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HomeMy WebLinkAbout; School Site Kelly & Hillside Addendum; Soils Report; 1968-09-263.67 I(“* str*el September 26, 1968 S." M.80 C.lMmni. 92110 Project No. 67-156 01.) 224.2911 Addendum No. 1 Carlsbad Union School District 801 Pine Avenue Carlsbad, California 92008 Attention: Mr. Fred H. Lance SCHOOL SITE AT KELLY & HILLSIDE DRIVES CARLSBAD, CALIFORNIA It is our present understanding that the subject site is to be graded to the elevations shoiqn on the Preliminary Grading Plan dated July 1967, revised September 11, 1968, and prepared by Albert A. Webb Associates. We also understand that tentative plans are to place buildings in that area located.east of the 5-foot fill line, as indicated on the above plan. On the basis of these plans, it is suggested that preparation of the subgrade be limited to this eastern portion of the site for tile inital grading. If building locations are planned for the western por- tion of the property at some later date, the subsoils can be undercut and properly prepared in the localized areas, as required. It is recommended that the grading on the east side of the 5-foot fill line be done in accordance with the Recommendations and Specifications for Controlled Fill as presented in our report entitled "Soil Investi- gation for the Proposed Elementary School at Kelly Drive and Hillside Drive, Carlsbad, California", dated June 30, 1967. If you have any questions please call at your convenience. JGK/LJL/jsk (2) Carlsbad Union School District (1) Kamar Construction Company, Attention: Mr. J. Rombotis (1) Brandow & Johnston Associates, Attention: Mr. M. Kanda (1) Ruhnau, E vans & Steinman (1) Albert A. Webb Associates CITY CJF l:;,fi_;?!,.,:L, 1) ~~i,“i7c+~4r>,i ;‘~ ~:,i ;,, =a. &.. 111,“) -3 ,- I - - - - -., 7 - - -. - ,- - - -. - - SOIL INVESTIGATION FOR THE PROPOSED ELEMENTARY scHooL AT-KELLY DRIVE At40 HILLSIDE DRIvE CARLSBAD, CALIFORNIA for . . CARLSBAD UNION SCHOOL DISTRICT 801 Pine Avenue Carlsbad, California by WOODWARD-CLYDE-SHERARD & ASSOCIATES Consulting Soil and Foundation Engineers and Geologists TABLE OF CONTENTS - _._ - - .- - - PAGE LETTER OF TRANSMITTAL SCOPE FIELD INVESTTGATION LABORATORY TESTS SITE AND SOIL CONDITIONS 1 1 2 3 DISCUSSION 4 CONCLUSIONS AND RECOMMENDATIONS 5 LIMITATIONS 8 FIGURE 1 - SITE PLAN FIGURE 2 - LOG OF TEST BORING 1 FIGURE 3 - LOG OF TEST BORING 2 FIGURE 4 - LOG OF TEST BORING 3 FIGURE 5 - LOG OF TEST BORINGS 4 & 5 FIGURE 6 - GRAIN SIZE DISTRIBUTION CURVES FIGURE 7 - CONSOLIDATION TEST - SAMPLE 3-3 TABLE 1 '- RESULTS. OF CONFINED COMPRESSION TEST ATTACHMENT 1 -,SPECIFICATIONS FOR, CONTROLLED FILL - - - - - WOODWARD4LYDE*SHERARD&ASSOClATES CONS"LTING ENGINEERS AND GEOLOGlSTS June 30, 1967 3467 Kwtz street Project No. 67-156 San Lmgco Callfornla 92110 (714) 224.2911 Carlsbad Union School District 801 Pine Avenue Carlsbad, California Attention: Mr. Fred H. Lance In accordance with your request and our proposal for a soil investi- gation dated May 16, 1967, we have made an investigation of the underlying soil conditions at the site of the proposed elementary school at Kelly Drive and Hillside Drive in Carlsbad, California. The accompanying report presents our conclusions and reconnnendations, as well as the results of the subsurface exploration and laboratory tests upon which these recommendations are based. The Project Engineer assigned to this project was Mr. Joseph G. Kocherhans of our firm. r/ Louis J. Lee JGK/LJL/pf (2) Carlsbad Union School District (2) Ruhnau, Evans & Steinmann - - - - - -. -. -- SCOPE This report describes an investigation of the underlying soil conditions at the site of the proposed elementary school to be constructed at the southwest corner of Kelly Drive and Hillside Drive in Carlsbad, California. The study is intended to determine the subsurface soil conditions, the condition of areas to receive fill, the presence and effect of any expansive soils, the most suitable type and depth of foundation and the allowable soil bearing pressures to be used in design, I,,~, as well