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HomeMy WebLinkAbout; Lowder Lane - Paseo Del Norte; Soils Report; 1975-04-09I . - ,' i '~ A -, .. ** SOIL INVESTIGATION REPORT PROPOSED CmERCIAL COMPLFX ,, 6 ,,"~ , .. .\yri ' , ,y,, t : : %~. MAY 2 4 1977 CITY OF CARLSBAD PREPARED FOR : Building Department Chamac, Incorporated 747 Enterprise Street Escondido, California 92025 PREPARED EY: Southern California Testing Laboratory, Inc. Post Office Box 20627 6280 Riverdale Street San Dieqo, California 92120 (.” April 9, 1975 Chamac, Incorporated 747 Enterprise Street Escondido, California 92025 SCT 512069 Report No. 1 Attention: Mr. Tony Buckman SUBJECT: Soil Investigation for the Proposed Site of a Commer- cial Complex, Lowder Lane, Carlsbad, California. Gentlemen: In accordance with your request, we have performed an investiga- tion of the soil conditions at the subject site. We are trans- mitting herewith a report of this investigation. The analysis of our findings is intended to provide the required information to design the foundation and grading plans for the proposed development. In general, we found the existing on-site fills to be relatively free of deleterious material and to have low to moderate settle- ment characteristics. Provided the recommendations presented within the body of this report are followed, it is our opinion that the site will be suitable for the proposed development. not hesitate to contact this office. If you have any questions after reviewing our report, please do This opportunity to be of service is sincerely appreciated. Respectfully submitted, SOUTHERN CAJ-IFORNIA TESTING LAB., INC. CHC : j le cc: (6) Submitted (2) Mr. Russ Richards (1) SCTL, Escondido REPORT OF SOIL INVESTIGATION PROPOSED SITE OF A COMMERCIAL COMPLEX LOWDER LANE CARLSBAD, CALIFORNIA PROJECT DESCRIPTION AND SCOPE This report presents the results of our soil investigation for the Lane and to the south of Palomar Airport Road in the City of Carls- site of a commercial complex to be located on the west side of Lowder bad, County of San Diego, State of California. A brief legal descrip- tion of the site is Parcel 1 of Parcel Map No. 3415 filed in the Office of the County Recorder. It is our understanding that six single story concrete block structures with slab-on-grade construction are planned for the site. It is further understood that the proposed site grading will consist of the following: 0) The placement of approximately 17 feet of fill in the drainage channel on the south side of building pad no. 1 and lowering the north portion of this pad by approximately nine feet. 2) Lowering building pad nos. 2 and 3 by approximately two to four feet. 3) Raising building pad nos. 4, 5 and 6 by four to seven feet. The site configuration and test boring locations are shown on the attached plot plan (Plate No. 1) . This soil investigation was undertaken to: a) Determine the physical properties of the prevailing soils teristics. including their supporting capacities and settlement charac- b) Provide design information regarding foundations and site grading including stability of cut and fill slopes. . - SCT 512069 April 9, 1975 Page Two c) Determine potential construction difficulties and provide recommendations concerning these difficulties. FINDINGS Site and Soil Conditions The present site topography slopes gently downward in a southerly direction. Near the southerly boundary the topography falls off relatively steeply to an inundated ,drainage channel. This topo- graphy is approximately shown on the attached plot plan (Plate No. 1). The existing slope between the drainage channel and the upper pad has experienced severe erosion damage that has resulted in two Concrete chunks and other debris including deleterious material have eroded channels with near vertical side walls 10 to 15 feet in height been dumped in the northerly eroded channel apparently in an attempt to retard the erosion rate. During the construction of the Interstate 5 freeway, fill material was placed within the site boundary to form the upper gently sloping area. Our field explorations indicated that the fill is relatively exposure on a portion of building pad no. 6 to approximately 26 feet free of deleterious material and that it varies from natural ground used to construct the fill were found to consist of a mixture of in depth in the vicinity of building pad nos. 1 and 2. The soils silty sands and clayey sands