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HomeMy WebLinkAboutCT 73-02; Santa Fe Glen; Soils Report; 1972-11-14SENTON ENGINEERING. INC. APPLIED sotI. MECHANICS - FO”NOITION5 674, EL CAJON sO”LE”ARD SAN DIEGO. CALIFORNIA 92115 ._ - Attention: MI. Irving Roston - - - - - - - - - - PHILIP HENKINO BENTON PrlEPIDINT ClYlL LNLlllEEll November 14, 1972 La Costa Land Company Costa Del Mar Road Ranch0 La Costa, California 92008 Subject: Project No. 72-8-2BC Preliminary Soils lnvestigotion Santa Fe Glen Tan Diego County, California Gentlemen: CONCLUSIONS SAN DICCO. s-4.665. LA ME**: 468.565. ENGINEERING DEPT. LIGRARY City of Carlsbad 2075 Las Palmas Drive Carlsbad CA92009-4859 It is concluded from the field investigation and lobomtory test resulk that: 1. The soil conditions within the subject property ore basically favorable for the proposed development. In general, the soils within the subiect property can bs separated into three main groups based on colors and locations. The first soil group is the residual soils of sandstone which consist mostly of clayey sand, slightly clayey sand, silty sand, slightly silty sand and occasional sandy clay such as those found in Borings 1, 3, 4, 5, 7 and 12 areas. The soils in this group appear mostly brownish or yellowish In color with occasional intrusion of light gmy or gmy-brown layers that have higher clay contents. The brownish or yellowish soils in this group except the grayish lryers are generally not expansive and have good engineering characteristics. These should present no particular problems for site grading. The second *iI group, geologically classified OS recent alluvium, covers most of the canyon oreos in the east portion of the site such as the sails in Borings 8, 10, 11 and 13. The soils in this group also consist of clayey sand, slightly clayey sand, silty sand, slightly silty sand, silty clay and sandy cloy. The upper layers of these soils are relatively loose and compressible based on the labor- atory testing results. Therefore, the upper porous or loose soil layers in the conyon areas should be removed to depths estimated from the preliminary findings to be 4 feet in thickness and should be recompacted prior to placement of any fills in the canyons. The soils in this group also appear ta be brownish, greenish or grayish in color. The brownish soils are not expansive but the greenish or greyish soils are expansive. The third soil group, consisting mainly of silty cloy and sandy clay soils with some clayey sand and silty sand, can be found in the sloping hillside areas along the east boundary of the site. This group is generally gmonish or grayish in color with SOM yellowbh or brownish clayey sand or silty sand. The soils in this group are expamive and exhibit unfavor&le rpin- eering characteristics. These should b treated with special precautions and the 3esfgn sharld consider the physical characteristics of these soils. *d - - - - i: .- - - - - Project No. 72-8-2BC Lo Costa - Santa Fe Glen -2- November 14, 1972 2. Potentially critical soil zones such as slickensided, highly fractured or gouge materials were found at boring 2 between the depths of 1.8 and 37.2 feet; ot boring 6 between 28.5 and 33.5 feet ond at boring 9 at a depth of 26.5 feet. it is recommended that the grading plans be prepared in such a way that the excavations through these zones be kept to a minimum height and the flattest slope gradient possible. These zones should be carefully examined during grading operations, or if possible, the grading plans should be designed not to cut into these unstable zones. 