as to estimate the magnitude of possible settlements. Details of the proposed construction are not known as this time; however, it is anticipated that the proposed buildings will be of one-story wood frame construction with concrete slab-on-grade floors. It is also anticipated that the maximum column and wall loads will be on the order of 25 kips and 2,000 pounds per ft, respectively. It is also understood that grading of the site will include a cut slope on the order of 50 ft maximum height, along the west edge and fills of unknown height along the east edge. It is anticipated that fills will be less than 15 ft, maximum height. FIELD INVESTIGATION Five test borings were made with a 6-in. diameter truck mounted power auger at the locations shown on the Site Plan, Fig. 1. The drilling was done on May 26, 1967, under the supervision of a staff engineering geologist. Field boring logs were prepared by the geologist on the basis of an examination of the samples secured and the excavated material. The Logs of Test Borings presented on Figs. 2 through 5, are based on an inspection of the samples, on the laboratory test results, and on the WDDDWARD - CLYDE - SHEAAAD & ASSDCIATES CarvltlnpSoaadP isndnnnand- Page 2 - - - - - - - - field boring logs. The vertical position of each sample is shown on the Logs of Test Borings. The test borings were located in the field with the aid of a Tentative Map Laguna Riviera dated January 20, 1965, and prepared by Roy L. Klema. Engineers, Inc. The,approximate extent of the site and the general area of the buildings was marked on this map by your office. LABORATORY TESTS The soils encountered were visually classified and evaluated with respect to strength, swelling and compressibility characteristics, dry density and moisture content. The classification was substantiated by grain size analyses and the determination 'of plasticity characteristics, on representative samples of the soils. The strength of the soils was evaluated by means of unconfined compression tests and a direct shear test on selected samples, and by consideration of the density and moisture content of the samples and the penetration resistance of the sampler. Swelling characteristics were determined on the basis of grain size distribu- tion and plasticity characteristics. Compressibility characteristics were established by a confined compression test and a consolidation test on undisturbed samples. The results of tests on undisturbed samples, except for the consolidation test and the confined compression test, are shown with the penetration resistance of the sampler at the corresponding sample location on the Logs of Test Borings. The grain size distribution curves and the plasticity characteristics are indicated on Fig. 6. The results of the consolidation test are reported on Fig. 7 and the confined compression test on Table I. WDDDWARD -. CLYDE - SHERARD & ASSOCIATES C~SdlandPalmad&Q B-d-H Page 3 - - - - - -. -. - SITE AND SOIL CONDITIONS The western one-half of the site is situated along the eastern side slopes of a north-south trending ridge that extends down into a small valley within which the eastern one-half of the site is located. The ground surface elevations of the site ranges from approximately 15 ft in the southeast corner to approximately 70 ft on the west side. At the present time the site is vacant of structures and has a fairly. dense growth of weeds and small brush. The basic geologic unit that underlies the site is the San Mateo formation of Pliocene age. This formation consists of dense sandstones and siltstones interbedded with some hard claystone strata. The formational material are overlain, in the valley bottom, (below the approximate elevation of 30 ft) by alluvial deposits having thicknesses in excess of 15 ft. The soil mantle, overlying the entire site, generally ranges in thickness from l-1/2 ft to 5 ft. The soils, as encountered in the test borings, generally consist of l/2 ft of loose silty sand underlain by 0 to 2-l/2 ft of soft to stiff Silty and sandy clay in the higher elevations (Borings 1 and 2) and loose silty and clayey sand in the lower elevations (Borings 3, 4 and 5). These materials generally comprise the soil mantle and in the valley bottom grade into the alluvial deposits which consist of up to 15 ft or more of stiff to hard silty and sandy clays with some interbedding of sands. The formational materials which underlie the area consist of interbedded medium dense to dense silty and clayey sand and stiff to hard silty and sandy clays to the depths explored, a maximum of 49-l/2 ft. WINDWARD -‘CLYDE - SHERARD & ASSOCIATES C~So(l.uldP .E-~~~ Page 4 - Water was encountered at a depth of 30-l/2 ft in Boring 2, 11 ft in Boring 3, 14 ft in Boring 4 and 11 ft in Boring 5 at the time of drilling. No water was encountered in Boring 1. DISCUSSION Two requirements must be fulfilled by any foundation material. First, it must be safe against shear failure, which would result in lateral movement of soil from under the load. Second, the vertical movement must not exceed the amount permissible for the particular type of structure. Granular soils, such as the silty sands encountered at the site, have good shear strengths when properly compacted and confined. Settlement on such soils is not excessive if the bearing capacity is governed by the compactness of the material. Compactness of natural granular soil is best measured by the resistance to penetration of the sampler. Uniform compactness of granular fill material can best be secured by engineering supervision of the placement of the fill. Results of the consolidation test on a representative sample of the clayey strata within the alluvial deposits indicates that these clays have been preconsolidated, either by desiccation or by previous overburden loads, to loads on the order of twice the existing overburden pressures. When these alluvial soils are subjected to loads less than the preconsolidation value, the resulting settlements will be due primarily to recompression and will have a maximum magnitude on the orde~r of l/2 in. or less. It is also probable that such settlement will be short term and should occur as the load is applied. If loads greater than preconsolidation pressure are added, settlements due to normal WDDDWARD -, CLYDE - SHERARD & ASSOCIATES. CarultbyJcudF lhubwmondm Page 5 - - - - - -. consolidation will occur and a somewhat greater magnitude may be expected. The time for these settlements to take place may take several months, depending on the load and the overall thickness of the clay strata. When it is required to use loads in excess of the perconsoli- dation pressure, two possible methods of foundation supportor treatment may be considered: (1) the use of deep foundations (piles, pier, etc.) and (2) surcharging the area with fill of a thickness sufficient to develop the anticipated stress conditions. Adequate field control and the use of settlement monuments should be employed in conjunction with any surcharging.scheme in order to determine the actual rate and magnitude of settlement. The silty and sandy clays encountered on the site as soil mantle, alluvial deposits and as clay strata in the formational, have potentially expansive characteristics; that is, they are susceptible to fairly large volume changes upon changes in water content. Structures and pavements supported on potentially expansive soil will be subject to harmful differential movements if not properly treated. Where, . feasible, the most practical method of handling expansive clays is to undercut these materials where exposed at finish grade and replaced with a properly compacted nonexpansive soil. CONCLUSIONS AND RECOMMENDATIONS 1. It is our opinion that the proposed structures may be founded on shallow spread footings on either the undisturbed formational sands or on properly compacted fill soils prepared in accordance with the attached specifications for controlled fill. WWDWARD -. CLYDE - SHERARD & ASSDCIAYES conaumngsdlamiFnndollon Bng&ummld-~ Page 6 - - - 2. If structures are to be placed in areas underlain by alluvial deposits, generally the eastern one-half of the site, it is recommended that footings be placed on a mat of compacted fill having a minimum thickness of 5 ft below the bottom of the footing and extending a minimum of 5 ft beyond the building limits. This recommendation will require undercutting in cut areas underlain by alluvial deposits. Footings supported on properly compacted fill may be designed for a maximum dead plus live load of 2.000 psf. 3. Footings supported on the dense formational sands may be designed for a maximum soil bearing pressure of 5,000 psf for a dead plus live loads. 