with occasional pockets of sandy clay. We estimate that approximately 60 to 70 percent of the fill soils will be detrimentally expansive. Laboratory tests indicate that, in dense wtth occasional pockets of loose to medium dense material. general, the consistency of the fill ranges from medium dense to Consolidation tests performed on the fill material indicate that the fill has low to moderate settlement characteristics. The natural undisturbed soils underlying the fill raterial in the northerly one-half of the site were found to consist of approximately two feet of medium dense silty sands to clayey sand topsoils which, one-half of the site, the dense formational materials are overlain in turn, are underlain by dense formational soils. In the southerly The depth of these sedimentary deposits are believed to be in excess by saturated drainage channel sediments which contain organic matter. Uf 10 feet. Apparently the loose sediments in the drainage channel were not removed and recompacted prior to placing the existing on- and 29 feet below the surface in test boring nos. 4, 5, and 6, respec- site fills. Free groundwater was encountered at a depth of 34, 31, channel at the southerly end of the site. tively. Free groundwater was also noted in the bottom of the drainage SCT 512069 April 9, 1975 Page Three At the time of our investigation, the site was free of existing struc- tures and vegetation was noted to consist of sparsely scattered brush and low grass. RECOMMENDATIONS General The settlement characteristics of the existing fill and channel sedi- mentary deposits warrant special consideration with regard to site preparation and/or footing design. Methods to alleviate potential settlement problems consist of removinq and recomDactina the entire designed foundatipa system in connection'with a mat of uniform1 fill, Etilizinq pier or pile foundations 02 WJizinq a specially- chnpacted soil. The general intent oi tnls recmendatioii?s to minimize the possible settlements and the projects report is to provid2 development cost. With this in kind, the use of a compacted ioii mat with specially designed footings should provide the most econ- omical means for developing the proposed project. Based on this, the following recommendations are provided. Site Preparation conditions to an extent that spread footings can be used to support In order to minimize the potential settlement of the existing soil on a mat of uniformly compacted soil. The general configuration the proposed structures, we recmend that the structures be founded of the mats necessary to provide adequate support for the structures addition to the construction of the soil mats, special preparation is shown in the typical cross-section provided on Plate No. 1A. In will be necessary in the drainage channel located in the southerly portion of the site. We anticipate that excessive time dependent consolidation could'oocur in the channel sediments due to the imposed fill loads. In order to minimize the settlement potential and reduce the consolidation time, the following preparation is recommended. 1) Since the anticipated settlement will be time dependent, the southerly building pad should be the first of the six pads to be constructed. 2) A drag line should be used to remove all organic matter and at least 2 feet of the sediments from the bottom of the chan- nel. Consideration should be given to removing the sediments ment, as well as the time required to achieve the ultimate tQ depths greater than two feet since the ultimate settle- settlement, will be reduced proportionately. SCl' 512069 c. April 9, 1975 Page Four Once the channel is processed as recommended above, the or crushed rock. The use of crushed rock for the bridging inundated areas may be bridged with either the on-site soils in lieu of the on-site soils would accelerate the consolida- tion time by providing both a self-compacted fill and a free drainage surface to dissipate pore pressure build up in the underlying sediments. The bridge lift should be at least 3 feet higher than the water level to reduce the possibility of excessive pumping. Once the building pad is complete, settlement monuments should be placed at finish grade to monitor the settlements which will occur in the old fill and sedimentary deposits which are not removed. These monuments should be read at least once a week until it can be determined that secondary consolidation has been established