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Home My WebLink AboutCT 72-24; SPANISH VILLAGE UNIT 1 AND 2; PRELIMINARY SOILS; 1973-05-10'. ;::-/~,£ C-r '1'2-~ t 4 . . E.liIEEIIli (!T 7d-o?/I BENTON ENGINEERING. INC. APPLJ.ED SOIL MECHANICS ~ FOUNDATIONS 6717 CONVOY COURT E/-IJ~g/f /l-/ffh;clk-j • • PHILIP HENKING BENTON· PRES!DENT • CIVIL ENGINEER' La Costa-Land Company . Costa .Del Mar Road CQrlsbad, California 92008· Attenfion: Mr. Irv Roston SAN DIEGO, CALIFORNIA 92111 May 10,' 1973 TELEPHONE (714) 565.1955 • Su~iect: .' Pr~jecf No. 73-3-16BC Preliminary Soils .Investigation Spanish Village Units 1 and 2 (Supplement to Project No. 70-11-18B 'Phase I of Pre-Preliminary Soil Investigation '. . MBD Property, Rancho La COsta • • '. • • • · G~nt.l em en: Dated December 11,1970) Rancho La Costa Carlsbad, California CONC~USIONS AND RECOMMENDATIONS It is concluded fron, the results of field investigations and laboratory tests that: 1. The subsurface conditions within the subiect property are generally favorable .for the proposed development with some precao.tions as described in paragraphs 2 to 4, inclusive., · that follow. . 2.' The unfavorable geotechnical features that deserve special attention for the proposed developments are tabulated below: ci)Evidence of previous movement oholl rnantl:es was noted to a depth of 16.0 feet (to approximately Elevation 107.0 feef) below the existing ground surface in the area ·of Bori"ng 2A, anc:fpotentially expansive clay and cla~tone layers Were t.mcoo.nt!r!!d .. b~:~to~J.6 .• JL£e.elIQ..s!.@Bth., ~-~-=----':"----:'-' --.. ~-~."-.-- b) Soft cla)!Stone withblack_(;~:u:b.Q.o<Q.c~e~~:.IJI.E.!!!:La.lt!l~_~ncoul1ter.e~;Ltn~s.QIDJit.%,ones · below a depth ofJ.Z •. O_feeUn the area of Bor,fns.J :ot beto,w Elevatio!1 113~ Q. feet. c) G1-.9~d water was f<?u'1d at a deP-tb-oL2 •. 6~fe-eJ....belQY(JbfL~Ki.stJOg...9IQ_u.osLsurface or bel ow . EI·ewtlof'l..-44_4Jeet-i.n-the-ar.ea-of-Bor.ing_6_Lo_~ated at ·the_sOYJbwest CCmlE1.LQf...tb.e..:..sltQ.! ......... C.Qv- ingofthe boriri.g~\'{as~not.ed..Q~I9..w-t.h!LW.P'l~lJ.ghle. ' . 1 " ~ ~ - .,..-------_:--_-------------------- • • • • • • • • Project No~ 73-3-16BC La Costa La.nd Company -2-, May.l0, 1973 d) A previous landslided zonfLw.as.Jou.nd_b_efv(e_e.Il_4'he_~~thLOl2.Q~.5, an~~Q,J).J~EttJIi the are~f Bori n9 1 O:'0t..C1pp.r.o):dmatel¥ .. bet:ween-~1 ev.Qt,tQ.~-l6J .• ~_ an.d._lsz.~Q_{ ... et • . _ e) Ano~h~ stiR-Elane w9s '1o~fL~~twe~.!1}he. ~§l?th!"'QfA·.!Jt~I'!~~.~.d.i~et,...2!:J~~tt!§.en _ Elevations lL~'L(mf!JJk3 fe~t at_l3.or.i.ng .•. J"l'? f) A lan~~,.!.z_on~~ ... !,~~~!!ter.ed. o!'.L~_ofq ~'9y __ hori2:on. ~t Etey.a_ti.on.8.~ •. 5.feet in Borin.Q 1 oLSp.anls.b...Y.ltLgg~_w..e.s!,_z..A.ctes-S1teJ!rRi,e.ct_uode.r Project No. 73-3-9BC. The boring locations of this project are also shown on Drawing No.1, in the sout.hwest corner of the site. This clay horizon and slip zone will be exposed by the grade excavation along most of the street from EI Camino Real eastward to the first road intersection. The slip plane dips downward out of slope 31 0 and should be either buttressed or excavated at a flatter slope. - g) A landslid~ zone was encounterec!.~n t~~f a .c1al... hori;oll.g,t_Ej~Y$lJt~r:d~~..!.OJeet. 'l-.ol} in. Boring 2 ?f Sl?a8is~I!?~~te Pro.jectunder . Project No .• 73-:3-9B~.: This '. ... sl"p'plane dips 29 out of slope. Care should be taken to lay these slopes back If thtfsl,p .plane and underlying clays ore encountered during grading. h) Wherever the characteristic La Costa green cl,g)!s a1.El..Ettl.9_cwn.tJtre~i!lL9!£9lng, they_should be laid ba~c~ to s!Q.~s:¥~~ntqljp_v~r.ttcal~or~f.l.at.ter. We anticipate that they wiH be found below Elevation ~in_the-nor:th_p.or..t1on,_bfiJ.QlY~~evat.i~ .?O~~ feet. in the southwest area, below Elevafton 120.0 feet in the central area, and below Elevation, . ..:. 160. o feet in the eastern area. . , 3. Present plans ,c;~:J! I for excavations through the problematic zones of (a), (b), ,(cO) (e)/ (f), (g) and (h) described above. It is therefore recommended the excavations iii these'<,::I~s be, kept to a minimum height at a .slope flatter than 3 horizontal ,to 1 verth:al. T.bt,$jums.ta~l.e , , zones shoul d-'~,e~. cflr.efI,l1l-y_~~gmllJ~.~L.d~'!.I:i.r19~grgdJog--9peJ:qttQ"$. .tQ _ dscetic;ti n .. wh~.tb~r...$tqbl~ed f.j U s OfbUt.!!:~ fills...Q.!:~ nj!ec;lQ.dJ9"£Qrr..eSLt!J!J!l"!s!~~le .c:.~!'~.~tj~. If possible, grading shouldbe""" planned to avoid constructing exposed cut slopes in these unstable zones. 4. Present plans call 'for fills up to approximately 7.0:' feet in thickness in the problem- . ati c zone of (c) described in paragraph 2. Because of J'he .. e!!!-~ru;e~ofJhe-gro.uod_wdt'r_~Q.hl!Jlnd caying in the b_o..r.tog,~ildings wit~ high concentrated colu!"n 1·~_~J!.!9h ~I~e)l!iJf!!~gs_sbQ_uld ~avoided io BQr!nS 6aJ:e9,-un!~e!.ciarfOUrid.J!!!~':'.9b .. 9 .. s ... cfrlxerLRiJ.~.~ .. 2!~U~!~g'!.,,, 5. The favorabl,e geotechnical conditions of the subject property are that the soil 'mantles can be excavated by convEmtiohal equipment without resorting to extra heavy excavatioo equ.ipment. 6. In estimates of earthwork quantities; a shrinkage factor of 3 percent may be used for • the excavated soils below the topsoil and up to 25 percent in the loose topsoil layers. • In that the upper 2 feet of soils encQUntered in all the borings drilled for this project are loose, settlements of the upper soils up to 6 inches may also be taken into account for earthwork estimates.' . 7. The excavated granular type of soils such as silt~nd, slightly silty sand, cI~yey salld and fine to medium sand may be. used for structural support both as natural soils and as com- pacted filled ground. The fine.-grclined types of soils such as clQystone, clay, silty clay, and clayey silt should not be used for strUctural support· because of their eXP5l.!1.sive potentials as indi- cated by ,the results of laboratory testJ and our pa$t eXperhmce with the fine-graihedtypes Qfs9i1s in the LaCost~ a!.~~!_.u~less ~p~cial desrgn .. precauttonsar.e.~used . .for f()()tings, and concrete slabs. • Projec;t No. 73-3-16BC . ~a Costa land Company -3-. May lO, -1973 . 8. When used CIs compacted fill material, ffhe fine . .:grairted soils shoufd be placed, . nQ"closer,to. exposed slopes t:hsn 2Q feet I for -reasons of stabrtTfy of fill slpoes. • When these types of soils are placed in approved areas, (i.e., 20 feet or mQre • • • • •• • • • • ., inside: of 'fill slopes), either ,of the two following altemative.p.rocedures mQy be used. A) Place these 's'Qi'ls at depths of 3 feet or more belOw finish grade, in whi~h case no special design precautil:ms will be needed •..... ~ ..... ; ._ ,". ~: .7, , ~ • , " ';B)· If such soils are placed within the upper 3 feet betow final grade, the spe'cial ' design precautions presented in the attached Appendix C should be adopted. _ , . . . If, duringgrdding, these expansive soils are found·to·exist within the upper 3 feet below finished grad~ in cut areas, either of the two options presented above is acceptable. Alter- riCl~'ive (A) can be effected: by Qver-excavating these sons to a depth of 3 feet andr~placing the e><cavated soils with properly compacted nonexpansive soils. In' any case, it is recommendedthQt aU lots be inspected at the time'of grading in order to determine those lots which contain poten- tiglly expansive clay soils within the upper 3 feet below grade; in some cases it mID! be necessary' tt;? hc:"~-auger ~ f~~:,~e~e·J:lql~~..Ln ?rdeL:~w ~.~ke !!tis .d!!ermi~~f1on. . ~ . .:~ 9:. A one-foot wi~:le cont·inuous footing placed one' foot below the proposed·..finished grade,S of both compacted filled ground and . natura I ground., may' be designed for a safe allowGiple bearing value of 12:i8 pounds per square foot. This value is applicable ,to both fine-grained type and granular type of soils. The settlement of a one fOl;)t wide continuous footing placed as recom- mended and loaded to 1658 plounds p~r square foot is est·im,ated to be less than 1/4 inch.. . 1(). When bedding plane failures are not involved, cut slopes may be made 'safely 'up to the foliowing maximum heights with adequate factors of safety: Mofn Soil Type, In Cut Slope F.ine-graine.sJ..J.QJls Slope Gradient Horizontal to Vertical ------\ 2 : 1 \ -.. \ 3 :1 1 -: 4 :1 L:-----i " , Safe Maximum Heighb in Feet :- Case (A) . Case' (B),:, 23 , '.