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HomeMy WebLinkAboutCT 76-12; Lake Calavera Hills Unit 1; Soils Report; 1977-01-28- - - SOIL AND. GEOLOGIC INVESTIGATION LAKE CALAVERA HiiS; UNIT NO, 1 TAMARACK AVENUE CARLSBAD, CAL I FORN IA PREPARED FORI Mr. Roy Ward 4321 Birch Street Newport Beach, California 92660 - - - PREPARED kY: Soil, Geology & Testing Consultants, Inc. 6280 Riverdale Street San Dieqo, California 92120 Cf 7d-125 PLLkJS< ENGINEERiNG DEPT. LIBRARY City of Carlsbad 2075 Las Palmas Drive Cartsbad, CA92009-4859 January 28, 1977 .- t--r. Roy Ward 1 121 Birch ~Street SGT 710002 Newport Beach, California 92660 Report No. 1 - ! JBJECT: Report of Soil and Geologic Investigation, Proposed Lake Calavera Hills, Unit No. 1, Tamarack Avenue, Carlsbad, -. California. Lzar Sir: l-1 accordance with your request and our Proposal dated November 17, 1 '76, we have performed a soil and geologic investigation for the subject site. We are transmitting.herewith a report of our findings Nd recommendations. In general, we found the site to be suitable for development as pro- posed. If you have any questions after reviewing our report, please C 1 not hesitate to contact the undersigned. This opportunity to be of service is sincerely appreciated. .- Respectfully submitted, - SOIL, GEOLOGY & TESTING CONSULTANTS, INC. - .- , TJTrL:ml i c : (4) Submitted (2) Rick Engineering -- Attn: Mr. Bob Ladwig - - - - - TABLE OF CONTENTS PAGE NO. Project Description and Scope. ..... -Findings ........ - ....... Site and Soil Conditions. ...... - Site Geology. ............ Faulting. .............. Other Geologic Hazards. ....... -Recommendations. ............ Site Preparation. .......... - Earthwork. ............ Transition Lots. ......... Alluvium ............. - Foundations ............. Expansive Characteristics. ... : Bearing Capacity ......... Settlement ............ - Slope Stability ........... Earth Retaining Structures. ..... --Field Explorations ........... Laboratory Testing ........... - ATTACHMENTS . . . . . . . . . . . . . . . . . . . . .......... .......... .......... .......... . . . . . . . . . . .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... . . . . . . - . . . . . . . . . . . . . 6 1 1 3 3 3 3 3 4 4 4 4 5 5 5 PLATE NO. PlotPlan..........................1&2 -Trench Logs. . . . . . . . . . . . . . . . . . . . . . . . . 3 - 11 Boring Logs. . . . . . . . . . . . . . . . . . . . . . . . .12 - 13 -",rain Size Analysis & Atterburg Limits . . . . . . . . . . .14 & 15 Direct Shear Test Results, Maximum Density & - Optimum Moisture Content. . . . . . . . . . . . . . . . . . 16 ,,ExpanSiOn Test Results . . . . . . . . . . . . . . . . . - - 17 - Slope Design, Recommended Grading Specificaton, Special Provisions, Unified Soil Classification Chart . . .Appendices - - REPORT OF SOIL AND GEOLOGIC INVESTIGATION PROPOSED LAKE CALAVERA HILLS UNIT NO. 1 - CARLSBAD; CALIFORNIA - PROJECT ,DESCRIPTION ANDY SCOPE *is report presents the results of our soil and geologic investigation ar Lake Calavera Hills Unit No. 1. The site, consisting of approxi- mately 63 acres, is located roughly 4,000 feet east of El Camino Real along the proposed extension of Tamarack Avenue in the City of Carlsbad. pproximately 10 acres of the site has tentatively been reserved for a ature school and was not included in the scope of this report. The remaining 53+ acres are planned for 138 single family residential lots -nd open space. It is anticipated that the residential structures will Insist of one or two story woodframe buildings with slab on grade con- struction. It is further understood that FHA and/or VA financing is bPing contemplated and, therefore, the findings and.recommendations .?ich follow have been presented with that in mind. G_raaing for the project will generally consist of cuts and fills of less xan 20“feet, as indicated on the Tentative Map and PUD Plan No. 4, -arlsbau Tract No. 76-12, by Rick Engineering, revised October 22, 1976. An exception to this will occur along the south side of