and that further settlements are not likely to be excessive. Only at this time should building construc- tion begin. In order to further accelerate the consolidation process, con- sideration should be given to using this building pad as a stockpile area for the soils excavated from the other pads during the construction of the compacted soil mats. Foundations General: Tn order to reduce the pbssibility of structural damage due mentary deposits, we recommend that continuous footings that will sup- to 1Ong-tenn consolidation in the old fill material or channel sedi- port the concrete block walls be founded a minimum of 18 inches below adjacent finish grade and be reinforced with a minimum of one No. 5 bar pO8itioned three inches below the bottom of the footing and one No. 5 li)*r positioned one inch clear below finished floor. The isolated interior column footings should be founded a minimum of 12 inches be- low the bottom of the slab and should have a minimum width or diameter of 24 inches. The interior on-grade slabs should be constructed as free floating slabs and should be reinforced with 6" x 6"-10/10 welded wire mesh. The On- grade slabs should have a minimum nominal thickness of four inches and should be underlain by a four inch blanket of clean sand, crushed rock or pea gravel. Beatin@ Capacity: The allowable soil bearing pressure for the pre- vailing Soils prepared as recommended above under "Site Preparation" circular spread footings: i6 expreeaed by the following formulas for continuous, square and SCT 512069 '. - " " " Continuous Footings Circular Footings Square Footings April 9, I975 Page Five q = 1.40 + 0.77D + 0.40B q = 1.68 + 0.77D + 0.32B q = 1.68 + 0.77D + 0.24B Where q = Allowable soil bearing pressures as limited by shear in kips per square foot for full live and dead loads. D = Footing depth below adjacent grade in feet. B = Footing width or diameter in feet. The above allowable stresses may be increased by one-third for wind and/or seismic loading and should be decreased by one-fourth for dead load only. The allowable soil bearing pressure as determined by the above equa- tions should be limited to 4.5 kips per square foot in order to reduce at different bearing levels should be so located that the slope from the possibility of excessive settlements. Adjacent footings founded bearing level to bearing level is flatter than one horizontal to one vertical. Settlement Characteristics: Provided the recommendations presented within the bodv of this reDort are followed, the anticipated total and/or differential settlements may be considered to be- less than the settlements necessary to produce structural damage or distress within the proposed buildings. It should be noted, however, that after construction. some minor cracks may occur and that minor repairs may be necessary Slope Stability The cut and fill slopes as proposed on the grading plan presented by Roy L. Klema Engineers, Inc. dated January 20, 1975, were found that the proposed slopes are changed, this office should be contacted to be stable with relation to deep-seated failures. In the event for verification of the slope stability. Earth Retaining Structures AlbWable Passive Pressure: The allowable passive pressure for the prevailins soil condition is 180 DSf at the sruface, increasing at -*e tate of 136 psf per foot of dipth. This passive pressure has one-third for wind and/or seismic loading. bean cdlnputed using a factor of safety of three and may be increased The coefficient of friction of concrete to soil may be assumed to be 0.43 for resistance to horizontal movement. . I- ,- ,- ,- " (- i J SCT 512069 April 9, 1975 Page Six Active Soil Pressure: Active soil pressures for the design of earth retaining structures may be assumed to be equivalent to the pressure of a fluid weighing 35 pcf and 55 pcf for unrestrained and restrained retaining walls, respectively. These soil pressures are for no sur- charge and for a drained and level backfill condition. If the backfill will not be level, or if a surcharge is anticipated, this office should be contacted for the necessary increase in soil pressure. EARTHWORK Earthwork and grading contanplated for site preparation should be Specifications and Special Provisions. Structural backfill should accomplished in accordance with the attached Recammended Grading mined by A.S.T.M. 1557-66TI Method A. be canpacted to a minimum relative compaction of 90 percent