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Home My WebLink AboutCT 72-20; La Costa Vale Unit 2-4; Soils Report; 1971-05-23I-- i T. FUNNEKOTTER ENGINEERING GEOLOGY PLGISTEPEO GtcxOGISr CEDTiFlED ENGINEERIN: CxOLOGlST P. 0. BOX 171 ESCONDIDO, CALIF. 92025 746.2793 - - - - - - - La Ccsta kc. San 3ie:;o comty, Caiif. Sir:c?s ~113 thm Kl3 GEOPHYSICAL IN”ESIICATIcJNS For S”bd~“lrion llerign P,peliner Roodr SekrnlC Rqqdilbty Studies SlOlO .17.87 T. FUNNEKOTTER - REGiZlERED GEOLOGIST CEWiFlED ENGlNEERlNG GEOIOGIS‘ P. 0. XIX 571 ESCONDIDO. CALIF. 92025 74*-2793 ENGINEERING GEOLOGY GEOPHYS,CAL IN”tSTIGArIONS For Subdivirion Design ~,~e,ine. Roods seismic Rippobility Sf"dk. _ Purpose: To evaluate subsurface conditions at several select locations in order to provide design and excavation irZornation. - %&hod: Refraction Seismography. Geologic reconnaissance. Dis&ssion: All areas investigated are underlain by the Black Eountain Volcanlcs; however two areas indicate extensive low velocity sandstone and/or siltstoce. This report includes lines Al3 thru H13, C13X1, and C13X2. Total Seisnic coverage is 3750 lineal feet. Line Al3 indicates high velocity material fron 18 feet to 28 - feet deep. Overlying this is low velocity depositional material with velocities of 2300 to 2900 ft/sec. Line.Bl3 is conposed of Black Mountain Volcanics (E&IV) with the high velocity material appearing at depths of 22 feet to 40 feet, Line Cl3 is also E;fl - the high velocity naterial here varies in depth from 5 feet to 38 feet. The cross lines on Cl3 indicate siailar conditions. The southeast half of line Dl3, line E13, and line F13 all indicate high velocity volcanics from 9 feet to 30 feet deep. On lim D13 from station 4.5 northwest, a different situation exists. Here the high velocity volcanics were not encountered. Rather, three low to moderate velocity layers were mapped, i.e., 1300 ft/sec, 1800 to 2000 ft/sec, and 3400 to 4000 ft/sec, This situation indicates that this particular area is, in ?art, depositional in character. I.1axim.n genetration here is 45 feet deep. Lines Cl3 and H13 are co:ri::osed of BbIV with the harder high vclocit;y material - - - ‘- T. FUNNEKOTTER REGISKRED GEOLOGISr ENGINEERING GEOLOGY CER,,FlED UKlNFtRlNG GEOLOGiSi Pi 0. BOX 575 ESCONDIDO. CALIF. 92025 74&27P3 - tLOPHYS,CAL ,N”ts1,GAI,ONS For S”bd~“i~iO” Design Pipel;“el Roads seismic Rippabiiify Sfudie. - Discussion: (cor.%I r.t ~~pt:~s of ,!+ 22%: to 28 feat deep. .:.s usual, the creser.ce cf scattered blocks oi^ hard volcanic material should be anticipated, especialljr where noted on the velocity profile. Conclusion: Virtually all lims investi.Ssted indicate a three layer profile - - soil, decoqxec: md fractured volcanics, and the parent, high velocity volcxiics. 'P&o cxceptior,s are noted - 1ir.e A13 and north- - west half of Dt3 - both are, in part, depositional and conposed - of softer sandstone and siltstone. In t3r.m of ri?pnbility, the following schedule would ap~lg: Velocity (ft/:;cc 1 ticovation Kethod 0 to 2oco Scraper 2000 to 5000 Ripper 5000 to 5500 iiarginal Over 5500 Drill & Shoot - - - - - Submitted ~~~~~z<~$& 'i. Funnekotter --.- . T. FUNNEKOTTER ENGINEERING GEOLOGY REGISTERED GEOLOGIST CERTlFlED ENGINEERING GEOLOG15T p. 0. BOX 571 ESCONDIDO, CALIF. 92025 - 746.2793 Benton Engineering Inc. 6741 El Cajon Blvd. San Diego,Calif. 