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HomeMy WebLinkAboutCT 72-03; Tri-City Auto Plaza Lots 1-9; Soils Report; 1972-10-16- - -~ - - - - - - SOILS INVESTIGATION Tentative L Y-City Auto Ply20 b 1 to 9, Inclwlve, and Lot 11 Southeasterly of Intenection of Interstate Highway 5 and Proposed Cannon Road Carlrbad, California c;T -7-a-3 for La Costa Land Company ksoclated Englneen Prolsct No. 72-8-21A October 16, 1972 BENTON ENGINEERING. INC. BENTON ENGINEERING, INC. APPLIED SOIL MECHANICS - FO”ND*TION* 6741 EL ca,cm BOULEVARD SAN DIEGO. CALIFORNIA OZIIS -. - - - - - PHlLlP HENKING BENTON PT(ESIL1ENI CJVIL ENGINEEI SAN DOFG.3 5*1-5654 LA ME**: 469.S654 SOILS INVESTIGATION Introduction This is to present the results of a sails investigation conducted ot the remaining portion of the site of the proposed Tri-City Auto Plaza. The site is located southeasterly of the inter- section of Interstate Highway 5 with the proposed Cannon Rood and hos been tentatively divided into ii lots. A previous investigation was conducted for designated Lot 10 of the site and the results of this were transmitted in our report dated September 8, 1972. This report will addmsr the mmoining Lots, 1 through 9, inclusive ond Lot ii. An advance report on these remaining ten lots concerning the areas of immediate concern, i.e. interceptor drainage system and retaining wall design, was transml ted on October 12, 1972. T e conclusions and recommendations of that *c-g- - advance report have been included in this final report. It is our understanding that the proposed new construction on these remaining lots will generally be of concrete block construction and probably 1 ta 2 stories in height. Presently, grading plans show that grading operations will require cuts on the order of up to 8 feet on the !ojtern L&s and compacted fill of up to 4 feet on the western lots. At the time of drilling the site was an open field, previously plowed, relatively free of any plont life and sloped gently downward in a westerly to southwesterly direction. The property to the eost and south is currently farmed with the crops being heovily irrigated. At several isolated locations on the site, primarily in the middle western area, them was water standing in previously excavated pits. Some organic growth was present in these areas. -2- The objectives of this investigation were to determine the existing roll conditions at the remoining lots on the proposed site ond to determine some of the primary physical characteristics of the soils 10 that engineering recommendations could be presented for the xrfe and economical support of the buildings, and for the accomplishment of the necessary grading. In order to occom- pllsh these objectives, ten borings were drilled ot selected locations and representative undisturbed and loose bag samples were obtained for laborotory testing. These ten borings, numbers 5 through 14, are numbered consecutively from the original 4 borings which were drilled and reported In the - Investigation for Lot 10. - Field Investigation ,- - - Ten borings were drilled as a port of this investigation with a truck-mounted rotary bucket- type drill rlg at the approximate locations shown on the attached Drawing No. IA, entitled “Location of Test Borings. ” The borings were drilled to depths of 7.0 to 15.0 feet below the existing ground surface. A continuous log of the salls encountered in the borings was recorded at the time of drilling and is shown in detail on Drawing Nos. 2 to 11, inclusive, each entitled “Summary Sheet. I’ The soils wem visually classified by field identification procedures in accordonce with the Unified Soil Classification Chart. A simplified description of this classification system is presented in the attached Appendix A at the end of this report. Undisturbed samples were obtained ot frequent intervals in the soils ahead of the drilling. The dropweight used for driving the sompling tube into the sails was the “Kelly” bar of the drill rig which weighs ~1623 pounds, and the overage drop was 12 inches. The general procedures used in field sompllng are described under “Sampling” in Appendix 6. Laboratory Tests Laboratory tests were performed on all undisturbed samples of the sails in order to determine the dry density, moisture content, and shearing strength. The results of these tests are presented on Drawing Nos. 2 to ii, inclusive. Consolidation tests were performed on representative samples - BENTON ENGINEERING. INC. - - - - - - -. -3- in order to determine the load-settlement characteristics of the soils. The results of these tests are presented on Drawing Nos. 12 to 14, Inclusive , each entitled “Consolidation Curves. ” The general precedures used for the above laboratory teah are described briefly in Appendix B. Compaction tests wem performed on representative samples of the soils to be excavated to establish compaction criteria. The sails were tested according to the A.S.T.M. D 1557-66T method of compaction which uses 