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HomeMy WebLinkAbout; Rancho La Costa Lot 380; Soils Report Preliminary; 1987-05-28PRELIMINARY SOIL INVESTIGATION PROPOSED SINGLE-FAMILY RESIDENCE LOT 380, FOSCA STREET PANCHO LA COSTA, CALIFORNIA *~~ _, d ,.~, JOB X1192-87 PREPARED FOR: MR. MICKEY CHRISTIAN 6537 BASALT0 STREET CARLSBAD, CALIFORNIA 92008 MV ENGINEERING, INC. 2450 Vineyard Avenue, #102 Escondido, California 920251330 619/743-1214 Job #1192-87 May 28, 1987 Mr. Mickey Christian 6537 Basalto Street Carlsbad, California 92008 PRELIMINARY SOIL INVESTIGATION, PROPOSED SINGLE-FAMILY RESIDENCE, LOT 380, FOSCA STREET, PANCHO LA COSTA Pursuant to your request, MV Engineering, Inc. has performed an investigation of the surface and subsurface soil conditions at the subject site. The enclosed report has been prepared to present the results of our preliminary soil investigation. This report includes the results of our field investigation, laboratory analyses, and our summary of findings and recommendations for site development as understood. From a geotechnical standpoint it is our opinion that the site is suitable for the proposed development provided the recommendations presented in this report are incorporated into the design and construction of the project. Thank you for choosing MV Engineering, Inc. If you have any questions concerning this report, please do not hesitate to call us. Reference to our Job #1192-87 will expedite response to your inquiries. We appreciate this opportunity to be of service to you. MV ENGINEERING, INC. / ZfiM. Vinje RCE X25115 RMV/lr TABLE OF CONTENTS Page I. General Information .................. .I II. Purpose of Investigation ................ 1 III. Field Investigation .................. 1 A. Surface Conditions ................. 1 B. Fieldwork ..................... . C. Subsurface Conditions ............... 2 D. Geologic Hazards .................. 3 IV. Tests and Results ................... 3 A. Maximum Density Test ............... 3 B. Field Density Tests ............... C. Expansion Test ................... : D. Direct Shear Test ................. 4 V. Bearing Capacity .................... 4 VI. Lateral Load Parameters ................ 5 VII. Conclusions and Recommendations ............ 6 VIII. Reference ....................... 8 IX. Limitations ...................... 8 APPENDIX Plate Test Pit Location Map . . . . . . . . . . . . . . . . . 1 Logs of Test Pits (and Key). . . . . . . . . . . . . .2 & 3 Appendix "A" - Specifications for Construction of Controlled Fills; and Unified Soil Classification Chart PRELIMINARY SOIL INVESTIGATION PROPOSED SINGLE-FAMILY RESIDENCE LOT 380, FOSCA STREET PANCHO LA COSTA, CALIFORNIA I. GENERAL INFORMATION A Preliminary Soil Investigation has been prepared for the above-mentioned site located on the west side of Fosca Street as shown on the vicinity map, Plate 1. The site is legally described as Tract 7950, Carlsbad Tract Number 72-20, Unit Number 3, in the County of San Diego, State of California. The Assessor's Parcel Number is 223-211-27. It is understood that the site will be used for a single- family residence. The house will be a wood frame structure. The foundations will use continuous concrete wall footings with slab-on-grade and/or raised wood floors. The grading or site plans were not available at the time of this investigation. II. PURPOSE OF INVESTIGATION The purpose of this investigation is to determine the following: 1 - the existing soil conditions; 2 - the presence and effect of any expansive soil; 3 - the allowable soil bearing pressures; 4 - the presence of existing fill or ground water; 5 - the geologic conditions and obvious geologic hazards; 6- any construction problems that can be anticipated, and to make appropriate foundation recommendations. III. FIELD INVESTIGATION A. Surface Conditions The site is an irregularly shaped parcel. The dimensions and orientation are shown on the enclosed Test Pit Location Map, Plate 1. The site is located on hillside terrain that slopes down 10% to 15% to the southwest. Fill slopes from the adjacent house pads border the east property MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X102 l ESCONDIDO, CALIFORNIA 