Tamarack Avenue ,-nere a 2:l fill slope having a maximum height of 60 feet is planned. The aforementioned Tentative Map was used as an aid to our studies and analysis. The site configuration and exploration locations are shown II Plate No. 1 of this report. Enis investigation was undertaken to: 4 Determine the physical properties of the prevailing soils including their supporting capacities and settlement characteristics. - b) Provide design information regarding foundations, slope stability and site grading as well as grading for the improvement of Tamarack - Avenue. c) Determine potential construction difficulties and provide recom- mendations concerning these difficulties. .- FINDINGS >te and Soil Conditions Topographically, the site is characterized by rounded hills and ridges %rderinq on numerous randomly oriented drainage courses. On-site levations vary from a low of 160 feet along the southerly margins to a high of 300 feet in the northern extremes. Natural drainage is pri- marily to the south and west. No man-made structures or significant past radinq was observed. The site is presently being used for agricultural ,urposes. - - <I P 710002 January 28, 1977 Page Two I-general, the soil conditions were found to consist of dense to very dense siltstones and sandstones ultimately underlain by weaker iiudstones. These materials tend to be interfingered and somewhat lt--naitic and therefore, preclude accurate mapping. The siltstones a. i muastones are highly expansive while the sandstones are pre- iominantly nonexpansive. This-cond.i-tion~~L~~~~~~~cti~ ~~iiF-n~~p~c~ud-~~tu~a~-dmagpriu~~a~radePxFansirse y L-l*. With the exception of the fault zone area, it can be said tilat, in yeneral, the-~~~~-stone~~r-oncentra~ed--a~ve-260--fee(, t~~sanastoneslbetweell-~levat.io~.:!O"fe~~~~dO‘"~~~~and--the-mud- s ~~~~-~.e2evat-ion--;!.20~eet. The prevailing soils will be rippable with normal earth moving equip- ;I-nt, however, some hardrock may be encountered in the construction of L< t NO. 1 (opposite Trench No. 1) where a metavolcanic rock outcrop encroaches on roughly a third of the lot. L 3se alluvial soils (on-site), are limited to the narrow ravine bottoms anti probably do not exceed five feet in thickness. The proposed align- Ilent of Tamarack Avenue will cross a significant alluvial deposit at i s western end in the vicinity of Trench No. 9. No free water was en- c-antered, however, it should be anticipated that the upper three to four feet of existing soils are soft and wet and will require removal a-i recompaction to provide a stable subgrade. rJith the exception of Boring Nos. 6 and 7, groundwater or seepage was nat encountered in the test explorations. Boring Nos. 6 and 7 encountered a small amount of seepage at a depth of 21 feet. The source of the seep- aqe is not known but may be the result of tomato field irrigation. Close inspection during grading will be necessary to insure that if a seepage c edition is present, appropriate remedial measures can be readily in- c-rporated. Z-IE GEOhOGY This area is underlain by fine sandstones and siltstones of the Santiago Fnrmation. In the Oceanside, Carlsbad area this Formation can be divided i to three separate members, known as Member A, Member B and Member C. M-nber A is generally characterised by green mudstones interbedded w th greenish-gray sandstones. Member B usually consists of very fine to medium qrained, moderately well indurated sandstones. Member C g-nerally is a coarse grained sandstone. At the project site Member A anti Member B are apparently interfinqered, with Member B predominating. below approximately elevation 200 mudstones of Member A are dominant. The Santiago Formation is deposited~upon metavolcanic rocks known as t e Santiago Peak Metavolcanics. These rocks surface in the extreme northern tip of this project and consist of highly fractured gray, hard metavolcanic rocks. - Page Three - s I! 710002 January 28, 1977 - _F IJLTING This site is cut by numerous north:northeasterly trending faults. 