25 blows of a 10 pound rammer dropping 18 inches on each of 5 layers in a 4 inch diameter i/30 cubic foot mold. The results of the tests are presented as follews: Boring Bag No. Sample 5 1 6 I 6 2 7 1 8 1 9 1 Depth in Feet 1 .o-2.0 0.5-1.5 2.0-3.0 0.0-1.0 1.5-2.5 Brown silty flne to medium sond Red brown clayey fine to medium sand Brown silty fine to medium sand Red brown clayey fine to medium sand 125.5 9.2 130.7 9.2 0.5-1.5 Brown silty fine to medium sand 132.6 7.8 Soil Description Dark brown silty fine to medium sand Maximum Optimum Mois- Dry Density ture Content Ib/cu ft % dry wt 129.4 8.4 122.3 8.9 127.2 10.8 Direct shear tests were performed on one loose soil sample remolded to 90 percent of maximum dry density and on selected undisturbed samples that were all saturated and dralned prior to testing. The results of those tests are presented on the followlng page. BENTON ENc3INEERINO. INC. - - - - - - - - - - - - - - -4- Normal Load in kips/sq ft Boring 5 Sample fret 1 0.5 0.65 Depth: 3.0 1.0 1.53 2.0 3.06 Borlng 6 , Sample 2 0.5 Depth: 5.0 feet 1.0 2.0 Boring 7 Sample Depth: 5.0 fist 2 0.5 1.0 2.0 1.57 1.79 3.12 0.51 0.97 1.95 Boring 8 , Sample 2 0.5 0.46 Depth: 6.0 feet 1.0 0.61 2.0 1.16 Boring 9 , Sample 0.5 0.96 Depth: 4.0 feet 1.0 1.93 2.0 2.71 Boring 10 Sample f6et 2 0.5 0.73 Depth: 5.0 1.0 1.01 2.0 2.23 Boring 8 Bag I*’ Depth: 1.5-i.0 feet 0.5 1.0 2.0 Max imum Shear load kips/sq ft 0.54 0.93 1.51 Angle of Internal Friction Degrees 40+ Apparent Cohesion Ib/sq ft 0 23 450 m 50 22 60 38 250 32 250 34.5 80 l Arbitrarily Reduced l * Remolded ta 90 Percent of Maximum Dry Denslty at Optimum Moisture Content BENTON ENGINEERING. INC. - - - - - .- - - - >, - - - - - -5- DISCUSSION, CONCLUSIONS AND RECOMMENDATIONS Sol1 Strata In general the roils at this site wem sandy solls containing varying amounts of clay and silts. The entfre sfte was covered with a 1 .O to 2.9 foot layer of loose silty and slightly silty fin0 sand topsoi I. Boring S(Lot 9)- At this borlng, under the topsoil, a medium firm silty fine sand was found to a depth of 3.0 feet. Beneath this a slightly silty fine sand was encountemd to the depth of exploration of 7.5 feat and contained an interbedded layer of medium loose fine sand from a depth of 4.2 to 5.8 feet. Boring 6 t w )- Under the topsoil a medium compact slightly silty flne sand extended to o depth of 1.8 feet where the soil changed to a slightly clayey fine sand whose consistency became w-7 compact at a depth of 3.5 feet. Below 6.0 feet, a 1.5 feet layer of very firm silty fine sand was / found. Below this was a slightly silty fine sand to a depth of 10.0 feet where a very compact fine to medlum sand was found to a depth of 12.8 feet. From 12.8 to 13.0 feet, the depth of explor- ation, a cemented silty fine to medium sand was found. Boring 7(Lot 7)- Beneath the topsoil, a medium compact slightly clayey fine sand was found to a depth of 3.5 feet. Under this a medium compact fine sond was encountered to the depth of exploration of 9.0 feet. compact slightly clayey fine sand was encountered beneath 1.2 feet of kslightly silty fine sand topsoil and to 5.0 feet where it merged with a medium loo= fine sand. The fine sand was found between 5.0 and 14.8 feet except for a layer from ii .5 to 13.0 feet where the sand became silty. Below ii .5 feet the soil consistency changed to very firm. Boring 9&ot 5)- Below the 1.5 feet of topsoil, the soi I was a medium compact slightly clayey fine sand to a depth of 5.0 feet where it changed to a medium loose fine sand. At a depth BENTON ENGINEERING. INC -6- - -~ - .- - - - -. - - - ,- of 9.0 feet, the sand grain size increased to fine to medium to the depth of exploration of 13.0 feet. Boring iO(Lot 4)- Beneath the upper 2.0 feet of loose slightly silty fine sand topsoil was a medium compact slightly clayey fine sand to 6.0 feet. Between 6.0 and 8.8 feet a fine sand was found and was underlain by a very compact silty fine to medium sand to a depth of 12.0 feet where it became slightly silty to the depth of exploration of 13.8 feet. Boring 11 (Lot I)- At this boring, the loose slightly silty fine sand, at a depth of 3.0 feet, merged Into a loose fine sond to a depth of 9.0 feet. At this depth a very compact slfghtly silty fine sand was encountered to 15.0 feet, the depth of exploration. Baring iZ(Lot 2)- A slightly silty fine sand was encountered to a depth of 3.5 feet. This was loose from 0 to 1.7 feet and medlum loose from 1.7 to 3.5 feet. Below this a medium loose slightly clayey fine sand was found from 3.5 to 5.5 feet. Underlying this a 2.0 foot layer of medium loose sand was encountered from 5.5 to 7.5 feet. Fram 7.5 feet to the depth of explora- tion of 10.8 feet a very firm silty fine to medium sand was found. Boring 13(Lot 3)- A loose slightly silty fine sand was encountered to a depth of 3.0 feet whem the soil merged to a loose fine sand. At a depth of 6.0 het the fine sand was underlain by a clayey fine sand to the depth of explorotion of 7.0 feet. Borlng 14&ot 1 I)- Beneath the upper 1.0 foot of loose topsoil, a 0.6 foot layer of loose fine sand wos encountered. Below this, from 1.6 ta 5.5 feet, o medium loose slightly silty fine sond was encountered. Underlying this, a 1.5 feet layer of loose fine sand was found. From 7.0 feet to ii .O feet, the depth of exploration, a slightly clayey fine to medium sand was encountered. This was firm from 7.0 to 9.0 feet and became very firm below 9.0 feet. At the time of drilling ground woter was encountered below the existing ground surface at the depths indicated on the following page. BENTON ENeINEERING. INC. -7- bpth .to Water in-Feet Below Ground Surface at Time of Drilling Boring No. ..