~ 35 '19 51 26" Granular_soils __ ! t L 5J1 \ 2 :1 1_- 30 54 .,.. ------~---- Case (A)dpplies to the excavations made through a relatively integrated soil mass that contains few or none ~f the conspicuous previousl.y-described,sUding planes. If excavati9'ns . are to be made through the problematic zones as described in paragraph 2 of this report, a cut' slope 3 horizontal to 1 vertical or flatter should be used. Under this condition Case (8) would .QPply • 11. Compacte~ fill slopes that are made of the excavated soils compacted to at least 90 percent of maximum dry density obtained by the A.S. T.M. 0 1557-70 method of compaction may be safely constructed to the maximum heights presented below, with adequate factors of safety: ' " BENTON ENGINEERING, INC. • • ., • • Proiect No~ 73-3-16BC ua'~"CQ~t~ land Company , <.' ': ~ ; '. ": ", ; ~ iT: . Fill SIQPe' ~,' Herizental to V.iiieal 1 5·1 ~,~, '",,' , •• ..;:.:! 'f ~', 2 :1 '~, . '2:5:1 . , -4-May 10, "1973 Recommended Maximum , HeitJhts in Feet 38. . ·66 :,--'~ :,154 , " ' L .;,,' ,:~ " ,,' i-• . , , ' '. " ", • " : ,It fs assume~ 'thctt,the excavated fine...grained soils will be placed at least 20 :~etO.r rnc;;r~'f:r~ any compacted fill slq>e and that grading operations wi'll be conducted under contin:';'; , lcJq~,,~ngin.ering inspection in' oc::cordance with the applicable sections ef the dttachedAppendJx AA,i ,entitled "Standard Specifi~ations fer the Placement of Compacted Filled Ground. ~II '. ' ' .' .,':." . :. .---. , , 12~ The recO.mmended maximurp he19hts~L!>9.t~ ~y!~1q?,~s_9.11~_~2!!!eac;~~_~.fW . .!!!ees , ~,re...eredi~Qf~d ,uP-Qn'Yth~.su.mp-.tt~o..tb.9t.et2I?.E!tA~,~_99.nt~tJ;rQ.c!.~ .. ab)~g,e,_d~x~e.fjs.Y.t:iJJ..J:>'ELP!O ,v.itJ!£I.,,~!..:t~e~ ~s ~f ,s.t,~,!, i,n ers,r t~ erevent !~s:e~~~~rf2S.e_~.!~..!rgn.-Jh!!!L~,~~tb'~oe.es • . '. '. ' . . :'::''7:.13,~ Residential~b,ui!dings may be constructed partly on cut and partly Qn compacted 'fn],.d,ground provided the IlXld-settlement characteristics of the: bearing soils are comparable.: ,:' . , " ,14. If any soil, types are encountere~ during grading ope~tiO.ns that were not t~st~d in tl:ii's',rinvestigation, additicbnal:ltsboratory tests should be conducted in O.rder to' determine th~' ;physic~I:'characteristics and engineering behaviour O.f the sO.ils~ Supplementary reports and' recom~ : I mendati~ns: will then become a part O.f this report. ,:,' ' • ~ '" 15. A report era' geO.IQgic.s!1 investigation conducted (.It this site will be fO.rWarded in the near !uhtr.ee.,' " ---" '::, --" , • , • ~ .'-~ .. Re~pec:;tfully submitted, • ' B~NT®N ENGINEERING, INC. ' .', ,. • . ! , ~', ':8.:.",', ',~~~ __ ,y.~. " ...... } ,-...' . ", ::,;$. M. Shu, CIVa! Engineer," , ... ", ':'. DjStr:, M. V. Pothier /¢ivi'l Engineer Chief Engineer; (4) Addressee (1) Attention: Mr. Bob Sterk (2) Rick Engineering, Sari Diego. Attention: Mr. 59mGaines , , ,~ SENTON ENGINEERING, INC. SHS!MVP!ew • • • • • • • • •• . Project No .• 73.-3-16BC .ta Costa ~and COmpany -5- PISCUSSION .:>. A 'preliminary soils investigotiQn has been completed on the subject property, known as Spani!h "ViHdge' Units 1 and 2 and racated southerly of La Costa Avenue and easterly of EI Camino Real .. '~n Carlsbad,'-SahDtego. County; California. . '. ihis report is intended to serve as CI supplement to a limited soil investigation undertaken previolJsly by our firm under Proiect No. 70-11-18B with a report dated December 11, 1970 entitled "Phase 1, Pre-Preliminary Soils Investigation, MBD Preperty, Rancho La Costa, San Die'go County, California." The objectives of this investigation were to study the general subsurface conditions within the subject property that were not prevtouslyinvestigated, to identify potentially problematic or hm;ardcus areas to the proposed developments, and to present appropriate soil parametel"$ for preparing 'grading plans and fGundatfan design. The general topography of the area may be described as gently rolltlig to steep sloping terrain. " A high rfClge extends in an east-west direction in the north central portion of the site thQt has . a limited run-off to the north, and a valley in the southern portion directs the major drainage to the west. According to the "Soil Map" prepared by the U. S. Department of Agriculture, the upper soils in the area are described as Huerhuerto flne sandy loam, Carlsbad loamy fine sand, Los flores' '"my fine sand, and Botella loamy sand. The soflSenco\"!ntered in'6oth investigations consiSted primarily of slightly silty fine t.o'medfUm sand., fIne to medium sana, silty very fine to ftne sand, slightly silty fine sand, very fine sandy silt, clayey fine sand, fine sandy Clay, slightly clayey fine sand, clay, silty clay and clayey very fine to fine sand. . Field Investigation A total of fourteen borings were drilled with a truck-mounted rotary bucket-type drill rig at the approximate locations shown on the attached Drawing No.1, entitled "Location of Test Borings." The borings were drilled to depths of lU~"§"~J@.~tJ~elq\'f the existing ground surface. !'-c9ntin- uous log of the solis encountered in the borings was recorded at the time of drilling and"h!<shown in detail on Drawing Nos. 2 to 28-, inclusive, each entitled "Summary Sheet. II Also shown on Drawing No. 1 ore-several locations of borings mode adj_oc£lnt to the sobjec.t property in order to provide cross-sections of the subsurface cQnditjons of the adjacent areas. The soils were visually classified by field identification procedures in accordance with the Unified Soil Classification Chart. A simplified description of this classlfication system is .presented in the -attached Appendix A at the end,of this report • ...; Undisturbed samples were obtained at frequent intervals in the soilsohead of the drilnng. The drop weights iJ$ed for driving the sampling tube .into the soils 'Were the "Kelly" bar of the drUI rig whIch weigh 1623 pounds and 2200 pounds, and the average drop was 12 inch~s •. The general procedures used in field sampling are described under "Sampling" in Appendix B. : BENTON ENGINEERING, INC. ,. • • • • • • .- • • ·P.r~lect No. 73-3-16BC yo. :G~sta Land Company ilaboratory Tests ',;~ ,-. -6- .. "":' .. . May 10, 1973 'Laboratory tests. were performed on selected undisturbed samples of the soils in order to determine the dry density and moisrure,content •• They ore 'presented on Drawing -Nos. S, 10, l~i' 13, 14 $lnd 16 to 28,·inclusive, ConsoUdation tests were performed on representative samples obtained in the p.~~posed filled ground area and in the representative excavated sotls that might be used for corn- p~~t~dlfills in order to determine the "oad-settlement characteristics Qf these soils. The·results of . these tests are presented on Drawins Nos •. 29 to 31, incltJsive~, each entitled ,IIConsolrdatiQn Curves. II i~ :. In ~ddition to the above laboratory tests, expansion tesf'$ were':p~rformecf on 0 representativ~ clay- stone sample and some representative excavated soils to deter.mine their volumetri-c change character ... istics with change in m(l)isture.content. The recorded expansions 9f the samples arepresent~cf ,as f~t'9WS: " ., ;' 86r.ing ,.:Sample NC?~:: No. :~; ·6 8. .,. Bag 2 II .,. Bag 1 :11 .,. Bag 3 -:- " 'C • . Percent Expansjon Under Unit. Load of 150 Pounds per Square Depth 'of: Sample;: . in Feet :,.:. Soil Foot from Air ()'ry Description to Saturation :.,'. 26.0, ;-':'.. Cla},stone 4.0 ~ ~i~~5~ll.·. SiltYfine to . "; ,',-'! :,medium sand 3.0 -":4'~0 Alternating " sUty fine. sand and clayey nne sand 25.0 -26.0 Clayey silt 1.78 3.01 2.39 .,. Remolded to 92 per~ent of maximum dry density. Percent Expansi'on Under Unit Load of 500 PQUnds per$qyare Foot from Ai.r Dry' to Saturation . 5.75 The g.eneral procedur~s used 'for the above laboratory te'sts a':' described bri-efly in-Appendhc' B,. C<,?mpaction tests were perfonnedon representative samples of the soils to be excavated to ~tClbUsh compaction criteria. The soils were tested according to the A.S. T .M. D 1557-70 method of compaction which uses 25 blows of a 10 pound rammer dropping 18 inches on each of 5 layers in a 4 inch diameter 1/30 cubic foot mold. The resul·ts of the tests are presented as follows: . . Maximum Optimum Mois- Boring Bag Depth Soil . Dry :Density tore Content No. Sample in Feet:. , Description . I~/cu ft % dry wt· "j' -:.: 8 2 4.0-S.O Silty fine to medium sand 119.2 lL4 11 1 3.0-4~O: Alternating silty fine sand 114.-3 14.0 and cI ayey fi ne sand 11 3 25.0-26.0 Clayey silt 113.4 15.1 12 1 5.0-6.0 Silty fine to medium sand -114.0 13.6 12 2 26.0-27 •. 