'I ese faults are apparently minor features and do not offset topsoil n.,terials within this project. Such faults are common in the Carlsbad- Oceanside area and are considered inactive. The majority of the faults :-~. this site appear to be concentrated in the areas of Trench NO. 11 i Ed Boring No. 6. A trench profile showing the faults encountered in Trench No. 11 is presented on Plate No. 8. It has been our experience -5 nearby areas that these faults are discontinuous enechelon features i mi cannot be traced for any significant distance. It is our opinion that these faults do not present a seismic hazard to the proposed develop- ment, however,. if a structure is located across a fault which has juxta- ] >sed materials of considerably different.shrink/swell characteristics, L.len foundation problems could result. Therefore, we recommend that our engineering geologist be present at the time of grading to inspect ,-It pads for this occurrence. We recommend that such pads be treated ; pacs which are underlain by expansive materials as recommended here- inafter. ThER G;OLOGIC HAZARDS No other geologic hazards, such as, landsliding, high groundwater, r potentially liquifiable soils were noted within the boundaries of Lhe area investigated. Loose, wet, sandy material was encountered near the west end of the major drainage, just to the west of this project, .-here the extension of Tamarack Avenue is proposed. If Tamarack Avenue s constructed according to the recommendations within this report, no significant geotechnical problems are anticipated. - RECOMMENDATIONS site Preparation iarthwork: All earthwork and grading contemplated for site preparation -should be accomplished in accordance with the attached Recommended Grading ipecifications and Special Provisions. Utility trench backfill within iive feet of the proposed structure and beneath asphalt pavement should be compacted to a minimum of 90 percent. The maximum dry density of each Yoil type should be determined in accordance with A.S.T.M. Test Method ~557-7OT, Method A or C. -Transition Lots: Foundations bearing partially on cut and partially on :ompacteci fill are not recommended. The tendency of cut and fill soils to compress differently may result in unequal structural support and subsequent cracking of the foundation/slab system. Therefore, where this -condition occurs it is recommended that either 1) the footings be deepened such that all portions of the footing system bear on firm natural ground or that 2) the cut portion of the building pad be undercut at least one -foot below the base of proposed footings and replaced with properly con- pacted nonexpansive soil. -Alluvium: As indicated previously, if is anticipated that only minor amOUnts of alluvium will be encountered within the subdivision, and these , ST 710002 January 28, 1977 Page Four -ill generally be confined to the bottoms of the two major drainage tri- utaries. Where existant, the alluvial soils shall be removed to firm natural ground and properly recompacted as structural fill prior to the -1acement of additional fill and/or structural loads. For the construction of Tamarack Avenue the alluvium should be removed .and recompacted for a depth sufficient to provide a firm subgrade upon hich additional fill and/or pavement may be placed. We estimate that a depth in the order of four feet over a length of 200 feet to 300 feet would be necessary. oundations -xpansive Characteristics: The expansive characteristics of the clayey oils described previously (siltstones and mudstones) will require special consideration and/or design so that structural damage is not .likely to occur. Lt is recommended that wherever expansive soil is used in fill, it be placed a minimum of 2.5 feet below finish grade and wherever it ocurs within 2.5 feet of finished cut grade, it be removed and be eplaced with nonexpansive soils. The lateral extent of this recom- mendation shall apply to the entire level building pad area. Con- -.entional footings designed as recommended hereinafter may then be .sed