- - - - - - - - - - - - 5 9 4.3 6 8 6.9 7 A7 6 5 10 4 No water encountemd 11 1 10.5 12 2 5.5 13 3 4.2 ii 6.5 \L It IS concluded from the field investigation and the results of laboratory testing that the medium firm silty fine sandas found below 1 .O foot in Boring 5, the medium compact to compact slightly clayey fine sand such as that encountered below 1.7 feet in Boring 6, below 1.5 feet in Sorings 7 and 9, below 1.3 feet in Boring 8 ond below 3.0 feet In Eorlng 10 and that the loose to medium loose slightly silty fine sand found below 2.0 feet in Borings ii and 12, and below 1.5 feet in Boring 14 and that the loose fine sand encountered below 3.0 feet In Borlng 13 are suitable for use as lood bearing soils. Although several of the foregoing load bearing soils have a loose consistency, as determined during the sampling process, laboratory tests show that the “in siiul;‘;nit densities are sufficiently high enough to consider them as suitoble for support of the exA%tFcJ - “.-..“_ ._.- _,X.” .,,.-_ ,. .,,_,, .___~_._...,,, ,_.,.-..----.-‘~ foundation and/or compacted fill loads. ----..-._c --._-..^ -.-_.- An underground drainage system will be required to permanently lower the existing relatively high ground water lever under most of the lots. Also, deeper but temporary dewoterlng may be needed during groding in order to allow far removal and mcompoction of unsuitable solls in certain areas. Deeper excavations for trenches and foundations should be laid back to a slope ratio of 1 horizontal to 1 vertical or flatter to preclude caving and sloughlng. All loose topsoil and upper soll strata not considemd suitable as load bearing tolls should BENTON ENGINEERING. INC. -8- be removed and recompacted prior to placlng compacted fill and/or pouring concrete slabs. The depth of mmoval may be expected to vary between test borings or the soil conditions are found to vary in the various areas. All organic materials should be removed and wasted off the - - - - - - - - rite. Recommendatlom Foundation Support Moderately loaded structures can safely be supported on shallow spread footings for column loads and contfnuous footings for wall loads,when these footings are placed in the previously descrfbed natural load bearing soil& fill soils uniformly compacted to at least 90 percent of maximum dry density in accordance with A.S.T.M. Test Method D 1557-66T. Allowable bearing capacities for the design of footings will be predicated on the type of footing, the size of the footing, the depth of the footing and whether the footing is located in natural or compacted fill sofls. The following is a tobuloted listing of the allowable bearing capacities recommended depending on the previously mentioned factors: I Allowable Rearing Capacity* I (pounds per square foot) Continuous Footing depth effect width effect Natural Load Compacted Bearing Soils Filled Ground 1go(r* - 1450** 400 600 100 200 - Square Footing depth effect width effect 110(r* 400 1529’ ; 600 75 175 I - - - The tabulated bearing values marked with an asterisk (‘“) are allowable bearing capacities for c 2 foot wtdo footing placed 1 foot deep into the respective type soil below the lowest adjacent ground 0 Ieimt ion. Thers basic bearing capacities may be increased by the indicated depth effect value for l The allowable bearing capacities presented assume a depth to the final stabllized water level equal to or greater than the width of footing beneath the footing. For other conditions, the soils engineer should be contacted to determine the permissible bearing value. BENTON ENGINEERING. INC. -?- - - - each additional increase of footing depth and may also be increased by the indicated wldth effect for each additional foot increase of width. The higher bearing values allowed for the compacted filled ground as presented above can only be used If sufficient thickness of compacted filled ground exists below the base of the foundation. “Sufficient thickness“ in this context shall be defined as a layer of compacted filled ground beneath the footing uniformly equal to or greater than the maximum width of the footing. If a sufficient thickness of compacted filled ground is not present then the allowable bearing values should be limited to those of the natural soils. These values am for dead plus live loads and may be increased by one-third for combined dead, live and seismic loads. Based on the results of load-consolidation tests, the total settlement of 3 foot wide square footing or a 2 foot wide continuous footing located as recommended and loaded to 2000 pounds per square foot is estimated to be less than l/4 inch. Concrete Slabs-on-Grade Concrete slabs may be poured directly onto the previously mentioned load bearing natural AuLQI.3 4 soils found below finish grade$)on filled ground where the fill is uniformly compacted to at least -. -. 