3. The soil of Groups 1 and 2, except clay soils and expansive clayey sand soils may be safely excavated and reused as compacted fills for structural support. The excavated soils, when properly compacted to at least 90 percent of maximum dry density in accordance with the A.S.T.M. D 1557-70 method of compaction and in accordance with the applicable sections of the attached Appendix AA, entitled “Standard Specifications for Placement of Compacted Filled Ground,” will have a safe allowable bearing value of 2000 pounds per square foot for one foot wide continuous footings placed at a minimum depth of one foot below the lowest compacted ground surface. The settlement of a one foot wide continuous footing placed one foot below the final compacted ground surface and looded to 2000 pounds per square foot is estimated to be on the order of l/8 inch. 4. if the excavated soils are compacted in accordance with the procedures described in Section 3, the compacted fill slopes may be safely constructed up to the following maximum heighk. Soil Type Nonexpansive silty sand, slightly silty sand, clayey sand and slightly clayey sand of brownish or yellowish color Slopes (Horizontal to Vertical) 1.5: 1 2 :l 2.5 : 1 Recommended Maximum Heighk (Feet) 30 47 106 Expansive silty clay, sandy clay, and clayey sand of greenish or grayish color 3 :l 14 4 :1 5 :l :i The above recommended maximum helghk of compacted fill slopes ore based on a factor of safety of 1 .5 that included a 0.1 g factor for seismic effeck. It is assumed that suitable erosion control devices will be provided to prevent surface NnOff from sheeting over the gmded slope surface. 5. When bedding plane failures are not involved, the recommended maximum heighk or cut slopes in natural soils are shown in the following tabulation. The recommended heighk were also based on a factor of sofety of 1.5 that included o 0.1 g factor for seismic effeck. it is also assumed that suitable erosion control devices will be provided to prevent surface runoff from sheeting over the graded slope surfaces. BENTQN ENGINEERING. INC. Project No. 72-8-2BC La Costa - Santa Fe Glen -3- November 14, 1972 - - -2 .- i, - - - - - ,- - Soil Type Nonexpansive silty sand, slightly silty sand, clayey sand and slightly clayey sand of brownish or yellowish color sb= (Horizontal to Vertical) 1.5: 1 2 :l 2.5 : 1 fhcommended Maximum Heighk (Feet) 17 32 112 Expansive silty clay, sandy clay and clayey sand of greenish or grayish color 3 :l 32 4 : 1 70 It is recommended that this office be called upon to review the grading plans when these are available and also to inspect the cut slopes during and after rough gmding. This is to insure that no unstable conditions exist as a result of excavation. If the design does not limit excavations in the greenish silty cloy or sandy clay of Soil Group 3 to heighk equal or less than those presented above, then stabilized fills or buttress fills will be recommended. 