inches into the soil and a six inch section of the center portion of the sample is taken for laboratory tests, the soil being stl/ I 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 sampl ing tube through one foot of soi I at the depth at wh ich 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 mad!? 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 sampling. 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 moistL!re 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 increment. Generally, each increment of load is maintained on the sample until 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 cit 105° F for at least 48 hours prior to placing into the expansion apparatus. A unit ioad 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. Continu~us observations are made until downward movement stops. The'dial reading is recorded .and expansion' is recorded until the rate of upward movement is less tha~ :1/10000 inch 'per', ho~r. . '