90 percent of maximum dry density in accordance with A.S.T.M. Test Method D 1557-&T. The concrete slabs should be normally reinforced OS necessary, not only to provide structural support for the expected live/dead loads, but also to resist minor possible differential movements between natural and compacted fill soils where the slab is supported by both. Grading Requirements .- - - As concluded from laboratory test data and field observations, it is recemmended that for construction of the proposed retaining wall and for trenching operations, the slopes of cuts and excavations should be excavated on a slope ratio of 1 horizontal to 1 vertical or flatter. This will prevent unnecessary caving and sloughing. All compacted fill operations should be conducted in accordance with approved specifications. BENTON ENGINEERING. INC. - - - - - - - - - -lO- In this regard, Appendix AA, “Standard Specifications for Placement of Compacted Filled Ground” is attached in order to provide the basic requirements. Lateral Resistance Lateral forces exerted on the structures by wind and seismic forces may be resisted by sliding friction on the bottom of the foundation or by passive pressures developed by the soils. The xrfe posive resistance on the side of footings cast against the soils may be assumed to be equal to that developed by a fluid with a density as follows: For the recommended natural load beoring soils - 95 pcf; for properly compacted fill soils - 155 pcf. For frictional resistance of the concrete msting on soil, a coefficient of friction of 0.4 is recommended. Lowering the Ground Water Table it is recommended that a permonent system be constructed which will maintain the ground water level at a minimum depth of three feet below the finish elevation of Lots 6, 7, 8, 9 and 10 and in the street area along the proposed Auto Plaza Boulevard. Deeper dewatering may also be needed during grading in order to allow for the removal and recompoction of unsuitable existing soils in certain areas. it is suggested thot the permanent system consist of o trench excavated to a minimum depth of three feet below the lowest elevation of the adjacent lot. Perforated pipe, capable of handling the anticipated maximum flow , should then be placed in this trench and sur- rounded by graded pea gravel to depth of ot least 6 inches above the top of pipe. The trench con then be backfilled and properly compacted. A pipe slope of at least 0.2 percent is recommended to allow proper drainage. This drainage system may be designed to drain Into the storm drain system if invert elevations are compatible. Due to the generolly low apparent cohesion values of the less clayey sonds on the site and the caving in of the borings experienced during drilling operations, it is recommended that the ex- cavation for installation of the interceptor dminage system be sloped back to a slope ratio of 1 horizontal to 1 vertical or flatter. BENTON ENGINEERINc3. INC. -ll- The attached Drawing No. IA indicates the location of the recommended interceptor dminoge system. The system shown on this drawing is the minimum considered necessary and, if desired, may be extended to allow drainage outflow at the western edge of the site. A possible trench in the vicinity of Let 11 might be the most economical means of conducting water into the open channel along Highway 5 at the west side of the property. Where possible, the drainage system shown con be instolled in the same trench OS that excavated for the storm drain system, if desired. Rotoining Wall Design - Present grading plans for Lots 4 to 9, inclusive, show that finished elevations will mquire a cut along nearly all of the eastern property line. This cut in the natural soils should expose the in place medium compact to compact slightly clayey fine sand and the medium firm silty firm sand, which are considered suitable as load bearing materials for support of the re- taining wall foundation. For a three feet wide continuous footing placed 1 foot into these load bearing soils, on allow- able bearing capacity of 1100 pounds per square foot is recommended. For each additional foot increase in footing width, the allowable beoring value con be increased by 100 pounds per square foot. For each additional foot increase of depth below the final adiacent soil elevation, the ollow- able bearing value may be increased by 400 pounds per square foot.’ The mtolning wail may be backfilled with either the natural slightly silty fine sand or fine sondwhich presently exists on the site or with imported clean sand or silty sond. Depending on the type of backfill sol1 used, the mtoining wall con be designed to msist on active lateral pressure equivalent to thot developed by a fluid with a density OS follows: for the existing on site natural soils as lust mentioned - 36 pounds per cubic foot; for the imported clean sand or silty sand - 32 pounds per cubic foot. These values are based on the following assumptions: (1) The fill is compacted at optimum moisture content to 90 percent of maximum dry density based on A.S.T.M. Test Method D 1557~66T, and (2) The backfill will hove a maximum slope angle of l The allowoble beoring copocities presented assume o depth to the final stabillzed water level equal to or gmoter thon the width of footing beneath the footing. For other conditions, the soils engineer should be contacted to determine the permissible bearing value. BENTON ENGINEERING. INC, - - ,- - ,- - - - - - - - 4.5 degmes up from the horizontol. These values also assume 110 hydrostatic pmssures will develop behind the walls. The backfill behind the mtoining wall should be protected from both internal ond extemol excessive moisture conditions. Droinoge control extemol to the retoining wall con be accomplished by construction of o brow ditch located behind the wolf on the backfill sell. This ditch should be lined with concrete or gunite and sloped to allow droinoge to en site storm drains. internal dminoge control con be accomplished by constructing the woll with grovel backfilled weep holes ot the bore of the wall to allow drainage or, if no weep holes ore desired, by constructing a horizontal continuous drain located at the base and behind the retaining wall. This drain should consist of o perforated pipe surrounded with o filter loyer of pea gravel and, also, should be sloped to allow drainago away from behind the retaining wall. With the retaining well to be located in the some general vicinity OS (I portion of the recom- mended interceptor drainage system, certain precautions should be token OS to relative locations. It is recommended that the toe of the mtoining wall be kept a minimum of 16 feet horizontolly from the location of the interceptor droinoge system if the droinoge system is located on the toe side of the wall. If the drolnage system is on the heel side of the wall, then the heel of the wall footings should be located at least 1 foot horizontolly from the location of the droinoge system. Respectfully submitted, BENTON ENGINEERING, INC, BY Distr: (4) Addmssee (2) Associated Engineers Attention: Mr. Wayne Llll sENTON ENGINEERING. ,NC, DFL/PHB/prw - - - - - - - - - - - - , SUMMARY SHEET BORlNO NO. 5 ELEVATION 63.9’ SILTY FINE SAND I DRAWlNO NO. BENTON ENGINEERING, INC. 2 -. -~ - - - - - - - - - SUMMARY SHEET BORING NO. ,5 ELEVATION 67.0’ SLIGHTLY SILTY ight Groy-green, Soturoted, Firm, Micoceous Light Groy to Groy-brown, Saturated, Very Firm, With Some Coarse Groins SLIGHTLY SILTY MEDIUM SAND MEDIUM SAND PROJECT NO. 72-B-21A ORAWNG NO. BENTON ENGINEERING, INC. 3 - - i -, z , i - : f 2 - - - - - - PROJECT NO. 72-S-21A SUMMARY SHEET BORING NO. 7 ELEVATION m.0’ bark Brown, Dry, loose, Porous, Rootlots, Slight Clay ;Iightly Moist hange-brawn, Moist, Modturn :ompact , Porous ight Brown, Very Moist oturated hay and Brown, Occasional hvel to 3/4 Inch SLIGHTLY SILTY FINE SAND Ww$ / SLIGHTLY CLAYEY FINE SAND FINE SAND - 5, 5% s YY > ;t > - - .6 .6 .4 16. G6. 36. 1.29 - - - BENTON ENGINEERING, INC. DRAWING NO, - - i - r - - - - SUMMARY SHEET BORING NO. 8 ELEVATION 75.0’ CLAYEY FINE Saturated, Very Firm FINE SAND PROJECT NO. DRAWING NO. R-S-21A BENTON ENGINEERING, INC. 5 - - - - _. - :- r - c - - - - 5 c Y $ 3~ 0 0-- 1-E 2x 3- 4:@ s- 6- ,‘IE 9- 10 - II - 12 - 13x -L SUMMARY SHEET BORING NO. 9 ELEVATION 75.0’ MEDIUM SAND PROJECT NO. 72-B-21A 1.6 - I.6 3.2 6.2 96.3 - 7.9117.1 l.c.2 I BENTON ENGINEERING, INC. DRAWING NO. 6 I~ - _. - - - - I- - - - - d 1 L-L.2 z..Ll c E z G.i-2 2 z L L2.L LG-2 w ,:,: ,: ,,’ ~..‘,. ., [ : .._ !$j :. b ‘. ‘. PROJECT NO. R-B-21A SUMMARY SHEET BORING NO. 10 ELEVATION 73.7’ tark Brown, Dry, Loose, Porous, Rootiets I ight ly Moist Irange-brawn, Moist, Medium :ompact , Porous tronge-yellow-brown, Moist bdium Compact bttied Gray, Yellow-brown, nd Orange-brown, Slightly bist, Very Compact ight Gray, Slightly Moist, hry Compact SLIGHTLY SILT) FINE SAND SLIGHTLY tiAYEY FINE SAND FINE SAND SILTY FINE TO MEDIUM SAND SLIGHTLY SILTY FINE SAND 1.6 3.2 5’ .A 04. .Oi ORAWNG NO. BENTON ENGINEERING, INC. 7 -. - - - - - - - - - - SUMMARY SHEET BORING NO. 11 ELEVATlON 66.0’ SLIGHTLY SILTY SLIGHTLY SILTY PROJECT NO. DRAWING NO. 72-8-21A I BENTON ENGINEERING, INC. I 8 - - - - L x 25 LA 26 it i 290 SUMMARY SHEET 6% ;g iz: .ZG yjt 2: sgg BORING NO. 12 2- ws & t 43 ;gg 23 z m2 kj z YY c-0 :q ELEVATION 63.0’ > Et P x zig $2 a 0-I :z SLIGHTLY SILTY Orange-brown, Moist, Medium FINE SAND 1.6 6.7 109.5 0.41 Loose, Slight Ciay~Binder . -Orange-brawn, Moist, Medium ----Loose, Porous SLIGHTLY CLAYEY FINE SAND 1.6 10.2 105.5 0.81 FINE SAND .