6. After excwations, the exposed silty sand or slightly silty sand solls from Soil Group 1 and 2 may b-e used for structural support. An ollowoble bearing value of 2015 pour& per square foot may be used for one foot wide continuous footings placed one foot below the finished grades. The settlement of a one foot wide continuous footing placed one foot below the flnlshed grade and lwded to 2015 pounds per quare foot is estimated to be less than 3/S inch. 7. No long term settlement of either compacted fill or conventional footings is expected aS no ground water or soft satumted clay deposits were found during this investigation. 8. For earthwork estimates, shrinkage factors of 9 percent may be ued for the clayey sand or silty sand soils from Soil Groups 1 and 2; and 13 percent for the silty clay and aandy clq soils from Soil Group 3. 9. The silty clay, sandy clay and gmyish and brown-gray clayey sand are potentially expansive. it is therefore recommended, that these soils not be placed in the upper 3 feet of any finished gmdes where the soil prisms will be used for foundation support. The expansive soilr in this prism should be replaced with nonexpansive gmnular~soils properly compacted to 90 percent of the maximum dry density in accordance with the testing procedure described in Section 3 and the attached Appendix AA. if the expansive soils ore left in the upper 3 feet of finished gmdes to support any structures, then special foundation designs for expansive soil conditions wilj be required. It is fvrthsr recommended that the excwated expansive soils be placed ot least 5 feet owoy from an exposed compacted fill slope and 5.0 or more feet above the contact SW%W between in-place natural soils and compacted fills. The expansive clayey soils should be thor- oughly mixed with equivalent volume or more of nonexpansive soolls before using as canpacted fill soils. it is recommended that this office be called upon to check the soil typa encountered in the upper 3 feet of excavated surface so that the exposed soils may be properly classified according to their expansive potentials. BENTON ENGINEERING. INC, - Project No. 72-B-2BC La Costa - Santa Fe Glen -4- November 14, 1972 10. if any soil types ore encountered during grading operations that were not tested in this investigation, additional laboratory tests will be required in order to determine the physical characteristics and engineering behwiors of the soils. Supplementary reports and recommendations will then be provided. Respectfully submitted, BENTON ENGINEERING, INC. 5. H. Shu, Civil Engineer Philip H.‘Benton, Civil Engine& Distr: (4) La Costa Land Company (1) Attention: Mr. Irving Roston - SHS/PHB/ew BENTON ENGINEERING. 1NC. - - - i :,. - - - L - Proiect No. 72-8-2BC La Costa - Santo Fe Glen -5- November 14, 1972 DISCUSSION A preliminary soils investigation has been completed on the subject property commonly known as Santa Fe Glen in San Diego County, California. The oblectives of this investigation were to study the general characteristics of the soils within the sublect property, to identify potentially problematic areas; to determine the influence of geotechnicol conditions of the site on future developmenk and to recommend appropriate soil pammeten for the preparation of gmding plans. The topography consisk primarily of gently sloping hills in most park of the site with three distinctive northward canyons along the eastern boundary of the subiect property. A shallow canyon up to approximately 35 feet in depth is also situated in the northwest comer of the