92025-l 330 l 6191743-l 214 SOILJTE8TINO PEAC TEST SOILIH”E*TI(IATwNS (IEOTECHNIC*LIN”ESTI(I*TIONI PRELIMINARY SOIL INVESTIGATION LOT 380, FOSCA STREET, RANCH0 LA COSTA PAGE TWO 5/28/87 line as shown on the Test Pit Location Map, Plate 1. The ground surface is covered with wild grasses and occasional brush. A stockpile of soil, rocks and debris is found in the central portion of the lot as shown on Plate 1. B. Field Work Two test pits were dug with a backhoe on May 6, 1987 in the subject area as shown on Plate 1. The test pits were entered and inspected by a staff geologist from this office. Samples of the soils were visually classified by field identification procedure in accordance with the Unified Soil Classification. A simplified version of the Unified Soil Classification is included in the Appendix of this report. Continuous logs of the soils encountered in the test pits are shown on Plates 2 and 3. C. Subsurface Conditions Geologically the site is underlain by the Jurassic Age Santiago Peak Volcanics. The native soil horizon consists of a thin topsoil of clayey silty sand that grades to a decomposed zone of the hard volcanic rocks. Below this weathered rock zone is the very dense fractured volcanic bedrock. There are essentially two soil types based on engineering properties as described on the logs which were encountered during the investigation. The soil types are referred to later as Soil Type 1 and Soil Type 2. Soil Soil Unified Soil Type Description Classification 1 brown clayey silty sand SC 2 gray volcanic rock No ground water, existing fill or detrimentally expansive soil was encountered during the investigation. Along the upper east end of the lot wet soil was encountered apparently from over-watering of the upper lots. Finish grading should direct this water from all slopes and structures. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, X102 l ESCONDIDO, CALIFORNIA 92025-1330 . 6191743-1214 SOILJTESTINO PERCTEST SOIL lNYEST!OATWNS GEOTECHNlCILlNVEITlOlTlONS PRELIMINARY SOIL INVESTIGATION PAGE THREE LOT 380, FOSCA STREET, PANCHO LA COSTA 5/28/87 D. Geologic Hazards There were no known landslides in the immediate area nor is there any reason to suspect the site is situated on a landslide. There were no mapped faults projecting through the site nor were any detected during the investigation. Until recently the nearest known active fault was the Elsinore Fault approximately 22 miles to the northeast. A 5.3 magnitude earthquake and subsequent aftershocks have occurred approximately 25 miles southwest of Oceanside during July 1986, suggesting the possibility of future seismic events. There were no observed faults or slide planes in the test pits. It is believed the greatest geologic hazard would be from earth shaking in the event of an earthquake. IV. TESTS AND RESULTS A. Maximum Density Test A laboratory compaction test was made on Soil Type 1 to determine the maximum dry density and optimum moisture content as specified by ASTM D-1557 (Method A). This test uses the minus #4 sieve soil in a 4-inch diameter 4- inch high cylindrical mold. The sample is formed with a lo-pound hammer falling 18 inches for 25 blows on each of 5 layers. The results follow. LABORATORY COMPACTION Soil Soil Maximum Dry Opt. Moist. Location Type Description Density(pcf) Content(%) TP 1 @ 1' 1 brown clayey 117.3 14.3 silty sand TP = test pit These results may be used during grading where applicable. B. Field Density Tests Moisture contents and densities were determined on three paraffin coated undisturbed samples using the water displacement method. The results are presented on the logs at the corresponding locations. The relative compaction noted on the logs is defined as the ratio of the field dry density to the maximum laboratory dry density. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, RI02 l ESCONDIDO,CALlFORNlA 920251330 l 619/743-1214 FOlLFTESTlND PERC TEST sOlLlN”ESTlGIT,ONS GEOTEC”NlCILlN”EBTlDlTlOHS PRELIMINARY SOIL INVESTIGATION LOT 380, FOSCA STREET, RANCH0 LA COSTA PAGE FOUR 5/28/87 C. Expansion Test One expansion test was made on a representative sample of Soil Type 1. The soil was remolded to 90% of the maximum dry density in 2f-inch diameter l-inch high ring mold. The sample was instrumented, loaded with 1 psi and submerged in water. The ratio of the change in height from the air dry to the saturated condition is defined as the percent expansion. The results are presented below. Soil Initial Saturated Location Type W 0 w JO Expansion (%I TP 1 @ 1' 1 TP = test pit 13.5 106.0 20.4 104.9 1.2 w = moisture content (%) 10 = dry density (pcf) D. Direct Shear Test One direct shear test was performed on a representative sample of Soil Type 1 for strength parameters in the lateral load and bearing capacity calculations. Three specimens of each soil were prepared by molding the soil in 2f-inch diameter l-inch high rings to 90% of the maximum dry densities and optimum moisture contents and soaked overnight. The specimens were loaded with normal loads of 1, 2, and 3 KSF respectively and sheared to failure in an undrained shear. The results are presented in the next section. V. BEARING CAPACITY The values of internal friction and apparent cohesion derived from the direct shear test were used in the Terzaghi Formula in accordance with the procedure outlined in Reference 1, Page 171, to compute the allowable bearing capacity. Terzaghi Formula: Bearing Capacity = 2/3 cNIC + d DfN'q + l/2 JBN/ ' Assumptions: for a two-story structure Depth of Footings, Df = 1.5' MV ENGINEERING, INC. . 2450 VINEYARD AVENUE, Xl02 . ESCONDIDO, CALIFORNIA 92025-1330 l 6191743-1214 SOlLSTESTlND PERC TEST *OILIN”ESTIOATwNS (IEOTECHNICAL IN”ESTIO*TwNS PRELIMINARY SOIL INVESTIGATION PAGE FIVE LOT 380, FOSCA STREET, RANCH0 LA COSTA 5/28/87 Width of Continuous Footing, B = 1.25' Nc1toIq6f ;jfe;ydznsionless parameters, Ref. 1, Fig. 75 ALLOWABLE BEARING CAPACITY Wet Angle of Apparent Bearing Location TP 1 @ 1' 1 119.8 27 200 1165 TP = test pit VI. LATERAL LOAD PARAMETERS The lateral load parameters to be used in design of the retaining and restraining walls (using level backfills) are derived from the friction angle, 0, obtained from the direct shear test using the following formulas: A. Active Pressure Coeff., Ka = l-sin0 = 0.38 l+sin0 B. Passive Pressure Coeff., K P = l/k, = 2.1 C. At Rest Pressure Coeff., K. = l-sin0 = 8.55 The equivalent fluid pressures are obtained by the formulas: Peq. = Ka ‘II = 0.38 x 119.8 = 45 pcf (active), Peq. = Ko% = 0.55 x 119.8 = 65 pcf (at rest), Peq. = K p‘d = 2.7 x 119.8 = 319 pcf (passive), As applicable wherea= wet density = 119.8 pcf, for 0 = 27' Recommended design values based upon anticipated conditions are found in Section VII, Conclusions and Recommendations. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, #IO2 l ESCONDIDO, CALIFORNIA 92025-1330 l 6191743-1214 SOILSTESTIN~ PERC TEST solLlN”ESTlQATwNs DEOTEC”NlCILIN”ESTIOITION6 PRELIMINARY SOIL INVESTIGATION LOT 380, FOSCA STREET, RANCH0 LA COSTA PAGE SIX 5/28/87 VII. CONCLUSIONS AND RECOMMENDATIONS l- It is recommended that the preparation of the native soil and any grading be done in accordance with the enclosed "Specifications for Construction of Controlled Fills" except if superseded by the following recommendations. 2 - It is recommended that any septic tanks or other large buried objects detected during the grading be removed. The voids should be filled with compacted soil and tested per soil engineer in charge. All roots, irrigation lines, and other objectional debris should be hand picked and removed from the site. 3- All underground utility trenches should be compacted to a minimum of 90% of the maximum dry density of the soil unless otherwise specified by the respective agencies. Care should be taken not to crush the utilities or pipes during compaction of the soil. 4- The tests and observations indicate there are no large geotechnical problems with respect to the geology or the soil conditions on the site. There were no obvious geologic hazards encountered during the investigation. It is felt that the biggest geologic hazard will be from ground shaking during an earthquake. Design in accordance with the latest Uniform Building Code Seismic Zone IV specifications should be adequate to minimize damages. 