‘,’ 43.3 12.6 115.8 1.49 Mottled Green-gray and Light Brown-gray, Saturated, Very SILTY FINE TO MEDIUM SAND PROJECT NO. DRAWING NO. 72-8-21A BENTON ENGINEERING, INC. 9 - - - - - - - > - - - - SUMMARY SHEET BORING NO. 13 ELEVATION 61 .O’ SLIGHTLY SILTY ttled Dark Brown, Brown, FINE SAND o Gray-brown, Moist C.8 7.0 96.6 0.37 FINE SAND CLAYEY FINE SAND 122.7 16.3 110.8 1.35 PROJECT NO. I I DRAWING NO. 72-8-21A BENTON ENGINEERING, INC. 10 -~ - - - - - / - a ! ” i i: . . - r: r - SUMMARY SHEET BORING NO. 14 ELEVATION 60.4’ SLIGHTLY SILTY CLAYEY FINE TO MEDIUM SAND PROJECT NO. DRAWING NO. BENTON ENGINEERING INC. - - - - - - - - - - - CONSOLIDATION CURVES LOAD IN KIPS PER SQUAKE FOOT 0 1 :: : x2 0 E !!I 3 i $4 z 0 ii Pyl 1.6 0.8 1.0 2 4 6 8 IO I I IJ) I I& ring ! i IIll- I I I ample 1 87 epth 3’ 0 INDICATES PERCENT CDNSOLIDATION AT FIELD MOISTURE . INDICATES PERCENT CONSOLIDATION AFTER SATURATION PROJECT NO. 72-8-21A I DRAWINS NO. BENTON ENGlNEERiNG , INC. 12 CONSOLIDATION CURVES LOAD IN KIPS PER SQUARE FOOT - - - - - L - -~ - - - - - 0.8 1.0 ti - - - - 1 ==I u - - - - - 0 INDICATES PERCENT CONSOLIDATION AT FIELD MOISTURE . INDICATES PERCENT CONSOLIDATION AFTER SATURATION PROJECT NO. DRAWING NO. 72-h21A I BENTON ENGINEERING, INC. I 13 -~ - - - - - - Fi 0 - Z e < 5 ; - - - 0 1 2 3 CONSOLIDATION CURVES LOAD IN RIPS PER SOUARE FOOT 0.4 0.6 0.6 I.0 2 4 6 8 IO - I I I1111 I I I i I iRnrtnn in - I ( 1 ( 1 JGJ6 ‘2 1 I I I III+, I I I I I h 5’ 0 INDICATES PERCENT CONSOLIDATION AT FIELD MOISTURE . INDICATES PERCENT CONSOLIDATION AFTER SATURATION PROJECT NO. DRAWlN6 NO. 72-S21A I BENTON ENGINEERING, INC. I 14 ,- - EiENTON ENGINEERING, INC. APPLIEO SOIL MEC”ANICB - FOUND*TION* 6717 CONVO” COURT 6*N OICGO. CALIi~ORNIA 9211, PHlLlP HENKINC( BENTON s-“l.1”Kt+, CIIIL I*‘?IY‘e” TELEIWOW~ ,714, SBO-IO~~ APPENDIX AA STANDARD SPECIFICATIONS FOR PLACEMENT OF COMPACTED FILLED GROUND I. General Description. The objective is to obtain uniformity and adequate internal strength in filled ground by proven engineering procedures and tests so that the proposed structures may be safely supported. The procedures include the clearing and grubbing, removal of existing structures, preparation of land to be filled, filling of the land, the spreading, and compaction of the filled areas to conform with the lines, grades, and slopes as shown on the accepted plans. The owner shall employ a qualified soils engineer to inspect and test the filled ground as placed to verify the uniformity of compaction of filled ground to the specified 90 percent of maximum dry density. The soils engineer shall advise the owner and grading contractor immediately if any unsotisfactoly conditions are observed to exist and shall have the authority to reject the compacted filled ground until such time that corrective measures are taken necessary to comply with the specifications. It shall be the sole responsibility of the grading contractor to achieve the specified degree of compaction. 2. Clearing, Grubbing, and Preparing Areas to be Filled. (a) All brush, vegetation and any rubbish shall be removed, piled, and burned or other- wise disposed of so os to leove the areas to be filled free of vegetation and debris. Any soft, swampy or otherwise unsuitable areas shall be corrected by draining or removal, or both. (b) The natural glouncl 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 (6”), 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. (c) Where fills are mode on hillsides or exposed slope areas, greater than 10 percent, horizontal benches shall be cut into firm undisturbed natural ground in order to provide both lateral and vertical stability. This is to provide a horizontal base so that each layer is placed and compacted on a horizontal plane. The initial bench at the toe of the fill SIIUII be ut least 10 feet in width on firm undisturbed natural ground at the elevo- tion of the toe stoke placed at the natural angle of repose or design slope. The soils engineer shall determine the width and frequency of all succeeding benches which will vary with the soil conditions and the steepness of slope. _- - - - - - .- - - - - _. - - - 3. Materials and Special Requirements. The fill soils shall consist of select materials so graded that at least 40 percent of the material passes a No. 4 sieve. This may be obtained from the excavation of banks, borrow pits of any other approved sources and by mixiw soils from one or more sources, The material uses shall be free from vegetable matter, and other de- leterious substances, and shall not contain rocks or lumps of greater than 6 inches in diameter. If excessive vegetation, rocks, or soils with inadequate strength or other unacceptable physical characteristics are encountered, these shall be disposed of in waste oreas as shown on the plans or as directed by the soils ellgineer. If during grading operations, soils not encountered and tested in the preliminary investigation are found, tests on these soils shall be performed to determine their physical characteristics. Any special treatment recommended in the preliminary or subsequent soil repark not covered herein shall become an addendum to these specifications. The testing and specifications for the compaction of subgrade,subbase, and base materials for roads, streets, highways, or other public property or rights-of-way shall be in accordance with those of the governmental agency having jurisdiction. 