0 Silty fine sand 114.0 11.5 BENTON ENGINEERING, INC. • '. • • • • Preieet No. 73-3-16BC -7-May 10, 1973 L&G"~ Land Company ~ ~. . ~ ; " M"e~,~Priical'analysis tests were performed on representative samples in accordance with A.S.T.M. , P 42~~lT and the results are presenfed in the following tabulation: , . ~~;.,:.}. ~'/""'" ,(.:." 1 " ,.' U~S~" ' Boring 8 Boring 11 Boring 11 Boring 12 Boring 12 'Bag 2 Bog'l Bag 3 Bag 1 Bag 2 Sie'v.,,: , "Depth: ' Dep~h: Depth: Depth: Depth: , •• ,' 't SIze 4.0-5.0' 3.0-4.0' ,25.0-26.0 . 5.0-6.0' 26.0-29.0' .<' Percent Finer b~ Weiiht . ' l/t'lri:ch ,100'~!0' No. ,,"4 100.0 "99 .. 9' 100.0 100.0 100.0 No~': 10 99.1 98~4. '99.9 99.9 99.9 No. ,30 96.6 96.7 ' 98.4 98.5 99.1 No. 40 89.1 95.7 97.9 95.0 98.1 No •. (;0 .56.2 92'.4 95.6 ,62.5 85.9 No.,:'loo 35.6 . 77;0 89.4 31.0 49.1 . .' ·No. 200 23.6 33~8 47.6 16.2 '19.6 Soil Silty fine Silty',fine Clayey very Silty fine Silty fine , CI ass i.fi'.;; to medium sand'" fine sand to medium sand cation sand sand I~' order bett~r to classify the firie~ grained son., Atterberg Limit tests were performed on selected samples in accordance with A.S. T .M. Designations D 423-61T and D 424-59. The results of the tests and the final group symbols are presented as follows: Boring' No. 2A 3 8 11 11 Sample No. Depth , in Feet 6 ' 25.5-26.0 Bag4 21. 0-22 ,0 Bag 2 4.0-5.0 Bag 1 " 3.0-4.0 Bag 3 25.0-26.0 Soil Description Clay Clew Silty fine to medium sand with cloy binder Alternating silty fine sand and clayey fine sand CI,ayey very fine" sand Liquid Limit 56 62 31 37 36 * Minus No. 40 sieve sample that contains clay binder BENTON ENGINEERING, INC. Plastic Limit 18 22 21 20 17 Plasticity Index 38 40 10 17 19 Group Symbol CH CH CL * CL * CL * • • • • • • • • • • • Project No. 73-3-16BC -s-May 10~ 1973 La Costa Land Company Direct shear tests were performed on selected loose soil samples remolded to 90 percent of maximum dry density and on selected undisturbed samples that were ,all saturated and drained prior to testing. The results of these tests are presented below: Maximum Angle of N~rmal Shear Internal Apparent Load in Load Friction Cohesion kips/sq ft kips/sq ft Degrees Ib/sq Jt (A) Undisburbed Samples Boring 8, Sample 2 0.5 1.23 31.0 930 Depth: 11.0 feet 1.0 1.53. 2.0 3.78 Boring .10, Sample 1 0.5 1.01 35.-0 660 Depth ~-_ 3.0 feet 10 0 1.54 2.0 2.23 Boring 11, Sample 5 0.5 4.59 15.0 1900 Depth: 25.0 Feet 1.0 4.07 2.0 4.98 Boring_ 13, Sample 5 0.5 2.27 30.0 1330 Depth: 25.0 feet 1.0 1.92 20 0 3.15 (B) Remolded Sample Boring 8, Bag Sample 2 0.5 0.72 32.0 380 Depth: 4.0 to 5.0 feet 1.0 1.02 2.0 1.67 Using the lower values of internal angle of friction and -apparent cohesion, and the Terzaghi Formula for local shear failure, the safe allowable .bearing pressures for both compacted filled ground and natural ground are determined on the following.page. BENTON -ENGINEERING, INC. • • • • • • • • • PrejeCt NQ. 73-3-16BC L(:I Costa Land Company Local Shear Formula: Assumptt ons: Undisturbed Natural Soils <t> = 15 Degrees N'c = 10 -9-May 10, 1973 Q"d = 2/3 C ~IC + Y Df N'q + Y BN'y (1) Continuous footing 1 foot wide = 2B (2) Depth of footing = 1 foot = Df. . C = 660 Ib/sq ft N' =4 q y= U5 Ib/cu ft N'y=2 Qld = (2/3 x 660 x 10) + (115 x 1 x 4) + (115 x 0.5 x 2) = 4975 Ib/sq ft Qld Safe = Qld -f3 (~actor of Safety) = 1658 Ib/sq ft Fill Soils Compacted to 90 Perc~nt of Mc:Jximum Dry Do~nsity Q == 32 Degrees N' = 21 c C = 380 Ib/sq ft N'.q = 11 y = 116 Ib/cu ft N'y~7 Qld = (2/3 x 380 x 21) + (116 x 1 x 11) + (116 x 0.5 x 7) = 7002 Ib/sq ft Qld Safe = Qld +3 (Factor of Safety) = 2334 Ib/sq ft BENTON ENGINEERING. INC. !-r7 ---.-------.... --., ~~'-,-~~----....--'" .--......... -~-..~-..... ~. --~---~-~~.-----.---.r ____ ~_ .. : I " • • • •• .• , • • 1 2. SUMMARY SHEET BORING NO.--o:.]_ ELEVATION 194' * Brown, Dry, LQOse, Topsoil SLI GHTL Y SILTY FINE TO' MEDIUM . ~f~::~~::~;~'::' SAND }...---.j.-;.-!-----i-'----!--....,.-t ~n~t\/ '-B-rQ-w-n-,-D-r-y,-M-e-d-iu-m-Fi-rm-,-V-e-r-y-l--------oJ :~:::{(~~ .-Slight Clay Bind~r . ." )~~U~S'( SII~htly Moist, Very Firm . §] ;:::;;::,.:.; FIN'E TO' MEDIUM 276 ----_------....;......j SAND' . .,. Moist Brown, Moist, Very Firm, p . .r'3:<rf"d Slight Clay 'Binder (Merge$) ALTERNATING LAYERS OF SILTY VERY FINE TO' FINE SAND AND SLIGHTLY SIL:rY FINE SAND Continued on Drawing No .• 3 o .. Indicates Undls~urbed Drive Sample o Indicates Loose Bag Sample' 35.7 '24.4 * -The elevations presented herein were determined by interpolating between fheconfour line~ shown on a plan furni$he~LbyRick Engineering' Company. PROJECT NO. " , Tr~a-3,.lt6BC BENTON ENGINEERING, IN.C. DRAWING NO. 2 • ~ ... I ... II. ....... Z ~ .. ! ... i a • • • • • • • • , . : ... .... 'a a:::t ~z ." . ... .,,111 -ca 0 ... >-."U." SUMMARY SHEET BORING NO.1 (Cont.) Brown, Moist, Very Firm, Slight Clay Binder P.OJECT NO. 73~3"".l~BC,- 30.8 ALTERNATING 60.0 LAYERS OF SILTY VERY FINE TO FINE SAND AND SLIGHTLY SILTY FINE SAND BENTON ENGINEERING, INC. 35.8 41.6 I).AWING NO. 3 • • • • • 0 cO • ~ • ,:!!, .t .2 8 u' • 0 ....l • N oc'S - • • • SUMMARY SHEET BORING NO. 1 (Cont.J Brown, Moist, Very Firm, AlTERNATING .38 :',: ":': Slight ..... C=I_aL.-:=..Bi;.;.;.n=d!l;...;...r_· _-,.-_-..,...j LAYERS OF SILTY , ;. :',:' Few Siltstone and Clayey VERY FINE TO , 39 '.::---, ',: Siltsfone Lenses FINE SAND AND , ®, • .:: --:.: SLIGHTLY SILTY 40 : .. )\.;.>~ Brown, Moist, Very Firm, FINE SAND 54.5 <:~~:::== Cemented, Few Shells SANDSTONE' 41 ~';~-:'n-:b"'r---~-------------~----------~---+--~--~--~~ .:/.: .... "'. Light Brown and Light Gray, 42 : :":. ".: Moist, Very Firm ,43 45 :46 51 52 53 , 5 PROJECT NO, o ! 73':'3': 16BC SILTY VERY FINE TO FINE·SAND AND SLIGHTLY SILTY FINE SAND BENTON ENGINEERING, INC. 67.4 46.0 42.1 DRAWING NO. 4 I' I I (. • • • • • • • • • - j. 1 . 2 6 7 8 9 10 13 14 16 17 18 ,'19 SUMMARY SHEET BORING NO • .J_ ELEVATION 1551 SLIGHTLY SILTY FI NE TO MEDIUM J-;----I~-+--+---+---t ~.~~,~~.~,:.M:'~R~~-d--b~~-wn--a-n-d-g-r-ay---b-~-wn--~---; SAND (,,.; , ,.' Slightly Moist, Firm " ,: .,:.... -----~I ~ /." Moist, Very Firm ALTERNATING LAYERS: OF SLIGHTLY SllfY 19.5 ______ ----I FINE SAND AND Vf.7.rrn Yellow-brown SILTY VERY Light Gray Light Gray; Moist, Very Firm FINE TO FINE SAND ALTERNATING LAYERS qF SLIGHTLY SltTY FINE S~ND, SILTY VERY FINE TO FINE SAND, 27.6 SILT AND VERY 29.2 ',;:>:' 'te.'. Light. Gray, Moist, Very Firm FINE SANDY SI.LT . SILTY VERY FINE ro FINE SAND Continuec/o on Drawing No. 6 37.3 ~'~~~~r---------------------~------~ PROJECT NO.' DRAWING NO. , 73 .. 3~16Be BENTON ENGINEERING, INC. S • • • .. 4 .-~- SUMMARY SHEET- BORING NO. 2 (Cont .) Light Gray, Moist, Very-Firm , PROJECT NO. .. 73-3-]68<: BENTON ENGINEERING, INC • , ' ~.AWING NO • 6 • • • • • • 0 co ~ i! • .t .2 tit 8 0 ...J • ('II c6 - • • • I-III ' •• ' ~ ... III, .". ............ ." IG =aa o!5 ~ .. e::l ." u ." ... '" z 0, n. .......... . .. ........ .......... 1 .......... .......... .......... .. .. .. .... .. .. .. .. .. .. .. .. .. .. .......... .. .. .. .... .......... .. .. .. .. .. .. .. .. .... '7-.......... .. e-..... .......... .. .. .. .. .. 8 ' .......... .. .. .. .... .. .. .. .... .. .. .. .... .. .. -t"" .......... SUMMARY SHEET BORING NO~' '2A ELEVATION ] 2a' Light Brown, Dry, Medium Loose Slightly Moist, Firm CLAYEY FINE SAND (Merges) , FINE SANDY eLA Y (Merges) CLAYEY FINE SAND : : : :: Lenses of Brownish-gray Clayey : : : :: Fine Sand c;md Pock~ts of )- ". )00. _ t: ",..:'" t: '" t:' III...... _ 3t iii U Zllle~ Z,::)-Z' III ....... )00 ~ U ceo -",III_ ......... IllI-Ja III lIII: ii: 0--.:z: III ...... >. ... )00 III ... -III _... or lie IG .'111 .. _ U. ..... _... "'-e ...... '-lIII: 19.5 19.5 .... , Slightly Silty Fine Sand With ..... ~Ia""'ck ea ........ :.. ... ---II .. Material J 4.9 13 14 15 ~ .. .. .. .. ...... " .. .... e ..... .......... .. .. .. .. .. .......... Yellow-brown, Moist, Medium Firm ~ Y~'lIow-bi'Own, L!ght Bro~nand '" , ,:" Firm, Chunks, of Cemented SliGHTLY CLAYEY FINE SAND .. SILTY VE-RY FINE TO FINE SAND I.~> .", Gray-br~wn' Moist, Medium j~ ~i1ty fin~ Sand and Pockets of ,~ Slightly Silty Fine Sand. 16 ® ,~ Evidence;of Previous Movement ~/.'.r.. Above 16, Feet _. J 17 18 19 2()', - :~". ' " Ollve~grOY;' Very Moist to Moist, It"":' '=ttvWdiumSoft to Medium Firm, r C ,-~Iay Surface DiDS 23 11 to N 63"" CLAYSTONE CLAY t==3 Oltve-,gtOy, Moist, Very firm i Continued on Drawing No.8 PIOJEC:r!NO. 73-..;.3-16B€ BENTON ENGINEERING, INC. 3.3 / DRAWING NO. 7 "j"-.. •• :. , t • • 0 co ~, • • or! :2 .8 'v ,0 ...;.I • • • ill, ',~ Z a • t- Ill .. = ~ ..... .,,' ...... ..."G SUMMARY SHEET" Z ~~ -c ~ t-0(:» 0 ... >-.... Z ."u." BORING NO. 2A (Cont.) ! ...... . r~v ~A '" -" ': Olive-gray, Moist, Very Firm' 21 5 ~""l',;r/,;t]' ' ~~'(/'Y.