for the proposed structure.. It is our opinion that there is a sufficient quantity of nonexpansive oil to properly cap the proposed building pads provided that selective yrading techniques are incorporated. If it is not economically feasible to cap all of the pads it will be necessary to use specially designed -ootings and on grade slabs to reduce the potential for structural dis- .ress. Such recommendations would be included in the final compact~ion report after completion of grading. - ;earin q Capacity: Conventional spread footings having a minimum depth and width of 12 inches and founded in either nonexpansive compacted fill .nr nonexpansive firm natural ground are recommended for the support of :he proposed structures. Such footings may be designed for an allowable soil bearing pressure of 1,800 psf.for full live plus dead loads. This bearing pressure may be increased by one-third for wind and/or seismic - .oadinq and should be decreased by one-fourth for dead load only. Adjacent footings founded at different bearing levels should be so located Rhat the slope bearing level to bearing level is flatter than one horizontal I 10 one vertical. Where a footing will be located near the top of a slope the footing should be deepened such that the outside edge of the footing ! is at least five feet horizontally from the face of the slope. Jettlement: The anticipated total and/or differential settlement for foundations designed as recommended in this report should be less than yhree-fourths of an inch. A majority of this settlement should occur luring construction. - - GT 710002 January 28, 1977 Paqe Five -'lope Stability The proposed 2:l cut and/or fill slopes will be stable with respect t0 Teep seated failure if limited to a maximum height of 70 feet. This llowable height was determined by using a factor of safety of 1.5 and a horizontal seismic force of O.lg (see attached "Slope Design" chart). slopes steeper than 2:l may also be safely constructed, however, the jermissible height will be reduced substantially. If steeper slopes are anticipated, we should be advised so that additional analysis may be performed. 20 reduce the potential for surface sloughing, all slopes should be planted with erosion resisting plants land surface drainage should be lirected away from the top of all slopes. Earth Retaining Structures - ,ctive and passive soil pressures for the design of earth retaining structures will be dependent upon the particular soil condition being considered. Should this information be necessary for design purposes, Ilease ‘provide this office with the location and type of wall proposed. FIELD EXPLORATIONS - ,'wenty-one subsurface explorations were made at the locations indicated on the attached Plate No. 1 on May 10, 1973 and January 5 and 12, 1977. -These explorations consisted of two borings drilled by means of a rotary lucket type drill rig and nineteen trenches dug by means of a backhoe. The explorations were conducted under the observation of our engineering Teology personnel. The explorations were carefully logged when made. These logs are pre- Sented on the following Plate Nos. 2 through 13. The soils are described Ln accordance with the Unified Soils Classification System as illustrated >n the attached simplified chart. In addition, tion, the wet color, the apparent moisture, -3re given on the logs. Soil densities for granular soils are given ! a verbal textural descrip- and the density or consistency / $ as either very loose, loose, medium dense, dense, or very dense. The consistency of silts or clays are given as either very soft, soft, -neaium stiff, stiff, very stiff, or hard. 1, Representative core samples were obtained by means of a split tube sampler driven into the soil by means of the "kelly bar" of the drill rig. The energy required to drive the split tube sampler is indicated / on the boring logs as the "penetration resistance".. The core samples were carefully removed, sealed, and returned to the laboratory for j -testing. Disturbed samples of