as deter- FIELD EXPLORATIONS Six subsurface explorations were made at the locations indicated on the attached Plate No. 1 on March 21, 1915. These explorations consisted of borings drilled by means of a rotary bucket type drill rig. The explorations were conducted under the observation of our engineering geology personnel. The explorations were carefully logged when made. These logs are presented on the following Plate Nos. 2 through 9. The soils are described in accordance with the unified Soils Classification System as illustrated on the attached simplified chart. In addition, a verbal textural description, the wet color, the apparent moisture, and the density or consistency are given on the logs. Soil densities for granular soils are given as either very loose, loose, medium dense, dense, or very dense. The consistency of silts or clays are given as either very soft, soft, medium stiff, stiff, very stiff, or hard. 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 were carefully removed, sealed, and returned to the laboratory for on the boring logs as the "penetration resistance". The core samples testing. Dimturbed samples of typical and representative soils were also obtained and returned to the laboratory for testing. LABORATORY TESTING Laboratory tests were performed in accordance with generally accepted American Society for Testing and Materials (A.S.T.M.) test methods or suggested procedures. Representative samples were tested for their natural densities and moisture contents. The results of these tests are presented on the boring logs. April 9, 1975 Page Seven i,- 1 I. The expansive potential of clayey soils was determined in accordance with the following test procedure and the results of these tests appear on Plate 10. I..- Allow the trimmed, remolded sample to air dry to a constant ; moisture content at a temperature of looo F. Place the dried sample in the consolidometer and allow to compress under a load its expansion from an air dried to saturated condition. - of 150 psf. Allow moisture to contact the sample and measure - In addition, the maximum density and the angles of internal friction The results of the tests are presented on Plate 10 of this report. and cohesion were determined for typical and representative samples. - Four consolidation tests were performed and the results of these tests are presented in the form of curves on Plate Nos. 11 and 12. CLASS j BORING NUMBER 1 DBSCRIPTION E - Medium Dense, SANDY CLAYS, FILL - Multi-Colored, Humid, CLAYEY SANDS, AND SILTY SANDS 12 13 12 (Plastic Bags) 12 9 organic Order, Piece of Lumber NATURAL TOPSOILS - Brown, Humid 7 to Moist, Med. Dense, VERY CLAYEY SAND Olive-Gray, Wet, Stiff, VERY CLAYEY - SlWD 8 (Continued on Plate No. 9) FOR LEGEND SEE PLATE NO. 9 Y - 117.4 121 .o 102.5 P - 3.8 11.2 22.5 Sr(l0 MVERMIJ? STREET (uw -0, CALIFORNIA 82120 Carlsbad, California *.i, . .: Cl (' BORING NUMBER 2 1 DESCRIPTION Medium Dense, CLAYEY SANDS, SANDY CLAYS & SILTY SANDS Tract of Organic R.emains NATURAL TOPSOILS - Light Orange-B Dry to Humid, Medium Dense, SILTY Light Gray, Humid, Dense, SILTY SAND .. -. . 18' FOR LEGEND SEE PLATE NO. 9 E - 10 12 13 11 'rown, SANE 19 Y - 120 .o 116.1 129.3 120.5 t,! - 9.2 14.6 16,l 9.4 Commercial Complex Carlsbad, California Louder Lane BORING LOG BY DH 3/21/75 No' 512069 I PLATE NO. 3 BORING NUMBER 3 CLAYEY SANDS, AND SILTY SANDS Dark Yellow-Brown, Humid to Moist, Dense, SILTY SAND .. -. . 14-: : :. .. . I.. _. .. 16 ' " FOR LEGEND SEE PLATE NO. 9 E - 18 19 14 Y - 10 4.3 M - 2.3 SOUTHERN CALIFORNIA Commercial Complex TESTINQ LABORATORY, INC. Louder Lane "E STREET Carlsbad, California MN DIMO, CALIFORNIA 02l20 BORING LOG BY DH PLATE NO. 4 512069 M*E 3/21/75 1 BORING NUMBER 4 DESCRIPTION E FILL - MultiWolored, Humid, Medium Dense, SANDY CLAYS, CLAYEY SANDS, & SILTY SANDS 15 7 Plastic Bass - 7 7 Organic Traces 17 NATURAL - Der# Gray-Brown, Wet, Medium Dense, CLAYEY SAND (Continued on Plate No. 6) 13 Y - 0. 