4. In areas where cuts are made potentially expansive soils may be encountered within 2 ft of finish grade. It is reconended that where these potentially expansive soils are encountered within the building area they be undercut to a minimum depth of 2 ft below finish grade and be replaced with properly compacted nonexpansive soils. The building area is defined as 5 ft beyond the building limits. 5. It is recornnended that all footings for a structure be founded entirely on cut soils or on properly compacted fill soils. This recommendation may generally be most easily fullfilled by undercutting the formational soils to a depth of 2 ft where required. These areas may be best determined in the field at the time of grading. 6. The soil bearing pressures given above may be increased by one-third for loads that include wind or seismic forces. It is recom- mended that all footings'have a minimum width of 1 ft and be founded a minimum depth of 1 ft below the lowest adjacent finish grade. WDDDWARD -.CLYDE - SHERARD & ASSOCIATES canllfnl soft and Pm a--Id-m - Page 7 - - - 7. If column and wall loads in excess of 25 kips and 2,000 pounds per lineal ft, respectively, are required, this office should be notified so that supplemental recommendations may be made, if required. 8. In proposed paved areas, it is recommended that, potentially expansive soils encountered within 2 ft of finish grade be removed to a minimum depth of 2 ft and be replaced with properly compacted non- expansive fill soils; or that tests be made so that adequate pavement design criteria can be established. 9. In our opinion, fill slopes having an inclination of l-1/2 to 1 (l-1/2 units measured horizontally to 1 unit vertically) and a maximum unsupported height of less than 20 ft and the cut slopes having an inclination of l-1/2 to 1 and an unsupported height up to about 50 it will have an adequate safety factor against slope failure if constructed in accordance with the plans and specifications. It is recommended that cut slopes in excess of 25 ft be constructed with a bench at mid-height. The bench should have a minimum width of 6 ft and be provided with a concrete, gunite or asphalt concrete lined drainage ditch on the inside of the bench and be sloped to drain away from the slope. 10. It is recommended that loose surface soils not removed by grading operations be excavated or scarified as required and compacted before fill. footings or slabs are placed. The maximum depth of these loose soils encountered in the borings is about 5 ft; however, the depth of compaction should be controlled in the field by a qualified Soil Engineer upon visual examination of the exposed soil. 11. It is recommended that the upper 2 ft of fill in building areas and areas to be paved, be constructed of nonexpansive soil. WWDWARD CLYDE - SHERARD & ASSDCIATES cdsdl*F- Enehmrd- Page 8 - -. - - - The potentially expansive soils may be spread throughout the lower portions of the fills. 12. It is recommended that all grading operations be done in accordance with the attached specifications for controlled fill and . under the observation of this office. 