92115 Attn: P. Eenton . GEOFnYSlCAL IN”ESTIGATIONS For S”bdi”iSi0” resign Pipeline* Roads Seismic Rippability S,“di.l January 1,1973 - Dear Sir, Enclosed is the Subsurface Investigation Report 0ALaCosta Vale - Unit 2 - -. lines Al6 thru E16. Original velocity profile of these lines is also included. Very truly yours, my:,&& T. Funnekotter - T. FUNNEKOTWR ENGINEERING GEOLQGY REGISTERED GEOLOGIST CERTlFlED ENGINEERING GEOLOGlST P. 0. BOX 575 ESCONDIDO, CALIF. 92025 746-2793 GEOPHYSICAL IN”ESTIGATIONS For S”bdi”irim Derign Pipeline. Roads Seismic Pippobility Studies SUBSUXFACE INVESTIGATIOM LA CCSTA VALE - UNIT 2 S&ISKIC LINES Alb THHlI El6 January 1,1973 - - - - T. FUNNEKOTTER REGlSTERED GEOLOGIST CERilFlED ENGlNEERlNG GEOLOGIsT P. 0. BOX 57s ESCONDIDO, CALIF. 92015 - 746.2793 ENGINEERING GEOLOGY GEOPHYSICAL lN”ESTlCATlONS For Subdivirion Design Pipelines Roadr SeilrniC Rippobility Studier - - Purpose: To evaluate subsurface conditions in three select areas in order to determine what excavation problems may he encountered. Method: Refraction Seismography. Geologic reconnaissance. Discussion: The Seismic traverses are in the Black Mountain Volcanic unit - the material ranges from andesite to rhyolite. This report includes lines A16,B16,C16, D16,and El6 - located approximately as shown on the enclosed plat. In general, three velocity zones were mapped azs follows: Velocity Range (ft/sec) Material 1300 to 2000 Soil & fill 2800 to 4200 Decomposed & fractured volcanic 7500 to 10,000 Hard, rigid volcanic Lines .klC,B16, and Cl6 are in one area and cross each other. fiigh velocity volcanics were located here from 12 feet to 26 feet deep. The intermediate layer of decomposed and fractured volcanics has a velocity range of 2800 to 4100 ft/sec. The upper soil layer has a velocity range of 1300 to 2000 ft/sec and is up to 12 feet deep. Kost of the high velocity material in this area appears to fall between a depth of 12 feet and 20 feet. The area immediately west of line Cl6 has -~ T. FUNNEKOTTER REGISTERED GEOLOGIST CERTlFlED ENGlNEERlNG GEOLOGIST P. 0. BOX 575 ESCONDIDO, CALIF. 92025 - 746.2793 - - - ENGINEERING GEOLOGY GEOPHYSICAL lN”ESTlGATlONS For svtdivirion Design Pipeline* Roods Seirmic Ripp.bility Studier Digcussion: (can't) a considertible amount of rubble and boulders on the surface. Line D16 is in the second area. High velocity volcanics were located here at 28 to 32 feet. The intermediate zone velocity here measured 3500 ft/sec. Line El6 is in the third area investigated and indicates high velocity material at 17 feet. The overburden velocity here is 4200 ft/sec. All runs indicate the presence of boulders and blocks in various degrees of profusion. Some of these are quite large, especially so where indicated on the profile. These blocks appear to be most concentrated in the area of line Cl6 and the northwest end of line A16. Conclusion: Hard, rigid volcanic material was located on all Seismic runs. The depth of this material is from 12 feet to 32 feet - mostly falling between 12 and 20 feet. The overburden velocity falls within a range of 2800 to 4200 ft/sec. In terms of rippability, based on a D-9 Cat, the following schedule should apply: - T. FUNNEKOTTER ENGINEERING GEOLOGY REGISTERED GEOLOGIST CERTlFlED ENGNEERNG GECLOGlST P. 0. BOX 575 ESCCNDIDC. CALIF. 92025 746.2793 - Conclusion: (can't) Velocity (ft/sec) 0 tc 2000 2000 to 5000 5000 to 5500 Over 5500 For trenching, based on a should apply: Velocity (ft/sec) 0 to 3800 3800 to 4300 Over 4300 GEOPHYSICAL IN”ESTltATIONS For S”bdi”irion Design Pipeliner Roods Seismic Rippobility Studier Excavation Nethod Scraper Ripper Marginal Drill & Shoot Kohring 505, the following Excavation Method Ripper Marginal Drill R: Shoot Submitted by ,. .., - - - - ~. ,<%- . __ 2-a ‘-._ $ z-1:! _ -, ‘. -‘-u,.. ‘~ . . . c-c’ .’ A_. \. .:> *e<,.-. ,‘-._,, ‘. c T- ‘4*, ‘ . ‘.__ . . c;. ’ ,s .’ ‘- c- ‘- ‘\, ‘L -4, . < .-‘-‘x. ,“,\ - - SLIS!"XC - RIPPABILITY INFORMATION !- - - - - The following points should be considered when evaluating Seismic information: 1. All velocities, depths, and thicknesses are averages and qualified according to the following schedule: F" - good - fair TP- poor - very poor ? - questionable Grades of G, F, and P can be considered reliable; VP and ? should be considered as indications only. 2. Each profile provides information in the immediate area of that profile - extrapolation outward from this area must be considered speculative unless additional information is available. 3. As the velocity of the material increases, ripping becomes progre- ssively more difficult until at some point it is more economical to drill and shoot the material prior to excavation. This point occurs within the marginal zone. Rippability figures vary with the type of material, however, in general, D-9 ripper performance is as follows: Velocity Range (ft/sec) Excavation Method 0 to 2000 Scraper 2000 to 5000 Ripper 5000 to 5500 Marginal Over 5500 Blasting These figures are based on several hundred job studies. 4. For trencher and backhoe operations the rippability figures must be adjusted downward, i.e., velocities as low as 3500 ft/sec may indicate material that is not rippable, depending on the homogeneity of that material, whereas material measuring over 4300 ft/sec almost certainly would require explosive work. As an average, materials measuring over 3800 ft/sec would mean difficult trenching and the economics of the situation would probably dictate explosive work first. The above figures are based on a machine similar to the Kohring 505. T. FlJNNEKOTTER RKISTERED GFOLOGlST - - - .- - - Renton Lnginteri~l:,~ Inc. 6717 Convoy Ct San Dieuo,Calif. 92111 kttn: Sob Zemer ENGINEERING GEOLOGY GEOFHYSKAL lN”ESTlGATlONS For Subdivirion Design Pipelines Rood* Seismic Rippobilif” Studier February 26,1?73 &ar sir, is the Subsurface Investigation s the orip,inals of the Seismic profiles of these lines. If there are any maps which can locate the stake I mention near line 517 this would help to locate the nosition of this line. This stake is a 2x2 nainted white with the upper part painted red and tied down with wire. If you have any qestions please call. Very truly yours, cl:I;31 $p-&C~;$f Ted Funnekotter L . T. FUNNEKOTTER ENGINEERING GEOLOGY REGISTERED GEOLOGIST CERIIFIED ENClNrERlNG CEOLOCilST - P. 0. BOX 575 ESC”NDI@O. CALIF. 970?1 746.2793 - - - IA CC;i’l’ii VAI,?, StL3NlC LIiu'Lj: A17 THiiU 517 February 26,1973 GEOPHYSICAL IN”ESTIGATlONS For S”bdi”~SiO” rhr*gn P,peliner bdr Sei,mic F!+ymbilil” Studier ‘- 1 . T. FUNNEKOTTER RLGlSTERED GEOIOGISI CERTlFlED ENGINEERING CECXOGIST - P. 0. BOX 575 ESCONDIDO, CALIF. 92025 746~2793 - - ENGINEERING GEOLOGY GrOP*YSICAL IN”EST,GATIONS Far S’Jbdi”irion Derign Pipeline* Pod Seirmic Rippability Studies To evaluate subsurface conditions in nine select 2 r f! 3 s in La Costa Vale in order to determine what excavation nrohlems may be anticipated. Xef'raction Seisrno;:ranhy. Geologic reconnaissance. The areas investigated are all within the Black !