% Light Gray, Slightly Moist, 22 ~~:~ Ve,,>: Firm, Scattered Coarse ~. .7/:' Gra inS ' .' 23-Olive-gray, Moist, Very Firm t:::~ Dips 90 to Sf ,24-; .-: 25-"" ' 26-0 "",,:, - 27 ~----------~------~ Oltve-gray and Orange-brown , " : ,,', ,28 ---- " "Color Merges t::::=:J Light Red-brown With Yellow- 3(}Brown and Rust-brow,fO.LI_ . ...,.., ---~ ® ' Few Small Pockets of Silty Fine 29- 31 7 tioi'!"'-' ... ' .... Sand and Gypsum erystals 1:"=:1 Merges to Softer Claystone 32-.. " , . · ,', ·33 , ,", 34 " ~ Light Gray With Y ~lIow-bro~ri ,35-~ and Ru~t-brown, Slightly Moist, CLAYSTONE SLIGHTLY SILTY FINE TO MEDIUM SAND CLAYSTONE SI~TY VERY FINE TO FINfSAND 16.2 15.6 U4.0 16.2 59.0 19.5107 .9 40.0 ® ~"" y,', Very Firm 8 ~., ~ 54 3~' ~"~"'"'~~:~ ________________ -L~~~~--~~.~6L-~~-L--~~ · · 'ROJECT NO. 73-3 .. 16BC ) BENTON ENGINEERING, INC. DRAWING NO. 8 • • • • • 0 CO ~ .t! • J:! CJ u 0 ..oJ • - .... III .. . III ... ,111 ~A.. :z: ~ ~ too 4(=» A. 1ft Z III ' CI' 2 SUMMARY SHEET BORING NO.~3_ ELEVATION ..:,.13;;.,;0;;..1 __ ~~ ';::::.:' I ;~ht Brnwn n~ 1,tV\CA. P~rftllc ~. Firm ~----~----~---, . Very Firm ' 3~~ 4 . '." 5 ~GraY-~, Slightly Moist, 11.4 {!l ~ Slightly Porous 6 SILTY VERY FINE TO FINE SAND 9.7 7 - 8 ~ 9 I I ~ ,. -. . . ... . .. Light Brown, Moist, Firm ..... 10-..... ...... 14 15 Olive-gray, Red-brown and r!iE1 Yellow-brown, Moist, Very ,L1 Firm 16@~ €LAYEY FINE 'SAND VERY FINE 6.5 SANDY CLAY, WITH VERY FINE , SANDY SILT AND SILTY VERY FINE SAND SILTY CLAY, 9.7 1"7: [iJ !.~'~:~' ~lLi~9;;;ht~R~ecld.-~b;;ro~wn~wVii;'th~Y~e;jill~ow~-~t--~----.:.~t-t~t-r~rl ~3 brown, Moist, Very Firm, 18 19 20- -: . CLAYSTONE 1= Soft Black Carbonaceous E'::' :3 Material. in Some Zones - Olive-green With 'Red-brown and Yellow-brown Streaks Continu,d on Drawhig No. 10 PROJECT NO. ·73-3 ... 16BC BENTON ENGINEERING, INC. DRAWING NO. c> • • • • 0 c:l ~. II • .E ~l u 0 ...l • • I Ie . • • .. " ... SUMMARY SHEET' BORING NO.m 3 (Cont.) . -~=3 Olive-green With Red-brown and 21-G) ~ Yellow-brown Streaks, Moist, [] . Very Firm 22 23 24 25 -Q 26 V:V S· ~. ::1 27 28· Becoming Firmer With Increase CLAYSTONE 29 t:::::::1 in Depth 30 ~~ 31"® E ... :_ ... 32- - 33 ' --- PROJECT NO. 73-3-16BC Continued on Drawing No. 11 BENTON ENGINEERING, INC. . 16.2 2S.6 97.6 23.3 22.8 99.8 25.8 DRAWING NO. 10 I , . ' , >-I-.. -SUMMARY SHEET· o· ..,..: r; . ..,' ... _ t: iilt: ut: ... ...... ." . a~~ II. '" ....... z . _z . e ...... .. -... ."l1li A (Cont.) z '" ,~ ~ ~~fl :z: ,.1 -cl BORING NO. '.., .. m"," l-e=» 0 ... ,. '" 52 ---z"" .. .,Z ."u." > . 1I.0a ,. vi ",;;;~ ... -I-~~ ., III ..: II. "'-CII,' a a ... -=-: I.,., Oliv .... green With Red-brown 34 and Yellow-brown Str~ks, N\oist I Very Firm 35 ; ;. ® 33.3 36 37 CLAYStONE :. 38 , ' , 39 · 40 , '. , 41· {~) 41.6 · · " • 0 · CQ , ~ • ,t!' • .t ,g s: u 0, ...I • N · ~ ..... OJ '. '. · " '. PROJECT NO. DRAWING NO. 73-3.,..16.,BC BENTON ENGINEERING, INC. n • • • • • • • • .it • • . ' SUMMARY SHEET BORING NO ...... ·, ...t..4_ ELEVATION 106' .-, ,'... Light Gray-brown,. Dl'y', Loose ........ 1 . .'.' Firm 2-cD .:~\~ Gray-brown, Slightly Moist, ~ Very Firm . . 3 ~-. . ' . @ Firm, Porous. . _ 4 ® . L,ightBrown With Rust-brown -'01':: .. ··· 5 :,(;'.. . 6 ~I·:~.·i.y Very Firm 'a'~ 7-\V~ 8~ .......... Brown, Moist, Firm .... " ..... '. .. .. .. .~ 9~ ...... -"" .. " ...... .......... SILTY VERY FINE TO FINE SAND CLAYEY VERY FINE TO FINE SAND 10 .. .. .. .. .. .. " ...... .......... l3.0 6.5 7.1 85.2 9.7 11 f4\1'.~"~'~' __________ ~ ____ -L ____ ~ __ ~~6-.5~~~~~~-4 ~ ,.;.: .. -. ". '" - -- 'ROJECT NO. 73-3-16a~ BENTON ENGINEERING, INC. DRAWING NO. 12 • >-~ ... .... SUMMARY SHEET c . . IoU": ti ~ti .. -~ I .. ..... o~~ II. .. -... :::.i IoU", :; ~~fi .-. Z f :z: ~~ -c~ BORING NO. 5 iiI",>-IoU U IoU _ .0 ... 0(2 0 ... >-IoU ~ ----. !l!t; ....... .. "'Z InUIn 71' > . "'0 0 )io vi ",;rf III ELEVATION -... ~~ • !t ·W"_ 0 -... 0 -~ 0 " • -:.~. :.:::.:.\.~ .. :;. Light Gray-brown, Dry, Loose SILTY VERY FINE '0-:'--: ..... : P2ro~~ TO FINE SAND 1 .':~'.'.::.: :.'. o· . ;?{).~.: I'.Firrn I CD Light Brown, Dry, Firm SIL TY VERY FI NE 6.5 :2 ... '.' ." TO FINE SAND • .. " ... WITH eLA YEY / \"!'W; 3 1\ VERY FINE TO CD FINE SAND 4.9 4.4 88.1 4 Lfght Brown, Dry, Firm, SILTY VERY FINE • [j] •••• 4 Small Chunks of Claystone TO FINE SAND ., • 'I • 5 WITH CLAYEY · .. -.. · .. , . Moist VERY FINE TO ~ .... : .. • 6 :·{UU{J; FINE SAND AND ::::i) .... CD SLIGHTLY SILTY 1-14.6 . ~ 7 · .... ......... VERY FINE TO ...J · ... -. / ...J ., .-.. Gray-brown, Moist, Very Firm ~ FINE SAND < " ... •• '! ... 8 • CLAYEY · .... ' ....... -'," .... -FINE SAND 9' ,', .,' ... · ... '. a co ~ J • :! · . .-.. . . 0 - 1:0 ., .... 16.2 · ." .. '. · '-' ... . , .... .2 11 ... " .. ... . . . .-.. -.-. S u ,e' ••• , 12 ... " .. -: 0 • ...J - .. , • . - • • .- • o· ".OJECr NO. DIAWING NO. • 73-3-16BC BENTON ENGINEERING, INC. 13 ie '. •• • 0 cD ~ • l! ~ .E 8 c ....I • • • • • ... .. ~ III III ... 111 ~ . SUMMARY SHEET .... " Z ... .. III a I 1 ,2 4 B 16 '7 11 12 13 14 15 16 .. -~~ 0(:1 ·Ift Z ... ."aI -C~ 0 ... >-,~U~, . BORING NO. 7 ELEVATION 134' Light Brown, Dry,. Loose Firm ... ;.':. ':: . Light Yellow ... brown and :;',:~.,. Gray-brown, Moist ::". :.:":. Lightly Cemented • ~ < ·.1 .. ;:::-:: ::': Iv\ore Cemented With Increase .,> .. :' .. :. in Depth .17 [!]':>:':' ;~ With Interbe?ded Layers of 18 . '.:' .' Red-brown Fane Sandy SiJ.t, ... , .It , .. ~ /.' : " .. ~ It... .. " .. , . SILTY VERY FINE TO FINE SAND o Fi-==--t. Gray, Moist, Very Firm, Cemented CLAYEY VERY FI NE ~--'_---'-' ___ -I-_4-----f P.OJECT NO. . 73-3-t6BC BENTON TO FINE·SAND ENGINEERING, INC • DItAWING NO. 15 • • • • • • • • I • • • N ~ .... .r! .-c :::), f -.-> -5 -c 0 Co. Vl I 0 .... en 0 u 0 -J w :!: 4: z /XI o ., '"" W W II. "'"-:r: I-a.. W 0 0' 1 2 3 4 5 6 7 8 9 <10 11 12 1 ' 1 ' 15 z 0 wo: ' i= .... .J~o SUMMARY SHEET .J,w ' _tJm a..m :!::2 Oii::!: BORING NO. S 4:;:) CI)_> Cl)Z ~CI) ELEVATION 247.01 4: ...I tJ G1 : '; : ; :~ Dark brown, No.ist, Loose, Roots ~ , ..... Porous, Topsoil, Seashells Scattered 0 n Surface Orange-brown, 51 ightly Noist I "''''"'''...... Firm, 51 ightly Micaceous • ht n "'" : ....... Light Brown To Light Gray, CD ': ': :::'" Slightly Moist, Very Firm, Clay Binder, Slightly Micaceous Slightly Moi~t To /IAoist, Micaceous .'. : .... 6 Inch Highly. Cemented Arid .-::':.':: < Calcareous Zone CLAYEY , FINETO ,MEDIUM , 'SAND SILTY FINE TO MEDIUM SAND > o· >. W' 0:1-w~ 1-1-tJl- w!:!: 00: Ciiu. zu. Z " o:~ • zCl) .J~> w;:) ~I-a w2: WCl)O: O~ wCl)~ w~ ii:(50 :r:-CI) >. >CI) Cl)CI)a.. :!:~ o:/XI w--I-o:~ 0:11. 0...1 0 85,.8 8.6 103.0 50.6 7.3 113.1 Continued on Drawing No. 17 PROJECT NO. 73-3-16BC o -Indicates Loose Bag Sample o Indicates Undisturbed Drl~ Sample * _ Elevations Shown Were ObtaIned Fro~ The Tentativ~ Map, "r and Specific Plan Prepared by :mck Engineering of Carlsbad; CalifornIa Which Is Entitled Carlsbad tract 72-24, Spanish Village at La Costa, Units 1 and '2, and dated July 20, ' 1972. DRAWING NO. BENTON ENGiNEERING, INC. 16 • • • • . "~. • • •• , •. , • w :e « z r;a o ., I-w W II. ..... :r I-Q. W C z o i=...1 ...1«0 -CJr;a oii::e (1)-)-~II) « ...I 1 S CJ -0 J6-' - SUMMARY SHEET BORIN~ NO. ,8 (Cqnt) Light Bre>wn To Light Gray, Slightly lVoist, To lVoist, Very Firm, Clay Binder, Micaceous ::= ~ ...;. ~ Light Orange-brown, With Some' SILTY FINE TO MEDIUM SAND •.. : .: .... <.r'\. Clay i;·:·~·;·/:·;:':} '-H";;'i9~h;..Lfy-C-em-en-t-ed-,-S-e-as~h:-e'"":"I~I$---t-S-A-N-D-S-T---O'--N-E---'J--..1-_...L.-_..L...o._-J---I 19-- - 20-\~----~----~----~--------~ - - - ...,. ...:. ...; - - - - - - -- -- - -\ - - -' - ; ..., - - - - - - - - - PROJECT NO. 73-3-16BC BENTON ENGiNEERING, INC. DRAWING NO. 17 .~------~~------~--------~--~--------------------- • • .' . • • • - • C/) I • 0 ..... III 0 U 0 -' :. W ::E « z IX) 0 .., • ... W W II. -J: Ii: z > 9 0..: .~...: ..J~5 SUMMARY SHEET ffi!:!: Q~~ ~~ _CJIX) zen ..J ... ::!> w::! Oii:::E BORING NO. 9 w!!: Wena: Q~ en-> -wlIt: ii:oQ " ~en ELEVATION 2oo,QI ~..: ::ECIC! ~~ ::!i a: II. O..J Q-r __ ~~CJ~~~--~~~~ ____ ~ ____ ~~ ____________ ~~Q __ ~ __ ~ __ -+ ____ ~ __ ~ rown, 1St, LAYEY'FJNE TO W Q 1 ~~'!d..l<oots Topsoil EDfUM SAND J---+---I-----4---+---I C\' \<.: : . .-;' W"--h i-te-To-=--"L-ig-h-t -~-ra-!"":"T"""o"""'L-i-9-ht-~~~~::'!"!!''!:''J 2 \J.) " ... ' .;., Brown, Slightly Morst, Very :.:' ,':: ,':' Finn, Micaceous, Rootlets, Clay .' .... : .. :. Filled Fractures 3 4 6 7 8 9 . 