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HomeMy WebLinkAboutCT 72-20; LA COSTA VALE UNIT NO1. (LOTS 219- 225); PRELIMINARY SOILS INVESTIGATION; 1971-10-22I BENTON ENGINEERING, INC. PHILIP HENKING BENTON P'IUCSIDltNT • CIVIL ENGINIEEII Rancho la Costa Route 1, Box 2550 Encinitas, Californta 92024 APPLIED SOIL MECHANICS -FOUNDATIONS 6741 EL c.-.JON BOULEVARD SAN DIEGO. CALIFORNIA 92115 October 22, 1971 ~r - SAN Dl~GD, 583-5654 LA M,;SA: 469-5654 Subject: Profect No. 71-10•18F l!r.!,limJnary Solis lnvestlgatJoft C, -=, ;;)-;}O L/t'\,l1 1 Lo Costa Vale No. 1 Gentlemen: Northwest of the Intersection of La Costa Avenue and Rancho Santa Fe Road Lo Costa Area, Son Diego County, California CONCLUSIONS It is concluded from the field Investigation and laboratory test results that: 1. The medium firm to very firm natural soils are suitable for support of the pro• posed ff lls and/or residential structures. However, loose or porous compressible upper soils, slmilar to those encountered to a depth of 6.5 feet in Boring 2-11, and to 6.0 feet In Boring 18-IV, may be expected to exist In certain low areas. lt Is recommended that these materials, and similar materfals be removed, and that the compocted filled ground and/or footings be placed on the underlying natural soils determined suitable for foundation support. Alto potentlally expansive clayey fine sand, sandy clay, silty clay, and clay soils were found in certain areas and speclally designed footings and slabs are recommended where these ex- pansive soils are allowed to remafn in place withfn the vpper 3 feet below finished grade. 2. It ts concluded from the results of the laboratory tests t~at the natural solls, suitable for structural support, have a safe bearing capacity of at lea1t 2500 pounds per square foot for one foot wide continuous footi~s placed at leaSt one foot below firm undisturbed natural ground surface. The settlement of a one Foot wide continuous footing loaded to 2500 pounds per flneal foot and founded on suitable undisturbed natural soUs Is estimated to be less thon 1/8 Inch. 3. The results of the laboratory expansion tests Indicate that certain of the clayey fine sand, silty clay, sandy clay, and clay soils encountered in the Investigation would be con- sidered as "expansive" sotls. Therefore, In order to avoid the use of specially designed footings and slabs, it fs recommended that, wherever practfcable, the "expansive" sofls h&moved to a I ----,ytlHiNq bt;::,• St p lifrl/lf (/.; /JJ r l9J2 . s1010.21 ?11 Project No. 71--10-lSF La Costa Vale No. 1 -2-October 22, 1971 depth of 3 feet below proposed finished grade and be replaced with nonexpanslve soi 11 unfformly compacted to at least 90 percent of maximum dry density. In fl fled ground areas, all "expansive 11 soils should be placed at least 3 feet below the ffnal compacted flll surface. If "expansive" soffs are allowed to remain in the upper 3 feet below ftnlshed grade, it Is recommended that footings and slabs be specially designed. The required special design will be dependent upon the degree of expansion potential of the soil, the thickness of the layer, and the location of the expansive loyer witli respect to the footings or concrete slabs, The lots requiring specially designed footings and slabs wlll be listed upon the completion of grading. 4. All of the soils moy be satlsfactorlfy compacted In the flll areas and, when com• pacted to at leost ~ percent of maximum dry density, hove a safe bearing capacity of at least 1650 pounds per square foot for one foot wide footings placed 1 foot below the compacted ground surface. The settlement of a one foot wide continuous footing placed on fill solls uniformly com- pacted to at least 90 percent of maximum dry density ts estimated to be on the order of 1/8 Inch. It is recommended thcit all t0ft, loose, or compressible sollt exlstlng In proposed compacted filled ground areas ba removed as required by the soils engineer and the compacted fl lled ground ba placed on firm natural sofls. Recommendations for tho plac:emont of FIiied ground are presented in the attached "Standard Speciftcotions for Placement of Co~acted FIiied Ground," Appendix AA. S. A. Past experience ts making excavations in the dlty clay onddayey-sllt formations in the La Costa area has indicated that the slopes should be cut on a slope ratio of 2 horizontal to 1 vertical or flatter. It should be noted that any cut slopes in areas such as the plastic clay and claystono below 8.5 feet tn Boring S-11 should be no steeper than 3 horizontal to 1 vertical. It is concluded from the test data that cuts mode tn other types of 10ils and rock formations may be safely excavated on a slope ratio of 1 1/2 t-ortzontal to 1 vertlcal for heights up to at least 50 feet. Slope stabtltty analyses ore shown on Drawing Nos. 22 and 23. 8. The fill soils, when uniformly compacted to at least 90 percent of maximum dry density tn accordanc• with the approved specifications, will be stable wtth an adequate factor of safety when constructed on a 1 1/2 horlzontaJ to 1 vertical slope for heights up to 30 feet. The above conclusions auurne that suitable erosion control and proper drainage will be provided to prevent water from runnfng over the top of exposed slopes. 6. Both cutting and fllllng ore r•qutred for development of the site. Residences may be constructed portly on cut and partly on fill provided the load-settlement characteristics of the natural solls and the compacted fflled ground ore comparable. If any soll types are encountered during the grading operations that were not tested In this investigation, additional laboratory tests will be conducted in order to determine their physical characteristics ond supplemental reports and recommendations wlll automatically become a part of the specifications. Pro I ect No. 71-10-1 SF La Costa Vale No. l -3-October 22, 1971 The data presented on page 1 to 8, tnc lusivo, and on Drawing Nos. 1 to 23, inclusive, as well os Appendices AA, A and 8, are a part ef this roport. Respectful fy submitted, BENTON ENGINEERING, INC. By ~/ft-7~k Mc ae . opl Reviewed by,~ ~ WIiiiam ~-Cotlln,v ngneer Distr: (4-) Rancho La Costa, Inc. (2) Rancho La Costa, Inc. Attention: /IN. Burton L Kramer (2) Rick Engineering Company Project No. 71-10-lSF La Costa Vale No • 1 Discussion -4-October 22, 1971 PRELIMINARY SOILS INVESTIGATION A preliminary soils investigation has been completed on the proposed La Costa Vale Unit No. 1; located northwest of the intersection of La Costa Avenue and Rancho Santa Fe Road, San Diego County, California. The location is more specifically referred to as a portion of Section 31, T. 12S., R. 'J,N ., portions of Section 36, T. 12S., R. 4W ., portions of Section 1, T 13S., R. 4W ., and portions of Section 6, T 135., R. w-/ ., San Bemardino Base and Meridian, San Diego County, Callfomla. The obiectives of the investigation were to determine the existing soll conditions and physical properties of the sofls in order that engineering recommendations could be pre- sented for a safe and economical foundation design and for the development of the proposed building sites. In order to accomplish these objectives, ten borings were drilled, and repre- sentative undisturbed and loose bag samples were obtained for laboratory testing. General The proposed subdivision Is located on the south side of the valley extending easterly from Batiquitos Lagoon. La Costa Vale Unit No. 1 is located primarily on the higher lands near the crest of the hills forming the south rim of the valley. Drainage is primarily northerly; future dratn~e will be Info streets and stonn drains. According to the soil map prepared by the U. S. Department of .AGriculture, the upper soils have been grouped into four categories. They are as follows: 1) Altamont clay, which consists of 0.8 foot of moderately compact cloy, 0.9 to 3.5 feet of very compact irregularly calcareous clay, and bedrock. 2) OIJvenhaln loamy fine send, which consists of 0.5 to 1 .4 feet of friable loamy ftne sand, 1.5 to 1.7 feet of very compact solonetz clay, and bedrock, partially consolidated. 3) Huer.huera fine sandy loam, which consists of 0.7 to l .4 feet of frfable fine sandy loam, 0.7 foot of very compact solenetz sandy clay loam, 1.0 foot of moderately com- pact columnar sandy clay loom, 1.7 to 1.9 feet of moderately compact, moderately calcareous, fine sandy loam, and slJghtly compact sandy loam. 4) Les Posas stony fine sandy loam, which consists of 0,5 foot of friable stony fine sandy loam, l .0 foot of slightly compact columnar stony fine sandy loam, 1.1 to 1.7 feet of moderately compact stony fine sandy loam, and bedrock. The major soil types encountered in the exploration holes, as classified in accordance with the Unified Soil Classtflcatlon Chart were clayey sand, sandy clay, claystone, cloy, stlty sand, silty cloy, and sandy siltstone. Profact No. 71-10..JSF La Costa Vale No. 1 Field Investigation -5-October 22, 1971 Ten borings were drilled with a truck-mounted rotary bucket-type drlll rig at the cipproximate locations shown on tho attached Drawing No. 1, entitled 11 Locatlon of Test Borings .. 11 The borings were drilled to depths of 12 to 63 feet below the existing ground surface. A continu- ous log of the soils encountered in the borings was recorded at the time of drilltng and Is shown in detail on Drawing Nos. 2 to 18, fncluslve, each entitled 11Summory Sheet. 