5- It is our opinion that the main geotechnical problem will be the treatment of the rocky material encountered on the site. The amount of rocky material suitable for placement as structural fill will be determined at the time of grading by MV Engineering, Inc. It is recommended that the cut portion plus ten feet outside the perimeter of the structure be undercut a minimum depth of three feet below the proposed pad grade and replaced as structural fill. This precaution will decrease the potential of cracking of the slab along the daylite line and allow easier excavation for the footings. It may be necessary to import soil to complete the grading. If any import soil is needed to complete grading, it should be granular and non-expansive. The soil should be examined and approved by our field representative prior to delivery of the soil to the site. It is recommended that the hillside shall be keyed and benched prior to placement of compacted fill or any structures. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, #IO2 l ESCONDIDO, CALIFORNIA 92025-1330 l 6191743-1214 SOlLJTESTlNE PERC TEST SOILIN”ESTIO*TwNS GEOTEC”NlCIL,N”ESTIO*TIONS PRELIMINARY SOIL INVESTIGATION PAGE SEVEN LOT 380, FOSCA STREET, RANCH0 LA COSTA 5128187 If any boulders are encountered during the grading they should be removed and the voids filled with soil that has been compacted to not less than 90% of the maximum dry density and optimum moisture content. No rocks larger than 12 inches shall be placed in the fill within three feet from finish grade. An option to grading the site would be to build along the existing grade using stemwalls founded in hard rock. This office should be notified to inspect the foundation trenches prior to pouring the concrete. The stemwall foundation should be designed by a structural engineer. This office should be notified once the foundation design is decided upon in order to give additional or revised recommendations. 6 - Foundation recommendations for granular non-expansive soils are listed below. a- It is recommended that normal concrete wall footings be used in accordance with Uniform Building Code design (i.e. 12 inches deep by 12 inches wide and 18 inches deep by 15 inches wide for one- and two-story structures respectively, minimun depths, measured from the lowest adjacent ground surface). b - Use two #4 reinforcing rods in the footings. Place one rod three inches from the top and the other rod three inches from the bottom of the footing. c - Use 6x6/10x10 welded wire mesh placed mid-height in all slabs. Use 3f-inch minimum thick slabs and a minimum of four inches of clean sand (S.E. 30 or greater) under the slabs. A plastic moisture barrier is optional. If used it should be placed mid-height in the sand. Provide weakened plane joints spaced 15 feet on center each way for all slabs. 7 - Our tests and calculations indicate an allowable bearing capacity of 1165 psf for continuous and isolated footings. Experience and good engineering practice would limit this value to 1000 psf. a - It is recommended that lateral design loads of 45, 65 and 319 pcf be used as equivalent fluid pressures for the active, at rest, and passive conditions respectively. Use a coefficient of friction of 0.32 for concrete on soil. These recommendations assume drained and level backfill conditions as well as a granular non-expansive type of backfill material. MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, #IO2 l ESCONDIDO, CALIFORNIA 920251330 l 619/743-1214 SOILSTESTIN(I PEW TEST SOILIN”EETI~ATIONI GEOTECnNlCILIN”E*TIO*TIONB VIII. IX. PRELIMINARY SOIL INVESTIGATION PAGE EIGHT LOT 380, FOSCA STREET, RANCH0 LA COSTA 5/28/81 9 - Footings located on or adjacent to top of slopes should be extended to a sufficient depth to provide a minimum horizontal distance of 5.0 feet between the bottom edge of the footing and the face of the slope. Use cut and fill slope ratios of 2:l (horizontal:vertical) for overall gross slope stability. 10 - During the course of our investigation test pits were dug to various depths. After logging and sampling of the test pits they were backfilled, rolled and tamped. This backfilling process does not acquire the necessary compaction for the support of any future overlying structures or pavement. Therefore, during the grading of the site, the test pits should be re-excavated and backfilled to not less than 90% of the maximum dry density for the soil. The approximate locations of the test pits are shown on the Test Pit Location MaPI Plate 1. 