13. If fills in excess of 15 ft are placed in building areas it is recommended that the plans be reviewed by this office in order to evaluate the probable settlements and to determine if the use of settlement movements may be required. LIMITATIONS The conclusions and recommendations made in this report are based on the assumption that the soil conditions do not deviate appreciably from those disclosed by the test borings. If variations are enc0untere.d during construction, we should be notified so that we may make supplemental recommendations if this should be required. -. -~ -- - - WDDDWARD - .CLYDE - SHERARD & ASSOCIATES Catul&lpScildP E-ad- FIG. 1 - - - - - - -. ~- GENERAL AREA *i-- OF BUILDINGS -> / i \ I ? .A I ‘\. I -- -- 20 -- /--A,,’ SCALE I 1 “-100’ l 4 KELLY e INDICATES AP+IXIU~TE LOCATION Of TEST BORING. ,20-/1NDICATES APPROXIMATE EXlSTlNP CROUND SURFACE / CONTOUR. < WDDDWARD, CLYDE. SHERARD & ASSOClATES SITE PLAN SCHOOL SITE - LAGUNA RIVIERA PROJECT NO. 67-156 6-29-67 LC - - - - - - - - - - -. - - - -~ - - -. a 10 L :: I 8 20 ;: 2 ZJ g ” 30 g ii m F 2i D 40 50 FIG. 2 6ORlNG 1 BROWN SILTY SAND BLACK SANDY CLAY GRAY SANDY CLAY GRAY BROWN SILTY LIGHT BROWN,CLAYEY DAMP, LIGHT BROWN ;g”,: r,,:::: 1~ -GRAVELLY &::. _ \‘{I& ,() - ,:,;:;::: OD=1 07 7 ;;!~!;j:$ SC- 21 ;i_::::::i: j’ fi 32* -~~.r c-200 _ DENSE, DAMP, LIGHT BROWN SILTY MEDIIJU SAND (SM) SC- 38 LEGEND WC - V!ATER CONTENT IN PERCENT OF DRY WEIGHT. Do - DRY DENSITY IN PCF. SC - NUMBER OF SLOWS BY 140-La. HAMMER FALLING 30 INCHES TO DRIVE SAMPLER 12 INCHES. SAMPLER DATA: IO - 2.0”, OD - 2.5”. DS - DIRECT SHEAR TEST DATA: - ANGLE OF APPARENT FRICTION IN DEGREES. C - APPARENT COHESION IN PSF. 6.M) - G ROUP CLASSIFICATION SYMBOL IN ACCORDANCE WITH THE UNIFIED SOIL CLASSIFICATION SYSTEM. WOODWARD, CLYDE, SHERARD 8, ASSOCIATES LOG OF TEST BORING 1 SCHOOL SITE - LAGUNA RIVIERA PROJECT NO. 67-156 LEGEND IL 7 -WATER LEVEL AT TIME OF DRILLING. b’) - G ROUP CLASSIFICATION SYMBOL IN ACCORDINCa WITH THE UNIFIED SOIL CLASSIFICATION SYSTEM. - - BORING 2 BLACK SANDY CLAY DENSE, DAMP, - HT FIG. 3 FIG. 3 - - -. LOG OF TEST BOR I NG 2 -. FIG. 4 - - -- - - 0 10. 2@ 30- 0 43 BORING 3 WiTH’SAND LAYER BC- 28 STIFF, WET, LIQHT BROWN SILTY LEGEND WC - WATER CONTENT IN PERCENT OF DRY WEIGHT, DD - DRY DENSITY IN PCF. BC - NUMBER OF SLOWS BY 140-LB. HAMMER FALLING 30 INCHES TO DRlYE SAMPLER 12 INCHES. SAMPLER DATA: ID = 2.0’1, OD - 2.511. UCS - UNcoNfiNm COMPRESSIVE STRENGTH IN PS~.. v = -WATER LEVEL AT TIME OF DRILLING. (Si) = G RDuP CLASSIFICATION SYMBOL IN ACCORDANCE WlTH THE UNIFIED SOIL CLASSIFICATION SYSTEM. ,,,,. 1 WOODWARD, CLYDE, SHERARD & ASSOCIATES LOG OF TEST BORING 3 SCHOOL SITE - LAGUNA RIVIERA PROJECT NO. 67-136 6-29-67 LCM FIG. 5 - - - - - - - ,- 0 10 hi f 20 I % iz 3 !i? z 30 ei g ;= 0 m I k ; 10 15 BORING 4 WC- 4 1t-i LOOSE, DRY, DARK BROWN SILTY DDE108 , SAND (SM) BcB a -’ ~~ l. DENSE, DAMP, CRAY SILTY SAND DARK BROWN SANDY <_“, \--, LIGHT BROWN SANDY .:;i:i;;i_i::_ MEDIUM-DENSE, SATURATED, LIGHT 5:;:::: BROWN CLAYEY SAND (SC) i::,:.:::,::::; BORINQ 5 LOOSE, DRY, DARK BROWN SILTY LOOSE TO MEDIUM-DENSE, DAMP, BROWN SILTY SAND (SM) T TO WET, DARK GRAY SILTY CLAY (CH) LEGEND WC - WATER CONTENT IN PERCENT OF DRY WEIGHT. DD - DRY DENSITY IN PCF. BC - NUMBER OF SLOWS BY 140-b. HAMMER FALLINQ 30 INCHES TO DRIVE SAMPLER 12 INCHES. SAMPLER DATA: ID - 2.0”. 00 - 2.5”. UCS - UNCONFINED COMPRESSIVE STRENGTH IN PSF. g - WATER LEVEL AT TIYE OF DRILLING. - (SM) - G ROUP CLASSIFICATION SYMBOL IN ACCORDANCE WITH THE UNIFIED SDIL WOODWARD, CLYDE, SHERARD & ASSOCIATES CLASSIFICATION SYSTEM. I LOGS OF TEST BORINGS 4 & 5 SCHOOL SlTE - SCHOOL SlTE - LAGUNA RIVIERA LAGUNA RIVIERA PROJECT NO. 67-156 PROJECT NO. 67-156 b-29-67 b-29-67 LCM LCM FIG. 6 SILT and CLAY Sieve Number Hydrometer Analysis GRAIN SIZE - MILLIMETERS I SAMPLE CLASSIFKATION AND SYMBOL uLL *PI 1-l CLAYEY SAND (SC) 36 18 i 1-5 1 SILTY SAND (SM) 3-2 CLAYEY SAND (SC) 38 20 3-3 SILTY CLAY (CH) 58 35 4-l SILTY SAND (SM) 5-l 1 SILTY SAN0 (SM) 5-2 1 SILTY CLAY (CH) 46 27 *LL - LIQUID LIMIT *PI - PLASTICITY INDEX WCIODWARD, CLYDE, SHERARD I ASSOCIATES I GRAIN SIZE DISTRIBUTION CURVES I I SCHOOL SITE - LAGUNA RIVIERA PROJECT NO. 67-156 6-29-67 LCM .640 .600 0 $ .560 .520 ,480 .Ol 0.1 1.0 10 PRESSURE IN TONS PER SO. FT. Initial Dry Density, PCF Initial Water Content, % Initial Saturation, % Final Dry Density, PCF Final Water Content, % Final Saturation. % 104 30 88 110 28 100 Initial Void