<ount,ain Volc;~riic structure - this unit. is princij~a11y *:xtrll:;ive ii:rjeous f‘low:; ranf:ing l'rom andesite to rhyolite. The layer sequence is soil, decomposed and fractured volcanics with sparse to heavy concentrations of volcanic blocks within the overburden, and the parent volcanic rock. Ten lines were investigated by the Seismic method - lines A17 thru 517. The approximate location of these lines is shown on the enclosed plat. The location of lines fi17, 117, and 517 should be considered as very general - no good distinctive features here permit very accurate orientation. However, note on the plat the position of a red-white stake near the southeast end of line J. All other lines were oriented from high voltage towers or poles and distinctive topographic features. In general, high velocity volcanics were located on all of the Seismic runs. The depth of this material is from 4 feet to 4b‘ feet. The intermediate layer has a velocity r‘an~e of 2500 to 4600 ft/sec - averaging around 3600 f‘t/sec. The soil layer is from 2 feet to -- ..~... .~ ._ I T. FUNNEKOTTER ENGINEERING GEOLOGY REGISTERED GEOLOGIST CER,,F,ED ENGINEERING GEOLOGIST - P. 0. BOX 575 ESCONDIDO. CALIF. 92025 746.2793 - - - - GEOPHYSICAL IN”ESTlGATIONS For S”bdi”iSi0” D&g” Pipeline* Roodr Seismic Rippabillly 3udier DISCUSSION: 9 feet thick. Line Al'7 indicates from 25 to 29 feet of over- burden (3800 ft/sec) over 10,OOC ftjsec volcanics. i/n l~ine Bl'?, the high velocity volcanics rise from 24 feet to 12 feet from the surface and has an over- l~urd~or~ veloci~ty of' 3100 ft/sec. Line Cl7 shows the high velocity vo!canics from 23 feet to 48 feet deep, howr:vt:r , tl0t.e tht‘ owr-hurcien velori t.y .from station 0 c 0 statiorl 1 .5 - it was 1,800 ft/sec in this area. This is approaching the marginal rippable category of 5000 f‘t/sec. Line Dl'i shows high vel~ocity material rising steeply towards the east and southeast - from about 40 feet deep to 12 feet deep. Lines b-17, F17, and Cl7 are all in one general area and show the hard volcanics to be from 4 feet to 29 feet deep, mostly quite shallow. The overburden velocities here range between 3300 and 4200 ft/sec. This hard volcanic horizon appears to rise towards the southwest and northwest. Cn line #C17, this layer is very shallow - from 4 to 9 feet deep. Lines Hl’? ami <J17 ;jr~: on a mrthwest trrrltiiny; rjripe anti thr high velocity material here anpears to be roughly conformable to the surface. Note the rise and fall of this material across line H17 and the rise along line J17 towards the southeast. Line I17 indicated high T. FUNNEKOTTER R,I,,:~>,tKC~, 1;1010~~1s1 < EK,,F,iD ENGINFERINC, CFO,“~;IST - P. 0~ BOX 515 ESCONDIDO. CALIF 92075 746.2793 ,, r,l,, ..:. ~_ ENGINEERING GEOLOGY GEOI’HYSICAL IN”~STIGAIIONS lo, Subdlvirion Deqn Pipelines Roads Seismic Rippability Studier DISCUSSION: velocity material at a depth oa approximately 12 feet. - - - - - - The overburden in these areas contain volcanic blocks in various degrees of concentration - this is so innicated on the profile. CC~~CLUSIC~~: The most troublesome areas in terms of near surface hard volcnnics aonear to be lines G17, F17, the south- easterr) end of‘ line Dl7 and the area around lines H17, 517, and I17. In much of these areas the high velocity volcanic material is less than 10 feet deep. In terms of rippability, based on a D-9 Cat, the followin:- schedule should apply: Velocity (ft/secl Excavation Method 0 to 2@OO Scraper 2000 to 5000 Ripper ~000 to 5500 iv;arginal Over 5500 Drill & Shoot For trenching, based on a Kohring 505, the following scheaule should