typical and representative soils were also obtained 1 -ana returned to the laboratory for testing. t - f - ST 710002 January 28, 1977 Page Six LABORATORY' TRST~IfiG Laboratory tests were performed in accordance with generally accepted- -nerican Society for Testing and Materials (A.S.T.M.) test methods r suggested procedures. Representative samples were tested for their dry density and moisture content.' The results of these tests are present- -a on the trench and boring logs. The expansive potential of clayey soils was determined in accordance with the following test procedure and the results of these tests appear n Plate No. 17. Allow the trimmed, - sample to air dry to a constant moisture content, at a temperature of 100' F. Place the dried sample in the consolido- meter and allow to compress under a load of 150 or 645 psf. Allow moisture to contact the sample and measure its expansion from an - air dried to saturated condition. In addition, the gradation, maximum density and the angle of internal .friction and cohesion was determined for typical and representative amples. The results of the tests are presented on Plate Nos. 14 through 16 of this report. - - - - - - - - -. i--7- 7eefwc.4 ,YtcGa7/aN -&a/w TEST LdLl7/ONS SC,L,OEOLO~Y GTESTINO CONBULTANTS.IN’=. - DTrlrp DT.nN ijcLkQ: /‘k SO3 Lake Calaveras Hills Unit No. 1, Tamarack AvCnUC Carlsbad, California f JC DATE l/25/77 - 3’ t / 4 f /’ / /-‘ I / /’ . I r” BOIL.OEOL003Y 5.TESTlNO CONSULTANTS, INC. Lake Ctlaveras Hills Unit No. 1, Tamarack Avenue Carlsbad, California BY DATE JC l/25/77 SP.” .I_ I TRENCH NUMBER 1 Existing Elevation 290+ -0 CLASS DESCRIPTION .- 2 6 - Bottom - TRENCH NUMBER 2 Existing Elevation 271+ - B,,;;SCRIPTION , Loose to Medium Dense, SILTY SAND Green-Gray, Mottled Yellow-Brown, Wet w Medium to Stiff, SANDY CLAY -2 _ ICL, w . ‘I.1 - 'i‘. .I SM Light Green-Gray, Moist, Dense, FINE SANDSTONE Blue-Gray, Moist, Very Stiff, SILTSONE Bottom (difficult digging) - TRENCH NUMBER 3 Existing Elevation 264 t ^ CLASS DESCRIPTION Dark Brown, Wet, Loose, SILTY SAND Brown, Wet, Soft, CLAY CL/ Green-Gray, Mottled Yellow-Brown, CLAYEY SAND SM 1 Lisht Green-Grav with Orange-Brown ILTSTONE ,..P_. _~ _. Bottom (arrricult digging) - FOR LEGEND SEE PLA! 501L,DEOLOOYtZTTE~T,NO CONSULTANTS. INC. .- TRENCH LOGS Y !! 118.3 10.2 : NO. 11 Lake Calaveras Hills Unit 1~0. 1, Tamarack Avenue Carlsbad, California BY DATE KLS l/5/77 .^_ ..^ TRENCH NUMBER 4 -. Existing Elevation 25i'f - - - - - T % SM, SP DESCRIPTION Brown, Wet, Loose, SILTY SAND x Gray-Brown, Wet, Moist, CLAYEY SAND Buff to Gray, Moist, Dense to very Dense, Fine SANDSTONE 117.3 Bottom .TRENCH NUMBER 5 Existing Elevation 250f CLASS DESCRIPTI,ON SM 1 Brown, Wet, Loose, SILTY SAND F-l ~Buffr Wett Loose, CLAYEY SAND Y SM/ Buff to Gray, SP Moist, Streaked Orange-Brown, Dense to Very Dense, Fine SANDSTONE Bottom TRENCH NUMBER 6 Existing Elevation 245f ^ CLASS DESCRIPTION , 1 . . Brown, Wet, Loose, SILTY SAND . . Light Brown, Wet, Medium, CLAY 2 f& . : SM Buff, Moist to Wet, Dense, Very Fine SANDSTONE Gray , Moist, Very Dense to Hard, CEMENTED SANDSTONE Bottom (difficult digging) M - .0.7 FOR LEGEND SEE PLATE ~0.11 Lake Calaveras Irills sOlL.l3EoLO5YhTESTINC3 Unit mo. 1, Tamarack Avenue CONSULTANTS, INC. Carlsbad, California I - BY TRENCH LOGS KLS DATE l/5/77 InI3 wn I - ” TRENCH NUMBER 7 Existing Elevation 273* - - - - - - - n CLASS DESCRIPTION /jCH '1 Green-Brown, Wet, Soft, CLAY Green-Yellow-BrQwn. Wet. Soft to 6 TRENCH NUMBER 8 0 CLASS DESCRIPTLON CL Gray-Brown, Wet, Medium, CLAY Tan to Brown, Moist, Medium, SANDY CIAY Brown, Wet, Stiff, CLAY -. :, / Buff to Brown, Moist, Dense, CLAYEY /..CW TO CLEAN SAND 61,’ Asc)‘ Brown, Moist. Dense to Stiff. CLAYEY SAND TO SANDi! CLAY - 8 / L / 113.6 11.5 Bottom FOR LEGEND SEE PLATE NO. 11 Y M - 111.2 19.0 Lake Calavcras 1Iills Unit No. 1, Tamarack Avenue Carlsbad, California BY TRENCH LOGS KT.S DATE l/5/77 - - - _~ - - - - - .- _- 0 ?y,, DESCRIPTION .'