1 1 1 1 '0" :' •• ' PROJECT NO. 73-3-16BC SILTY FINE TO MEDIUM SAND BENTON ENGINEERING, INC. 37.4 5,,4109,9 44.0, 6.~ nO.2 46,2 7.8 110, DRAWING NO. 18 • • • • • • • • • •• • N cd ~ .... SUMMARY SHEET BORING NO. 10 ELEVATION, 18Z.0' _ ~:-~ Brown To Dark Brown, Jv\oist, ]._ ~ LooSC!, Porous, Roots, Top~i1, _ ~ . Lenses of Clayey Fine, To Medium 2-..... U\$and -, _ f.:\ .... , : BroWri-gray and Gray-brown Witt 3-0 -.... : Orang~ Yellow Streaks., Moist, _ r::t . Very FIrm, Lenses of FlOe To 4_W ..: Medium Sandy.Clay, Rootlets, 5= ~I\rown Clay Filled fractures _ ~ Light Yellow To Yellow-brown, 6-0 :'. S!ightly ~ist, Very Firm, Clay . _ 0lBlOder, Micaceous SILTY·FINE TO MEDIUM jSAND'.~, CLAYEY FINE TO MEDIUM SAND (Merges) SILTY FINE TO J I :~ 2 ~ . _ ~ 'Occ~ional LenlSe of Clayey Fine MED IUM $-AND 9-.': To Medium Sand IO=®~ .. 11-~ -I~~, ~ , -12-.~ -~ . Mixed Orange, Yellow and CLAYEY FINE TO r:::I:~ ~ Light Gray" Slightly Moist,Very MEDIUM SAND > >. W:~ 0' w~ ..,,1-a: I-ca: -~ e.)~ w!!:. ~::) . a:~ . zlf -J~> 04:1-0 w_ ~W (I)-a: We.) W(l)~ w~ ~oc c,: ~u;~ >' :::e~ >~ w--I-2i...l a:~ a:~ C 11.0 10.3 107.7 81.4 7.1 110.0 , 99.0 9.2 114. 1- ~ .-c ::::> G 13='~ .>--............ Firm, Micaceous ALTERNATING ...... WITH LAYERS OF! ,-. . . . . . SILTY FINE TO 14= :: : :: : ~' MEDIUM SAND 1'5-0: : :: : : Mixed Orange, Yellow and Light CLAYEY ',68.2 _ : ::: :1\Gray, Slightly Nolst, Mlcaceou~ FINE 15.0 112 .. 8 U') I C ..... en 0 -V 0 ....J I~~'I\ SAND 16-..... : Lense~ of Clayey Silt (U_ .--~), -Brown To light Brown and 17....: '\. -Gray-brown, Moist, Very Firm, --r:I Micaceous 18-L!.J - - 19-Fractured CLAYEY SILT -0 w ~ 20- ~ -Z III 21-o -. Continued on DrawIng No. 20 PROJECT NO. 73-3-16.BC BENTON ENGINEERING, INC. "" .. 45.0 19.6007;5 DRAWING NO. 19 • • • • • • o w • :i ~ 2 .. al o ... I-w' w u. ....... :r: I-Q. w, C 21 ,... 22- - 23,... - 24- - 25- - 26- - 34- - - - - - - - - - - -, - - wa: .Jw Q.al ~~ ~:J (1)2 Q SUMMARY SH~ BORING NO. ~V I$S:~~ Brown To Light Brown and ~~~~a Gray-brown, M>ist I Very Firm, .. . Micaceous iii 'Bedding Dips 5v -HP, High \ : Angle Fractures :t 60 Degrees ) ., ~---_. -'-.... ----.---~ .. ,-" .. ~~ t, \ Lenses of S i I ty Fine Sand ... CLAYEY SILT CLAYEY FINE TO MEDIUM SAND PROJECT NO. BENTON ENGINEERING, INC. 73-3-16,BC 68.2 18.9 '108.3 13.2111.5 1259.6 12.6 111.3 J DRAWING NO. 20 ,. • • '. • • • • • w :E "' z' en 0 ., • z ... 0 SUMMARY SHEET ,W wa: ' j:..J W ..Jw ..J«O BORING NO. 1 ] II--..: "-al _°al :t :E:E Oii::E ... ELEVATION 177.0· ",j (1)-> "-(l)z ~CI) w « Q 0 - 1- - ..J ° . : : : :~ Brown, Motst,LoO,!8,Porous, · . . .. Roots, Topsoil :.: : :: Brown To Orange-brown,lv1oist, • ... ·1\ Arrn Porous Rooflets 1 \1, , " ~~ _ .~~~ :~ lyOld SHe PIq!1e Qips .... 12 Degrees 3-~~:: North 20 Degrees West 1/2 Inch , r:l ~', D, .... ,-Cl'av Gouae · ~ W ~.l, Light Gray To Light Brown With ~.~' , Pods and Streaks of Orange and 5= CD ~~~" Yellow,Sl.ightly J\t1o'ist,Very Firm 2- · . l1(~~<.Micaeeous,Slight)y Porous, -l'" ,'X Rootl ts F t ,ct· ~,"'-'~ .. , . eon rae ures, . lqy 6-:~~~ Filled Fractures ......... ).. - ~LAYEYFINE TO MEDIUM SAN.D CLAYEY FINE SAND I .. SILTY FINE SAND ALTERNATING WITH LAYERS OF, FINE SAND AND,' ',' 7-l'~"""" '.'. \ .:-;.~ ': ~ .:; ,S~~""'~]""'i=':-~-e""'" J21'--~-rlP--iru-L..;3=.5"--D-e---y-re-e-s..-.l -~ ~ ': cf f ~t.i D~'·F: as'West 1 8 • A..~, ,\AIn I . ,..V ' 8 - : N ".' :.u.u-:., ,.". " .. ',. '. CLAYEY FINE SAND '__ ~ ~ Slip Plane Olpping 45 DegreflS '9-~ : : ~: North 15 Degrees West, 1/8 > CJ' a:'" w!!: z~ w_ w~ >. _ ... a: II- 0 _. ,C;; " > Inch Brown Col qy o ~25.4. · 10-\t.J ~"'::~~ Light Yellow-Gray to Light SL/GHTL Y SILTY > . ~~' W' ...... 0'" .(ii II-zll-OJ . z' a:", . ..J ... > wj "' ... 0 WCl)a: o~ WCI)~ ii:e O >!a ~(ii~ :E~ w-~ ... a:~ - 10.6~13.a -01 ~::. :.,~ Vellow-brown, Slightly Moist, TO SILTY fiNE ,11'""' ~~ Very Compact ° MEDIUl¥tySANQ "= ~~~:-~::'~:]~~ ______ ~ ______________ ~_{,UA~k'~'1~)--~~~--~--~---+--~ , 11~3= I,::.":~,:~.·::.,:~,:,·,· .. ~~g~~ty'~~~,~~ryG~~~ SILTV FINE TO ,_ M~D luM, 'j S.A.N D -~:".< 14-:,:::':~'::.'. Light Brown To Light Gray, , : -G) :::-.::::'::: Slightly lV1oist, Very Firm, FINE sANDY CLAY . 15= ~\Slightly Porous .. 16...., ~ Light Gray To Light Brown, :SLlGHTL Y SILTY / •. ~ ~ Slightly Noist,VeryCompaet TO SILTY RENE 17-: : : : :. 1\ . ITo MEDIUM., / 1\ r ,SAND (Mer9~) -..... ~--------------------+---~~~~~ 18... : : : :: Light Brown,Slightly Moist To _ : : : :: .Moist, Very Finn, Lenses of Silty 191-: : : .:: Fin~ Sand, Micaceous, CLAYEY FINE SAND 94.6 12.2 111.2 : ... , Thlnbedded With Pink Clqy , 20= 0~t\Seams . /107.8 14.6113. 1 " ,..., ~ L!ght Gray, Slightly Ntoist, Very SIL TY · 2' 1 r'-" ~',0: Finn, Micaceous FINE SAND 1-· Continued on Drawing No. 22 DRAWING NO. 21 BENTON ENGINEERING, INC. PROJECT NO. 73-3-16BC • • • 2 • 26 27 28 • ,29 3 • 3'1 32 33 N • ~ -3 £! .-:5, 3 ID W -• -.-> ..c .!! 37 (I) 38 I • 0 ..... I/) 0 39 U 0 -' I • w :?! 41 < Z III 0 42 .., • z 0 wo: j:..1 ..1<0 SUMMARY SHEET ..Iw Q.1lI' -CJIlI :?!:?! oii::?! BORING.NO, 11 (Cont) <::> (1)-> (l)z, gj(l) < ..I CJ iSSss:' l:!" light Orange-brown To Brown , .: '" With Orange Streaks and Pods, Noist,· Very Firm, Micaceous ~~. >~ ' .. ~. ." @ " ~ " ',"t Dark Orange-brown, Gray, and Red-brown, Slightly Noist, Very Firm, Lenses of Silty Fine Sand, Micaceous Light Gray To Light Gray-brown Occasional Lenses of Clayey Fine Sand ' SILTY FINE SAND CLAYEY VERY FINE SAND SLIGHTLY SILTY FINE TO MEDIUM SAND > ' > ' 0' w~ 1-1-W' 0:1-CJI- w!!: cO: u;u. zu. z(l) ..I~> zci 0:< ' <1-0 w!!: W(l)O: WCJ W(I)~ W~ ii:oQ 0-, ~Ciilf >' >(1) -I-:?!l\E! 0: III w- a:u. 0..1 o:~ C 66.0 15.8 109.1- 56.1 17.5 108. 136 .4 11. 5 109 • 1 94.6'7.6,101.9 Continued on Drawing No. 24 PROJECT NO, 73-3-16BC DRAWING NO, 22 BENTON ENGINEERING, .INC. • • • • • • C"I • c<5 -!'! .-:C ~ II) • . 0 ...... 5 :5 .-S til .' I b .... II) 0 u 0 --' • w :E c( z co 0 ~ • > >. 0' W' a:'" w...: ...... ut:; -II. w!:!:. o~~ !2' a:~ • z[f ..J .... > w:;) c( a w_ Wcna: oS; wt;cn wlli:: u::oo :t-i >. >Ia 11)11) _ ... :E~ w--a: II. lS..J a:~ 0 z ... 0 w wa: i=..J w ..Jw ..Jc(o !!:: Q.co _Uco :t :E :e 0 u:: :e ~ _~~ cn~~ 4~ ~~~~'\ . _ rn ~::. ~ Light Gray To Light Gray-brown, 43-.'.:: .... : Slightly Iv\oist, Very Firm, _ . Micaceous, Lenses of Silty Fine 44 " Sand, Occasional Lenses of SLIGHTL Y SILTY ~-'. Clayey Fine Sand FINE TO MEDIUM SUMMARY SHEET BORING NO. 11 (Cant) ~ ®~ SAND ~13.9 9.3 104.9 ~_ F~_'$'~'~~ ______________ ~ __ ~ ____ ~ ____ ~~~-L--~--~~ - - - - -' ...., - - - - -. - - - - ...,. - - - - - -. - - -.... --. - - ..... , - - - PROJECT NO. 73-3-16BC ( BENTON ENGINEERING, INC. " .. t. :/ DRAWING !\IO. 23" . , . • Z I-0 w wee i= ... w · ... w ",<,0 LL. -,11.111 -(.)'111 :J: :!l::E oii:::E I-c(::J en_> a. enz ~en w 0 c( ... .' 0 (.) 1 ,2 • 3 4 • 5 6 7 8 9 • 10 11 12 N • ~ -' 13 jg .-S 14 .1) '. 15 V'l I • 0 ..... ' CIt 0 U 0 ...J 19 :. w ::E 20 < Z III 0 21 ., PROJECT NO. • 73-3-16.BC > >. 0' W' SUMMARY a: I-w...: 1-1-(.)1- SHEET w~ o a: 3: u;LL. zLL. zen ... ~> Z,:j ~<d BORING NO. 1? w!!: w(.) wI-en w~ wena: 0 .... :J:en-ii:5° >!a enu;!e ELEVATION 235,0· >. ::E~ w--I-~ ... a:~ a:LL. 0 Brown, Slightly' fv4oist,Medium ' Firm, Slight Clcy Binder, Porous, Roots, Plowed Topsoil SILTY FINE SAND J-,--+----I----I----I--....,..-I o range-red-brown, Moist, Medium Firm, Pods of Fine Sandy Clay, Porous, Roots Light Gray To Light Brown With Streaks of Orange, sl ightly Moist, Very Firm, Micaceous, Lenses of Slightly Silty Fine To Medium Sand, Brown Clay Filled' Fractures LAVEY FIN.E SAND SILTY FINE TO '--________ ---iMEDIUM SAND Lenses of Silty Fine Sand, Occasional Clay Pods Yellow-gray-brown and Ligh~ Gray, Slightly Moist, Very Firm, Micaceous SILTY FINE SAND ConHnued on rawing No. 26 BENTON ENGINEERING, INC. 81.4 7.3 111.2 99.0 9.7 112. 1 88.0 9.3 105.4 83.6 10.6 109. DRAWING NO. 24 '1 • z ""' 0 w wa: j:...J w ...Jw .... ~o U; -Q.III -(.)111 :J:c ~~ ou::~ .... ~::,:) "'-> Q. "'z ~'" w Q ~ ...J • 2:1. (.) 22 23 • 24 25- • 26 27 28 • • 31 32 33 N • 3 35 • 36 37 38 • 39 40 • w 41 ~ ~ Z III 0 .., ,PROJECT NO. • 73-3-16BC SUMMARY SHEET BORING NO. 12(Cont) Light Gray and Light Brown With Yellow Streaks, Slightly Noj.st, .. Very Firm, Micaceous,L~nses or Silty and Slight-ly Silty Fine To fv4.edium Sand Occasional 1/8 Inch Clayey Sand Streaks Light Brown To Brown With Orange Streaks, 4 To 6 Inch Lenses of Clayey Fine Sand SILTY FINE SAND Continued on Drawing No. 27 BENTON ENGINEERING, INC. > >. 0"': W' Q~~ ""I-(.)1-a:u. -u. a:Zu. . w-~ . Z-'" ...J~> w::,:) ~~d w2:: wt;~ w~ w",a: Q~ >. U::oQ >gJ ~u;8! -I-:E~ w-a:u. a:...J a:~ Q Q 12.2 10.8108.1 17.7 12 • .1 107. 