apply: Velocity (ft/sec) Excavation Nethod 0 to 3800 Rippable 3300 to 4300 IGarginal Cver 4300 Drill & Shoot Submitted by T. F‘unnekotter BENTON ENGINEERING, INC. APPLIED SOIL MECHANICS - FOUNDATIONS 6717 CDNVOI COURT SAN DIEGO. CALIFORNIA Sc?lll February 4, 1977 Lo Costa Land Company 2100 Costa Del Mar Road C&bad, California 92OCB Subject: - Gentlemen: Project No. 74-5-2D Final Report on Compacted Filled Ground Lo Costa Vole Unit Nos. 3 Cc&bad Tract [Nos. 72-20 Carlsbad, California This is to report the results of tests and observations made in order to inspect the compaction oi, filled ground placed on certain areas of La Costa Vale Unit Nos. 3 and 4 in Carlibad, California. “‘The fills were ploc& during the period between June 10, 1974 and January 24, 1977. Also included in this report are the results of tests taken in trench backfill placed over certain utility I ines. - The approximate areas ,and depths of filled ground placed under our inspection in accordance with the approved specifications are shown on the attached Drawing Nos. 1, 2, and 3, each entitled “Location of Compacted Filled Ground.” The grading plan used for the placement of - filled ground, doted April 18, 1974, WCIS prepared by Rick Engineering Company. The approximate locations at which the tests were taken and the final test results ore presented on pages TLl to T-53, inclusive, under the “Table of Test Results.” The laboratory determinations of the maximum dry densities and optimum moisture contents of the maior fill materials are presented on page L-l, under the “Laboratory Test Results.” Some of the maximum dry densities shown in the “Table of Test Results” were combinations of these. The tests were taken during the weekly periods indicated below: Test Numbers Week Ending - 1 to 6, inclusive June 15, 1974 7 to 9, inclusive March 13, 1976 10 to 37, inclusive March 20, 1976 38 to 117, inclusive March 27, 1976 118 to 184, inclusive April 3, 1976 185 to 248, inclusive April 10, 1976 249 to 321, inclusive April 17, 1976 322 to 400, inclusive April 24, 1976 401 to 450, inclusive May 1, 1976 451 to 473, inclusive May 8, 1976 Project No. 74-5-2D Lo Costa Vale Unit Nos. 3 and 4 -2- February 4, 1977 Test Numbers 474 to 483, inclusive 484 to 496, inclusive 497 to 520, inclusive 521 to 545, inclusive 546 to 575, inclusive 576 to 608, inclusive 609 to 635, inclusive 636 to 675, inclusive 676 to 697, inclusive 698 to 743, inclusive 744 to 771, inclusive 772 to 811, inclusive 812 to 875, inclusive 876 to 925, inclusive 926 to 970, inclusive 971 to 1044, inclusive 1045 to 1095, inclusive 1096 to 1131, inclusive 1132 to 1186, inclusive 1187 to 1230, inclusive 1231 to 1287, inclusive 1288 to 1365, inclusive 1366 to 1440, inclusive 1441 to 1527, inclusive 1528 to 1581, inclusive 1582 to 1587, inclusive 1588 to 1595, inclusive 1596 to 1614, inclusive 1615 to 1624, inclusive 1625 to 1650, inclusive 1651 to 1660, inclusive 1661 to 1680, inclusive 1681 to 1688, inclusive 1689 to 1692, inclusive 1693 to 1699, inclusive 1700, 1701 and 1702 Week Ending Moy 15, 1976 May 22, 1976 Moy 29, 1976 June 5, 1976 June 12, 1976 June 19, 1976 June 26, 1976 July 3, 1976 July 10, 1976 July 17, 1976 July 24, 1976 July 31, 1976 August 7, 1976 August 14, 1976 August 21, 1976 August 28, 1976 September 4, 1976 September 11, 1976 September 18, 1976 September- 25, 1976 October 2, 1976 October 9, 1976 October 16, 1976 October 23, 1976 October 30, 1976 November 6, 1976 November 13, 1976 November 27, 1976 