. : Brown, Wet,~ Very Loose, SILTY SAND z: .i/.l SC Dark Gray-Brown, Wet, Loose, CLAYEY SAND Gray-Brown, Taoist, Loose, SILTY Dark Brown, Wet, Stiff, SANDY TRENCH NUMBER 9 Y M - 101.9 13.2 102.6 10.0 Bottom TRENCH NUMBER 10 DESCRIPTION SIi!TY SAND Li ht Tan-Brown, Wet, Very Loose, Brown, Wet, Loose, SILTY CLAYEY SAND Gray-Brown, Wet, Loose, FAIRLY CLEAN SAND Bottom FOR LEGEND SEE PLATE NO.11 ScJIL.DEOLOII)Y&TESTINO CON5ULTANTS.INC. - TRENCH LOGS I BY DATE KLS 1 ,1-z I77 - TRENCH NUMBER 11 ‘- 0 y.AF. : - 2 Ii:,:, r $I:1 .- 4 ;$j/i SW SC SW SM SM/ SP DESCRIPTION Brown, Wet, Loose to Medium, SILTY Buff to Gray, Wet, Dense to Very Dense, Fine SILTY SAND TO MEDIUM CLEAN SANDSTONE Bottom Note : This trench was extended for 160' to the west. See attached Trench Profile, Plate No. 8 TRENCH NUMBER 12 DES----- CKIPTION Brown, Wet, Loose, SILTY SAND Y M - - 111.1 10.1 10.3 Gray-Tan, Wet, Dense, SUGARY SANDSTONE 112.3 11.1 Gray, Wet, Dense, Very Fine SANDSTONE Bottom FOR LEGEND SEE PLATE NO.11 I e.O1L,OEOLC3GYfiTESTINO CONSULTANTS. INC. Lake Calaveras Hills Unit No. 1, Tamarack Avenue Carlsbad, California - TRENCH LOGS BY DATE KLS l/12/77 Inn cln I - - - - - - ,- - FRENCH NUMBEP 13 DESCRIPTION Brown, Wet, Loose, SILTY SAND Gray, Wet, Dense, Very Fine SANDSTONE Y M - - 14.2 Bottom TRENCH NUMBER 14 DESCRIPTION Brown, Wet, Loose, SILTY SAND Pink and Green, Wet, Soft to Stiff, CLAY Green-Gray, Moist, Stiff, SILTSTONE Gray , Moist, Very Dense, SILTY SANDSTONE Green-Gray, Moist, Very Stiff, SILTSTONE Bottom FOR LEGEND SEE PLATE NO. 11 TRENCH LOGS Lake Calaveras Hills Unit No. 1, Tamarack Avenus Carlsbad, California v BY DATE KLS 1(12/77 8r.D .,n I j ! I it : II ,, I: E :! I , L I -- _ - - 0 -’ 2 - 4 - 6 0 - TRENCH NUDER 15 DESCRIPTION Brown, Wet, Loose, SILTY SAND Green-Gray and Orange, Wet, CLAY Blue-Gray, Wet, Medium to Stiff CLAY Blue-Green, Moist, Very Stiff MUDSTONE Bottom TRENCH NUMBER 16 . DESCRIPTION to Very Stiff, SANDY CLAYEY SILTSTONE WITH THIN LENSES OF CLAY J....\SP 1 Buff to Oranse. Moist. Dense SANDSTONE - Gray-Green, Moist, Stiff, SILTSTONE Bottom - FOR LEGEND SEE PLATE NO.11 - TRENCH LOGS I Lake Calaveras Hills Unit No. 1, Tamarack nvcnue Carlsbad, California BY OATE KLS l/12/77 .^^ .,^ - - - - - - - - - - - - - - - TRENCH NUMBER 17 DESCRIPTION Brown, Wet, Loose, SANDY CLAY Blue-Green, Wet, Medium to Stiff CLAYEY SILTSTONE Blue-Green, Moist, Very Stiff, CLAYEY SILTSTONE Bottom TRENCH NUMBER 18 DESCRIPTION Brown, Wet, Loose, SILTY SAND Buff to Green-Gray, Wet to Moist, Medium to Dense, SANDSTONE Bottom TRENCH NUMBER 19 O CLASS :. ‘, .I’ x/ .: ’ 2 4 Ff .l.I.I. SW :1:1:1: sp DESCRIPTION I gE;n, Wet, Loose, CLAYEY SILTY Buff to Green-Gray, Moist to Wet, Dense SANDSTONE Bottom 4 : Sample Lo~cation Y: Natural Dry Density (pcf) M: Natural Moisture Content (% of Y) Lake Calaveras Hills Unit No. 1, Tamarack Avenue Carlsbad, California I -. BY DATE TRENCH LOGS KTS l/12/77 Inn L&n I BORING NDMBER 6 DESCRIPTION I Light Brown, Dry, Loose, SILTY SAND Fault Movement Zone, Interbedded, Moist, Dense, SILTY SANDS AND SANDY D - - Pink-Olive, Moist, Stiff, SANDY SILT and Orange-Brown, Moist, Dense SILTY SAND (Horizontally Bedded) : : SM . : . . ML f Olive-Gray, Moist, Very Dense, SILTY SAND 52 123.6 10:s Olive-Gray, Moist, Humid, CLAYEY VERY SANDY SILT 30 99.5 21.3 FOR LEGEND SEE PLATE NO. 11 SOUTHERN CALIFORNIA TESTING LABORATORY, INC. Lake Calaveras Hills 62.30 RIVERDALE STREET Unit No. 1, Tamcrack Avenue SAN DIEQO, CALIFORNIA 92120 Carlsbad, California 29 119.9 9.8 40 110.9 18.0 Olive Slight Seepage Pink-Tan, Moist, Hard, SILT - BORING LOG BY CHC MTE s/10/73 JOB No. nr xcnc un BORING NUMBER 7 - - ML SM - TM DESCRIPTION Brown, Moist, Soft, SANDY Light Green, Humid, Dense.to Very Dense, SILTY SAND Light Green, Humid, Hard, Very SANDY SILT and Dense, VERY SILTY SAND 43 116.0 14.0 52 118.2 13.5 Light Orange-Brown, Humid, Very Dense, VERY SILTY SAND (Slight Seepage at 21 Feet) 48 113.6 7.5 48 - - - FOR LEGEND SEE PLATE NO. 11 SOUTHERN CALIFORNIA TESTING LABORATORY, INC. 6280 RIVERDALE STREET SAN DIEQO. CALIFORNIA 92120 Lake Calaveras Hills Unit No. 1, Tamarack Avenue