6 121.2 118.1 104.2 Y - 13.5 13.0 11.5 12.9 FOR LEGEND SEE PLATE NO. 9 $OUTHERN CALIFORNIA Commercial Complex TESTINQ LABORATORY. INC. Louder Lane "L€ STREET 6RN DiEQO. CALIFORNIA 02120 Carlsbad, California I WRIWG LOG BY DH 3/21/75 lJoB 512069 I PLE.TE NO. 5 I c BORING NUMBER 4 (CONTINUED) DESCRIPTION SC/ Dark Gray, Moist, Loose, VERY CLAYEY SAND Gray to Yellow-Gray , Saturated, Medium Dense, CLAYEY SAND 38’ FOR LEGEND SEE PLATE NO. 9 E 5 - 9 Y M - - 107.9 17.6 SOUTHERN CALIFORNIA Commercial Complex TESTIN(3 LABORATORY, INC. Louder Lane 0900 RlVEROALE STREET (UN “0. WWORNIA 92120 Carlsbad, California -#G LOG By JOB NO. DH 1” 3/21/75 61 3nca DTnmP x1n c \ , 1, 1 BORING NUMBER 5 DESCRIPTION FILL - Multi-Colored, Humid, Medium Dense, SANDY CLAYS, CLAYEY SANDS, & SILTY SANDS "- Wet NATURAB CHANNEL VUCX - Black, Moist, Medium Stiff, SANDY CLAY Material) (Cbntains Plastic Bags & Organic Gray, Wet, Med. Dense to Dense, z xv ~~ E - 18 7 9 9 7 7 Y - 106.0 106 .O 106.5 112.9 106.4 102.4 ~~ M - 8.9 8.9 11.4 11.2 21.2 19 .8 FOR LEGEND SEE PLATE NO. 9 SOIJTHERN CALIFORNIA TE&TlNa LABORATORY, INC. Commercial Complex Louder Lane 8AN Dlabo. CALIFORNIA 92120 Carlsbad, California WERDALE STREET BORING LOG BY DH I"' 3/21/75 512069 I PLATE NO. 7 k" ,- BORING NUMBER 6 DESCRIPTION FILL - Multi-Colored, Humid, Medium Dense , SANDY CLAYS, CLAYEY SANDS & SILTY SANDS 7 Loose to Medium Dense NATURAL CHANNEL MUCK - Black, Foist, 5 Medium Stiff, ORGANIC CLAY 3oJ FOR LEGEND SEE PLATE NO. 9 Y - 126.9 108.2 114.9 M - 10.7 10.6 10.9 8oufmRN CALIFORNIA TESTlNQ UBORATORY, INC. Commercial Complex Louder Lane (IAN -0, CALIFORNIA 92120 "LE 8TftEET Carlsbad, California BOzyNG LOG BY DH 1" 3/21/75 512069 I PLATE NO. 8 Z! i .I ' E' JURING NUMBER 6 (CONTINUEL?) 1 +- CLMS DESCRIPTION E Y M - - - Gray, Moist, Loose to Medium Dense, CLAYEY SAND 5 105.6 18.9 34J LEGEND - : Sample Location - - v. Water Table E: Samples Penetration Resistance (Ft. Kips/Ft.) Y: Natural Dry Density (pcf) M: Natural Moisture Content (% of Y) - fDWHERN CALIFORNIA TESTING LABORATORY. INC. Commercial Complex Louder Lane MU DIC(I0, CALIFORNIA 02120 "LE STREET Carlsbad, California I BORING LOG BY DH I"' 3/21/75 lJoe 512069 I PLATE NO. 9 ' DIRECT SHEAR C :'EST RESULTS SAMPLE I DESCRIPTION B2 @3.5' Undisturbed 33 200 B2 @2.5-3.5' Remolded to 90% 33 150 B5 @4.5-5' Remolded to 90% 33 150 B6 @5-6' Remodaed to 90% 22 200 MAXIMUM DENSITY 8 OPTIMUM MOISTURE CONTENT ASTM 1557-70" METHOD A I SAMPLE I DESCRIPTION Cmtent P/d B2 e2.5-3.5 Yellow-Brown, Clayey Silty Sand 130.0 9.4 B4 @1.5-2.5 Lt. Orange-Brown, Clayey Silty Sand 122.7 11.7 J B6 @5-6 12.2 120.0 Yellow-Brown, Clayey Silty Sand I. EXPANSION TEST RESULTS SAMPLE B2 @ B6 @ B4 @ 2.5-3.5' 5-6 ' 1.5-2.5' CONDITION Air Dried Rem. @go% Air Dried Air Dried Rem. @90% Rem. @90% INITIAL M.C. (@/e) 4.6 5.1 4.2 I tNlTlAL DENSITY(pcO I 127.6 I 123.4 I 121.3 I I I NORMAL STMS (Wf) 150 150 150 WPANSION (*/e) 11.5 11.1 2.4 SOUTHERN CAUFORNIA TESTING LABORATORY, INC. DATE 4/4/75 BY CH i 8AN DIEGO. CALlFORNlA 92120 0 RIVERDALE STREET JOB NO. 512069 PWTE NO. 10 LOAD kips/sq. ft. Southan CaPtFnta % CONSOLIDATION vs LOG PRESSURE BY CHC DATE 4/8/15 gesttng Sfabohatohy. 9nc. . PLATE NO. 11 Jo8 NO, 512(369 LOAD kips/q.ft. Southem Cu&@rra % CONSOLIDATION vs LOG PRESSURE BY CHC DATE 4/8/75 Fksttng Sfabonatoay. 9nc. JOBNO, 512069 I PLATE NO: 12 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 soi.l'to the lines and grades shown on the accepted plans. The recommendations contained in the prelim- inary soil investigation report and/or the attached Special Provi- sions are a part of the RecoAended Grading Specif,ications 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 neces- sary that the soil engineer or his representative provide, adequate inspection so that he may certify that the work was or was not accom- plished 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 certi- fications. If, in,the opinion of the soil engineer,'substandard conditions are encountered, such a,s questionable soil, poor moisture content, inade- quate compaction, adverse weather, etc., he will be empowered to either stop construction until the conditions are remedied or corrected or reconmend rejection of the work. APPENDIX A, PAGE 2 JOB NO. 512069 DATE 4/9/75 8. [<' ,i k. ;.- Soil tests used to determine the degreq of compaction will be performed in accordance with the following American Society for Testing and Mat- $:: erials test methods: ',< L' , " ,is *.. ._ Maximum Density h 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 6 inches, brought to the proper moisture con- tent, compacted and tested for the minimum density specified in the .