145.2 7.6 113.5 195.8 17. 93.4 DRAWiNG NO. . ·25 . • • • • • • • • • • W :E « z t-w wa: w I&. ..Jw -Coal x :E:E t-«::I Co enZ w c 41 - 42-- 43- ..,.. - - - - - - - - -' - -- - - - - - - - - - - - - - - - - - - Z o j:..J ..J«O _Ual OU'::E (1')-> ~en « ..J U I] ~ ~. . .. ,-- .SUMMARY SHEET BORING NO. 12(Cont) Light Brown To Brown WHli Orange Streaks, Slightly Moist, ~ILTY FINE SAND Very Firm, Micaceous .......... .......... .......... Light Gray To pght Brown With I"::~, :-'-:-'-: -'-I: Orange, fv\oist, Very Firm, CLAYEY FINE SAND Micaceous > >. o,,: W.,;: t-t-a:.1&. ca::t ~': w-zen ..J~> w::I w!: wena: c~ w~ ii:5-C >. >~ _t-:E~ 15..J a: I&. c Light Gray To Brown,Slightly Moist, Very Firm, Micaceous 83~6 11.6107.2 SILTY FINE SAND w· u'" zl&. a: « . «t-0 wense x-Ie en8l_ a:~ PROJECT NO. DRAWING NO. 26 BENTON ENGINEERING, INC. 73-3;"16BC ". • • • •• • C'I 06 • -l! .. -c ::> • • W ::E < Z III 0 ... • -! - -~ t,. ____ -. ... W Will: W· ..JW II. ..... Q.1Il :t ::E::E ... <:::> Q. Cl)Z W Q 1 Z 0 i= ... ... <0 -Olll Oii:::E CI)_> gjCl) < ... U SUMMARY SHEET BORING NO. 13 ELEVATION 180.01 Brown, Motst, Loose, Roots, Very Porous Topsoil To 2 Feet Very Moist, LIght Gray To Light Brown With Streaks Of Yellow and Orange, Moist, Ve Very Firm, Clay Btnder, .. . . Micaceous, Brown Clay Filled > >. O· W~ ... .... ec'" wl!: a:: ~~ Z~ Q:::> ...... ,> W'U W_ WCI)'a: W~ Q~ >. ii:OQ >en _ ... ::E~ a: III a: II. Q'" Q l25.4 12. 106. ...... : .. ::. Fractures 1/8 To 1/.4 Inch 5 . G) ~ .......... : :: W· .. .::: ::' 6-.... -.. ~-:-.":" "" ." ... 7 8 9 10 11 12 1 15 16 17 .18 19 2 21 .. ' .. :;.J.I---..,...-------....--...,.......j Lenses of Clayey Fine Sand, 1/8 To 1 Inch Clay Seams . ~~~ Dark Brown To Orange-brown, J~~<"!I' YeHow-brown and Light Gray, I_~"'" Moist,Soft To Medium Firm, '"""""."",..., ...... Root Holes, Porous,Occasional ~,:yy...,. Shell Fragments, Friable Orange, Moist, Compact, Occasional Coarse Grains, Occasional Clam Shells SILTY FINE SAND LAYEY FINETO EDIUM SAND MIXED WITH SILT FINE TO COARSE SAND . 85.8 10.S 10.0 123.2. 9.2 106.3 SLIGHTLY SILTY 28.6 9.6 102.5 FINE TO MEDIUM SAND Continued on Drawing No. 29 w· u'" Zll. a:< • . < ... 0 wenS!? ~U;~ W-a:~ PROJECT NO. DRAWING NO. 73-3-'1~BC BENTON ENGINEERING, INC. 27 • • • • -. • V) I • C .... 8 u C ...J • w :E 01( Z a:.I 0 .., • ... w w u. ..... ::E: .... Q. W 0 2l - 22- - 23- - 2~ we: ..Jw Q.a:.I :E:e 01(:;:) CI.Iz SUMMARY SHeEt .. BORING NO. 13{Cont) '.~~~~ Dark Brown To Qrange-brown, ~~~~~ Noist, Soft To Iv\ediur'n Firm, t==I,I\,able, Shell Fragmenl1 ,..,LAYEY FINE TO MEDIUM SAND MIXED WITH ~LIGHTLY SILTY J FINE TO MEDIUM SAND 10--" Gray-green To Green· With 25= ®t==::f\Streaks Of Yellow and Orange, 1==:1 Moist, Soft To Ntedium Firm, i----tl Highly Fractured and Mixed - 26- -[§J t::::::::I 27- Into 1/4 To 1/2 Inch Chunks, GYP$um and Yellow Iron Stain Filling Fractures In All - 28- - - Directions \ layers of Brown With Streaks . . Of Yellow, Red, Orange Mixed With Green And Gray CLAY > >. w· c,. . o~~ ... ... u'" a:'" -u. zu. w!:!:. ~. a: 01( • z~ ..J ... >. w:;:) 01( ... 0 w_ WCl.la: o~ ~CI.I5e. wlloi: ii:oo >la CI.Iu;ff ~..,:. :ElII! w-a:u. ~..J a:lIoi: .0 33.0 25.6 99.1 70.420.2102.9 31-\LV~, .~t~~F~i~rm~ ____________ ~ __ ~ ____ ~~l~. ---+--~--~~~~~ - 32- - 33- - 3~ Moist, Very Firm, Gypsum Common, Pockets o.f White Clay,Lenses Of Over 50 Percent Shell Fragments,Lenses SILTY CLAY 35= CV 1=:==1 Of Ntedium To Coarse Sandy Clay Gray-green And Green With Streaks Of Orange And Yelloy, - - - - '- - - - - - - ....: - - .PROJECT NO. 73-3-16BC i \ Moist,Very Firm,Highly Fractured In Many Directions, SI ickensldes Common CLAY BENTON ENGINEERING, INC. J '.50.6 18.8108.3 I DRAWING NO, 28 • • • • • • .2 8' u • " ...J 0 al ~ • • -.... • ... :II c Z lit o· ., • en en ... z ~ ~ :c ~ I&J ~ Q. :II C 7 en II. 0 ~ 8 z I&J U III: 9 I&J Q. Z 0 i Q :::; 0 0 en ! u 1 2 3 4 5 PRO"ECT NO. -"0='1'1'='1'88-73-3-16BC CONSOLIDATION CURVES LOAD IN KIPS PER SQUARE FOOT o INDICATE.S PERCENT CONS01.IDATION AT FIELD MOISTURE • INDICATES PERCENT CONSOLIDATION AFTER SATURATION BENTON ENGINEERING ,. ·.INC. DRAWING NO. 29 ;. t q .' ...... ;,. ,"< •• ,' , , '~;. I' i' I ~. j .-.'-'-" . .... ; ':j I : , 9----..:....-. . . l ----& , 2 i--. 3 4 -r'" -i I I i I , i' , A ' I ) 5 ~~t ~ ~.-_..i=-=-.:..::-i __ ·'t=.L 6 . . -'"---,''' -' ",--.. ··~--.. ~~;"::'~·~·~·~::FT~:~':·:~~·:'.·~~·, .. -",~ .. ' -1 If! -"I ',.,,' I i- : I ~ . • • • ('II -0' C 0 -~ 'c • ::> CI) 0). o· :> ..s:: III, ·c • 0 0.. en ',. i. i • III a c z ID 0 ., • +1 0 1 0 1 ., ., &II z '2 ¥ 2 % ... 3 &II ~ L :. =+4 "-0 +3 ... Z &II C,) ffi +2 a:. ~ +1 tc 0 :J 0 0' ., ! C,) 1 CO,NSOLIDATION, CURVES LOAD IN KIPS PEl SQUAIE FOOT· Boring 8 Bag 2 Depth 91 ~===r===f::Fff=Ft~::::r==-r-rl Remolded to 900/o)of I Maximum Dry Density o INDICATES PERCENT CONSOUDATl.ON AT FIELD tilO.ISTURE • INDICATES PERCENT CONSOLIDATION AFTER SATURATION PROJECT NO. ENGINEERING. INC. ,DRAWING NO. 31 73-3-16BC BENTON .... --------------------------------------~--~---~-~- • • • • • • • • • • • BENTON ENGINEERING, INC. APPL.IED SOIL. MECHANICS --' FOUNDATIONS 6717 CONVOY COURT SAN DIEGO. CAL.IFORNIA 92111 ,PHIL.IP HENKING BENTON JO'U!8IDIrNT -CIVIL ENGINEER APPENDIX A TELEPHONE (714) 565-1,955 Unified Soil Classification Chart* SOil DESCRIPTION GROUP I. COARSE GRAI NED, More than half of material is larger than No. 200 sieve size. ** GRAVELS More than half of coarse fraction is larger than No.4 CLEAN 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. FINE GRAINED, More than half of material is smaller than No. 200 sieve size. ** SilTS AND CLAYS liquid limit Less than 50 SILTS AND CLAYS liquid Limit Greater than 50 III. HIGHLY ORGANIC SOILS SYMBOL GW - GP " GM " GC / SW SP SM SC ML CL OL MH CH OH PT TYPICAL NAMES Well graded' gravels, gravel-sand mixtures, little or no fines. Poorly gra-ded gravels, gravel-sand mixtures, little or no ft'nes. 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-si It mixtures. -'Clayey sands, poorly graded sand-clay mixtures. InorganiC silts and very fine 'sands, rock flour, sandy silt or clayey-silt-sand mixtures with sl ight plasticity., Inorganic clays of low to medium plas- ticity, gravel'ly clays, sandy clays, silty clays, lean clays. Orga~ic silts and organic si.lty-c1ays 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. * Adopted by the Corps of Engineers and Bureau of ReClamation in January, 1952. ** All sieve sizes on this chart are U. S. Standard. ~ . --, • • • • • • • • • • • PHILIP HENKING BENTON PRIESIDENT . CrVIL ENGINEER Sampling BENTON ENGINEERING. INC. APPLIED SOIL MECHANICS -FOUNDATIONS 6717 CONVOY COURT SAN DIEGO, CALIFORNIA 92111 APPENDIX B TELEPHONE (714) 5615·191515 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 soil 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 field-moisture until completion of the tests. The driving energy is calcu lated as the average energy in foot-kips required to force the sampling tube through one foot of soil at the depth at which the sample is obtained. ' Shear Tests The shear tests are run using a direct shear machine of the strain control type in which' the rate of deformation is approximately 0.05 inch per minute. The machine is so designed that the 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 ang Ie of friction and cohesion .• Where considered necessary, samples are saturated and drained before shearing in order to simulate extreme field moisture conditions. Consol idation 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 pla'ced in contact with the top and bottom of each specimen to permit the read>, addition orrelease of water. Expansion Tests One inch high samples confined In the brass rings are permitted to air dry at 105° F for at least 48 hours prior to placing into the expansion apparatus. A unit load of 500 pounds per ·square foot is then applied to the upper porous stone in contact with the top of each ·sample·. Watet . 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 d.ial reading is recorded .and expansion r~ recorded until the rate of upward movement is less than :1/10000 inch per: hour. • • • • • • • • • • • APPENDIX C BENTON ENGINEERING, INC. . , \ ( • • • • • u x i « • • I • • • Case (I): RECOMMENDATIONS FOR EXPANSIVE SOILS For soils with an expansion potential over 6 ,percent under unit load of 150 pounds per square foot from air dry to saturation.(Tests to be made after grading), 1. Use continuous interconnected re.!"