Ratio, E. 0.649 Final Void Ratio, Ef 0.541 Compression Index, Cc 0.175 Swell Index, Cs 0.0~ Existing overburden press.,P,,TSF 0.45 Max. aast aressure. P,.TSF 0.8 WOODWARD, CLYDE, SHERARD EL ASSOCIATES CDNJ$D~TlON TEST I - SCHOOL SITE - LAGUNA RIVIERA PROJECT NO. 67-156 6-29-67 LCh RESULTS OF CONFINED COMPRESSION TEST DEFORMAT I ON LOAD IN PSF ADDED - Attachment 1 Project No. 67-156 June 30, 1967 Page 1 of 4 - SPECIFICATIONS FOR CONTROLLED FILL I GENERAL This specification covers preparation of existing surfaces to receive fills; the type of soil suitable for use in fills; the control of compaction and the methods of testing compacted fills. It shall be the Contractor's respon- I~ sibility to place, spread, water and compact the fill in strict accordance with these specifications. A Soil Engineer shall be the Owner's representa- tive to inspect the construction of fills. Excavation and the placing of fill shall be under the direct inspection of the Soil Engineer; and he shall : give written notice of conformance with the specifications upon completion of grading. Deviations from these specifications will be permitted only upon written authorization from the Soil Engineer. A soil investigation has been made for this project; any recommendations made in the report of the soil investigation or subsequent reports shall become an addendum to these specifications. II SCOPE - The placement of controlled fill by the Contractor shall include all clear- ing and grubbing, removal of existing unsatisfactory material, preparation of the areas to be filled, spreading and compaction of fill in the areas to be filled, and all other work necessary to complete the grading of the filled areas. III MATERIALS 1. Materials for compacted fill shall consist of any material imported or excavated from the cut areas that, in the opinion of the Soil Engineer, are suitable for use in constructing fills. The material shall contain no rocks or hard lumps greater than twenty-four inches in size and shall contain at 'least forty percent of material smaller than one-quarter inch in size. (Materials greater than six inches in size shall be placed by the Contractor so that they are surrounded by compacted fines; no nesting of rocks shall be permitted). No material of a perishable, spongy, or otherwise of an impro- per nature shall be used in filling. 2. Material placed within twenty-four inches of rough grade shall be select material that contains no rocks or hard lumps greater than six inches in size and that swells less than three percent when compacted as hereinafter Attachment 1 Attachment 1 Project No. 67-166 Project No. 67-166 June 30, 1967 June 30. 1967 Page 2 of 4 Page 2 of 4 4. During grading operations, soil'types other than those analyzed in the report of the soil investigation may be encountered by the Contractor. The Soil Engineer shall be consulted to determine the suitability of these soils. Iv COMPACTED FILLS .- 1. General (a) Unless otherwise specified, fill material shall be compacted by the Contractor while at a moisture content near the optimum moisture content and to a density that is not less than ninety percent of the maximum density determined in accordance with A.S.T.M. Test No. D1557-641, or other density methods that will obtain equivalent results. (b) Potentially expansive soils may be used in fills below a depth of twenty-four inches and shall be compacted at a moisture content greater than the optimum moisture content for the material. - 2. Clearing and Preparing Areas to be Filled (a) -.. lb) (cl (d) All trees, brush, grass, and other objectionable material shall be collected, piled and burned or otherwise disposed of by the Contractor so as to leave the areas that have been cleared with a neat and finished appearance free from unsightly debris. All vegetable matter and objectionable material shall be removed by the Contractor from the surface upon which the fill is to be placed and any loose and porous soils shall be removed or com- pacted to the depth shown on the plans unless otherwise specified in writing by the