4. Placing, Spreading, and Compactiw Fill Materials. APPENDIX AA -*- (d) After the natural ground has been prepared, it shall then be brought to the proper mois- ture content and compacted to not less than ninety percent of maximum density in accordance with A. S . T .M . D- 1557-66T method that uses 25 blows of a IO pound hammer failing from 18 inches on each of 5 layers in a 4” diameter cylindrical mold of a 1/30th cubic foot volume. (4 (b) (cl (4 The suitable fill material shall be placed in layers which, when compacted shall not exceed six inches (6”). Each layer shall be spread evenly and shall be throughly mixed during the spreading to insure uniformity of material and moisture in each layer. When the moisture content of the fill material is below that specified by the soils engineer, water shall be added until the moisture content is near optimum as specified by the soils engineer to assure thorough bonding during the compactiw process. ‘&hen the moisture content of the fill material is above that specified by the soils engineer, the fill material shall be aerated by blading and scarifying or other satis- factory methods until the moisture content is near optimum as specified by the soils emineer . After each layer has been placed, mixed and spread evenly, It shall be thoroughly compacted to not less than ninety percent of maximum density in accordance with A.S.T.M. D-1557-66T modified as described in 2 (d) above. Compaction shall be accomplished with sheepsfoot rollers, multiple-wheel pneumatic-tired rollers, or other approved types of compaction equipment, such as vibratory equipment that is specially designed for certain soi I types. Rollers shall be of such design ~that they will be able q LNTON CNOINLERINO. INC - - ~- - .- - -., APPENDIX AA -3- t,o ccmpact the fill material to the speclfled denslty. Rolling shall be accomplished while the fill material Is at the specified molsture content. Rolling of each layer shall be continuous over Its entire area and the roller shall make sufficient trips to Insure that the desired density has been obtalned. The entire areas to be fllled shall be compacted. (8) Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equlp- ment. Canpacting operations shall be continued until the slopes are stable but not too dense for planting and until there Is no appreciable amount of loose soll on the slopes. Ccmpacting of the slopes shall be accomplished by backrolling the slopes In Increments of 3 to 5 feet In elevation gain or by other methods producing satisfactory results. (0 Field density tests shall be taken by the soils engineer for approximately each foot In elevation gain after ccmpactlon, but not to exceed two feet in vertical height between tests. Field density tests may be taken at Intervals of 6 Inches in elevation gain If required by the soils englneer. The location of the tests In plan shall be so spaced to give the best possible coverage and shall be taken no farther apart than 100 feet. Tests shall be taken on corner and terrace lots for each two feet In eleva- tion gain. The soils engineer may take addltional tests as considered necessary to check on the uniformity of canpaction. Where sheepsfoot rollers are used, the tests shall be taken In the compacted material below the disturbed surface. No addltional layers of fill shall be spread until the field density tests indicate that the speclfled density has been obtalned. (a) The fill operatlon shall be continued in SIX inch (6”) compacted layers, as speclfled above, until the flli has been brought to the flnished slopes and grades as shown on the accepted plans. 5. Inspectlon. Sufflclent Inspection by the soils engineer shall be maintained during the fill- ing and compacting operations so that he can certify that the fill was constructed In accord- ance with the accepted speclficatlons. 6. Seasonal Llmlts. No fill materlai shall be placed, spread, or rolled If weather conditions Increase the moisture content above permlsslble ltmik. When the work is lnterrrupted by rain, fill operations shall not be resumed until field tests by the soils engineer Indicate that the moisture content and denslty of the fill are as previously specified. 7. All recunmendaticms presented In the “Conclusions” section of the attached report are a part of these speclflcatlons. .INTBN CNeINImINB. INC __ - - - - -. - .- - .A - .