-for.!;~.d footings throu_ghout, and place these at a minimum depth oftWO'feei-helcwrtlielowesFadiacent exterior final ground surface. Avo'id the use of isolated interior piers where possible. 2. Reinforce and interconnect continuously with steel bars aU interior and exterior footings with a minimum of one 115 bar at 3 inches above the bottOlTl of all footings and orie 115 bar placed 1 1/2 inches below the tQp of the stems of the footings. 3. Use, rqi~~_wQodeI'lJJ~rs __ spanl'lil'lg between ~ontlnuous footings if possible. ' Reinforce all concrete slabs ,on grade with a min.imum of 6 x 6 -10/10 welded wtre"fabric and provide a base layer of at least 4 inches of crushed rock beneath all cOncrete. slabs. A-moisture barTier~'should be provided above the crushed rock and'fhen 2 inc;:hes of sand should be placed over the moisture barrier and below the bottom of the sl ab. 4. Separate garage slabs from perimeter footings by 1/2 inch thickness of construc- tion felt or equivalent, to allow independent movement of garage slabs relative to perimeter footings. Assure complete separation by extending the construction 5. 6. Case (II). 1. 2. felt over the ful·1 depth of the front thickened edge of the garage slab. Cut off garage door stops at least 1/2 inch above the garage slab. ' Provide positive drainage away from all perimeter footings with a vertical fan of at least 6 inches in a horizontal distance of 5 feet, outside the house walls. Exercise every effort to assure that the soil under the fot,lndafions and slabs has a uniform moisture content at least 1 to 3 percent greater than optimum throughout th~ top 3 feet Pelow finished grade at the time'of placing the foundations and , slabs. For soils with an expansion potential over 2 percent but less than 6 percent under unit load of 150 pounds per square foot from air dry to saturation. Same as Case (I) with the following exceptions: Continuous footings may be placed at a minimum ,depth of18 inches.in lieu of 2 fee,t as indicated in Item 1 under Case (I) No.4 reinforcing bars may be used in lieu of No.5 bars as Indicated in Section 2 under Case I. BENTON ENGINEERING, INC. • • • • • • , I • • • • • APPENDIX D Spanish Village Unit Nos. 1 and 2" Rancho La Costa Carlsbad, California Pro ject No. 13-3-16BC May 10, 1973 .:>1'11 .<:>Vllfl33VlI<:>Vl3 VlOTVl38 • • • • • • • • • I. i I ' • -2- As a part of the subject preliminary Soils Investigation, we have also comple'ted a reconnaissance g~ogic investigation and transmit herewith our findings. The intent of this appendix is to summarize our observations concerning thE!,geolog,}! and potentiqLs~9JQQ.tc ha]- ards on the subj!.£Ltite. The scope of this investigdtion consisted of a visual sHe examination, Iit~rch, and a review oJ several soilS ihv.estigation reports in. the immediQte vicinity. In general, the sfte is underlain by 'the D~lmar FormcitJQn, TO.r.r£Y.....?s!o.9!.i'Q.J;le, a,Upy.i,wtn, coliuvium lan9~I.id.!l! .... d~.b.ris, an.sLt~QR.so.jJ.s. Princip-aLg~o.logjc ha;C2.~ds include: oLdJdlJds.IJ.~'§..,6.Ql1es, the .sLQ}re,y_D.eJm.<:lr Fo rmati on wh i cb~i.sJ.andsl.i.de~pro,ne_and~c.onlain$ expansix~ c I Q~J.._ 9.11c!J;hLc;..~..ge pos i ts of $o£LC;9mp"re~sib I e aj I.!-Iv i.u.m.lD..J:be_mQj.o.["S.tLEtQ~",~.~. It is our understanding that ~ and/or two stoQ! wo,odJrarne dwellings are planned for this proposed development. . ." On April 6, 10 and 11, 1973, a visual site examination was made and surrounding. areas were inspected to provide relevant information for comparison. Available pertinenf literature was searched for data on geology and geologic hazards in the vicinity. Boring logs from this soils in- vestigation as well as from our previous so ils investigations in the immediate vicini,ty were reviewed .. This irregularly-shaped parcel consists of approximately 1.42 acres bounded by La Costa Ave- nue on the north, EI Camino Real and the proposed La Costa Plaza on the west, Wiegand_B.!:Q.p.acty (prqeosedr EI, ~9_11J.i.I)Q §~ns) on the south and La Costa South on the east and northeast. It lies in a port.ion or the SE 1/4 Section 35, the SW 1/4 Section 36 T12S, R4W, SBBM, and'the N 1/2 of Section 2, T13S, R4W, SBBM, CityofCatisbad, San Diego County, California. '1 Iv\o.:.derately sloping topography is predominant on this site which includes rounded hilltops, moderately to steeply sloping valley and canyon sIdes, ahd gently sloping valley bottoms. Drainage is in a westerly direction. Annual grasses and scrub brush cover most of this area which has been partly cultivated in the reCent past. Elevations vary from 49.3 feet in the valley bottom Qdjacent to EICamino Real along the southwest boundary to 252.9 feet on the hilltop in the northwestern part of the property. Total relief is 203.6 feet, which gives a good indication of the hilly nature and high topographic relief of the area • . The soils and geology were observed in natural su.rfa~e exposures and in nearby and adjacent cut slo,pes. In addition, boring logs from this soils inveStigation and from previous solis invest.igat- ions were reviewed. These previous investigations include th~ following: Project No. 70-11-18B, entitled IIPhase I, Pre-Preliminary Soils Investigation, MBD Property, Rancho La Costa, San Diego County, California," dated December 11, 1970; Project No. 69-9-8C, entitled "Prel.iminary Soils Investigation, La Costa South Unit Nos. 5, 6, and 7, East of the Intersection. of La Costa Avenue and EI Camino Real, San Di'egoCounty, California,1I dated No~ember7, 1969; Project No. 69-3- 24BC, entitled "Preliminary Soils Investigation, La Costa South Unit Nos. 2, 3, alid 4, East of the Intersec;tion of La Costa Avenue and EI Camino Real, San Diego County, California, II dated May 22, 1969; Project No. 73-3-1A, entitled lila Costa de Marbella, Lot 206, La Costa South Unit No.3, Carlsbad, California," dated April 11, 1973; Project No. 72-1-11A, entit·led "SoUs Investigation, Proposed Borrow Area, Southeast Comer of the Intersection of EI Camino Real and La Costa Avenue, La Costa, California,'1 dated February 18, 1972; Proiect No. 72-6-2BC, entitled JIPraliminary Soils Investigation, Wiegand 'Parcel, San Diego County:, California," dated July 20, 1972; and Pro- i~ct No. 73-3-9BC entitled" Preliminary Soils Investigation, Spanish Village -West - 7 Acre Site, La Costa, Carlsbad, California, II report forthcoming. BENTON ENGINEERING. INC. • • • • • • • • • -3- The 'entire area is underlain by the Middle Eocene .age (approximately 45 mill ion yearS before present) Delmar formation which crops out along the lower valle), side; •. ~JUs.ov~d,aJn by the Mtci9l!..£<?_~~~!:..JJlli.!L~a!'c!!!~\y.El.£h~fPP5.-Qyrqii}he~-bi.g.he'~'~elavation ridg~~ QIJ.d , hi 1I tops..!, __ Q~aterna!~'li urn andMcqJ I.l!,~ it,lm <?r~_p~~El!H~I'!._tb~_~c.qn,yon. aJJQ. y.alley~ot!Q~S cfnd lo¥(.eP/al·ley .. sides. Landslid!3. and slump debris i~_J~res!~t 19P9llx,_~sp_e~J.Qlly_gl.Rt19.lh~_sl~1~~""pf th~ __ 01alr:l*east=~t tren\ding valley':. and on. the ,st~~p-~~cS'rlLf2gJng"Ja .~.qstg Av..e~e .. a!qn~.l.b!'. nortr bctu.Dslary. Topsoils .are variable in thickness and have been deeply cultivated 00 most of the gently sloping and fl~ti-'lqlJd areas ... . , The Delmar Formation is the oldest and lowest elevation unit, underlying all of the other formations which are younger-in age. Due to a slight regional dip of approximately 1.50 down- ward in a west-southwesterly direction, the top of the Delmar Formation is 'at different elevations across the area. Along the northern boundarY the top is at about 107 feet elevat.ion, near the southwestern boundary th~f top is at about 87 feet elevation, and in the eastern section the top is at about 158 feet elevatiGi'l., The base of this formation is not exposed in this area, but it is at . least as low as 50 feet. elevation where the formation is exposecl, in road cuts along EI CaminctReal. The~S!r.£2Lmation is composed prima~!!~!~e,n ,9ncLg.tgr..:::9r.E3~ett91..qy.,.,..QIl,~Lc;lgJ'J!Y silt with interbeds of.llitht ~PrP.w.(u;IE.yP.,X-,9:I1d.."sllty_s.ot1d .• ,.. Clays in fhis formatigrl .. Sl.te_es- peeal1y wea~ andulalJ~~e.r.c?"r:'~. Sp~ial attentio!;!~shoulq P~~~!!3_to~Jh~m_w.h~IJ .... t.b~y~qtE! en- cou~~d duri.l;1g_gX .. Qging.J,g,.9ssur~ thqtc.Q_tg!).9to.r_ .. f1J.L.~tQP'~$",ar.~~h9t9.Y..~~t~!e~..:. In addi.tion to !h.eir l~~~.nggr.,;.th!}:' are a}:o c;:i!ically ~,~~~~~~~~~.,~e~EigJ..fQul1dQ,t,jQIJ~e;~i9,t!!,:ffl!.!.~be requlred.~f ~ are allowed to remain wltFi~foO,lU'l .... ~_qf""p.LQRQ.~.s:L.!trg.~!-"!..