11 The soils were visually classified by fleld identification procedures in accordance with the Unified Soll ClasslflcotJon Chart. A slmpltned description of thi, classffication system Is presented in the attached >ppendix A at the ~ of this report. Undisturbed samples were obtained at frequent Intervals, where possible, tn the aolls ahead of the drilling. The drop weight used for driving the SOl11)1ing tube into the soils was the II Kelly11 bar of the drill rig which weighs 1623 pounds, and the avora99 drop was 12 Inches. The general procedures used in tleld sa.,.,llng are described under 11 Sampllng11 In Appendix B. L~boratosy Tests Laboratory tests were perfonned on all undisturbed samples of the soils In order to determine the dry density, moisture content, and shearing strength. The results of these tests ore presented on Drawing Nos. 2 to 18, inclusive. Consolldctton tests were performed on representative sam- ples In order to determine the lead-settlement characterJ1tfcs of the_soils. The results of these tests ore presented on Drawing .Nos. 19 to 21, lncl.usfve, each entitled "Consolidation Curves.11 The general procedures used for the laboratory tests are described briefly in Appendix 8. Direct shear tests were performed on selected loose soll samples rernolded to 90 percent of maximum dry density and on selected undisturbed samples that were all sahJrated and drained prior to testing. The resulll of these tests are presented below1 Boring 1, Sample 2 Depth: 11 • 0 feet Boring 1, Sample 6 Depth: 31.0 feet Boring 2, Sample 5 Depth: 26.0 feet Borlng 2, Sample 8 Depth: 42 .O feet Normal Load in kips/sq ft 1.35 3.93 3.37 5.42 Maximum Shear Load kip¢sq ft 1.89 3.85 3.84 5.06 Angle of Internal Friction Degrees 38.0 Apparent Cohesion lb/sq ft 820 Project No. 71-10-1 BF -6-October 22, 1971 Lo Costa Vale No. 1 Maxtmum Angle of Normal Shear Internal Apparent Load in LO<Jd Friction Cohesion kips/sq ft kips/sq ft Degrees lb/sq ft Boring 1, Sample 5 1.0 1.43 28.5 900 Depth: 26.0 feot 2.0 2.10 4.0 3.01 Boring 4-11, Bag 2 * o.s 0.70 33.0 390 Depth: 4-5 feet 1.0 1.20 2.0 · 1.83 Boring 5-11, Sample 2 0.5 1.05 44.0 5"/0 Depth: 6 feet 1.0 1.98 2.0 2.9'2 Boring 16-IV, Sample 3 0.5 1.14 45.0 ** 640 · Depth: 8 feet 1.0 1.65 2.0 3.74 Boring 19--IV, Saffl)le 2 0.5 1.0"/ 27.0 820 Depth: 7 feet 1.0 3.33 2.0 1.84 Boring 19-IV, Bag 3 * 0.5 0.52 34.0 190 Depth: 14-15 feet 1.0 0.86 2.0 1.41 * Remolded to 90 percent of maximum dry densl ty ** ArbJ trarily reduced Using the values of angle of internal friction and apparent cohesion detennined as shown above, and the Terzaghi formula for local shear failure, safe allowable bearing values for the wecdcest soils are determined on the following page. . - Project No. 71-10-lSF La C05ta Vale No. f October 22, 1971 Local Shear Fonnula: Q'd = 28 (2/3 CN'c + Y Of N'q + Y BN'y) (1) Continuous footing 1 foot wide = 28 (2) Depth of footing = 1 foot = Of (3) Q I Safe = Q• cv'3 (Factor of Safety) Boring 19-IV, Bag 3 (Remolded to 90 percent of maximum dry density) Depth 14-15 feet <I>= 34.00 N'c = 23.0 C = 190 lb/sq ft N'q = 13.0 Y = 120 lb/cu ft N'y == 8.5 Q ' Safe= 2 {190} (23.0} + 120 (13.0) + 120 (8.5) = 1660 lb/sq ft 9 3 6 Use 1650 lb/sq ft . Bori"9 19-IV, Sample 2 Depth 7 feet <1>=27.rP N1c = 16.5 C 820 lb/sq ft N' =7.5 q Y = 119 lb/cu ft N'y=4.0 Q' Safe =2 (820) (16.5) + 119 (7.5} + 119 (4.0) = 3386 lb/sq ft 9 3 6 Use 2500 lb/sq ft In addition to the above laboratory tests, e>q><msion tests were performed on some of the clayey soils encountered to detennine their volumetric change characteristics with change in moisture content. The recorded expansions of the samples ore presented as follows: Percent Exponsron Under Unit Load of Depth of 150 Pounds per Square Boring Sample Sample, Soll Foot from Air Dry No. No. in Feet Description to Sarurotion 1-11 1 2.0 Grayish-brown fine sandy clay n .so 4-11 1 2.0 Brown clayey fine sand 4.84 4-11 5 21.0 Ollve-green claystone 9 .16 5-11 4 16.0 Olive-green claystone 10.28 16-IV 1A 1.5 P.eddlsh-brown fine sondy clay 8.18 19-IV 1 3.0 Olive silty clay 4;00 The general procedures used for the laboratory tests are described briefly In Appendix B. Profect No. 71 .. 10-lSF La Costa Vale No. 1 -8-October 22, 1971 Compaction tesb were perfom1ed on representative samples of the soils to be excavated to establish compaction criteria. The soils were tested according to the A.S.T.M. D 1557-66T method of compaction which uses 25 blows of a 10 pound rommer dropping 18 inches on each of 5 layers in a 4 inch diameter 1/30 cubic foot mold. The results of the tesb are presented as follows: Maxfmum Optimum Mols- B?ring Bag Depth Soil Ory Density ture Content No. Sample in Feet Description lb/cu ft % dry wt 1-11 1 1-2 Greenish-brown fine sandy clay 118.8 12.2 2-11 1 2-3 Brown clayey fine to medium 128.0 9.2 sand 4-11 2 4-5 Grayish-brown silty fine sand 117.0 13 .1 19-IV 3 14-15 ltght brown silty fine to 118.5 12.0 medium sand -~t ~ ~ ~ ~ ----~--~, '\ \ \ I \ \ \ _J__ ~--~z >~ LEVAHTE STREET u___~ -~,-~ . " ' \ . \ I \ l'P.OJfCT 80/INIMRY ,;.v \\ \r I I i.S"-Jl :~, I ';( ~ I ~ I~',,, l{t /4oJ /l ~ ,ndieat•• Approximot, Loco,1011 ot T11t Sorlttg MOJ£Cr NO. TO-6•/IJ~ * hdlc:atn ~ppro,,mot, L«ollon of ,.,, Boriftf ~HO.Jt,'TN4 70.,-2,, ■ lt1~c:OfH /JpprOJtimolt Locolion ol T•sl Borint/ /ll(OICCT NO. TO• Z -Z ¥8 BENTON ENGINEERING, SAN DUGO, CAL.,ORNIA LOCATION OF TEST BORINGS LA COSTA VALE UNIT NO. I INC. DIEGO COUNTY1 CALIFORNIA ,aouc, NO 71-IO-!6F DIAWIHQ. NO ·,·, - ..!! ~ 0 1 u -~; 0 -_, t "i!.. t- ... ~ Ill Q ·- ! % ... D. u 0 ,. .. : ! .... I _, ... ,-A.., u., ~~ ... ... i .,., z ..... ·.•· J .. ·-..... ::.:·:.::: Gray, Slightly i'Aoist, Firm, 2 · ·:·::::'.." lean ~fi light Yellow~rown, Slightly -~,1/-_ Unht VMv Firm ,J (// / Dork Olive-gray With Ora~e- .4,. / / brown, Moist, Very Finn, I/ ,, Badly Jointed Claystone 1 / j I: I,'• / ,J ·ft@ 6-·rr / . / / 7-i, / / / / / 8.,...1/ / / / -------------,. 9-V// / light Olive-brown to Light / , Srown, Moist, Very Firm / / ,., / / 1--r©7 / 2 I/ / /' / ~ / ~ / / . . . . . 14---. . . . - light Gray-brown With Orar-Ge- brown, Moist, Very Fi rm, Poc;kets of Slightly Silty Fine to . ..,__ _ _. Medium Sand 15-: : : : j~ ... -..... 17- -Indicates Loose BCG Sample VERY FINE SANDY CLAY SILTY Fl NE SAND SILTY CLAY CLAYEY FINE SAND □ 0 -f rdicotes Undisturbed Drive Sanple 9.7 16.6 ~05.0 3.76 14.6 l8.2 105.9 2.92 24.3 13.2 118.9 3.72 * -lhe elevations shown on these Summary Sheets were obtained by lnterpolotlrg between contours Utown on o topographic drawi~ prepared by Rick frgineering Company, dated Oc;tober JS, 1969 • ._ ____ ....,__----r.......,._ _.., ___ _ PROJECT NO ,-~~•ffl SEN i ON I kr """' _,.. !:a.::_ Ill 0 .., ~ ~= ! I ;~ ~; 1· SORING NO ____ L_J_Cont .) .,, z ! II ..,:.::o_ <.., --l7-._ __ L.. -·-·· .... _,_ . .,_. --·---·--·--. ------· ··-·-···-····-- :: : : Light Gray-brown, With Ora~e~ 8 : : : : brown, Moist, Very Finn, : : : : Pockets of Slightty Silty Fine to 19 : : : : Medium Sand VVVV Light Olive-gray With Oro~e- 20-/ J brown, Moist, Very Arm, ./ / Pockets of Slightly Silty Fine 21 -~~..,..4___,,. to Medium Sard and Silty Fine / / Sand / / 22 -/ / / / 23 " / / / V/ 24-✓ V // / / 25-.., V 26-(5ji; V VJ / / 27-V / V / / 28-/ / vv , V ,, 29 / / Light Olive-gray With Some Purple, Moist, Very Firm / / light Olive-gray With Oro~e-... / / 30 -· '/ / Brown ~ 31 /V V/ 32 ·-/ / / / 33 V/ /, . vV 34 vv / / , vv 35 -vv , ../ / 36 J7Y: CLAYEY FINE SAND SILTY CLAY (M11m"'" to\ SILTY CLAY {CLAYSTONE) Continued on Drowi~ No. 4 ·. PROJECT NO 16•2•!48 BENTON ENGINEERING. INC. 34.l 12,3118.9 4.84 66.8 11.8 120.7 4.33 58.0 12 .5 120.7 5.44 69 .6 11. 1 124. 9 7 .50 -- -. ] 2 -8 u .s ! I 1 I I I co 0 ... ~ xlZ ~.., a. ... w a ••.:. Light Olive-gray With Orarge- 40-~..,..... brown and Red-brown, Nioist, i.-,,<o_,.. Very Finn 53-- SILTY CLAY (CLAYSTONE) ContirYJed on Drowi~ No. 5 l'ROJECT-,.;;-T·---·-----------.. ~N48 BENTON ENGJNEER)NG, INC. "71-11L 101! 43.3 11.8122.17.50 63.0 12 .o 120.9 7 .50 82.8 12.2 125.1 7 .50 --~,~---..... ·"'--.. ------... -! I r.;11~.,..,t!G NO . A IO 0 ~ light Olive-gray With Oro~e- __ __._-1 brown or£! Red-brown, Moist, __ ..,. Very Finn --,-_..,.-. .. PRO:JECT NO ..::J./l,., o o,n SILTY CLAY (CLA YSTONE) 92.0 13.0 121.7 7.44 99 .6 13 .0 123 .9 7 .50 I i ,,... . 0 z C>: _, O • >: o, ..... g, -ul Q l ...J -t -' J I( . 41 . ~! t : 1.61 i tj i : t! (r -~I IO 0 ...., 1'. ,: ~· ~-,,., c.. ..... BORING NO._ .... t __ . "" I O i t.Ll\'AIIOF-A . _ 1_53_ __ r--o--___,+ .. ---..... ! Dark Gray, Moist, Medium j loose ! I I I I l I· I I ' I .,.__,_..._ Li9ht Olive-gray With Dork -~ .... Red-brown and Orarge-brown, _._""4 Moist, Medium Firm SILTY CLAY {CLA YSTONE) Continued on DrawirG f\b. 7 22.7 14.3 114.9 2.35 ·30,s 13.1 122 .. 0 4.49 I I I I 40.6 14.5 119 -~ 7 .50 I l I j I J ) . I ! I .,_ _____ ,.. __ ,,,~·-__.... ............. _. _________ ,,, ___ ,_,.. _ __...,,._ ____ f_._.;... __ , .... , .. ·-.. ·--i PROJH. T NO ~•IIA Y.•:t , NO. ! :,~4 a RfNTOfJ f:l'l.lf~il\.U:.cuuJ~ , .. 1r .... .:-. 0 z .! D -> D -... 0 u D ...I f _, 1 J j __.: j 1 -f ID 0 -, SUMMARY SHE·;~~-------l ~~T·-:·~[t ~-,r v]7 u,...__I ~JIit v..1 Z VI. 0 ::> Z :> II& Z · I BORING NO ___ 2. (C9nt.) ::; ~ ~ _ 0 ~ i ~ ~-~ ~ ~-\ > !►"" "'vi"' I _.,.. 1.·wlD w~ ' ~ ... •·o ... Oli~ I --18--rT-_ _ ___ . _____ .... ____ -•~ ... -1 / Light Olive-gray With Dark l 1 19-v // Red-brown and Orar,Je-brown, SILTY CLA y l / / Moist, Very Firm ' (CLA YSTONE} l 20 7 ~ l -~ light Olive-gray With Dork l 21--.4 ... Oraf'Ge-brown, Moist, Very 42.2 11.0120.5 6.69 I ··•·-····· Firm l 22_ :·:::·•.:::·.· j ...... ··· 23--:/::'~~::::_: • ,'· . •.·•·· .. 24--: : ·::.::: . ,··.• 25-· :::::: ·.-_·. ... •, ........ ·, .•,•·-···•· 27 .. :·::·:. .· .. -·-··· .. ·• .... ·.·. -... ···· .. 29-.----:·.:.-·.- ··.···. 30..-.. •.· .. ·•-·. ·:-·-.-... · :. '· ..... •,•.:.-.·.· .. . ..... 32--••:•.·· ,,, .. -..... . ·· ..... ·.•, VERY FINE TO FINE SANDY CLAY (CLA YSTONE) Continued on Drawi f'l1 No, 8 PROJECT N◊--·i-----~m-, seN10N \::NGINEERfNG. INC. I I \ I ' 63 .4 11.4 120 .2 4 .73 i 143.2 12.0 124.0 6.49 --------r··------~----·---"' D•.&.v<':t--G NO. ... . -11 I •• -· o · >l CJ I .... , 8! U ; .SI l· l t ... _ ~! ~ I l .. .. ~ w r t ~ ' l -JI U> 0 .... ... < :> I '" :z: . I 3 -. . . . . . . . . --. .. ·--. ---_, .... ---. --.. -.. -.... .. - •:···:····· light Olive-gray With Dark 34 _ :::.:.:·::: Ororge-brown, Moist, Very ··::::·:::: Firm ·.