- I Special Provisions or the recommendation contained in the preliminary soil investigation report. - When the slope of the natural ground receiving fill exceeds 20% (5 - horizontal units to 1 vertical unit), the original ground shall be stepped or benched.' Benches shall be cut to a firm competent soil condition. The lower bench shall be at least 10 feet wide and all " other benches at least 6 feet wide. .The horizontal portion of each bench shall be compacted prior to receiving fill as specified herein- before' for compacted natural ground. Ground slopes flatter than 20% Shall be benched when considered' necessary by the soil engineer. - - FILL WTERIAL - Materials placed in the fill shall be approved by the soil engineer and shall be free of vegetable matter and other deleterious substances. Granular soil shall contain sufficient fine material to fill the - APPENDIX A, PAGE 3 JOB NO. 512069 . DATE 4/9/15 voids. The definition and disposition of oversized and/or detrimental'soils are covered in the Special rocks, expansive Provisions. Ex- pansive soils, soils of poor gradation or strength characteristics may be thoroughly mixed with other soils to provide satisfactory fill mat- erial, 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 6 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 com- pacted to a minimum'specified density with adequately sized equipment, either specifically designed for soil compaction or of proydn relia- bility. The minimum degree of compaction to be achieved is specified in either the Special Provisions or the recommendations contained in the preiiminary soil investigation report. Pie14 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 2 feet in vertical rise and/or 500 cubic yards of embankment. . APPENDIX A, PAGE 4 JOB NO. 512069 . DATE 4/9/75 SEASON LIMITS Fill shall not be placed during unfavorable weather conditions. When work is interrupted by heavy rain, filling operations shall not be resumed'until the proper moisture content and density of the fill has been achieved. Damage resulting from weather shall be repaired be- fore acceptance of work. UNFORESEEN CONDITIONS In the.event that conditions are encountered during the site prepara- tion and construction that were not encountered during the preliminary soil investigation, Southern California Testing Laboratory, Inc. assumes no responsibility for conditions encountered which differ from those conditions found and; described in the preliminary soil investigation. .. .' . (' RECOMMENDED GRADING SPECIFICATIONS SPECIAL PROVISIONS The minimum degree of compaction to be obtained In conpacting natural ground and in the compacted fill shall be 90 percent. Detrimentally expansive soils is defined as soil which will - swell more than 3 percent against a pressure of 150 pounds per square foot from a condition of 90 percent density and optimum moisture content to saturation. - I . Oversized fill material is defined as rocks or lumps over 6 - inches in diameter. At least 40 percent of the fill soil shall pass through a No. 4 U. S. Standard Sieve. I Y .. UNIFIED SOIL CLASSIFICATION CHART SOIL DBSCRIPTION S;Rm SYMBOL 1. COARSE GRAINED, More than half of material is laruer than No. 200 sieve size. CLEAN GRAVELS GRAVELS More than half of coarse fraction is sieve size but larger than No. 4 smaller than 3". GRAVELS WITH FINES (Appreciable amount of fines) - SANDS CLEAN SANDS More than half of coarse fraction is smaller than No. 4 sieve size. SANDS WITH FINES of fines) (Appreciable amount 11. FINE GRAINED, More than half of material is smaller than No. 200 sieve size. SILTS AND CLAYS Liquid Limit less than 50 SIYrS AND CLAYS Liquid Limit greater than 50 HIGHLY ORGANIC SOILS ow GP OM Gc sw SP SM SC ML CL OL m CH OH PT TYPICAL NAMES Well graded gravels, gravel- sand mixtures, little or no fines . Poorly graded gravels, gravel sand mixtures, little or no Silty gravels, poorly graded fines . gravel-sand-silt mixtures. Clayey gravels, poorly graded gravel-sand, clay mixtures. Well graded sand,gravelly sands, little or no fines. sands, little or no fines. Poorly graded sands,gravelly Silty sands, poorly graded sand and silt mixtures. Clayey sands, poorly graded sand and clay mixtures. Inorganic silts and very fine sands, rock flour, sandy mixtures with slight plast- silt or clayey-silt-sand icity Inorganic clays of lm to medium plasticity, gravelly clays, sandy clays,silty clays, lean clays. Organic silts and organic silty clays of lm plasticity Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts. plasticity, fat clays. Inorganic clays of high Organic clays of medium to high plasticity. Peat and other highly organic soils. SOUTHERN CALIFORNIA TESTING LABORATORY