December 4, 1976 December 11, 1976 December 18, 1976 December 25, 1976 Jonuory 1, 1977 January 15, 1977 Jonuory 22, 1977 January 24, 1977 (Dote of lost test) Certain lots on Lo Costa Vole Unit No. 3 were not graded during this period. Those lots not graded were Nos. 428 to 440, inclusive, 457 to 468, inclusive, 472 to 481, inclusive, 485 and 486. The Final results of tests and observations indicate thot the compacted filled ground hos been placed at 90 percent of the maximum dl-y density or greater except in certain street areas which will be recompocted at o future dote. It hos been determined that the fill materials, compacted to 90 percent BENTON ENGINEERING. INC. Project No. 74-5-2L! La Costa Vale Unit Nos. 3 and 4 -3- February 4, 1977 of the maximum dry density, have a safe bearing value of 1800 pounds per square foot for one foot wide continuous footings founded at the minimum required depth and placed five feet or more inside the top of compacted 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 l/2 horizontal to 1 vertical line projected outward and downward from a point 5 feet horizontally inside the top of compacted filled ground slopes in areas of no rock disposal.* Footings founded at least one foot below the surface of the firm undisturbed natural soils may be designed using an allowable bearing value of 2000 pounds per square foot. “Expansive” soil conditions exist within the upper three feet below finished grade on certain lots. The classification of each lot with regard to “expansive” soil conditions is presented as follows: - Type “A” (Critically Expansive) La Costa Vale Unit No. 3 - Lots 406 to 410, inclusive 412, 415 487 to 492, inclusive La Costa Vale Unit No. 4 - None arginaily Expansive) La Costa Vale Unit No. 3 - Lots 416, 417 469, 470, 471 482, 483 and 484 La Costa Vale Unit No. 4 - Type “C ” (Nonexpansive) Lo Costa Vale Unit No. - Lots 296 to 405, inclusive 411. 413. 414 I a 418 to 427, inclusive 441 to 456, inclusive La Costa Vale Unit No. 4 - Lots 1 to 46, inclusive 49 to 71, inclusive 75 to 89, inclusive- -z 103 to lQ7, inclusive 7 112 to 114, inclusi7 ’ * In areas where rock disposal was made at the rear of certain lots as shown on the attached .- Drawing Nos. 1, 2, and 3, no footings should be placed closer to the top of slopes than 5 feet horizontally inside of the approved compacted filled ground limits shown by dashed lines. BENTON ENGINEERING. INC. - - Project No. 74-5-20 La Costa Vale Unit Nos. 3 and 4 -4- February 4, 1977 Lots Not Graded cm~~lusive Lo Costa Vole Unit No. 3 - Lots 42 457 to 468, inclusive 472 to 481, inclusive 485 and 486 La Costa Vale Unit No. 4 - None - These lots that hove not been graded should be classified at the time of construction. - - in order to minimize possible detrimental effects caused by the “expansive” soil conditions on the proposed residential lots, the following special design and precautions are recanmended: - 1. 2. 3. - 4. 5. 6. .- Type “A” (Critically Expansive) Use continuous interconnected reinforced concrete footings, wherever possible, and place these at cr minimum depth of 2.0 feet below the lowest adjacent exterior final ground surface. If isolated interior column footings crre required, these should be placed ot a depth of 2.5 feet below the lowest adjacent ground surface. If in-place rock conditions are encoun- tered at depths of less than 2.0 feet, then lesser depths of excavation are permissible to a minimum of 1 .O foot. Reinforce and interconnect