11 - Finish grading should direct and maintain drainage away from all slopes and building. 12 - It is recommended that a pre-grading meeting be held between the owner, grading contractor and a representative of this firm to discuss the operation and to arrange a testing schedule. Finalized development plans should incorporate these recommendations and be reviewed and approved by this office. REFERENCE l- Terzaghi and Peck, 1948, "Soil Mechanics in Engineering Practice", John Wiley & Son, N.Y. LIMITATIONS Our conclusions and recommendations have been based on all available data obtained from our field investigation and laboratory analyses, as well as our experience with the soils and formational materials located in the general area. Of necessity, we must assume a certain, degree of continuity between exploratory excavations and/or natural exposures. It is necessary, therefore, that all observations, conclusions, and recommendations be verified during the grading operation. In the event discrepancies are noted, we should be notified immediately so that an inspection can be made and additional recommendations issued, if required. MV ENGINEERING. INC. l 2450 VINEYARD AVENUE. Xl 02 l ESCONDIDO. CALIFORNIA 920254330 . 619/743-i214 MILSTE*TINo PERC TEST *OlLlN”EsTlGAT,ONS (IEOTECHNICILINVESTIOITIONS PRELIMINARY SOIL INVESTIGATION PAGE NINE LOT 380, FOSCA STREET, RANCH0 LA COSTA 5128187 The recommendations made in this report are applicable to the site at the time this report was prepared. It is the responsibility of the owner/develope,r to insure that these recommendations are carried out in the field. The firm of MV Engineering, Inc. shall not be held responsible for changes to the physical condition of the property, such as addition of fill soils or changing drainage patterns which occur subsequent to the issuance of this report. This report should be considered valid for a period of one year and is subject to review by our firm following that time. If significant modifications are made to your tentative development plan, especially with respect to the height and location of cut and fill slopes, this report must be presented to us for review and possible revision. Should any questions arise concerning this report, please do not hesitate to contact this office. Reference to our Job #1192-87 will expedite response to your inquiries. We appreciate this opportunity to be of service to you. a”“9 RCE #25i15 RMV/lr MV ENGINEERING, INC. l 2450 VINEYARD AVENUE, #102 . ESCONDIDO, CALIFORNIA 92025-l 330 l 6191743-l 214 SOILSTEOTIN~ PERCTEST SOILIN”ESTIa*TwNS (IEOTECHNICAL lN”ESTlGlTwNs rKiT P/i-LOCAT/ONMAP PROPDSEJ SIA’GL E FAAIL Y KESIDEKE LOT 380, FC’SCA STIi’EET RANCNO L A C OS 7, CAL i,%tNlA ------l LEGEffD r 4 Ti': APPROX/MATL TESTPITLDC47~ON SCALE I, I 1 0 2s' .w 7s J 1 PLATE ! JO8 NO. I192 - 87 PRIMARY DIVISIONS GROUP SECONDARY DIVISIONS SYMBOL a GRAVELS CLEAN GRAVELS GW Well ,,raded c,revela. grsvebaand mIxlures. little or no llne8. Bo y wo MORE THAN HALF ILESS THAN Gp 51 - G”1 OF COARSE Pmvty graded gra”els 01 ,,ra”et.sa”d mixtures. little 0, no lines, 5% FINES) FRACTION 6 0 YZyl GRAVEL - GM Silty grwdo. gravel-sand.sitt mlaiure8. non&sUc tines. 8 gz LARGER THAN WITH NO. 4 SIEVE FINES GC Clayey oravels. QraV&a”d-Clay “Ilxtures. plB8tiC 111188. % SANDS CLEAN 0 IKtIJ SANDS SW Well graded sands. gravelly sands. little or no fines. ii gg” MORE THAN HALF (LESS THAN sp Pwrty graded sands or gravelly sands. little or “0 fines. % E3 OF COARSE 5% FINES) 8 ga FRACTION IS SANDS - SM Silty sands. ennd-silt mixtures, mxvplastlc fines. SMALLER THAN WITH I NO. 4 SIEVE FINES SC Clayey sands. Mndalay mlxtwel), ptnstlc fines. ti ML Inorganic (lilt8 and very fine anda. mck flour. silty or clayey fine y g8a SILTS AND CLAYS sa”ds or clayey stlts “4th slight plaaticlty. i & LIQUID LIMIT IS CL lnor~anic clays of low to medium plastlclty gravefly clay8, sandy LESS THAN 50% clays, silty claya. lean clays. z 5@08 OL Orpanic silts and orpanlc silty clays