·•······· 35 -· ···,,·.·····.---- ~-~-Light Olive-gray With Dark 36 (J ~ Orarge-brown With Light ·:::·.-::··_-·. Yellow-brown, Moist, Very 37 ·:::::::·.:. Firm, 10 Percent Gravel and ·:.::.-.·:·••: Concretions to 2 Inches, 33 .... ·::.:::::·:. Pockets of Clayey Fine to ::··.:·.·:::· Medium Sand ......... ' 39 .. . .. :.: ..... . .... · :-·· 40-· · •' .· ... . • .. .. ··• .. 4 J . •,•.•,: ....... VERY FINE TO FINE SANDY i CLAY (CLA YSTONE) Merges ---.. .. .. -- 58.3 14.0117.6 7.CJt 33.3 13.8 110.0 7.50 I _, l • ! ~I GI a > .; 0 u 0 ...J ; ~ fi IIO 0 ..., ... -_,, "' IL. IQ ~~ I "'Z I .,.--.. t;i.EVATIOt, • 175' * 0 -----·· . ··-····· ·-···----·---..-cLA· YEY FINE SANID -·-: : : : : Brown, Dry, Lpose , ·•:::::· Gray-Brown, Slightly Moist, ~l;i!{r--...Moist, Madlum Firm _____ FINE SANDY CLAY 2--~-Molst, Very Firm 3 5 •· .. · .... -1-~·-:::-t··:1· -:--;-::----------····· ···· Red-Brown and Gray .. ·,'•, -..... -.... ··.· .-.... 8. 1 14.5 104. 9 4.30 6.5 19.7 103.0 2.89 6 J ·-· , .. · ;~-.I ~-------------~~------+-+--t--r-,--: I I I Light Gray, Moist, Very Firm CLAYSTONE I I 7 -I I I 8 -r!:f_3) - -~ 2 J;. 9 -I I I _ I I I I 10 -I I I I I I 11 -I I I I . I I I I 12 I . 13 ~4~ D 0 * 8.1 13.6 114.9 4.43 , 19.5 5.2 28.4 4.74~- Indicates loose bog sample Indicates undistrubed drivt somple The elevations shown on these Summary Sheets were obtained by interpolating between the contours on a map provided by Rick Engineering Company of San Diego. t------------............. -.. -........... -., .. _......,__,,.. ____ . ---·· ., . --..... , .. PROJECT NO. 1'0=-'8=-1'8f ENGINEERIMG 1t-1C .. : -. 0 z .!1 OI ~I 31 o, ..JI t Ill 0 ""' .:m~DC. SUIAIAARY SHEET BORING N0 .. 2...:.JL. tUVATfuti . J.92'._ __ BENTON FINE SANDY CLAY CLAY, MERGING TO CLAYSTONE ENGINEERING, INC. 4.9 4.9 109.2 0.81 0.8 17 .9 108.2 0.57 3.2 17.5110.4 1.54 4. 9 18.6 109.3 1.81 t:i:1-Wl,.,I'." tJ.f'. -&-10 ) ID 0 ~ ~ :z:t ... w Lllo. .., 0 SUIAMARY SHEET Brown, Dry, Loose, Topsoil Light Brown and Ught Gray ---1 .. , ... .-..,Moist, Very Finn 1 I 26.0 16.8 106.8 3.02 32.5 14.1 13.4 6.58 Continued on Drowii,g No. 5 ENGINl:EMING, INt.. t ft'.) 0 .., . .,.. .. -· ... ----~-~-.---............. ).. I I ;-'. I SUMMARY SHEET 2 :.: I LI.I ►~: ~ i;, 1 ~ l . -~ w• "'--0~31%.:i('':Z' .,j~ :x: :;; .. ., SORING NO 4 -II {s:ont'd) ! ~ .,j .... >-' w \J "",( :q >-w ~~ "' ic ~ ~ -1 0 ' i ~.;. IL "'-> . II. o 0 1 ► ,,, I"' iii r 1 LI.I "'z _,_ ,I ........... _. C ., ....• --,o -' ... .,, o I ... , -1 ~ -----........ --_ ... __ .... . -· . ····---------- -~ light Brown and Light Gray, SILTY VERY FINE .~ ~ist ~ Very Finn TO FINE SANO 1? I I I light Olive Green, Moist, 10 . Very Firm, Highly Fractured Cl.AYSTONE I I -I 1n I I , I . I I 20 . -. . . .... Olive Green, M:,re Massive -I 5 2; '"T 16.2 18.3 100,7 5.47 -I .. I ~ 'T 21 I I I I . . . 2~ I I I -. 2.A . . I I 2.:; . . . -;(6) 2v 54.5 16,2 114.6 5.10 I I I I ) I . 2"7 I I I . I I 2::: I . . I I I . I 2Y I . . I I I . l . . . 3 I t:I 7~ ,_. 31. 7 18.4 110. 1 6.33 31 .. .. ~-··-··•--... -----· -----·-.. _. ·-............. ,,. <I --•• • - ,,, ... • .. PROJECT NO I ;~ '· . :,.: .1Jl.4-~ 8fN";0N ENGJNEERING, INC. .5.. 1? ... ,.. , ,.. ...... : ' ; ! ' ' ' \ ; : ' ! j : ' ' . ; i . ; ' ........ •'. ..t C: tO 0 .... • .... ·. SUMMARY SHEET SORING NO .. ~-- ELEVATION • 298' ). )* 2t:: "'~~t: w, •>z"'. Z \II O :> ::> ..,!:yjl;;~~~ 1M :.c ..:o-o . > . ► "' _.,. ~---~.... ~ 0 ... _o-t::===t~--=-· -·-----------------+---i--+--t--t--: : : : : Brown, Dry, Loose, Topsoil CLAYEYFINESA -4.,~;,..;...:1-------------_L_,Jm.Jt:g§:SJ.-__ .,i__-i,...._-1--+--+--I Light Brown and Ught Gray, jSILTY VERY FINE 3 4 5 6 7 8 22.7 16.8 105.9 1.41 Moist, Very Firm l TO FINE SAND i I l I 16.2 16.4 106.2 2.10 9:IIIO~li~ve~G~r~e~en~,~Mo~is:t ,~V=e~ry:_F~i:rm:_,~I1~~~~~~.~~~~~~~]~~~J~~~][~~~I~~~1~~]-I Plastic, Shows Indication, of j CLAY 10 Pr~vi9u1 Movemont Brown, Mofst, Very Firm 11 I ~~~~~-------------r- SILTY FINE SAND Tt::c"""-:=..,._-c:._';:. ,.,,.d Olive Green, Moist, Very 12 Finn, Fractured , I CLAYSTONE 13 1 Continued on Drawing No. 7 .., 22.7 17.6 106.2 2.29 9.7 18.9 107:2 7.35 PROJECT NO. ~JAWING NO. L:·:::~~_t:!:; __ :!:!Z'·~!: __ :,__,_..L ___ s_E_N_r_o_N ___ E_N_G_,_N_E_ER_1_N_G_, __ ,N_c __ ·_____ _ . l -6-13 ,,.- ,_I Ill 0 ... 2? I ~ .. , ......... • 23 I I I I I I I I I I I 22 I I I ·---·-- I I i ,,. I I I I ---------1 2, • Cemented Lens 1 - , , ·, '\ Dips 3 Degrees Approx. N 70 °~ "U'I_ ', •• w. -Uf ,'1 Olive Green and Brown, Pockets .,, hA .. ?h of Fine to Medium Sand and I \Silty Claystorn, i I I : I • I ' I : i t 148.3 20.3p07.8 4.621 I i ! I I ' I I ! ! ! i l ! 3s.al21.sl103.7 4.48 l * Shear resistance exceeded 7 .50 kips per square foot, the limit of sheor machine. BENTON ENGINEElllN~ INC' . ----·· ·r ··-----·-···•· .. --·--. ORA Wi~IG ~10 -. , .. ! I ' l i ! l I l \ 1 t I ' : ' I i ' ' ! I ! I ' ! l I . \ ,-. ,, j - ·_1- t ! I I : I - ! I J- I I i I ~ "' -~ i Ill 0 .... SUMMARY SHEET BORING NO. 1 -JV ELEV A TION 1701 * FINE TO MEDIUM ! SANDY CLAY 1 ; : i 4.9 , 10.1, 89.o; -l ~~-=--------_j_ ____ _j____ i I : ___, __ Brown, Moist, Firm, 20 to GRAVELL y ; 13 O: 8 7. ,-------,:~~ 25 Percent Gravel and Cobbles, CLAYEY FINE TO ; • ; • : --~ With Rock Fragments to 8 Inches MEDIUM -tz:z:=: LJght Oliva-gray ond Ught -~"""'~ Red-brown, Very Moist, · Medium Soft, Contains Medium lr'ililf"-.. to Coarse Grains Between 6 .6 ~.._.""I and 7 .2 f"t SAND SILTY CLAY I i 1.6 19.4 107 .8 1.94; i . ; I Ii I I I I I . ! I i 3.2 ~ 19 .7 ;105.7! 1.20 I . i I , I . ; . _ 1 ~I: i ! : I I ' I I • • I ! ·----· ·-----~-L._____ 6.2; 12.6H3.014.~ 0 • -Indicate, Undbturbed Drtve Sompl• The elevations shown on these Summary ShHts were obtained by interpolating betwHn the contours on a map provided by Rick Engln .. rlng Company of San Diego. BENTON ENGINE=a;RINn DRAWING NO. -.,._..,..,,.._• . 0 Z , 4) . 0 . > o ; -+-: ~ I ul .:... - .., ~ 1 -. IQ 0 ..., - l : l. 1 ~ ~e I. . ' ... ..:, i ¢fE1~~i I ._ u. i ..,, ::, ' I U• I, _,, :z'. ! C: : SUMMARY SHEET BORING NO. 16 -IV 295, ELEVATION-------I I :-O-Ri,;,i;. .. -Fi •• ~-. Red~b-r;wn Dry, Loose I FINE SANDY I \ I 1 -; ;:Ri Sli;htly ~st, Firm ·---___ c_L_A_Y __ -t..;.13~.~0~1 I ~17:-=•:..:..9t 1' 987._3r::--r7 ~.';,:. ------1'i IJ.0!! -,; I - -' 2 _ ~ Light Gray, Light Brown and SILTY VERY 1 Red-brown, Moist, Very Firm FINE SAND }:: .. ~. -~---\ ----------+----1 !:_ ·, 3 .... -. \. l ·: ··.·.: Light Gray With Yellow-brown I 12 aj109 3 2 JO ~2'~ 16.2 • I • i, • I i -4 ·· ~J~ and Brown, With Zones of Very · ·~·:··:~ · · Fine Sondy Clay, Lean I I I I ii 5 ··.: .. · 1 1 I ~2~ I ! · ! 6 -· ::::··. .... ... .. , .. t·,. • .•• . . . ... •······ 12---•·····.· ........ .... , ... , i ... PROJECT NO. .;zo.a 1Bf= ~=ttfl Li~·.;;Gr~y -Wi~ Yellow-brown I and Brown, With Zones of Very 1 Fine Sandy Clay, Leon CLAYEY VERY FINE SAND BENTON ENGINEERING, INC. i ' I I • I i I I l ' I I ; : ; I a.,: 1s.4jH)4.2! 1.991 l I : i I 24.3 14.6 111.8 4.13 I OIAWING NO. ~ 016 )-;>-l ll ·7 C,.,_: ....: .... ~:, .... •~ I Z wDC at.._ ui. ;;; II. I l...w.. --' W IOI ;;;--0 ~ :' Z :) CIC Z ·' ~E ~~ BORING NO. 18-JV ~ !: ~~~ c{ ~ ~~~, SUMMARY SHEET L ... .,c ::> "" ~ ~ 0 0 . :r: ~ ----; I ~ "'Z nEv.t.noN_nL > .-2:. Z ~ V\~~I I ~,-" • • • • • ~ 16. ;;<-0 _, Ck ):'. \ ~ •.: ... :.:: Srown, Dry, Loose, Porous, ! I · · , · · · . Pockets of Clay and Sand I l I • ,.•• I I I 1 ........ i I I I I ·:.~·:::·· ---i : : i I I 2-~-~ Slightly Moist, Firm ! 1 8.1 j 13.4; 77.6 1 • ••• • • ! I I ··•· i '.·. I _I_ --.. .. .. .. : CLAYEY FINE TO 1 3 .• ··: :: _______ ------i: MEDIUM SAND i ; j i I 5 -~~~:.-:-:-. Moist I I, \ \ \ I J---, A, .... ·.·,-:: ..... ·,... I i I i ~ : •. ... ! I I : i l5 6 -;:~~ 1 1 6.5 12.8! 82.8! I r -------------...-----------·j·-·-·"1--+--1-· ·-' , ! I i Olive, Moist, Very Firm 1 , , 7 , ., 8 .. ... 3..., ~ 9 ,.. . , 1 10-, , , ,, ., 11 - 12 ll--. , , ,. 1 , ,, 1 ~ ~ 4~ - PROJECT NO. ,i:.':,~F SILTY CLAY I I : 1 I I I i ? i j I I I I . 1' I . I 8. 1 1 20 .4 ,104. 1 l I ; i i I i I 1 i I I ! _________ .,__ _____ 111 .4 22.4 02.9 I BENTON ENGINEERING _ INC I DRAWING NO. "'""' 1-, ' . - .:_ -. 0 z ., 0 > 0 SI u, 0 -J LU 1; o( z cQ 0 .., SUMMARY SHEET BORING NO. 19 .. IY ELEVATION 236' 2 : .. :·.::::. Olive, Dry, Very Firm ......... ~l F, Olive, Moist, Very Firm 3 . 4-..--~ s-~-... , 0-- Olive, Moist, Very Firm _ ""--Olive, Moist, Very Firm PROJECT NO. 70.&?P. I DIC,.ITl'\t..l CLAY CLAYEY FINE TO MF=l"'\11 IU'~A>-.ln SILTY CLAY FINE SANDY SILTSTONE 1 SLIGHTLY ) SIL TY FINE TO 1 MEDIUM SAND I I I 17 .9 20.2 98.7 9 .7 21.4 98,0 22 .7 7 .8 07 .1 I DRAWING NC. -. . ' Oi Z! I ....1. 11>! -· Ol >1 01 ai U! ol _., :C' ii j! ji ~ -t 1111 ~ ,-------·-----! ,n .,, ~ 2 111: 0 X: ... II.I _, A. 2 ~ ftl ~ 0 ... z "" c.) a: "" a. z 0 ~ 0 ~ 0 ~ ·i u CONSOLIDATION CURVES 5 ,-. I ! 6i ... --....;..---il,----,....,..,..,._~-+-,,.+.,-.,.i ___ .....,...,.+_..,.......,....,...........,.,.,,...~~T':":~~~~~~-= ! . ('. '< /t : : /, 1 ·, ,, \' /,}:t~1?;~l~f}'JJ1M ti¼ +1 ~~---:i...-_.;.'+-'-...;....i~;4....~,4....J..-.,_ ____ ~.;....._......,;~---~;..;;...i.i:..-4:.-+~ ...... ~~~ o INOICHES PERCENT CONSOLIO.ATIOk AT FIELD MOISTURE • IHOr.:;ATES PERCENT COHSOLIDATlOH AFTER SATURATIOM PROJECT NO. OR.AWING NO. ""Tf"I. , ,..,...._ II Ii .!.. .-. 0 z .! ~ g ... .. 0 u .3 :{. :+ ~, .Ji j ~, ( I -i m 0 ., ~--~u:-r,-ON--CU-R-VES .... J a,. ~ ◄ O'I ... 0 ... z .., CJ Ill:: w ~ (9.l, (" 4 0 6 0.8 I:;\ 2 4 •· 8 . ~ ,t, , .... _____ _;..,,.~-,---.-1• --..-... .;;.... ______ ....., ____ 1 ,......-T ---:-·-·i '"soring i 8~1\/ .... i,. ; i s ~ . r--___ ! , ampie 1 I . ·;----~-~, •. -i r' ., -1. . ··-----l .. } ... ~ I Deoth 2' ', I --~.. I ' : ~ ,-...._~ ! I 1;~ 'I 1 i I -.. • ..., J . .. ~-· t · I· .,-.. + -· ·----~--· -·---~ · --t ·-·➔• - . ' I 4 l. .. l . , ..... -· -. .,.. I 5 t · . -·---t----•♦ , l 0 , 7 .,_ i I 8 ~ .. I 9 ( -. ~- I I i I I ... :. .... .