continuously with steel bars all interior and exterior footings with Q minimum of one k5 bar at 3 inches above the bottom of all footings and one fi5 bar placed 1 l/2 inches below the top of the stems of the footings. Reinforce all concrete slabs with a minimum of 6x6 - lo/10 welded wire fabric and provide o base layer of at least 4 inches of 3/4 to 1 inch size crushed rock beneath all concrete slabs. A moisture barrier should be provided above the crushed rock ond then 2 inches of sand should be placed over t.he moisture barrier and below the bottom of the slab. Separate gcrrage slabs from perimeter footings by cr l/2 inch thickness of construc- tion felt or equivalent, to allow independent movement of garage slabs relative to perimeter footings. Assure complete separation by extending the felt over the full depth of the front thickened edge of the garage slab. Also, cut off the garage door stops at least l/2 inch above the slab. Provide positive drainage away from oil perimeter footings with o vertical foll of at least 5 inches in a horizontal distance of 5 feet outside the perimeter of the house. Exercise every effort to assure that the soil under the foundations and slabs has a uniform moisture content 1 percent to 3 percent greater than opt;msm through’ .- * The required design for commercial buildings may differ from the recommendations presented herein. sENTON ENGINEERING. INC. - - ,- .- .- Project No. 74-5-2D La Costa Vale Unit Nos. 3 and 4 -5 February 4, 1977 6. Cont. out the top 3 feet below finished grade at the time of placing foundations and slabs. The moistened soil conditions need not extend to a depth of 3.0 feet in those areas where rock or very firm nonexpansive soil conditions are encountered at depths of less than 3.0 feet. Type “B” (Marginally Expansive) Use the same design as recommended for Type “A” loh except items 1 and 2 should be modified as follows: 1. The continuous footings may be placed at a minimum depth of 1.5 feet below the lowest adjacent exterior final ground surface. 2. Single #4 bars, placed as directed above, may be substituted for the fi5 bars recommended for the Type “A” lok. Type “C ‘I (Nonexpansive) Special design for expansive soil conditions will not be required for lots classified in this category. Oversized rock were buried in certain designated areas in accordance with the project specifications. The approximate locations of these rock disposal areas are shown on the attached Drawing Nos. 1, 2 and 3. it is possible that natural in-place rock formations or large rock fragments may be encountered in excavating to depths of greater thon 1.5 feet below finished grade in certain areas. All buried exterior utility lines should be City of Carlsbad approved plastic lines due to the corrosive characteristics of the soils, unless sufficient field tests are taken to establish that noncorrosive soils exist in the utility trench areas. Two tests taken in street subgrade and areas of trench backfill that have been placed at less than the required degree of compaction will be recompocted at a future date. These tests are noted “To be Reworked” in the remarks column of the “Tatle of Test Results.” Respectfully submitted, BENTON ENGINEERING, INC. BY $ePL R. C. Remer Disk: (2) (1) (2) (1) (1) Reviewed by R.C.E. No. 10332 Addressee Attention: Mr. Burton C. Kramer City of Carlsbad, Eng. Depart. Rick Engineering Company, Corlsbad Warmington Development, Inc. Attention: Mr. Bart Pith BENTON ENGlNEERING. INC. - i - I I t- , .