- - - - BENTON ENGINEERING, INC. APPLIED SOIL MECHANICS - FO”ND*TIONS 6717 CONVOY COURT SAN DIEGO, CALIFORNIA 82,‘l PHlLlP HENKING BENTON PREDlDlHT Cl”lL ENTINLEI APPENDIX A Unified Soil Classification Chart* SOIL DESCRIPTION GROUP SYMBOL I. COARSE GRAINED, More then half of material is b than No. 200 sieve size.** GRAVELS CLEAN GRAVE LS s half of coarse fraction is larger than No. 4 sieve size but SmallerGRAVELS WITH FINES than 3 inches (Appreciable amount of fines) SANDS CLEAN SANDS More than half of coarse fraction is smaller than No. 4 sieve size SANDS WITH FINES (APP recioble amount of fines) II. FINE GRAINED, More than half of -issmaller than No. 200 sieve size.** SILTS AND CLAYS Liquid Limit Less than 50 SILTS AND CLAYS Liquid Limit Greater than 50 Ill. HIGHLY ORGANIC SOILS GW GP GM GC Well graded gravels, gravel-sand mixtures, little or no fines. Poorly graded gravels, gravel-sand mixtures, little or no fines. Silty gravels, poorly graded grovel- sand-silt mixtures. Clayey gravels, poorly graded gravel- sand-clay mixtures. SW SP SM SC Well graded sand, gravelly sands, little or no fines. Poorly graded sands, gravelly sands, little or no fines. Silty sands, poorly graded sand-silt mixtures. Clayey sands, poorly graded sand-clay mixtures. ML CL OL MH CH OH Inorganic silts and very fine sands, rock flour, sandy silt or clayey-silt-sand mixtures with slight plasticity. lnorgonic clays of low to medium plas- ticity, gravelly clays, sandy clays, silty cloys, lean cloys. Organic silts and organic silty-clays of low plasticity. Inorganic silts, micaceous or diotomaceous fine sandy or silty sails, elastic silts. Inorganic cloys oi high plasticity, fat clays. Organic clays of medium to high plusticity PT Peat and other highly organic soils. TYPICAL NAMES TELEPHONE ,714, 556.1SSS * Adopted by the Corps of Engineers and Bureau of Reclamation in January, 1952. ** All sieve sizes on this chart are U. S. Standard. BENTON ENGINEERING, INC. APPLIED *OIL MECHANICS - FO”NDAT,.aNB 0717 CONVO” COURT 8AN DIEGO. C*LIFORNI* 02, I I - PHILIP HENKING BENTON C”lllDIHT ClYlL INT,WIrI APPENDIX B Sampling TILrCWONL (,I‘, s(1s.1oss The undisturbed soil samples are obtained by forcing a special sampling tube into the undisturbed soils at the bottom of the boring, at frequent intervals below the ground surface. The sampling tube consists of a steel barrel 3.0 inches outside diameter, with a special cutting tip on one end and a double ball valve on the other, and with a lining of twelve thin brass rings, each one inch long by 2.42 inches inside diameter. The sampler, connected to a twelve inch long waste barrel, is either pushed or driven approximately 18 inches into the soil and a six inch section of the center portion of the sample is taken for laboratory tests, the soil being still confined in the brass rings, after extraction from the sampler tube. The samples are taken to the laboratory in close fitting waterproof containers in order to retain the field moisture until completion of the tests. Th e Ed riving energy is calculated as the average energy in foot-kips required to force the sampling tube through one foot of soil at the depth at which the sample is obtained. Shear Tests The shear tests are run using a direct shear machine of the strain control type in which the rate of deformation is approximately 0.05 inch per minute. The machine is so designed that the tests are made without removing the samples from the brass liner rings in which they are secured. Each sample is sheared under,a normal load equivalent to the weight of the soil above the pointy of sampling. In some instances, samples are sheared under various normal loads in order to obtain the internal angle of friction and cohesion. Where considered necessary, samples are saturated and drained before shearing in order to simulate extreme field moisture conditions. Consolidation Tests The apparatus used for the consolidation tests is designed to receive one of the one inch high rings of sail as it comes from the field. Loads are applied in several increments to the upper surface of the test specimen and the resulting deformations are recorded at selected time intervals for each Increment. Generally, each increment of load is maintained on the sample until the rate of deformation is equal to or less than l/10000 inch per hour. Porous stones are placed in contact with the top and bottom of each specimen to permit the ready addition or release of water. Expansion Tests One inch high samples confined in the brass rings are permitted to air dry at 105’ F for at least 48 hours prior to placing into the expansion apparatus. A unit load of 500 pounds per square foot is then applied to the upper porous stone in contact with the top of each sample. Water is permitted to contact both the top and bottom of each sample through porous stones. Continuous observations are made until downward movement stops. The dial reading is recorded and expansion is recorded until the rate of upward movement is less than l/l0000 inch per hour.