of low plasticity. d Fi” SILTS AND CLAYS MH Inorganic sills. micacews or dlatwnaceous fine aandy or silty : g%P 23oilo. elastic silts. LIQUID LIMIT IS t 255 CH lnpr.2anic clays of high pbsticity. tat clays. E GREATER THAN 50% OH Orpanic cloy8 01 medium to hlph plasticity. orpanic silts. HIGHLY ORGANIC SOILS PT Peat and other hiphly organic 80118. MAIN SIZES U.S. STANDARD SERIES SIEVE CLEAR SXARE SIEVE OPENINGS 200 40 10 4 314" 3" 12" SAND SILTS AND CLAYS GRAVEL FINE COBBLES BOULDERS MEDIUM COARSE FINE COARSE RELATIVE DENSITY CONSISTENCY SANDS, GRAVELS AND BLOWS/FOOT CLAYS AND NON.PLASTIC SILTS PLASTIC SILTS STRENGTH BLOWS/FOOT VERY LOOSE 0.4 VERY SOFT O.% 0.2 SOFT 1% . H LOOSE 4-10 2.4 MEDIUM DENSE IO.30 FIRM H-l 4.0 DENSE 30.50 STIFF 1.2 8. la VERY DENSE OVER 50 VERY STIFF 2.4 16.32 HARD OVER 4 OVER 32 1. Blow count, 140 pound hammer falling 30 inches on 2 inch O.D. split spoon sampler (ASTM D-l 566) 2. Unconfined compressive strength per SOtLTEST pocket penetrometer CL-700 A = undisturbed chunk sample I 24s - Standard Penetration Test (SPT) (ASTM D-l 586) 0 with blow counts per 6 inches = disturbed sample II '45 - California Sampler with blow counts per 6 inches KEY TO EXPLORATORY BORING LOGS Unified Soil Classification System (ASTM D-2487) Mr. Mickey Christian Lot 380, Fosca Street, Ranch0 La Costa MV ENGINEERING, INC. PROJECT NO. DATE 1192-87 1 5/26/87 KEY DRILL RIG Backhoe 1 SURFACE ELEVATION -------- 1 LOGGED BY R.W. I C )EPTk IT0 DRIL LEI - - - - = l- -J 8 i;5 L & BROWN CLAYEY SILTY SAND loose and moderately dry topsoil 25% to 30% angular, cobble-size rocks 11. - & 0 1 2 3 4 5 6 7 8 Q 10 11 12 13 14 GROUND WATER N/E BORINQ DIAMETER 24 ” -. DESCRIPTION AND CLASSIFICATION 1 5/6/87 - - i g i - 34.0 very fine grain sand Soil Type 1 - GRAY VOLCANIC ROCK - \ , \ very dense, fracture from cobble- to boulder-size, blocky and angular fracture, refusal @ 2' Soil Type 2 BOTTOM OF TRENCH @ 2' - - - MV ENGINEERING, INC. 2450 Vineyard Ave.. Suite 102 Escondldo. CA 92025.1330 Phone: 6191743.1214 - - I:. EXPLORATORY BORINQ LOG I Mr. Mickey Christian Lot 380, Fosca Street, Ranch0 La Costa PROJECTNO. ( PLY 1 Test Pit 1 MLL RIG B.ackhoe SURFACE ELEVATION _--___ LOGGED BY R*W- I I 51 6187 IEPTH TO GROUND WATER N/E ( BORING DIAMETER -_ DESCRIPTION AND CLASSIFICATION 0 1 2 3 4 6 6 7 6 9 ._ - 14 c IO 11 12 13 BROWN CLAYEY SILTY SAND dry and loose, fine grain, 40% to 45% anaular cobble-size rocks \ GRAY VOLCANIC ROCK Soil Type 1 very dense and hard, highly fractured, blocky and angular cobble- to boulder- size rocks, refusal Soil Type 2 BOTTOM OF TRENCH @ 2.75' 1 - - 2.4 - l2.f - 56.’ - = & & 7.6 - = == EXPLORATORY BORING LOG Mr. Mickey Christian Lot 380, Fosca Street, Ranch0 La Costa MV ENGINEERING, INC. 2450 Vineyard Ave., Suite 102 Escondido. CA 82025.1330 Phone: 619I743.1214 PROJECT NO. PLATE 1192-87 3 Test Pit 2 APPEND IX “A” SPECIFICATIONS FOR CON!;‘I’I~IIC:‘I’I ON OK CON’I’I~OI,I,I~:I) I,'1 loI,:; GENERAL DESCRIPTION The construction of controlled fills shall consist of an adequate preliminary soil investigation, clearing, removal of existing structures and foundations, preparation of land to be filled, excavation of earth and rock from cut area, compaction and control of the fill, and all other work necessary to complete the grading of the filled areas to conform with the lines, grades, and slopes as shown on the accepted plans. CLEARING AND PREPARATION OF AREAS TO BE FILLED A. All fill control projects shall have a preliminary soil investigation or a visual examination, depending upon the nature of the job, by a qualified soil engineer prior to grading. B. All timber, trees, brush, vegetation, and other rubbish shall be removed, piled and burned or otherwise disposed of to leave the prepared areas with a finished appearance, free from unsightly debris. C. Any soft, swampy or otherwise unsuitable areas shall be corrected by drainage or removal of compressible material, or both, to the depths indicated on the plans or as directed by the soil engineer. D. 