• • • - •. ·1 ·I- I t. I -t .. ----. -·-- I I t 1-.•. I j ! , .. I • -+ .. : • I I ! i J .. --~ ~--~-: i ! : ' ; ~ I ' +· 4 --~-i ! I i ' u INDICATES Pf.PtCfNT COHSOLIOATIOH AT f1EL0 MOISTURE • INOICATES f'ERCENT CONSOLIDATION AFTER SAl'llRltTIOk . ..; PROJECT NO . . 0 z CD ~ 0 ... 8 ~ ... :a • z G 0 ... CONSOLIDATION CURVES LOAO IN ~IPS PU SQUAii£ FOOT +:Pr'>----r--~-•~.._-o~.~6--~oT.6:...,..~1~0 ____ _:2.----r--~4;.--,,-~6-,nr. +1 0 o INDICATES PERCENT CONSOLID,\TION AT FIELD MOISTURE • IHDIC.A.TES PERCENT CONSOLIDArtON AFTER SATuiUT10N PROJECT NO. j -OR AWING No. r"JC' .. ATl"\.l..l --=f ,05; (> ~ ~ r ,, ... ..,.. ~ (l JI ': I.'; l: ',.,, ~~. -f-i -11 ~ ,j ... ~ ~ ; / i I t ' -.. ..,. /• --'· -. ~o Q \., ~ "' ~i ,, 11 .:. ::: .... -,.,., I~ -.;._ \d •. -~: ('l~ ~ ;. ·~ :;-"" ~ ,.;.. cj, ':\. :f, ;, -- 1: II ,, ,, I r ,., /;_ ,,.. r. ,.. •' r..~ (, I • .. ' -..: r ~->< ,.. ·.1. .. ·"' . '-' -,,:;. --., ..J I' 0 ·-> ·-.:: r •. ...... ,... .. r· I:", C' .,._ .s J· .; :--j_ -· ,. ... :, , .. )I ,. :• ,, ,\ 1 :~ 3 ,~ ~ ,, ,,... ::i ,. ,r, ,,, •w '' r-- ,_ ...... I' _.) ·-"> •• hJ C. 0 • .J ..r, ,_ :> CJ 0 ~ 1I ~ ' I I / / "HILlt-HENKING BENTON P'IIHICCNT • CIVIL IENGINll:EII BENTON ENGINEERING. INC. AP,.LIEO SOIL MECHANICS -l"OUNOATIONS 1741 EL CAJON BOULEVARD SAN DIEGO. CALIFORNIA •afllS APPENDIXM STANDARD SPECIFICATIONS FOR PLACEMENT OF COMPACTED FILLED GROUND SAN 011:Go: IIB3•11t!IIS4 LA MuA: 4t!19-IIIJ114 1. General Description. The obtective is to obtain uniformity and adequate internal strength Jn filled ground by proven engineering procedures and tests so that the proposed structures may be safely supported. lhe procedures include the clearing and grubbing, removal of existil\9 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. lhe owner shall employ a qualified soils engineer to inspect and test the filled ground as placed to verify the uniformity of compacHon of filled ground to the specified 90 percent of maximum dry density. The soils engineer shall advise the owner and grading contractor immediately if any unsatisfactory conditf ons are observed to_ exist and shall have the authority to reject the compacted filled ground until such time that corrective measures are taken necessary to comply with the specifications. It shalf be the sole responsiblllty of the grading contractor to achieve the specified degree of compaction. 2. Cle9rlng, Grubbing, and Preparing Areas to be Frlled. (a) All brush, vegetatfon 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 $hall 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 surfoce is free from ruts, hummocks, or other uneven features which would tend to prevent uniform compaction by the equipment to be used. (c) ½'here fills are made on hillsides or exposed slope areas, greater than JO percent, horizontal benches shall be cut into firm undisturbed natural ground in order to pro• vide both lateral and vertical stability. This is to provide a horizontal base so that each layer is placed and compacted on a horizontal plane. The initial bench at the toe of the fill shall be at least 10 feet in width on firm undishJrbed natural ground at the ~levation 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. (d) APPENDIX AA -2- 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-1557-66T method that uses 25 blows of a 10 pound hammer fallirg from 18 inches on each of 5 layers in a 4 11 diameter cylindrical mold of a 1/30th cubic foot volume. 3. Materials and Special Requirements. The fill 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 mixirg 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 greater than 6 inches in diameter. If excessive vegetation, rocks, or soils with inadequate stre111th or other unacceptable physical characteristics are encountered, these shall be disposed of in waste areas as shown on the plans or as directed by the soils e~ineer. If duri~ grading operations, soils not encountered and 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 specifications. 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 sha11 be in accordance with those of the governmental agency havi~ jurisdiction. 4. Placir-g, Spreading, and Compacti!'l1 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 throughly mixed during the spreadi111 to insure uniformity of materkil and moisture in each layer. (b) 'Nhen the moisture content of the fi II 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 durfng the compactfng process. (c) When the moisture content of the fill material is above that specified by the soils ellJineer, the fill material shall be aerated by blading and scarifyi~ 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, rt shall be thoroughly compacted to not less than ninety percent of maximum density in accordance with A.S.T.M. D-1557-66Tmodifled as described in 2 (d) above. Compaction shall be accomplished with sheepsfoot rollers, multiple-wheel pneumatic-tired rollers, or other approved types of compaction equipment, such as vibratory equipment that is specially designed for certain soil types. Rollers shall be of such design that they will be able APPENDIX AA -3- to compact the fl II material to the specified densl ty. Rolli~ shall be accomplfshed while the flll moterJal is at the specified mofsture content. RolH~ 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 ftlled shQII be compacted. {e) All slopes shall be compacted by means of sheepsloot rollers or other sultable equipment. Compactt~ operations shall be continued until the slopes are stable but not too dense for plant11'8 and until there is no appreciable amount of loose sotl on the slopes. Compactl~ of the slopes shall be accomplished by backrollirg the slopes In Increments of 3 to 5 feet In elevation gain or by other methods productrg satisfactory results. (f) Field density tests shall betaken by the solls eJlJineer for approximately each foot In elevation gaf n after compaction, but not to exceed two feet ln vert1cal height between tests. Field density tests may be taken at intervals of 6 inches in elevatton gain If required by the soils ereineer. The locatlon of the tests In plqn shall be so spaced to give the best posslble coverage and shall be taken no farther apart than 100 feet. Tests shall be taken on corner and terrace lots for each two feet tn elevatlon gain. lhe solls ergfneer may take addftfonal tests as consfdered necessary fo check on the unrfonnity of compaction. w-iere sheepsfoot rollers are used, the tests shall be taken ln the cort)- pacted material below the disturbed surface. No additional layers of flll shall be spread unttl the fleld density tests indicate that the ,peetfled density has been obtained. (g) The tlll operation shall be continued In stx Inch (6"} compacted layers, as specified above, until the fill has been brought to the flntshed slopes and grades as shown on the accepted plans. 5. Inspection. Sufficient Inspection by the solls ellJineer shall be maintained durlllJ the flllf~ and compactl~ operations so that he can certify that the flll was constructed in accordance wt th the accepted speclfi catf ons • 6. Seasonal Limits. No fill material shall be placed, spread, or rolled If weather conditions Increase the moisture content above permissible ltmt ts. When the work ls interrupted by rain, ftll operations shall not be resumed until fleld tests by the soils ergtneer lndfcate that the moisture content and density of the 'ftll are as previously specified. 7. LimltlllJ Values of Nonexpansive Soils. Those sorls that expand 2 .5 percent or less from alr dry to safUratfon under a unit load of 500 pounds per square foot are considered to be nonexpansl ve. 8. All recommendations presented in th·e 11Conclustons 11 section of the attached report are a part of these specifications. .. - BENTON ENGINEERING, INC. APPLIED SOIL MECHANICS -FOUNDATIONS e?.at EL CAJON BOULEVARD SAN DIEGO. CALIFORNIA 92.115 PHILIP HENKING BENTON ~111:SIOIINT • CIVIL l:NGINEEII APPENDIX A S"N Dui:co, 913-ISS .. LA MH"• AS9-9694 Unified Soil Classification Chart* SOIL DESCRIPTION I. COARSE GRAINED, M.ore than half of material is larger than No. 200 sieve size.** - GRAVELS More than half of coarse fraction is larger than No. 4 CLEAN GRA vas sieve size but smallerGRAVELS WITH FINES than 3 inches (Appreciable amount of fines) SANDS Mae than half of coarse fraction is smaller than No. 4 sieve siz:e CLEAN SANDS 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 Ill. HIGHLY ORGANIC SOILS GROUP SYM8OL GW GP GM GC SW SP SM SC ML CL OL MH CH OH PT TYPICAL NAMES Wei I graded gravels, gravel'."'Sand mixtures, little a no fines. Poaly graded gravels, gravel-sand mixtures, little or no fines. Silty gravels, poorly graded gravel- sand-silt mixtures. Clayey gravels, poorly graded gravel- sand-clay mixtures. Well graded sand, gravelly sands, little or no fines. Poorly graded sands, gravelly sands, little a-no fines. Silty sands, poa-ly graded sand--silt mixtures. Clayey sands, poorly graded sand-clay mixtures. lna-ganic silts and very fine sands, rock flour, sandy silt or clayey-silt-sand mixtures with slight plasticity. Inorganic clays of low to medium plas- ticity, gravelly clays, sandy clays, silty clays, lean clays. Organic silts and a-ganic silty-clays of low plasticity. lna-ganic silts, micaceous a diatoma- ceous fine sandy or silty soils, elastic silts. lnaganic clays of high plasticity, fat clays. Organic cla)IS <i medium to high plasticity. Peat and other highly organic soils. * Adopted by the Corps of Engineers and Bureau of Reclamation in Januarv. 