~ •. In general, we recommend laying cut slopes made entirely or in part Within this clayey formation back to at least 3:1 (horizontal to vertical) or flatter. Of particular note, in this regard, i~lhe grqgeelanned _-:'"-'"",,<~ __ ta ro: f .... =t .. ~:;;;-.,£ll\';~ ...... SIR'( .... ~........---...-"".-~--.-..", -"< --, ... $!>t~ __ l'<'f'J'_,~_~' for Levante = Street e.~t!~!!. a!;l! £9!]l!l£.."",-~L!i,~-,,~!'t!!:9! .b_v~~r~d!ee~t .~f< roa~~~ ,yIjJ}-:~.;~~9yn,ter the De-Imar Formation cia):'. . . 'Pol t i'1OiWlrOtd!:?~~ Tor.r~y Sandstone overlies the Delmar Formation and forms the high-relief rugged badlands- appearing topography in the 'higher elevations. It underlies the highest hills and ridges which stand out in 'bold relief in controst to the Delmar Formation which is found in subdued gentle rei ief only in the lower elevations alongJhe valley bott~m$. Torrey Sandstone is composed primarily of light gray and light brown slightly silty to silty (lod clayey fine to medium sand. Loeall)!.1 these...§oHs ca!] pe expansive and should be tested prior to H,s~.for !~.Iect.bo..rrrux. material • ...,.The Torre)! Sandstqne is .!i9toorro..oJfX_suoiicit)o JanC!sliding..e.Y.....wJ~jJ • However, since it ovetll~ the-lQn.d.~.Ltd~.::eL9nWflI .. mar Format.ion, it is often direc:!!x.Jnv.olv~td.Y'li.thJQ..."-d.sliding.l_!D_ effe~.!l._ri.g_1ng_dc?w.D",,::,plg.gx-:R.aFkll s~yle .w1tb~tb~~u<l)g.edxing"JgjlLQ.g_D.~Jmar clay-!" In this regard, whenever Torrey Sandstone and Pel- mar Forma~ion green clays are encoun~ered in ~he same cut slope, the entire cut slope should be treated as though it was all clay and be laid back to slopes fn the ord~r of 3: 1 (horizontal to vertical) or flatter to mitigate the possibility of landsliding. Q!:late!!!9...ry_aIL~xJ.v_m_cmg£qJll:'~!!.L.,.are presen~ in the .main canyon and valley bottoms and lower valley sides. Colluvium in this area is essential·ly slope wash that has not yet been transported downward into the creek bottoms and it may be treated like alluvium for grading purposes. Alluvium in the main east-west valley is. at least 20+ feet thick in its lower reaches. It consists of loose and 50ft, porous deposits of sand, silt and clay in varying mixtures •. In all cases, alluvial and colluvial materials should be removed and recompacted, or in the ~ase of deep valley fill partially removed and recompacted prior t9 placing additional fill or footings. The water table in fhe lower reaches of the mQin east-west valley is at abou~ 44 to 45 feet elevation. . BENTON ENGINEERING, INC. • • • • • • • • • • -4- Landsl ide. and slump deQ.r.iLis~p.resental9.llg~_$jg~~~(tf_the .. main .east-welt~'{,a.lte.y',.,and tllolJ9J:beri~ttb .. sJde-o.fJhe..P.rqB.ert~~v,J~!.lue.. In each case, failures are related fo the clayey Delmar Formatic;m. ~ outlined in our aforementioned Pre-Prel iminary.: ~yesti-_ ... ---=~ #~,.; -"",~) • _ ..... d!'~ ~ g~o.n C?f t~~_Mlg l(2e..e..rlXi~.~ti!I ... c!9 not I.!£~~:tfllQe.m~xlti>f th~ ~orthern e,q,r!. of .rbis ar~9..$p!l9J..9..,<;0~la Ay .. ~,nue... We .!-~~.IJ~ttb~gkqIJy_pl:op.osa(;Ld~x@JQP~~el?~e?" ~ ,!!!l!!.imum o~~lJ?g.<;;kJr?mJ:,h~Rl.Qe.sLt.h~$,c.a.t:p_aboy.e,.Lq_CQ.!i.t~QM .. Q.,. Along the si.des of the main east-west valley, numerous small slumps, poe":'outs ancLoJ.d. soil failures are e.!:!!ent. Most of these and their accompanying loose material can be removed and re .. ·compacted during grading. Two sli.des o.f.e.q,rtic1dJar.~~t were encountered in borings on the ridges on each side oUh~ .moutn ou.~!.>~.~kU~9§J:';:'W~.st_(Ik~<rJ09~:CCiJi[2=o[tne::$OUS:i:e~o::ct::Pn Spanish Village' -West -7. ,Ar;r,.e Site, iry e.r.2.9ress). These old, sl ide, zOIJ~w.eJ:eJ.!:tCS~.t:!.sUn .!~~ee!:.o.e.?rt oJ the DelJ)loLEo.rm.atlon_cla.y and are die.elns. ?dversel~,9R~Q';Y9r.~ o~t !if ~19~..:.Y.r:adIQg...2~rationS: around. these' !wo r! <;!9.!L(~~eeF:i~~J I ¥. a lorig~.IJjJLAYe.o.ue .. ,extensionL~bQtJ I d".Qeogone...w.t.tlu;SIJ t i on; buttressing or Iq~12p-es. back mqx be nes::essa!}J_<;L~e9.tlqi'1g_\.!P-ghl..99h tndJy.i~ual ~!~~tion. P.rtolrer .y(eakJ.gnds,l ide ;g,'lll:W~Q~Qouote,r.ed_tn...Bor..lng~o~.,JJLQj""'tbJs repolt at 2... d~~.,.of 253 to_2Zl.e.et ..... It dips'generally easterLy-C.crossJhe~~U:QP'..9.s_e"d~cut,~!2e£,' but it will day-Iignt dt Just about the ad elevation of the 10 in...tb.e~C!..~S,tre.et cul-de-sac. Buttressing or low slope rat- ios m'ay be regl:!ired try this area to mitigate possible slo~fOiI~ri~o-", -10 'I"" .. ~1Iili~~~' _AI ""'1 iI,(;O ..... __ ~ A,weak landsI15!ttz;one. wos_el1.G.q,untered in Bo~i~§}'~?:H1~_~fJ:h!s~e9.tl-gL<Ld~ptUJ?J..JA~:§ ·to 2~~~we~ di~ is favordbl~ ,nto ,the, Et?sJ!till.9J)JI1sJsI!U!nQlill~~~9ro.!.!.oJ'{J.t.Rro2-0!ed to cover Hie entire area. ___ --.. -....... -..... "~:~--.... .J Several major landslides and potential major landslides were observed during our reconnais- sance of the site. In additiori, shallow slumping cmd creep was noted in the topsoils and in the clayey Delmar Formation. The principal slide areas and weak landslide-prone Delmar Formation are discussed in the paragraphs above. Based on our observations to date, it is our opinion that cut slopes entirely within the Tc~rr.e.)!.,.~.Q.o~stone may be planned for ratios of 1, .5: l.(horizontal to verti- .cal) or flatter and ~ut slopes within the Q!L~9LmQtipl1~~~~~~ D~~...E2!.mqtion,;lo.t:rey Sandstone s~-ke!Q!!ned tor cut slop-§~ratJo.§ 0.fJ;J (horizontal to vertical) or flatter unless special recommendations are made to the contrary. Locally, srQalL£auJ.ts~at:e_p~EID!J.JJ...tb.e .... ar.e"C1,. but none are known to be a..s:.l1:!.~.;...q..t ,t~.i!..tlme. The closest potentiaIILc:!!=tiY~J.a~lJJt.is~.-:-.~o.r!h~$.t tre.Q~Ul1g_Ro!.~~.y"Q!!Jaul t located approx- imately 6.3 miles so~hwesterly unde~.theo.i.<:!.~!s. Ocean. N,..o maiE! eartb.g~~h~~,.a~l,l ... [~cord ed ~e ~n~Y'!), tC!'1~gye pccvrr.eCl.-along~t.hisJq~l:tJI)~r~~~.Dt . .bJ.~to!;X.. A few min_or jO~~$!i~~e . earthCJuakes l:laY..e...b.e.en re~ot:ted in the gene,!.al aree., __ h9_Weye!., ~~t"h.a\'~.~!=Iu.sed:little, if~~>,:,: .~~~a~e. The closest large active faults are the Elsinore and San Jacinto faults located 25.5 and 49 . mile~.n9rt.b.!9~teJIy.",..r~,§P~.SJ:J~ly. The closest ~ah?L§.QL~q~~!tl.b.QY..e~_cCUi!.EL4~.~_"~~!t1~,gsJ.E.!9E9 the S~!!J9.~l!:'t? }~lt.2nsJ.59.~s ~o,t~~<?~!.~vt~s..t'pIJ-'th.e N~.wport,:"r~9Iewood falJ.lt. These m~d.er ... ate-sized earthquakes .. had Rlchtefledle magnitudes ranging from 6.0 to 6.8 and produce~ Modified Iv\erc~dli scaIEWD~t.ti.es~Q.JJ."the .... oJ:d.e.r...oj.Ji..J;o""y-J"J.n..tb.e La Costa ared. These intensities are approx- imately equivalent to ground accelerations of 0.015 g to 0.032 g, respectively. In our opinion, simi- lar earthquakes in the future will generate similar ground qcceleratiOris in the La Costa area. BENTON ENGINEERING, INC. • • • • • • • • • • • -5- An area subjected to Iv\odified MercalLLs_c,qle !nt13n"$.i.ty_Y..LgrQV!Jd_a~E~le!Eti~!.l:t)Vo,uld ex- peri.en.cELt.b~...1ollo..Y{log_maximum effects: Felt by all; many frightened and run outdoorS. Some heavy furni-ture moved; a few instances of fallen plaster or damaged chimneys. Pendulum clocks stop. Damage slight. No damage is anticipated to buildings of good design and construction. Southern California'has been placed in Seismic Risk'Probability Zone No.3 (Uniform Building Co,de, 1970j PQge 122). In this zone, Modified Mercalli scale intensities of VIII (approx- imatelyequ-,al to aground 'acceleration of 0.149 g) or greater may be expected. An area subiected t6 earthquake induced N\odified Me rca II i scale VIII ground accelerations would exp,erience the fol- lowing errjaets: Damage slight in specially designed structures, considerable in ordtnary substantial. buildings,Orid great hi poO~ly built structures. Panel walls thrown out of frame structures. Fall of chinineys,columnsj and wal'ls. Heavy furniture overturned. Well-water levels change. Persons driving motor cars disturbe'd,. Howevel~, based on our experience in the area and the known seismic record, it is our opinion that Int~y_\i,lJLQL.9~~.~~!~Jl!.~Y~_~~~tQJLQlJs_are_u,n l.il<eJy_t~LRC.<:U~ i!,. t~e ,L,? .£2!!~"prea • Therefore, a normal seismic;: factor for tbis area of Southern California should be adequate for' most structural design. If you have any questions ,after reviewing this appendix, please do not hesitate to contact this office. This opportunity to be of service is sincerely appreciated. Respectfully submitted, BENTON ENGINEERING, INC. By GJ,~~ W. J. Eiott, Registered GE!ologist, 1101 Reviewed by _ .' M:V. 'Pothier:, Civ"t1 E~g'ineer Distr: (4) Addressee WJ t/PHB/meg BENTON ENGINEERING, INC.