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 (G") or deeper as specified by the soil engineer, and until the surface is free from ruts, hummocks, or other uneven features which would tend to prevent uniform compaction by the equipment to be used. E. No fill shall be placed until the prepared native ground has been approved by the soil engineer. F. Where fills are made on hillsides with slopes greater than 5 (horizontal) to 1 (vertical), horizontal benches shall be cut into firm, undisturbed, natural ground at the elevation of the toe stake. The soil engineer shall determine the width and frequency of all succeeding benches, which will vary with the soil conditions and the steepness of slope. G. After the natural ground has been prepared, it shall be brought to the proper moisture content and compacted to not less than 90% of maximum density, ASTM D-1557-64T. II. ~,:~II.IIII: i v<h ::<I i I :: ~“;ty I (~(111 i I ,I ::l)~s~.i ,) I ~~r~~~~~~i~~~l /CRIB ::f~,~.i I ic:;hl~ /OII:~ as directed in the preliminary soil investigation by the soil engineer. I. The cut portions of building pads in which rock-like material exists may require excavation and recompaction for density cdmpatibility with the. fill as directed by the soil engineer. MATERIALS ‘I’llc~ 1~ i ILI :;oils :;11;1l~ 1~ I:O!IS i~sC 0i SPIOC:I moCc,r ials, yr;~dcxL so that at least 40 percent of the material passes the No. 4 sieve. The material may be obtained from the excavation, a Lx>rrow pit, or by mixing soils from one or more sources. The m;~l~(~~-ii;ll used slla I I. LW I~,-<><: I-roll1 vfvJPCnb.LC? ,,,ilLccr illlCl ol:hr,r deleterious substances, and shall not contain rocks or lumps greater than six inches (6") in diameter. If excessive vegetation, rocks or soils with unacceptable physical characteristics are encountered, these materials shall be disposed of in waste areas designated on the plans or as directed by the soil engineer. If soils are encountered during the grading operatjon which wire not reported i n the preliminary soil investigation, further testing will be required to ascertain their engineering properties. Any special treatment recommended in the preliminary or subsequent soil reports not covered herein shall become an addendum to these specifications. No material of a perishabl~e, spongy or otherwise unstable nature shall be used in tllc fills. !‘~! +cL!!r I- ~~.~~~---~-~-.,.- .,., -.-~ SPREADING AND COMPACTION F'ILI,, MATERIAL ~~~~~ ~~~~~ A. The selected fill material shall be placed in layers which shall not exceed six inches (6") when compacted. Each layer shall be spread evenly and shall be thoroughly blade-mixed during tllc sprcadinq to insure uniformity of material and moisture in each layer. B. When the moisture content of the fill material is below that specified by the soil engineer, water shall be added until the moisture content is near optimum as determined by the soil engineer to assure thorough bonding during the compaction process. This is to take place even if the proper density has been achieved without proper moisture. C. When the moisture content of the fill material is above that specified by the soil engineer, the fill material shall be acratcd by bladinq and scarifyinq or other satisfactory methods until the moisture content is near optimum as determined by the soil engineer. D. After each layer has been placed, mixed and spread evenly, it shall be thoroughly compacted to not less than the specified maximum density in accordance with ASTM D-1557- 64~. Compaction shall be by means of tamping or sheepsfoot rollers, multiple-wheel pneumatic-tired rollers, or other types of rollers. Rollers shall be of such design that they will be able to compact the fill to the specified density. Rolling each layer shall be continuous over its cntirr area and the rollers shall make sufficient passes to obtain the desired density. 'L'hc entire area to be filled shall be compacted to the specified density. E. Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction operations shall be continued until the slopes are stable but not too dense for planting and until there is no appreciable amount of loose soil on the slopes. Compacting of the slopes shall be accomplished by backrolling the slopes in increments of three to five feet (3' - 5') in elevation gain or by other methods producing satisfactory results. If the method of achieving the required slope compaction selected by the contractor fails to produce the necessary results, the contractor shall rework or rebuild such slopes until the required degree of compaction is obtained. F. Field density tests shall be made by the soil engineer for approximately each foot in elevation gain after compaction, but not to cxcocd two feet (2') in vertical height between tests. The soil engineer shall be notified to test the fill at regular intervals. If the tests have not been made, after three feet of compacted fill has been placed, the contractor shall stop work on the fill until tests are made. The location of the tests shall be spaced to give the best possible coverage and shall be taken no farther than 100 feet apart. Tests shall be taken on corner and terrace lots for each two feet (2') in elevation gain. The soil engineer may take additional tests as considered necessary to check on the uniformity of compaction. Where shecpsfoot rollers arc used, the test shall be taken in the compacted materia.L below the disturbed surfacr. No additional layers of fill shall be spread un~til the field density tests indicate that the specified density has LXYCII obtained. G. The fill operation shall be continued in six-inch (6") compacted layers, as specified above, until the fill has been brought to the finished slopes and grades as shown on the accepted plans. SUPERVISION Supervision by the soil engineer shall be made during the filling and compacting operations so that he can certify that the fill was made in accordance with accepted specifications. The specifications and soil testing of subqrade and baseqrade mntcrial for roads or other public property shal~l be done in Clccorda~~cc with spccili~caLiol1s of tllc qovernilly aycllay. It should be understood that the contractor shall supervise and direct the work and shall be responsible for all construction means, methods, techniques, sequences and procedures. The contractor will.be solely and completely responsible for conditions at the job site, including safety of all persons and property during the performance of the work. Intermittent or continuous inspection by the soil engineer is not intended to include review of the adequacy of the contractor’s safety measures in, on or near the construction site. SEASONAL LIMITS No fill material shall be placed, spread or rolled during unfavorable weather conditions. When the work is interrupted by heavy rain, grading shall not be resumed until field tests by the soil enqinccr indicate that the moisture content and density of the fill are as previously spccificd. In the event that, in the opinion of the engineer, soils unsatisfactory as foundation material are encountered, they shall not be incorporated in the grading and disposition will be made at the engineer's discrctioll. UNIFIED SOIL CLASSIFICATION Identifying Criteria I. COARSE GRAINED (more than 50% larger than #200 sieve) Gravels (more than 50% larger than #4 sieve but smaller than 3") Non-plastic Group Symbol Soil Description GM GC Sands (more than 50% SW smaller than #4 sieve) Non-plastic SP SM SC II. FINE GRAINED (more than 50% smaller than #200 sieve) Liquid Limit less than ML 50 CL GW Gravel, well-graded gravel- sand mixture, little or no fines. GP Gravel, poorly graded,gravel- sand mixture, little or no fines. Gravel, silty, poorly graded, gravel-sand-silt mixtures. Gravel, clayey, poorly graded, gravel-sand-clay mixtures. sand, well-graded, gravelly sands, little or no fines. Sand, poorly graded, gravelly sands, little or no fines. Sand, silty, poorly graded, sand-silt mixtures. Sand, clayey, poorly graded, sand-clay mixtures. Silt, inorganic silt and fine sand, sandy silt or clayey-silt-sand mixtures with slight plasticity. Clay, inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays. II. FINE GRAINED - can't. Liquid Limit greater than 50 III. HIGHLY ORGANIC SOILS OL MH CH OH PT Silt, organic, silts and organic silt-clays of low plasticity. Silt, inorganic, silts micaceous or dictomaceous fine, sandy or silty soils, elastic silts. Clay, inorganic, clays of medium to high plasticity, fat clays. Clay, organic, clays of medium to high plasticity. Peat, other highly organic swamp soils.