Soil Engineer. The surface shall then be plowed or scarified to a minimum depth of six inches until the surface is free from uneven features that would tend to prevent uniform compaction by the equipment to be used. Where fills are constructed on hillsides or slopes, the slope of. the original ground on which the fill is to be placed shall be stepped or keyed by the Contractor as shown on the attached Figure. The steps shall extend completely through the soil man- tle and into the underlying formation materials. After the foundation for the fill has been cleared, plowed or scarified, it shall be disced or bladed by the Contractor until it is uniform and free from large clods, brought to the proper moisture content and compacted as specified for fill. 3. Placing, Spreading, and Compacting Fill Material (a) The fill material shall be placed by the Contractor in layers that when compacted shall not exceed six inches. Each layer shall be spread evenly and shall be thoroughly mixed during the spreading to obtain uniformity of material in each layer. WOODWARD - CLYDE - SHERARD & ASSOCIATES C~SoilMdFoundaua BQglnnnuul~~ ! t / / 1 I I / ! I I 1 / I / 1 1 j I I I j L Attachment 1 Project No. 67-156 June 30, 1967 Page 3 of 4 (b) When the moisture content of the fill material is below that speci- fied by the Soil Engineer, water shall be added by the Contractor until the moisture content is as specified. (c) When the moisture content of the fill material is above that speci- fied by the Soil Engineer, the fill material shall be aerated by the Contractor by blading, mixing, or other satisfactory methods until the moisture content is as specified. (d) After each layer has been placed, mixed and spread evenly, it shall be thoroughly compacted by the Contractor to the specified density. Compaction shall be accomplished by sheepsfoot rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers or other types of acceptable compacting equipment. Equipment shall be of such design that it will be able to compact the fill to the specified density. Compaction shall be continuous over the entire area and the equip- ment shall make sufficient trips to insure that the desired density has been obtained. (e) Surface of fill slopes shall be compacted so that the slopes are stable and there shall be no excessive loose soil on the slopes. V INSPECTION 1. Observations and compaction tests shall be made by the Soil Engineer during the filling and compacting operations so that he can state his opinion that the fill was constructed in accordance with the specifications. 2. The Soil Engineer shall make field density tests in accordance with A.S.T.M. Test No. D1556-64T. Density tests shall be made in the compacted materials below the surface where the surface is disturbed. When these tests indicate that the density of any layer of fill or portion thereof is below the specified density, the particular layer or portions shall be reworked until the specified density has been obtained. VI PROTECTION OF WORK (a) During Construction - The Contractor shall properly grade all excavated surfaces to provide positive drainage and prevent ponding of water. He shall control surface water to avoid damage to adjoining properties or to finished work on the site. The Contractor shall take remedial measures to prevent erosion of freshly graded areas and until such time as permanent drainage and erosion control measures have been installed. (b) After Completion - After grading is completed and the Soil Engineer has finished his observations of the work, no further excavation or filling shall be done except under the observation of the Soil Engineer. 8 WOODWARD - CLYDE - SHERARD &ASSOCIATES cavvwnp son and Fe E-d-N original Ground Slope Ratio - 5 Ii NOTES l’be minimum vidth ‘FL%” of key shall be 2 feet wid,er then the compaction equipment, and not less than 10 f&t. he outside edge of bottom key shall be below topsoil or loose surface material. Reys are required vhere the natural slope is steeper than 6 horizontal to 1 vertical, or where specified by Soil Engineer. . .