Carlsbed, California I BORING LOG BY CHC DATE 5/10/73 .K-m Na I GRAIN SIZE ANALYSIS AND ATTERBURG LIMITS L SAMPLE Tll T13 @ 6' @ 6’ @ :",I 86 @ 17' @ 3?31' @ 2%3. I 6” I I I 14"l I I +-FL- LIOUID LIMIT PLASTIC LIMIT PLASTICITY INDEX I UNIFIED CLASSIFICATION SM/SW Sp/SM SM ML ML SM - -y#p SOIL.cxEOLOGY.sTESiTING r”ru~l II TPNTS. INC. TABLE OF TEST RESULTS BY KT.S DATE T/24/17 GRAIN SIZE ANALYSIS AND ATTERBURG LIMITS SAMPLE @ ;7,* @ ;;-16’ (aB;?, 6” 4” I&- #30 99 38 93 #50 96 94 84 #loo 81 80 72 $200 51 43 45 \ .05 mni - .Oc ;5 mm -I - I I 4 ,001 mm LIQUID LIMIT PLASTIC LIMIT . PLASTICITY INDEX 1 UNIFIED CLASSIFICATION ML SM SM 1 - E--CT SHEAR TEST RESULTS -- L-AMPLE 6-@17' - 6 @31' 7 @6' - 7 @22-23' - _~~ DESCRIPTION - AXIMUM DENSITY & OPTIMUM MOISTURE CONTENT .- 5 rM.: 1557-70 METHOD: A DESCRIPTION SOIL, OEDLDGY L;TESTINO CONSULTANTS. INC. Blake Calaveras Hills Unit No. 1, Tamarack Avenue Carlsbad, California I ___- BY KLS DATE l/24/77 IAP wn I - EXPANSION TEST REsU-I- I SAMPLE T7 @5' >NDIT ION Undist.-AI - 1. AL MC.(%) 4.9 IITIAL DENSITY(PCF) -- 111.2 I, 9L M.&W.) 29.4 C-?MA L STRESSiPSF) 150 - XPANSION (*/.I 20.3 - SAMPLE - B7 @O-1.5' - :C qDITION I Remolded @90% -AD ?I-IAL M.C>(*I.1 NITIAL DENSITY( PCF) - =I AL M.C.(‘/.) WRMAL STRESSW’W - E,.PANSlON (‘/.I >AMPLE Lake Calaveras Hills Unit No. 1, Tamarack Avenue Carlsbad, California BY KLS DATE l/24/77 JOB NO. 710002 PLATE NQ,ly ~- 7 -~ - c----Ir" ,L"' T'," 6ta Itic ..lan ~,isiL .f 2-- kr;--lci--~es --kea,, 'th;, hse ,! a ILp i toL Jf saL&ty ~2 1.07' I' !~ and Taylor's charts is not significantly different from the use of a factor of safety of 1.5 and a seismic load of O.lG .The chart below,is based on factors of safety of 1.5 and 1.89 and Taylor's chart. Enter the chart from the bottom left .' with the given slope ratio. Go up to the appropriate"m"curve (dashed for seismic) proceed SkppeHeight with Seismic. 0 B 51 e. 2 '9 .I. ;I e '0 h . Slope Ratio ‘b’ JOB NO. 710002 DATE wa/77 RECOMMENDED GRADING SPECIFICATIONS GENERAL PROVISIONS GENERAL INTENT - The intent of these specifications is to establish procedures for clearing, compacting natural ground, preparing areas to be filled, .~ and placing and compacting fill soil to the lines and grades shown, on the accepted plans. The recommendations contained in the pre- liminary soil investigation report and/or the attached Special Pro- visions are a part of the Recommended Grading Specifications and ~- shall supersede the provisions contained hereinafter in the case of conflict. - INSPECTION AND TESTING A qualified soil engineer shall be employed to inspect and test the - earthwork in accordance with these specifications. It will be ne- cessary that the soil engineer or his representative provide ade- quate inspection so that he may certify that the work was or was not accomplished as specified. It shall be the responsibility of -the contractor to assist the soil engineer and to keep him appraised of work schedules, changes and new information and data so that he may make these certifications. - If, in the opinion of the soil engineer, substandard conditions are encountered (such as questionable soil, poor moisture content, in- - adequate compaction, adverse weather, etc.), he will be empowered to either stop construction until the conditions are remedied or corrected or recommend rejection of the work. -Soil tests used to determine the degree of compaction will be per- formed in accordance with the following American Society for Test- ing, and Materials test methods: - Maximum Density & Optimum Moisture Content: A.S.T.M. D-1557-70 Density of Soil In-Place: A.S.T.M. D-1556-64 -PREPARATION OF AREAS TO RECEIVE FILL All vegetation, brush and debris shall be removed, piled and burned -or otherwise disposed of. After clearing, the natural ground shall be scarified to a depth of six inches, brought to the proper mois- ture Content, compacted and tested for the minimum density specified .-. . , _.