1952. PHIi.iP HENKING BENTON P'RKalD£1'1T .. CIYU .. ltNGINl:EII Sampling BENTON ENGINEERING. INC. APPLIED SOIi. MECH1'NICS --FOUNDATIONS 6741 El. CAJON BOULEVARD SAN DIEGO, C1'1.IFORNIA 92115 APPENDIX 8 SAN DtEGO, 583-5654 I.A Mt:sA, 469-5654 The undisturbed soil samples are obtained by forcing a special sampling tube 1nto 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 .O inches outsrde diameter, with a specfal cut- ting 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, cainected 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 sttll confined in the brass rings, after extraction from the sampler tube. The samples ore taken to the laboratory in close fitting waterproof containers in order to retain the field mois- ture until completTon of the tests. The driving energy is calculated as the average en·ergy 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 cire run using a direct shear machine of the strain control type in which the rate of deformation is approximately 0.05 irich per minute. The machine is so designed that the tests are made without removing the samples from the brass liner rings in which they are se- cured. Each sample b sheared under a normal lood equivalent to the weight of the soil above the point of sampling. In some instances, samples are sheared under various normal loods 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 conditrons. Consolidation Tests The apparatus U$ed 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 at 105°F for at least 48 hours ptior to placing into the expansion apparatus. A unit load of 500 pounds per square foot is then oppl ied 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 s.tops. The dial reading is recorded and expansion ls recorded until the rate of upward movement is less than 1/10000 inch per hour. BENTON ENGINEERING, INC. 6717 CONVOY COUltr SAN OIEGO, CALIFORNIA 92111 PHILIP HENK I Ne. 91,,..,roN PRESIDENJ .. CIVH EfrilGIN.EE:A April 2, 1973 Lo Costa Land Canpony Costa Del Mor Road C".arlsbod, California 92008 Subject: Gentlemen: Project No. 72-8-18D Grading Pennit No. L6392 T .M. 3036 Interim Report on Cgnpocted Fi I lea Ground Lots 1 to 10 inclusive Lots 108 to~09, inclusive, and lots -f32 to 246 c indusiv,e la c"osta Vale Unit No. 1 Carlsbod, California 7-~ RECEIVED APR 4 1973 CITY OF CARLSBAD Tt, J!~J!~t~s. ~n,nent This iJ to report the results of te$ts and observations made in order to ins~ct the compaction of filled ground placed on certain areas of lots 1 to 10, inclusive, 100 to 209, inclusive, and 232 to 246, inclusive, of La Costa Vale Unit No. I in Carlsbad, Califomia, formerly a part of the County of Son Diego. Filled ground was placed on Lots 17 to 22, inclusive, on February 16, 1970 and the mafor grading of the subdiviston commenced on September 21, 1972. The results of field density test Nos. 1 to 1019, inclusive, taken during the period between FelJruary 16, 1970 and February 27, 1973, were presented in our interim report on this project dated March 1, 1973. The filled ground was placed under our inspection in accordance with the approved specifications. The grading plan used for the placement of filled ground was prepared by Rick Engineering Company and approved Augu$t 23, 1972. Some of the tests taken on the sub;ect lots were included in our previous report doted March 1, 1973. The results of field density test Nos. 1020 to 1109, inclusive, ore presented on pages T-28 to T-30, inclusive, under the 11Table of Test Results. 11 The laboratory detenninations of the maximum dry denslties and optimum moisture contents of the mof or fill materials ore presented on page l-1, under the 11 Loboratory Test Results. 11 Some of the maximum dry densities shown in the 11Table of Test Results11 were combinations of these. The tests were taken during the weekly periods indicat~ on the following page. Project No, 72-8--18D La Costa Vale Unit No. 1 Test Number 1020 to 1035, inclusive 1036 to 1040, inclusive 1041 to 10n, Inclusive 1073 to 1105, inclusive 1106 to 1109, inclusive . -2- Week Ending March 3, 1973 March 10, 1973 March 17, 1973 Morch 24, 1973 March 31, 1973 Aprrl 2, 1973 Only nonexpansfve soils were placed in the upper three feet below finished grade in the fill areas on the subfect lots. All exponslve sotls existing in the upper three feet below ftnished grade in cut areas and areas of shallow ftll were removed and were replaced with properly compacted nonexpansive fill soils. Therefore, special design for expansive soll conditions will not be required en the subject lots. The flnol results of tests and observations indicate that the compacted filled ground has been placed at 90 percent of the maximum dry density or greater. It has been detenntned that the fill materials, compacted to 90 percent of the maximum dry density, have a safe bearing value of 1650 pounds per square foot for one foot wtde continuous footings founded at a minimum depth and placed five feet or more inside the top of compocted filled ground slopes. If footings are placed closer to the exposed slopes than 5 feet Inside the top of compacted filled ground slopes, these should be deepened one foot below a 1 1/2 horizontal to 1 vertical ltne proiected outward and downward from a point 5 feet horizontally inside the top of compacted filled ground slopes. Tests indicate that the compacted filled ground is adequate to satisfactorily support the proposed one ancHwo story wood frame dwellings without detrimental settlements. A plan showing the approximate areas and depths of filled ground placed under our inspection In accordance with the approved speciflcattcns will be submitted with our final report on La Costa Vale Unit No. 1. Respectfully submitted, BENTON ENGINEERING, fNC. Dlstr: By'tf:C~--r- R. C. Remer (4) Addressee La Costa Land Company (1) Attention: Mr. Burton L. Kramer (1) Rick Engineering CompClly, Carlsbad San Diego County Engineering (1) Attention: Mr, H. M. Taylor (1) Attention: Mr. Willard Robinson, Rm, 260 City of Carlsbad (1) (2) Deparhnent of Building Inspection - Department of Engineering Reviewed b~ 0t£~ :i~l Pardee Constructfon Company, Los Angeles Attention: Mr. Russell R. Ofria Attention: Mr. Jack Wagner Attention: Mr. Bob Trede Phtltp H~ Benton, Cfvil Engineer (1) Pardee Construction Company, San Diego (1) Attention: Mr. Art Scott (1) Attention: Mr. Mike Capik (1) Delivered to Jcb site by Bud Beattie RCR/PHB/ew Project No. 72-8-18D T-28 Apr II 2, 1973 La Costa Vale Unit No. 1 TABLE OF TEST RESULTS (CONT.) Approx-Depth Maximum imate of FJII Field Dry Ory Test Location at Test Moisture Density Density Percent No. Lot No. in Feet % dry wt lb/cu ft lb/cu ft Compaction Remarks 1020 84 14.0 15. 1 107.5 115.2 93.2 1021 84 16.0 15.0 107.2 115.2 93.0 10'22 84 18.0 15.3 109.4 115.2 94.9 1023 84 20.0 12.5 107.1 J.15.2 93.0 1024 84 22.0 12.5 109.2 114.2 95.5 1025 84-24.0 11.7 109.0 115.2 94.5 1026 84 26.0 12.8 111.9 115.2 97.0 1027 83 I .0 JO.O 107.4 112. 8 95.4 1008 84 30.0 11.4 110. 7 115.2 95.8 1029 83 5.0 10.2 112.6 115.2 97.5 1030 84 34.0 15.3 110. 7 111.0 99.6 1031 83 9.0 13.1 109.5 114.0 96.0 1032 84 38.0 J5.8 101.8 109.3 92.9 1033 83 13.0 16.1 105.8 110. 9 95.4 1034 83 15.0 11.2 110.7 113.6 97.4 1035 83 17.0 13.3 107.5 115.2 93.2 1036 44 5.0 17.2 )08. 1 116.0 93.3 1037 48 4.0 17.0 108.0 118.1 91.4 1038 47 14.0 14.6 108.0 115. 7 93.5 1039 83 19.0 15.9 107.9 115.4 93.3 1040 55 2.0 15.2 112. 1 118. 8 94.6 1041 109 6.0 * 20.4 101. 9 111.8 91.2 Ck on 1952 1042 123 15.0 * 12.9 101.8 111.8 90.9 ~k on #983 1043 128 14.0 * 16.7 107.8 115.2 93.2 Ckon 1969 1044 136 1s.o• 11.2 105.0 111.8 94.0 Ck on #973 1045 137 10.0 • 16.1 105.2 115.2 91.4 1046 139 4.0 * 16.2 105.6 115.2 91 .5 1047 140 3.0 * 16.8 109.0 J 15.2 94.4 1048 141 3.0 * 16. 1 111. 0 I 15.2 96.2 1049 142 3.0 * 14.5 JJO. 9 115.2 96.0 1050 143 22.0 * 13.2 114. 1 117.9 97.l 1051 144 3.0 * 14.8 108.3 115.2 94.0 1052 145 10. 0 • 15.5 105.4 115.2 91.5 1053 146 28.0 * 11. 7 111. 7 115.2 96.7 1054 147 40.5 * 13.9 102.2 115.2 88.7 Reworked 1055 148 43.0 * 12.5 104.0 115.2 90.2 1056 153 8.0 * 11.4 103.8 111 .8 93.0 1057 149 29.0 * 17. 1 107.3 115.2 93.1 Ck on l9n 1058 156 16.0 * 12.3 103.8 113.5 91.3 Ck on 1677 1059 159 3.0 * 14.2 105. 1 115.2 91.2 * Finished Grade Project No. 72-8-HD T-29 April 2, 1973 La Costa Va le Unit No. 1 T ABlf OF TEST RESULTS (CONT.) Approx-Depth Maximum lmate of Fill Field Dry Dry Test Location at test Molsture Density Density Percent No. Lot No. In Feet % dry wt lb/cu ft lb/cu ft Compaction Remarks 1060 160 3.0* 12.8 101. 7 111.8 91.0 Ck on.1680 1061 162 14.5 * 16.0 105.2 115.2 91.3 Ck on 1682. 1062 164 36.0 * 16.0 101.7 115.2 88.2 Reworked 1063 166 34 .. 0 • 16.9 105.S-115.2 91.5 1064 167 14.b 17.2 108.O 115.2 93.6 Ck on #995 106.5 167 17.0 * 16.0 107.3 115.2 93. 1 1066 171 3.0 * 13.2 102.5 111.8 91.8 Ck on l743 1067 177 1.0 14.1 109.3 115.2 94.9 Ck on #925 1068 177 3.0 * 14.6 108.0 115.2 93.6 1069 178 3.0 * 16.1 104.3 115.2 90.S 1070 179 3.0 * 16.0 105. 1 115.2 91.1 1071 180 1.0 18.4 105. 1 115.2 91. 1 .Ck on #991 &1892 1-072 180 3.0 * 16.5 106. 1 115.2 92.1 1073 181 2.0 17.3 101 .8 111.8 91.1 Ck on #990 1074 181 5.0 * 17. 1 102.2 113.5 90.2 1075 201 1.0 8.6 107.0 111~8 95.8 Ck on la51 1076 lf32. 6.0 12.4 107.1 115.2 92.9 Ckon 1889 1077 182 9.0 * 15.7 105. 9 115.2 91.7 1078 183 14.5 * 15.7 108.2 115.2 93.8 1079 184 24.5 * 14.9 112. 1 115.2 97.3 1080 208 3.0 • 13.4 107.1 115.2 93.0 Ck on l94a 1081 201 7.0-* 13.5 106.6 115,2 92.4 Ck on 1885 1082 195 7.0 * 16.0 106. 1 115.2 92. 1 1083 194 10.0 * 19.4 100. 1 115.2 86.9 Reworked 1084 19'J 16.0 * 13.6 107.2 115.2 93.0 Ck on #1002 1CIJ5 19'l 21.0 * 14.9 107.7 115.2 93.3 1086 191 22.5 * 12.3 105. 1 115.2 91.1 Ck on 11000 1007 187 5.0 * 11.0 102.7 115.2 89.0 Reworked 1088 186 12.5 * 13.7 111.3 115.2 96.5 1009 185 22.5 * 15.4 112.0 115.2 97.1 1090 204 3.0 * 13.1 107.1 115.2 93.0 Ck on 1888 1091 242 8.0 * 13,;7 103.8 113.5 91.4 Ck on 1582 1092 243 17.0 * 14.3 103.7 115.2 90.0 Ck on 1661 1093 244 20.5 * 17.0 106.4 115.2 92.4 Ck on 1660 1094 70 10.0 18.7 101. 9 1J 1.2 91.3 1095 71 18.'0. 13.6 109. 1 115.2 94.6 1096 72 11 .. 