~ -. - - - - - - - BENTON ENGINEERING ~~SRW MECHANICAL ANALYSIS CF SOILS Project LA c,n-n-f. L-ALE !>t.JliLI 3 i- 4 No. 74 - .q -y:- <3 F Hole No. Sample No. +s?3& 1 Depth Date 3. 23.77 .Tested By J-J< (3, Checked By ANALYSIS of MATiRlAL ANALYSIS of MATERIAL Retal ned On -Sieve (WI) S leve wgt. Cum. Wgt. Cum. % of No. Retained Passlng Total, Passing I K I : I Y From Hydrometer Analysis Sieve wgt. Cum. Wgt. Cum. 5 of No. Retained Passing Total Passing I I I I I Pan Total I I I I I I I I I I Finer than D I5 30 I20 250 1440 -~. - - - ,- - .- .- - BENTON ENGINEERING MECHANICAL ANALYSIS OF SOILS Project 1.0. cfi~m L e/e’ /,&J/?-S 3 e + Date 3--23.-l-l No. 7-k-r ZDr( Sample No &V%-- Tested BY .T) @ Hole No. . Depth Checked BY ANALYSIS of MATiRlAL ANALYSIS of MATERIAL From Hydrometer Analysis SiW9 wgt. Cum. Wgt. cum. $ of NO. Retained Passing Total Pesslng Ret8 I ned On -Sieve (WI) I I I 1 / 1 1 Pan , Tota I ! I I I Pan Tota I Hydrometer Analysis :I,:i Corrected Partial Read i ncl Olam. mm ---I++- I 2 5 IO .- I.5 30 120 120 ---If++ -t- .- - - - I 250 I I 1440 22337w3 -. - - -. - .- - - - ,- - .- .- .- BENTON ENGINEERING ‘ProJect ~4 casix ti-4~~ fg,u~7-s 3 +-4 No. 74--s -2 c?F Hole No, Sample No.fi !/ = Depth MECHANICAL ANALYSIS OF SOILS Date 3-zs* 77 Tested i3~ :n/;3- Checked By ANALYSIS of MATiRlAl ANALYSIS of MATERIAL Reta I ned On -Sieve (WI) From Hydrometer Analysis I Pan Total 1 ! Sieve wgt. Cum. Wgt. Cum. $ of No. Retained Passing Total Passing Pan Total Time lM / 15 30 120 250 1440 2233708 - ,- - - -~ - - - - - - .- .~- - - .- - .- - BENTON ENGINEERING MECHANICAL ANALYSIS OF SOILS Pro.bct LA :- QSTA J/A ~25 c/.-17-‘r 3f-c Date 78 Z-577 No. .74- -s -2 OF Tested BY cw- x Hole No. Sample No. ,$c 4 Depth Checked By ANALYSIS of MATiRlAl Retalned On -Sieve (WI) Sieve wgt . Cum. Wgt. Cum. k of No. Retaii ned Passlng Total Passing f L I Y I j / x ?J :o z;o,a ,,,rYj 0 .d 3s /G/i17 g9,t / 35-1‘6 x. “T 57ic al.,0 1214 x Pan 1 Tots I s ANALYSIS of MATERIAL From Hydrometer Analysis Sieve wgt. Cum. Wgt. Cum. No. Retained Passing Total Passlng Pan Pan Tota I Tota I I i Hydrometer Analysis 250.0 22337118 - - - - - - - - -~ _~ Lot Y/I -33 44 L,, k bt 95 7’310 CLoca,” “a 3. BENTON ENGINEERING, INC. Lot 73,, q1 tid, APPLIEO SOlI. YECHANlCI -- FO”NDATION6 6717 CON”O‘r COURT SAN DIE00 CALIFORNIA DZlll Lot 1.3 i 19 &oio Lo+ 7q, //1 4fAlo PL- fL 4L- PHILIP HENIINa llENTON C”**IrarYI Cl”lL ZNC,PmI” October 7, 1977 T.LI.“ONL ,,I., s65-l*lss Lo Costa Lond Company 2100 Costa Del Mar Road Corslbad, California 92008 Subject: Project No. 74-5-2D Reclassification of Lots 47, 48, 72, 73 and 74 Lo Costa Vale Unit No. 4 C&bad Tract No. 76-3 Carlsbod, Califomio Gentlemen: This is to report the results of recent soils investigations conducted on the subiect lots in La Costa Vole Unit No. 4. The investigations were made in order to determine the presence of any expansive soil conditions. Exploration pits were excavated on the subject lots using a backhoe and it was ccncluded that only nonexpansive soil conditions exist in the upper three feet below finished grade. Therefore, these lots are now classified as Type “C” (nonexpansive). The subject lots were previously classified as Type “B” (marginal) in our report on this project dated February 4, 1977. Respectfully submitted, BENTON ENGINEERING, INC. BY ML? & R. C. Remer R.C.E. No. 19913 Distr: (2) Addressee (1) City ofcorlsbad, Building Department Attn: Mr. Ray Green (1) Westland Company (Delivered to site)