property. According to the “Soil Mop” prepared by the U. S. Department of &riculture, the upper soils within the rubiect property are described as Corkbad loamy fine sand and Las Floms loamy fine sand. The major soils encountered on the subiect property ore predominately clayey sand and silty sand which are generally yellowish or brownish in color. Most of these soils are derived from locally weathered sandstone. Silty clay and sandy clay were also encountered in the hilly areas along the east boundary of the property. Fleld Investigation Thirteen borings were drilled with a truck-mounted rotary bucket-type drill rig at the appmx- imate locations shown on the attached Dmwing No. 1, entitled “Location of Test Borings.” The borings were drilled to depths of 20 to 40 feet below the existing ground surface. A continuous log of the soils encountered in the borings was recorded at the time of drilling and Is shown in detail on Dmwing Nos. 2 to 21, inclusive, each entitled “Summary Sheet.” The soils were visually classified by field identification procedures in accordance with the Unified Soil Classification Chart. A slmpllfred description of this classification system is presented in the attached Appendix A at the end of this report. Undisturbed samples were obtained at frequent intervals, where possible, in the soils ahead of the drilling. The drop weight used for driving the sampling tube inta the soils was the “Kelly” bar of the drill rig which weighs 1623 pounds, and the average drop was 12 inches. The general procedures used in field sampling ore described under “Sampling” in Appendix B. Labomtory Tesk Labomtory tesk were performed on all undisturbed samples of the soils in order to determine the dry density and moisture content. The resulk of these tesk are presented on Dmwing Nos. 2 to 21, inclusive. Consolidation tesk were performed on selected loose soil samples remolded to 90 and 92 percent of maximum dry density and on selected undisturbed samples in order to determine the load-settlement characteristics of the soils and the resulk of these tesh ore presented graph- ically on Dmwing Nos. 22 to 27, inclusive, each entitled “Consolidation Curves.” The general procedures used for the preceding laboratory tarh are described briefly in Apptdix B. BENTON ENGINEERING. 1NC. - - - - i 1 - - Pm/ect No. 72-8-2BC La Costa - Santa Fe Glen -6- November 14, 1972 Compaction tesk were performed on representotive samples of the soils to be excwoted to establish compaction criteria. The soils were tested according to the A.S.T.M. D 1557-70 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 l/30 cubic foot mold. The resuik of the tesk are presented as follows: Boring Bag No. Sample 1 1 2 1 3 1 5 2 6 2 9 1 12 1 Maximum Optimum Mois- Depth Soil Dry Density ture Content in Feet Description Ib/cu ft %drywt o- 1 Clayey fine sand 118.5 11.2 o- 1 Clayey fine sand 114.3 13.6 2- 3 Fine sandy clay 118.4 11.4 11 - 12 Silty fine sand 120.0 13.5 6- 7 Clayey fine sand 115.1 13.5 o- 1 Fine sandy cloy 118.9 11.0 7- 8 Fine sandy clay 115.3 12.7 in addition to the above laboratory tesh, expansion tests were performed on some of the clayey soils encountered to determine tkeir volumetric change characteristics with change in moisture content. The recorded expansions of the samples are presented as follows: Percent Expansion Under Unit Load of Depth