~ - APPENDIX A, PAGE 2 JOB NO. 710002 DATE l/*8/77 - in the Special Provisions or the recommendations contained in the preliminary soil investigation report. - When the slope of the natural ground receiving fill exceeds 20 per- cent (5 horizontal units to 1 vertical unit), the original ground shall be stepped or benched. Benches shall be cut to a firm compe- - tent soil condition. The lower bench shall be at least ten feet wide and all other benches at least six feet wide. The horizontal portion of each bench shall be compacted prior to receiving fill as - specified hereinbefore for compacted natural ground. Ground slopes flatter than 20 percent shall be benched when considered necessary by the soil engineer. - FILL MATERIAL Materials placed in the fill shall be approved by the soil engineer - and shall be free of vegetable matter and other deleterious sub- stances. Granular soil shall contain sufficient fine material to fill the voids. The definition and disposition of oversized rocks, - expansive and/or detrimental soils are covered in the Special Pro- visions. Expansive soils, soils of poor gradation or strength characteristics may be thoroughly mixed with other soils to provide - satisfactory fill material, but only with the explicit consent of the soil engineer. PLACING AND COMPACTION OF FILL - Approved fill material shall be placed in areas prepared to receive fill in layers not to exceed six inches in compacted thickness. - Each layer shall have a uniform moisture content in the range that will allow the compaction effort to be efficiently applied to achieve the specified degree of compaction. Each layer shall be uniformly - compacted to a minimum specified density with adequately sized equip- ment, either specifically designed for soil compaction or of proven reliability. The minimum degree of compaction to be achieved is specified in either the Special Provisions or the recommendations - contained in the preliminary soil investigation report. Field tests and inspections to check the degree of compaction of the - fill will be taken by the soil engineer or his representative. The location and frequency of the tests shall be at the soil engineer's discretion. In general, the density tests will be made at an inter- - val not exceeding two feet in vertical rise and/or 500 cubic yards of embankment. SEASON LIMITS Fill shall not be placed during unfavorable weather conditions. When work is interru~pted by heavy rain, filling operations shall j - - - - - - .- APPENDIX A, PAGE 3 JOB NO. 710002 DATE i/28/77 not be resumed until the proper moisture content and density of the fill has been achieved. Damage resulting from weather shall be re- paired before acceptance of work. Uh'FORESEEN CONDITIONS In the event that conditions are encountered during the site pre- paration and construction that were not encountered during the preliminary soil investigation, Soil, Geology 6 Testing Consultants, Inc. assumes no responsibility for conditions encountered which dif- fer from those conditions found and described in the preliminary soil investigation report. APPENDIX B JOB NO. 710002 DATE l/28/17 RECOMMENDED GRADING SPECIFICATIONS SPECIAL PROVISIONS -The minimum degree of compaction to be obtained in compacting -The minimum degree of compaction to be obtained in compacting natural ground, natural ground, in the compacted fill, and in the compacted in the compacted fill, and in the compacted backfill shall be 90 percent. backfill shall be 90 percent. - %\ 3etrimentally expansive soil is defined as soil which will swell more than three percent against a pressure of 150 pounds -3er square foot from a condition of 90 percent of maximum dry density and optimum moisture content to saturation. -1versized fill material is defined as rocks or lumps over six -nches in diameter. At least;40 percent of the fill soil shall pass through a #4 U. S. Standard Sieve. 'ransition Lots: Where transitions between cut and fill occur within the proposed building pad, the cut portion should be undercut~a minimum of one foot below the base of the proposed ootings and recompacted as structural backfill.