0· 15.5 109.0 115.8 94.3 1097 46 16.0 22.2 102.8 110.9 92.7 1098 45 14.0 15.6 110.0 t 18.5 93.0 1099 233 3,0 * 11.6 104.5 115,2 90.6 * FtnllMCI Grade • "*. ~·-* .. ~·' Project No. 72-8-100 T-30 La Costa Vale Unit No. 1 TABLE OF TEST RESULTS {CONT.) Approx-Depth Maximum lmote of Fill Field Dry Dry Test Location at test Nolsture Density Density Percent hJo. Lot No. In Feet % dry wt lb/cu ft lb/cu ft Compaction Remarks 1100 245 15.0 10.2 109.2 115.2 94.6 1101 245 17.0• 16.4 · 109.5 115.2 94.9 1102 246 28.0 13.9 107.7 115.2 93.5 1103 246 30.0 * 18.1 104.1 115.2 90.3 1104 247 37.5 * 20.7 103.9 115.2 90.0 Ck on 1659 1105 18 40.0 20.7 106.4 115.2 92.4 1106 147 40.5 * 15.8 111.9 115.2 97.0 Ck on 11054 1107 164 36.0 * 17. 1 106.7 115.2 92.7 Ck on #1062 &1697 1108 187 5.0 • 10. 1 104.6 111. 8 93.6 Ck on IJQ87 &l999 1109 194 10.0 * 15.3 103.3 113.5 91. 1 Ck on IJ083 * Finished Grade Profeet No. 71-8-HD La Costa Vale Unit No. 1 L-l March 1, 1973 Revised -Aprll 2, 1973 LABORATORY TEST RESULTS The maximum dry densfttes and 0ptlmum moisture contents of the mafor fill materlalt 01 determined by the A.S. T .M. D 1557-661 method, that uses 25 blows of a 10 pound rammer falllng from a height of 18 Inches on each of 5 layers In a 4 Inch diameter 1/30 cubic foot compoctlon cyltnder, are presented as follows: MaxlnK.lm Optimum Mols- Dry Density ture Content Soil Description lb/cu ft o/o dry wt Light brown gray clayey slit 107.2 19.0 01 ive green sf lty clay 107.5 16.4 Brown gray silty c I ay 109.0 17.8 Light yellow brown sllty very fine to flne sond with 109.2 16.8 clay binder and chunks of silty clay Yellow brown and gray very fine sandy stlt 1 J0.4 15.4 Yellow brown very flne to fine sandy clay 110.4 15.5 Gray brown fine sandy clay 110. 9 14.3 Ollve green stlty clay 11 t.2 15.0 Ught brown silty nne sand 112.5 10.9 Lfght gray-yellow clayey fine sand 114.1 13.9 Light gray brown clayey very fine to fine sand 114.2 14.4 Gray with red brown and white sllty clay 114.7 15.3 Lfght 9roy brown clayey fine sand 115.2 14.7 Light gray silty very fine to fine sand with slJght 115.2 13.7 clay binder Gray-black stlty clay 116.8 11.8 Brown clayey fine sand with some fine sandy clay 117.8 13.3 light brown sflty fine sand with clay binder 118.3 11.9 Light brown and gray silty clay 118.6 14.0 Light yellow brown fine sandy clay 121.6 1 J .5 Light yellow sllty fine sand 123.6 10.5 Greenish-brown fine sandy clay 118.8 12.2 Brown 1:layey fine to medium sand 128.0 9.2 Groytsh=-brown sJlty fine sand 117.0 13. 1 Ught brown sflty fine to medium sand 118.5 12.0 Red-brown fine to medium sandy clay 111.3 15.0 Ught gray clayey silt with streaks of red brown 111.3 16.0 and yellow light gray silty clay with yellow streaks 110. 7 15.1 light gray st lty fine sand 111.8 12.5 ProJect No. 72-8-18D · la Costa Vole Unit No. 1 -2- Test Number 1142 to 1178, inclusive 1179 to 1210, Inclusive 1211 to 1251, Inclusive 1252 1253 to 1255, Inclusive 1256 February 28, 1974 Week Ending April 21, 1973 April 28 I 1973 May 5, 1973 May 19, 1973 June 9, 1973 February 6, 1974 Compacted filled ground was placed on on area west of Lot 1 outside the boundary of La Costa Vale Unit No. 1 and is designated on Drawing No. 1 as Area "A". The final resulb of tests and observations Indicate that the compacted filled ground has been placed at 90 percent of the mQXlmum dry density or greater. It has been determined that the fill materials, compacted to 90 percent of the maximum dry density, have a safe bearing.value of 1650 pounds per square foot for one foot wide continuous footings founded at a depth of one foofbelow the lowest adjacent compacted ground surface. This value may be increased to 1950 pounds per square foot for 16 inch wide footings placed 1.5 feet below the lowest adjacent com-- -pocted ground surfoce. If footings are placed closer to the exposed slopes thon 5 feet inside the top of compacted filled ground slopes, these should be deepened one foot below a 1 1/2 horizontal to 1 vertical line proiected outward and downward from a point 5 fe!!t horizontally inside the top -of compacted filled ground slopes. Tests indicate that the compacted filled ground is adequate to satisfactorily support the proposed one aid two story wood frcme dwellings withou~ detrimental settlements. Only ~exponsiv; soils were placed in the upper three feet below finished grade on the following lots: · A.t..L L 1 to 1 O, inclusive 11f/?R /108 to 209, inclusive =.ft_ OM IJt~tlSIV_. ! ;;,~ , · 219 to 225, inclusive ,-;JI' s;; 232 to 246, inclusive ~J( P/tN)/it/: -. . -r. ~"', ' All exponsive soil$ existing in the upper three feet below finished grade in cut areas aKcfa~eas of shallow fill were removed on the above lots and were replaced with properly compacted non- ·-expCJ1Uive fill soils. Therefore, special design for expansive soil conditions wllJ not be required on these lots. · ~· ----------~ ., -AJJ ~sc..,ets &.~ the subdivision were determi.ned to havew'itif~ll~e!~ive ~oilsjn the upper ttiree eef elow finishe~ grade• Therefore, m order to mcnim12':e poss, le detrimental effects caused by these potentially expansive soils, the followfng special design and preco~tfons ore -recommended. 1. Avold the use of isolated interior piers where possible. Use continuous footings throughout, and place these at a minimum depth of ~o feet below the lowest adJaeent ~xtortor final ground surface. . . J J J 1 l l.. L L L i ' ProJect No. 72-8--18D ta Costa Vale Unit No. 1 Februciry 28, 1974 3. 4. 5. Reinforce and interconnect continuously with steel bars all interior and exterior footings with one #5 bar at 3 inches above the bottom of all footings with one 15 bar placed l 1/2 inches below the top of the stems of the footings. Raised wooden floors that span between continuous footings are preferable. Concrete slabs on grade should be reinforced with at least 6 x 6 .. 10/10 welded wire fabric. Provide a minimum of 4 inches of crushed rock 3/4 to 1 inch in size beneath aJI concrete slabs. A moisture barrier should also be provided over the crushed rock and then 2 inches of sand should be placed over the moisture barrier_ and below the bottom of the slab. . . Separate garage slabs from perimeter footings by 1/2 inch thickness of construction felt or equivalent, to allow independent movement of garage slabs relative to perimeter footings. Assure complete separation by extending the construction 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 slab. Provide positive drainage aw<J'f from all perimeter footings with a vertical foll of at least 6 inches in a horizontal distance of 5 feet, to a distance of at least 5 feet outside the house walls. 6. Exercise every effort to assure that the soil under the concrete slabs hos a uniform moisture content at least 1. to 3 percent.greater than optimum · throughout the top 1 .5 feet below· finished grade at the time of placing the fuundations and slabs. · Respectfully submitted, BENTON ENGINEERING, .INC. By--7RC~ R. C. Remer Reviewed ~ ', 51 ( ~--- . ~ton, Civil Engineer RCR/PHB/pk Distr: (4) Addressee (1) Addressee, Attention: Mr. Burton L. Kramer Son Diego County Engineering Department (1) Attention: Mr. H. M. Taylor (1) Attention: Mr. Willard Robinson, Room 206 (2) City of Carlsbad 8utldin9 Department (1) Rick Engineering Company, Carlsbad (2) Title Insurance and Trust Company AttAntlnn• ~11th I l)",.f,. .. ., J BENTON ENGINEERING, INC. APPLIED BOIL MECHANICS -FOUNDATIONS 45'71 "1 CONVOY COURT SAN DIEGO, CALlf'OIINIA 92111 PHILIP KENKING ■EHTON PUSIIXICT • ~IVII. &NGIIUtD la Costa land Company Costa Del Mar Rood Carlsbad, Callfomia 92008 ~my 28, 1974 ~ TEU:l'HONS (714) S5S-ltSS Subfect: Gentlemen: Profect No. 72-8-18D Grading Permit No. L6392 . T .M. 3036 n.;--"1-> :x, Final R•~~t on· vi , ~- §mpocte Fflled Ground V ~ i.,o 1. La Costa Vale Unit No. 1 Cariibcia, Califomla RECEIVED MAft 4· 1974 CITY OF CARLSBAD Building Department This it to report the results of tats and observations made In order to Inspect the compaction of filled ground placed on certain areas of La Costa Vale Unit No. 1 In Carlsbad, Califomia. This report covers LotJ.11 to 10'14 Inclusive, 210 to 218, inclusive, 226 to 231, inclusive, 2,t!, and J48. FIiied ground was placed on Lots 1' to 22, inclusive, on February Jo; 1970 and t mafor grading of the aubdlvis1on commenced on September 21, 1972. The results of field denslty. test No,. 1 to 1109, Jncluslve, were presented In our previous reports dated March 1, 1973 and April 2, 1973. The final group of tesb token to the completion of the maJor grading on June. 7, 1973 are presented in this report. A flnal test was taken on Lot 211 on February 6, 1974. The approximate areas and depths of filled ground placed under our Inspection in accordance with the approved speclfic:atioN are shown on the attached Drawing No. 1, entitled 1'Location of Compacted Fllled Ground.•• The grading plan used for the placement of filled ground was prepared by Rick Engineering Company and approved August 23, 1972. Test Nol. 1 to 1109, Inclusive, were presented in our previous reports dated March 1, 1973 and Aprll 2, 1973. The results of the final group of tests taken on the project, Nos. 1110 to 1256, inelusive, ore presented on pages T-31 to T-35, incluslve, under the "Table of Test Results. 