of 150 Pounds per Square Boring Sample Sample, Soil Foot from Air Dry No. No. in Feet Description to Saturation 1 Bag 1 * 0 to 1 Clayey fine sand 10.51 1 3 8 Clayey fine sand 10.67 2 5 15 Silty cloy 9.82 3 1 2 Fine sandy clay 9.82 4 3 8 C loyey fine sand 3.04 5 2 4 Clayey fine sand 1.80 5 7 25 Silty clay 6.80 6 2 5 Clayey fine sand 7.49 7 2 : Clayey fine sand 0.65 9 2 Fine sandy clay 8.08 12 3 7 Flne sandy cloy 2.59 * Remolded to 92 percent of maximum dry density Mechanical analysis tesk were performed on representative samples in accordance with A.S.T.M. D 422-61T and the resuik ore presented on the following page. - BENTON ENGINEERINa. INC. .~. - .- - in sr -1 ,’ 1 i - - + - - - - 2 Pmject No. 7218-2BC La Costa - Santa Fe Glen November 14, 1972 U.S. Sieve Size Boring 1 b 1 (O-l’) boring 2 Boring 3 (E%l) b 1 (2’-3’) boring 5 k32 (ll’-12’) Percent Finer by Weight No. 4 100.0 100.0 100.0 100.0 No. 10 99.9 99.2 100.0 99.7 No. 30 99.0 97.4 99.6 98.7 No. 40 97.8 96.5 98.5 98.6 No. 60 94.4 93.9 91.6 96.3 No. 100 72.5 68.4 78.2 58.6 No. 200 41.8 36.5 61.6 22.2 Soil Clayey Classifi- Fine cation Sand U.S. boring 6 Sieve hJ2 Size (6’-7’) Cbv Fine Fine Sandy Sand Cloy boring 9 baring 12 Bag 1 &I 1 (o-1’) Percent Finer by Weight (7’-8’) Silty Fine No. 4 100.0 No. 10 100.0 No. 30 99.8 No. 40 99.3 No. 60 98.9 No. 100 84.2 No. 200 38.2 Sail C Iayey Clarclifl- Fine cation Sand 100.0 100.0 99.8 99.6 98.5 97.1 97.4 93.5 93.6 85.8 81.4 79.6 62.8 58.3 Fine Fine Sandy Sandy Clay Clay In order better to classify the finor gmined soils, Atterberg Limit tesk were performed on certain samples in accordance with A.S.T.M. Designations D 423-61T and D 424-59. The resulk of these tesk and the group symbols for the total soil scmple ore presented as 4llows: Boring No. 1 3 5 6 9 12 * Minus No. kl Sample No. 1 1 2 2 1 1 Depth in Feet Soil Description O-1 Fine sandy clay 2- 3 Fine sandy clay ii-12 Silty fine sand 6- 7 Fine sandy clay O-l Fine sandy cloy 7-8 Fine sandy clay 40 sieve portion only. Liquid Plastic Plasticity Limit Limit Index 35.4 12.1 23.3 45.1 12.8 32.3 31.8 25.0 6.8 33.4 20.2 13.2 38.3 14.0 24.3 38.0 19.2 18.8 Group Symbol CL l CL SM CL * CL CL BENTON ENGINEERING. w4C. .~ - - (6; i f; “L L L ;$.,~, ‘:’ x - L 2 t - - Pro&t No. 72-8-2BC -8- November 14, 1972 La Costa - Santa Fe Glen Direct shear tests were performed on selected loose soil samples 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 these tests are presented below: Boring 1 *, Bag 1 Depth: o-1 foot Boring 2, Sample 3 Depth: 8 feet Boring 3, Sample 3 Depth: 8 feet Boring 5 l , Bag Sample 2 Depth: 11-12 feet Boring 6, Sample 8 Depth: 30 feet Boring 9, Sample 4 Depth: 10 feet Boring 12 *, Bag Sample 1 Depth: 7-8 feet Normal Load in kids ft 0.5 1.0 2.0 0.5 1.0 2.0 0.5 1.0 2.0 0.5 1.0 2.0 0.5 1.0 2.0 0.5 1.0 2.0 0.5 1.0 2.0 Maximum Shear Load kb+‘~ ft 0.46 0.53 0.58 0.94 1.54 1.86 1.88 2.13 1.60 0.55 1.05 1.59 1.60 1.57 0.83 2.74 0.64 0.81 1.46 * Bag samples remolded to 90 percent of maximum dry density ** Recommended values Angle of Internal Friction Degrees 9.5 Apparent Cohesion lb/sq ft 250 19.0 780 25.0 570 29.0 270 0 ** 19.0 ** 18.0 1558 ** 200 480 BENToN ENGINEERING. INC. -9- November 14, 1972 - g - - - ; - - T - Local Shear Formula: Q = 2/3 C N’, + Y Df N’q + Y BN’y General Shear Formula: Q=C N,+YDfNq+YBNy Assumptions: (1) Continuous footing 1 foot wide = 28 (2) Depth of footing = 1 foot = Df Using the formula given above, the tiollowlng calculations are presented: In-place natural sails: Use local shear formula (1) Nonexpansive soils - silty sand, slightly silty sand Q = 36’ c = 100 Ibs/sq ft N’c = 26 Nlq = 14 Q=(2/3x100x26)+(118x1x14)+(118x0.5x12)=4030 Qsafe=Qf2=2015ltx/sqft Y= 118 lbs/cu ft N’y = 12 (2) Expansive soils - clayey sand, silty clay and sandy clay Q = o” c=200 N’, = 5.5 Nlq = 1 Q-(2/3x200x8)+(115x 1 x3)= 1411 lb&q ft Q safe = Qe-2 = 705 Ibs/sq ft (Special footing design required) Y= 115 N’y=O Compacted fill sails: Using general shear formula and selected strength parameters from each soil group (1) Nonexpansive soils - silty sand, slightly silty sand 0=290 C = 270 NC = 33 Nq = 19 Q=(270x33)+(108x1x19)+(108x0.5x18)=11942 Q safe = 3981 k/4 ft (2) Expansive soils - clayey sand, silty clay and sandy clay @=9.50 c -200 NC= 9 Nq=3 Q=(200x9)+(108xl x3)+(108x0.5x1)=2208 Q safe = Q-+3 = 736 IbJ 4 ft (Special footing design required) Y=108 N’y = 18 Y= 103 Ny=l BENTON ENGINEERING. INC. B% ~-‘~~‘,. -~ - - - 7 4 - “> - _ r -2 c : : $2 6 v il i A L i I 1 1 , , ii s 1: g I,’ .,, - PROJECT NO. R-a-2BC SUMMARY SHEET BORlNG NO. 1 ELEVATION 225.0’ .ieht Brown and Light ;ray-brown, Slightly Moist, irm .ight Gray with Red-brown, hoist ,enses of Very Fine Sondy Clay o 8 l/2 Feet lght Brown, Slightly Mlcaceous CLAYEY FINE SAND 16.2’ 17. 21.1; 14 26.0 7, 105.2 110.11 lO8.Oi I Continued on Drawing No. 3 cl - indicates Loose Bog Sample O- lndicotes Undisturbed Drive Sample + - Elevations Shown Won Obtained By Interpolating Between The Contours Shown On A Topographic Map Furnished by Rick Engineering Company DRAWN‘2 NO. BENTON ENGINEERING, INC. 2 ,~@ - - L i 2 i j& 2 ;:, i’ i 8 c:~ - - - - k 2 Y z i 15- 16- 17- 18. 19- !O - PROJECT NO, 72-8-2BC SUMMARY SHEET BORING NO. 1 (Cont’d) Brown, Moist, Less Clayey, of Gray Silty Clay 1 CLAYEY FINE - :$ & iso E&e - 9.7 - 06 -2. “--.-~.,. ING NO. BENTON ENGINEERING, INC. -~ . 6 5 < !$ 4 ti 1 2 1: 1 5 ; SUMMARY SHEET BORlNG NO. 2 ELEVATION 260.0’ - Slightly Moist, Medium Loose, Lenses of Clayey Fine Sand, CLAYEY FINE SAND 3, 4 5 6 7 2.5 I.7 05. 02. 3. 6. - - SILTY CLAY - - CLAYEY FINE SAND c - - 9. 6. - 3. ,2. 2.6 01. !.4 18. 8 SILTY CLAY 9 10 11 12 13, 14 15 16 17 18 19 1 2 i - CLAYEY FINE TO MEDIUM SAND i , i 1: 0 /II P.3 3.3 08. 12. SILTY CLAY 20 21, Contlnued on Dmwing No. 5 PROJECT NO. DRAWING NO, R-B-2BC BENTON ENGINEERING, INC. 4 48 - - L 2. *‘T i -. li k. : c ,>: : ?Z c : L 5 - , I 1 I i , i +;’ 9 - m s L f 2 k ?I 21- 22- 23- 24- 25- 26- 27- 18 - !9 - IO - 31 - 32- )3 - i4- l5- I6 - I7 - la- s9- to- SUMMARY SHEET BORING Na. 2 (Cont’d) q Light Green-gmy, Slightly SILTY CLAY :LAYEY FINE TO MEDIUM SAND 18.5 08.’ PROJECT NO. R-a-2Bc DRAWING NO. BENTON ENGINEERING, INC. 5 iq - - - 22 - i f 2, c ,t 2 :i ; L!-! 2 , I , , I , il : 2 - ! SUMMARY SHEET BORING NO. 3 ELEVATlON 225.0' BENTON ENGINEERING, INC. - L - i ,i - L zig E SUMMARY SHEET Et 5 BORING NO. 4 3 L; : I! ELEVATION 275.0' ;‘f 0 0 g” ..,... r Light Yellow-Brown, Red, and Light Gray, Slightly Moist, 32.5 8.8 107.8 3- . . . ,..... 4- 6- 16- 18- 19- Continued on Drawing No. 8 PROJECT NO. DRAWING NO. R-e-2Bc BENTON ENGINEERING, INC. 7 -- - - - j, - I 1. - . L j i -r: L 1 L i SUMMARY SHEET BORING NO. 4 Kont’d) Slight Cloy Binder SLIGHTLY SILTY DRAWING NO. ” -~ - - z. A - 1;. !: j L :,, : - 2 -6 VI - - L E SUMMARY SHEET z< k? IflE EC i %g 526 $g5” & g ,gi t $2 32 BORING NO. !j 34 f&o’ gq $r” : 4 ELEVATION~4.5’ $5 & “g ‘,1 zzti? od :z 0 Gmy-brown, Slightly Moist, h4edium Firm, Rrous, Rootlets 1.6 7.1 72.6 . 