11 The laboratory determinations of the maximum dry densities and optimum moisture contents of the maJor flll materials are presented on page L-1, under the "Laboratory Test Results." Some of the maximum dry densities shown in the "T oblo of Test Resul ts11 were c:ombinations of these. The tests were taken during the weekly periods indicated below: Test Number 1110 to 1113, inclusive 1114 to 1124, inaluslve 1125 to 1141, Inclusive Week Ending March 31, 1973 April 7 I 1973 April 14, 1973 Pro)ect No. 72-8-18D La Costa Vale Unit No. 1 -2- Test Number 1142 to 1178, Inclusive 1179 to 1210, Inclusive 1211 to 1251, Incluslve 1252 1253 to 1255, Inclusive 1256 February 28, 1974 Week Ending Aprtl 21, 1973 April 28, 1973 Maf 5, 1973 Mat 19, 1973 June 9, 1973 February 6, 197 4 Compacted filled ground was placed on an area west of Lot 1 outside the boundary of La Costa Vala Unit No. 1 and is designated on Drawing No. 1 as Area ·11A11 • The final results of tests and observatioN Indicate that the compac:ted filled ground has been placed at 90 percent of the maximum dry density or greater. It has been detennined that the fill materials, compacted to 90 percent of the maximum dry density, have a safe becring value of 1650 pounds per squcre foot for one foot wide continuous footings founded at a depth of one foofbelow the lowest odJacent compacted ground surface. This value may be Increased to 1~0 pounds per square foot for 16 inch wide footings placed 1.5 feet below•thef lowest adf acent com- paeted ground surface. If footings are placed closer to the exposed slopes than 5 feet inside the top of compacted filled ground slopes, these should be deepened one foot below a 1 1/2 horizontal to 1 vertical ltne protected outward and downward from a point 5 feet horizontally inside the top of compacted filled ground slopes. Tests Indicate that the compacted fllled ground is adequate to satisfactorily support the proposed one e11d two story wood frane dwelllngs without detrimental settlements. Only non~aruJve soils were placed in the upper three feet below finished grade on the following lots: / 1 to 1 O, inclusive AJ.L IJ111/?R /100 to 209, inclusive :"OK nPlt.NSIV~ . 219 to 225, inclusive ARc 232 to 2-46, inclusive FX P/tN>IIIIT · · ,y '1F''A'' All expansive soils existing in the upper three feet below finished grade in cut areas and areas of shallow fill were removed an the above lots md were replaced with properly compacted non- expansive fJII soils. Therefore, special design for expansive soil conditions will not be required on these lots. ~ ., ~ ot~!9~~ a,n the subdivlslon were determined to have crlticall e lve soils n the upper Fae eer low finished grade• Therefore, In order to ffl n maze poss1 e etr mental effects caused by these potentially expansive sotls, the followrns special design ond preca~tlons are recommended. 1 • Avoid the uae of fsolated Interior piers where possible. Use continuous footings throughout, and place these at a minimum depth of two feet below the lowest adJacent exterior final grou;id surface. Proiect No. 72-8-18D La Costa Vale Unit No. 1 -3-February 28, 197 4 2, Reinforce and interconnect continuously with steel bars all interior and exterior footings with one 15 bar at 3 inches above the bottom of all footings with one 15 bar placed l 1/2 inches below the top of the stems of the footings. 3. Raised wooden floors that span between continuous footings are preferable. Concrete slabs on grade should be reinforced with at least 6 x 6 -10/10 welded wire fabric. Provide a minimum of 4 inches of crushed rock 3/4 to 1 inch In size beneath all concrete slabs. A moisture barrier should also be provided over the crushed rock and then 2 inches of sand should be placed over the moisture barrier and below the bottom of the slab. 4. Separate gcrage slabs from perimeter footings by 1/2 inch thickness of construction felt or equivalent, to allow independent movement of garage slabs relative to perimeter footings. Assure complete separation by extending the construction felt over the full depth of the front thickened edge of the garage slab. Cut off gcrage door stops at least 1/2 inch above the garage slab. _ 5. Provide positive drainage awa, from all perimeter footings with a vertical foll of at least 6 inches in a horizontal distance of 5 feet, to a distance of at least 5 feet outside the house walls. 6. Exercise every effort to assure that the soil under the concrete slabs has a uniform moisture content at least 1 to 3 percent greater than optimum throughout the top 1 .5 feet below finished grade at the time of placing the foundations and slabs. Respectfully submitted, BENTON ENGINEERING, INC. By-£~~ R. C. Remer RCR/PHB/pk Distr: { 4) Addressee ( 1) Addressee, Attention: Mr. Burton L. Kramer San Diego County Fngineering Department (1) Attention: Mr. H. M. Taylor (1) Attention: Mr. Willard Robinson, Room 206 (2) City of Carlsbad Building Department (1) Rick Engineering Company, CarlJbad (2) Title Insurance ond Trust Company ALL~-L•-·-ft ... I Pit, I I June 29, 1973 Proiect No, 72-8-1 lD T-31 la Costa Vale Unit No. 1 Revised February 28, 1974 TA8lE OF TEST RESULTS (CONT.) Approx-Depth Maximum ........ lmate of FIii Fteld Ory Dry _· .. _;rest location at. Test Moisture Density Density Percent ...... No lot N In Feet .% drywt1 lb/cu ft lb/cu ft Compaction Remarks :~y. . .• . o. gi:~:1· . .:;~ .. ~~ .· ·-.... 118.8 93.4 f(-1110 16 54.0 15.5 111.0 · t:~1t11 15 48.0 15.9 114.4 118.8 96.3 t-:t'-!1' . : 16.5 113.7 118.8 95.7 ; .. -·.-1112 17 51_.0 - ·;. °1113 17 53.0 17.2 108.8 115.2 94.4 1114 11 59.0 * 15.1 105.2 116.3 90.4 . 1115 12 56.0 * 21.8 104.9 115.2 91.0 _. . 1116 13 51.5 * 16.5 108.9 116.3 93.5 1117 30 4.0 * 13.1 113.1 118.8 95.2 -.. 1118 18 41.0 20.2 108.1 118.8 91.0 . 1119 14 53.0 * 15.2 114.0 118.8 95.9 1120 20 29.0 15.4 110.1 118.8 92.7 1121 21 20.0 18.6 113.8 118.8 95.8 1122 19. 32.0 16.6 111.6 118.8 93.8 1123 54 2.0 17.3 108.0 111.2 97.2 1124 55 6·.o 19.6 100.2 111.2 90.2 1125 56 .1.0 12.5 109.0 116.3 93.7 . 1126 22 14.0 13.1 110.0 116.3 94.5 1127 Romerla St. 3.0 10.3 114.5 118.8 96.5 Opp. Lot21 1128 RomeriaSt. .5.0 12.5 110.1 1)8.8 92.6 Opp. Lot22 1129 RomerlaSt. 7.0 * 14.8 110.6 116.3 95.1 Opp. lot21 1130 29 1.0 13.5 114.5 118.8 96.5 1131 30 1.0 15.6 107.9 116.3 92.7 1132 29 3.0 14.9 111.4 118.8 93.7 1133 30 3.0 * 13.7 116.1 118.8 97.7 1134 28 1.0 14.0 107.8 l 16.3 92.6 1135 26 2.0 14.5 111.8 116 .. 3 96.1 1136 39 4.0 18.5 103.8 115.2 90.0 11"37 40 6.0 14.6 106.3 116.3 91.6 1138 41 2.0 17.0 103.7 115.2 90.0 1139 42 2.0 10.0 109.5 118.8 92.1 1140 39 6.0 16.5 105.6 116.3 90.7 1141 40 a.o 11.6 111.0 116.3 95.4 1142 31 2.0 12.3 113.9 118.8 ·. 95.9 1143 25 2.0 16.7 105.4 116.3 90.7 1144 La Costa Ave. 2.0 16.4 113.8 120.a 94.2 Opp. Lot 31 • Indicates Finished Grade Preject No. 72-8-180 T-32 June 29, 197J La Costa Vale No. 1 Reviied February 28, 1974 TABLE OF TEST RESULTS (~ONT.) ApplOX• Depth Maximum imate of FIii Fleld Dry Dry Test Location at Test Moisture Density Density Percent No. Lot No. In Feet. % dry wt lb/cu ft lb/cu ft Compaction Remarks 1145 LaCostaAve. 2.0. 14.2 116.0 118.8 97.6 .: .. ~ . Opp. Lot37 -::-J,-46 -· -LaCostaAve. ~-.o 12.7 112.0: ·. 118.8 94.1 Opp. Lot41 Stormdrain .1147 LaCostaAve. 2.0 11.8 110.8 116.3 95.2 Opp. Lot39 Backflll 1148 22 16.0 12.6 119.0 128.0 93.0 1149 58 2.0 17.1 112.7 123.6 91.2 .1150 59 1.0 • 12.6 111.0 116.3 95.4 1151 21 22.0 18.7 108.7 116.3 93.4 1152 20 31.0 16.2 112.7 116.3 96.9 1153 19 34.0 22.0 106.6 116.3 91,6 1154 18 41.0 15.9 114.3 116.3 98,3 1155 Azahar St. 9.0 15.7 112.4 116.3 96.6 & Romeria St. 1156 Azahar St. 11.0 13.0 119.3 123.6 96.6 & Romerla St. 1157 Cadencia St. 13.0 24. l 103.1 113.7 90.7 & Romerla St. 1158 Cadencia St. 15.0 20.8 106.7 113.7 93.8 & Romerla St. 1159 Garboso St .. 29.0 14.9 105.3 110.4 95.3 & Romeria St. 1160 RomertaSt. 25.0 15.5 117.7 128.0 92.0 Opp. Lot7&8 1161 21 24.0 * 11.9 117.6 128.0 91.8 1162 20 .33.0 * 17.4 111.3 116.3 95.7 1163 36.0 * . 94.-7 19 16.9 110.1 116.3 1164 18 43.0 * 17.2 113.4 123.6 91.7 1165 17 55.0 * 15.4 104.8 116.3 90.1 1166 16 56.5 * 18.5 106.3 116.3 91.4 1167 15 50"0 * 18.0 104.6 115.2 90.6 1168 29 3.0 • 13.3 117.4 123.6 95.0 1169 28 3.0 * 9.8 113.8 116.3 97.8 1170 CadenctaSt. 1.0 9.1 117.3 118.3 98.7 Opp. Lot99 1171 CadenciaSt. 1.0 19.2 104.0 111.2 93.5 Opp. Lot 102 Project No. 7l-S-18D T-33 June 29, 197J La Costa Vale No. 1 Revised February 28, 1974 TA8lf OF TEST RESULTS {CONT,) Approx ... Depth Maximum tmate of FIii Fleld Dry Dry Test Location at Test Moisture Density Density Percent No. Lot No. in Feet % dry wt lb/cu ft lb/cu ft Compaction Remarks 1172 CadenclaSt, 1.0 19.6 111.7 112.7 99.0 Opp. Lot 105 1173 Cadencla St. 2.5 * 12.0 107.8 116.3 92.7 Opp. Lot JOO 1174 Cadencta St. 2.5 * 13.4 104. l 111.2 93.6 Opp. Lot 103 1175 CadenclaSt. 2.5 * 17.8 101.4 111.2 91.2 Opp. Lot 105 1176 27 2.0 12.6 117.3 123.6 94,9. 1177 26 4.0 • 14.6 115,0 123.6 93.1 1178 22 18.0 * 12.2 117.6 123.6 95.1 1179 24 2.0 12.0 110.7 116.3 95. l 1180 25 4.0 * 13.9 110.4 116.3 95.0 1181 101 4.0 20.4 104.4 115.2 90.6 1182 71 19.0 * 15.4 112.2 118.8 94.5 1183 102 18.0 * 18.5 102.0 111.2 91.7 1184 70 11.5 * 16.2 112.7 118.8 95.0 1185 24 4.0 * 13.7 109.9 116.3 94.5 1186 230 35.0 * 17,9 113.0 118.8 95.0 1187 230 35.0 * 22.8 105.0 116.3 90.3 1188 229 40.0 • 20.1 107.4 116.3 92.2 1189 229 40.0 * 19.7 107.0 118.B 90.0 J.190 101 6.0 * 20.4 104.2 115.2 90.4 1191 103 19.0 * 19.1 109.3 116.3 94.0 1192 105 12.0 * 21.2 103.8 115.2 90.0 1193 106 s.o * 18.0 107.6 115.2 93.4 1194 107 7.0 * 22.3 102.2 113.2 90.2 1195 76 7.5 • 20.2 107.9 118.8 90,7 . 1196 75 19.0 • 19.7 106.2 116.3 91.3 - 1197 74 21.0 • 18.9 104.3 115.2 90.5 1198 73 21.0 • 14.6 108.7 115.2 94.4 1199 7l 14.0 • 16.4 108.2 116.3 93.0 1200 228 33.0 • 19.6 107.0 116.3 92.0 1201 228 33.0 * 23.2 105.5 115.2 91.6 1202 227 31.5 * 23.8 102.6 113.2 90.6 1203 227 31.5 • 17.5 107.1 118.8 90.2 1204 226 22.0 • 12.8 104.5 111.2 93.9 1205 83 21.0 17.2 105.7 115.2 91.7 Project No. i2-8~18D . T-34 June 29, 1973 UJ Costa Vale No. 1 Revised February 28, 1974 TABlf OF TEST RESULTS (CONT.) Appro>c• Depth Ma,clmum lmate of Ftll Fleld Dry Dry Test Location at Test Moisture Density Density Percent No. Lot.No. In Feet % dry wt lb/cu ft lb/cu ft Compaction Remarks 1206 83 24.0 • 13.1 114.0 118.B 96.0 1207 84 39.0 * 10.8 115.5 118.8 97.2 1208 58 3.0 * 13.1 104.3 115.2 90.5 1209 31 4.5 • 11.8 109.1 116.3 93.8 1210 39 8.0 * 13.7 104.6 116.3 90.0 1211 40 11.0 * JJ.4 113.0 JJ8.8 95.2 1212 55 8.0 20.4 101.8 111.2 91.6 1213 55. J0.5 * 17.8 100.9 111.2 90.6 1214 218 4.0 16.3 ll0.0 116.3 94.7 1215 217 4.0 2l.0 104.0 115.2 90.3 1216 218 6.0 17.7 104.5 115.2 90.7 1217 216 s.o 20.4 114.2 118.8 96.1 1218 218 s.o 18.7 102.8 113.2 90.7 1219 215 6.0 17.8 108~6 118.8 91.4 1220 21S .s.o 18.0 111.4 118.8 93.8 1221 216 10.0 19. l 105.8 116.3 90.9 -1222 215 12.0 20.6 107.8 116.3 92.7 1223 216 12.0 16.1 107.6 116.3 92.5 1224 211 6.0. 21.2 106.7 116 .. 3 91.7 -1225 212 8.0 20.6 109.2 118 .. 8 92.0 1226 218 10.0 • 12.6 107.1 116.3 92.1 1227 217 6.0 * 14.8 114.1 118,.8 96.0 -1228 216 U.5 • J3.6 1)2.7 118.B 94.B ·1229 215 14.5 • 14.3 107.0 116.3 92.1 1230 214 6.0 • 23.4 102.8 113.2 90.7 · -1231. 212 11.0 • 18.0 105.0 116.3 90.2 1232 41 10.0 • 12.6 112.0 118.8 94.J 1233 32 2.0 • 10.6 115.5 118.8 97.2 -1234 33 2.0 • 11.8 121.6 128.0 95.0 1235 34 2.0 • 12.4 117.8 118.8 92.0 1236 35 2.0 * 11.5 109.0 116.3 93.6 -1237. 36 ·2.0 • 10.0 120.0 128.0 93.9 1238 37 2.0 * 9.8 112.0 116.3 96.3. 1239 38 2.0 • 12.9 106.6 116.3 91.7 1240 104 16.5 • 19.2 104.0 115.2 90.3 1241 54 4.5 • 10.0 114.5 116.3 98.4 1242 56 3.0 * 11.5 113.0 118.8 95.1 -1243 48 a.o * 15.5 109.0. 118.8 91.8 1244 47 18.0 • 19.0 107.5 116.3 92.4 1245 46 19.0 * 19.8 107.2 118.8 90.2 -1246 45 16.0 * 12.6 115.4 118.8 97. 1 1247 44 11.0 * 11.6 113.7 118.8 96.4 · 1248 43 5.0 * 9.5 112.5 118.8 94.6 -1249 42 6.0 • 12.7 120.0 128.0 93.5 BENTON ENGINEERING. INC. "--" ...... ~· ,, . -· -~-,~ ...... Proiect No. 72-8-180 T-35 February 28, 1974 La Costa Vale No. 1 TABLE OF TEST RESULTS (CONT.) Approx-Depth Maximum Jmate of FIii Field Dry Dry Test Location at Test 1',/oisture Density Density Percent No. Lot No. In Feet % dry wt lb/cu ft lb/cu ft Compaction Remarks 1250 27 4.0 * 11.0 111.9 118.b 94.2 1251 SI 2.0 * 15 .. 6 114.0 118.8 96.0 1252 211 9.0 * 15.2 87.0 111.2 78.2 Reworked 1253 Electrical Box 2.0 10.1 109.0 120.6 90.4 Front Lot 222 1254 Electrical Box 4.0 12.4 118.1 123.6 95.6 Front Lot 222 1255 Electrical Box 6.0 * 11.3 118.2 123.6 95.7 Front Lot 222 1256 211 9.0 * 16.0 113.2 123.6 91.7 Check on IJ25: * Indicates Finished Grade BENTON ENGINEERING, INC. .I Profect No. 72-8-18D La Costa Vale Unit No. 1 L-1 Morch l , 1973 Revlsed -April 2, 1973 Revised February 28, 1974 LABORATORY TEST RESULTS The maximum dry densities and optimum moisture contents of the maJor flll materloJs as detennlned by the A.S. T .M. D 1557-66T method, that uses 25 blows of a 10 pound rammer falling from a height of 18 inches on each of 5 layers in a 4 Jnch diameter 1/30 cubic foot compaction c:ylinder, are presented as follows: Maximum Optimum J.Aois- Dry Density ture Content Soi I Description lb/eu ft % dry wt Light brown gray clayey sil~ 107.2 19.0 OUve green silty cloy 107.5 16.4 Brown gray silty cloy 10}.0 17.8 Light yeJlow brown slfty very fine to Rne sand with 109.2 16~8 clay binder and chunks of silty clay Yellow brown and gray very fine sandy silt 110.4 15.4 Yellow brown very fine to fine sandy clay 110.4 15.5 Gray brown fine sandy clay 110.9" 14.3 Olive green silty cloy· 111.2 15.0 Light brown Jilty fine sand 112.5 10.9 Light gray yellow clayey fine sand 114.1 13.9 Light gray brown clayey very fine to fine sand 114.2 14.4 Groy with red brown and white silty clay 114.7 15.3 Light gray brown clayey fine sand 115.2 14.7 · Light gray silty very fine to fine sand with slight 115.2 13.7 clay binder Gray block silty cloy 116.8 11.8 Brown clayey fine sand with some fine sandy clay 117 .8 13.3 Light brown silty fine sand wHh clay binder 118.3 11.9 Light brown and gray silty clay 118.6 14.0 Light yellow brown fine sandy clay 121.6 11.5 Light yellow silty fine sand 123.6 10.5 Greenfsh brown fine sandy clay 118.8 12.2 Brown clayey fine to medium sand 128.0 9.2 Grayish brown silty fine sand 117.0 13. l light brown sllty fine to medium send 118.5 12.0 Red brown fine to medium sandy clay 111.3 15.0 Light gray clayey sift with streoks of red brown 111.3 16.0 and yellow · light gray silty clay with yellow streaks 110.7 15.1 Light gray siJ ty fine sand 111.8 12~5 8£NTON EHGIN~£RING, INC, H . 5 g 0 Hti tlfll 11111 lutl "~ !11'1' n1 " f I . l /1 h / : I r ~ . -----------------~ : I I ! t: I \ ..... HETHERINGTON ENGINE:ERING, INC. SOIL & FOUNDATION ENGINEERING • ENGINEEHING GEOLOGY • HYDROGEOLOGY MLC Homes, Inc. 1500 West l 11~ Avenue, Suite 24 Escondido, California 92029 Attention: Mr. G1tn Carson Subject: GEOTECHNICAL FEASlBTL.ITY STlJDY Proposed Single-Family Residenres Romeria Street La Costa Vale -Unit No. 1, Lots 20 through 22 Carlsbad, California References: Attached Dear Mr. Carson: October 26, 2015 ProjectNo. 7802.I Log No. 17971 In accordance with your request, we have perfonned a gcotechnical feasibility study o:f the subject property. Our work was petformed during October 2015. It is our underBtanding that proposed construction consists of three single-.f.amily residences. We have not been provided with plans at this time. The purpose of our work was to evaluate general geofogjc and soil conditions at the site to determine the suitability of the lots for the proposed .smg]e-famiJy residences. With the above in mind, our scope of services included the following: • Research and review of available geotechnical reports and geologic maps/literature pe11inent to the site and immediate vicinity {see References). • A site reconnaissance of the property. • Eoginee1iug and geologic analyses. • Preparation of this rep011 presenting our findings, conclusions and recommendations. SITE DESCRIPTlON The subject property is located at the southwest comer of La Costa Avenue and Romeria Street in Carlsbad, California (see Location Map, Figure 1 ). The site is further identified as La Costa Vale -Unit No. 1, Low. 20 through 22. The .site com,ists of three contiguous rectangular shaped residential lots. The lots are vacant of improvements and support a low growth of scattered weeds, grasses, and several trees. 5365 Avenlda Encinas, Suite A• Carlsbad, CA 92008-4369 • (760) 931 -1917 • Fax (760) 931--0545 327 Third Street • Laguna Beach, CA 92651-2306 • (949) 715-5440 • Fax (949) 715-5442 www.hP.thminn1ominninP.P.rino.r.om ADAPTED FROM: The ThomolS Guide, San Diego Counly, 57ttl Erlition, Page1147 SCAl.E: 1• -2000' (1 Grid Equ;:ils: 0.5 :x .0.5 mil.es) LOCATION MAP HETHERINGTON ENGINEERING, INC. GEOTECHNlCAL CONSULTANTS Romeria Street/MLC Homes/Lots 20-22 Carisbad, California PROJECT NO. 7802.1 I FIGURE NO. 1 GEOTEC.HNICAL FEASIBILITY STUDY Project No. 7802.1 Log No. 17971 October 26, 2015 Page2 Topographically, the lots consist of three level building pads, separated by 6 to 9~feet high 1.5:1 (horizontal to vertical) slopes. A descending slope at the rear of the lots varies from 10 to 15-feet high at a 2:i (horizontal to vertical) slppe ratio. The site is bounded by Romelia Street on the east, La Costa Avenue on the north, an existing single-family residence on the south, and undeveloped property on the west. PROPOSED DEVELOPMENT We understand that three single-family residences are proposed for the lots. It is anticipated that the residences will be at about existing pad gra<ks. PUBLISHED DOCUMENTS/RESEARCH Research at the city of Carlsbad resulted in finding the referenced 13oj] reports and grading plans (References 1 thr.ough 3). These documents indicate: the subject three lots are underlain entirely by compacted fill placed incrementally during rough grading between 1970 and 1973. Based on the available-data, fµJ up to 30±-fe~ thiek was reportedly placed near the rear of the building pads with 5-feet or less. of fill placed adjacent to Romeria Street. Soils with a high to very rugh expansion potential reportedly underlie the Jots. A published geologic map (Reference 4) indicates the documented fill is likely underlain by Santiago Formation bedrock. Geo1og1c literature inqicates that .t10 active or poteutiaHy active faults or landslides have been mapped, or are known t.o exist withln the subject property and the site does not He within the presently defined lhnits of an .A:lquist--Priolo Earthquake Fault Zone. FINDINGS Based on the results of onr geotecbnica] feasibility study, the proposed residences are considered feasible irom a geotechnical standpoint, There are no obvious. reported, or known geologic haz.ards within the property that would preclude development of the site from a geologic standpoint. Conditions considered :favorable for development of the property include a) documented fil4 b) no evidence of faulting 01.· landsJiding within the subject site or reported in published documents, and c) no known or reported .shallow groundwater conditions, Geotechnical conditions which should be considered during the pJannfog for site development inc]ude: a) highly to very _highly expansive soils, b) 1.5:l {horiz9ntaf to ve1tical) fill slopes that reportedly exist between the building pads, and c) the effect of ground shaking generated from potential earthquakes on one of the major fault zones in the region. HETHERINGTON ENGINEERING, INC. GEOTECHNICAL FEASIBILITY STUDY Project No. 7802.1 Log No. 17971 October 26, 2015 Page3 A geotechnical investigation (including subsurface exploration, laboratory testing, and engineering/geologic analysis) is recommended to confirm the subsurface conditions. evaluate the existing documented fill, and provide relevant geotecbnical conclusions and recommendations for site grading and construction. A proposal for a geotechnical investigation can be provided upon request This opportunity to be of service is sincerely appreciated. If you have any questions regarding this report, please contact this office. Sincerely, HETHERINGTON ENGINEERING, JNC. ~cih Professional Geolo · Certified Engineer.ing c;e-di~~ Certified Hydrogeolo · (expires 3/31/16) · Attachments: Location Map Figure l Geotechnical E (expires 3/31/l Distribution: I-via e-mail (KevinJ500west@aol.com) HETHERINGTON ENGINEERING, INC. 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