2- Light Brown, Very Firm Continued on Dmwlng No. 10 PROJECT NO. DRAWING NO. 72-8-2BC BENTON ENGINEERING, INC. 9 - - - 2. i,~ - <. - - - 1 ,- A - SUMMARY SHEET BORING NO. 5 (cont.) Light Gray, Slightly Moist, Very Compact, With Some Medium Gmins PROJECT NO. DRAWING NO. 72-B-2BC BENTON ENGINEERING, INC. 10 A A - - i :i ; ,: i VI - -- - - - SUMMARY WEET BORING NO. 6 ELEVATIONS Light Gmy With Brown, CLAYEY FINE PROJECT NO. I DRAWING NO. 72-s2BC BENTON ENGINEERING, INC. 11 SUMMARY SHEET BORING NO. 6 (Cont’d) T -; :LAYEY FINE TO MEDIUM SAND, L i I 31 1 I 02. SILTY CLAY :LAYEY FINE TO MEDIUM SAND !‘Jjick_&ded I Medium Loose to Medium Compact, Fault Zone, Highly ractured to 33.5 Feet 26.; !l. SILTY CLAY 05. I j- 2i 1 I - - 2 1 - Green-gmy with Red-brown, Slightly Moist, Very Firm, S I ightly Cemented to 26 Feet Light Greengray Green-gmy, MOM, Very Firm, s of Clayey Fine to Medium 8. - T-d Blue-grey, Moist, Very Firm 08. - I I I PROJECT NO. DRAWING NO. 72-8-2BC BENTON ENGINEERING, INC. I 12 za - - i I I SUMMARY SHEET BORING NO. 7 ELEVATlON 220.0’ II !r. ,!..“.\J -II ’ I l??xslLial it Brewn, Dry, Medium, iim, Porous, Rootlets Light Yellow-brown and Red, Moist, Firm to Very Firm 5- - Light Groy-brown with Red- E brown, Moist, Firm to Very Firm ;p& c . . 8- 9 o I ~ f??$ Ll& Brown, Moist, Very Firm t Gray with Yellow ond SILTY FINE SAND CLAYEY FINE SAND :lAYEY FINE TO MEDIUM SAND CLAYEY FINE SAND 6 .: - 12.t - 6.0 9.2 - PROJECT NO. I DRAWING NO. 72-8-2BC BENTON ENGINEERING, INC. 13 - L 5 id SUMMARY SHEET 5 k BORING NO. 8 : ELEVATION 185.C’ A Light Gray with Red Patches, Moist, Firm to Very Firm 6 8 j@~-[ : : : Light Groy with Red and Yellow 16 17 18 I9 i B . . . . . SILTY FINE SAND CLAYEY FINE SAND 32.5 12.5 i 1’ ) A in 1 I 1 14.t Il.! 24.: 8.E Do.8 1 9.3 9.7 2.0 19. : ‘1.2 13.. 08. D3.1 - PROJECT NO. DRAWING ~0. 72-8-2BC BENTON ENGINEERING, INC. 14 ‘t? ,.~ ..~, ,, .- - i i 2 I i in - - ( L -7 (1 - - 1.6 9.7 9.5 9.7 8.1 3.1 tc G”: 23 “dy 2 a - 02. 95., 11.1 34.s 09. 09. SUMMARY SHEET BORING NO. 9 ELEVATION 200.0’ I I 1 1 1 1 Mottled in Color 11.2 !2.3 5.7 8.4 8.5 18.7 Green-gmy, Fractured, With Gypsum Filled Fractures I 8 -‘m ‘.‘. 1.: ‘.’ 1 inch Lens of Light Gmy Very -31 “.: Firm Cemented CIOYOY Fine to FINE SANDY CLAY Sand ’ ’ Gmen-gray with Red, Loose to Finn, Highly Fractured t*$ inn, Fractured l3- l4- l5- l6- l7- l8- IP- !O- !l- pi!J . . . . . . . ,. ,~ Continued an Drawing No. 16 PROJECT NO. 72-S-2BC I BENTON ENGINEERING, INC. I DRAWlNG NO, 15 .- - - ,- - - i 2 I z .l I: , ~~ i L L! 1 - ii 3 D 3 3 r s - $ - ,.:. - z+ Z” zi F k >li %- - 12, - - IO. - 04. - - - > 0,: Et 3 95 :t 0 - 54.: - SUMMARY SHEET BORING NO. 9 (Cont’d) BGrecn-gray, Moist, Firm, ractured SILTY CLAY 16.’ inch Layor of Very Firm Iemented Clayey Fine to iMedium Sand a reen-gray, Slightly CLAYEY FINE SAND I :LAYEY FINE TC MEDIUM SAND B5. - i6.t 13.: z Light Red-brown with Light m Yellow and Light Gray, t e Slightly Moist, Very Firm, x A ??I% Light Yellow-brown, Slightly s Moist, Very Firm and Light Red-brown C SLIGHTLY : LAYEY FINE TO MEDIUM SAND 5.; 4.( CLAYEY SILT , Moist, Very Firm, PROJECT NO. I DRAWING NO. 72-a-2Bc BENTON ENGINEERING, INC. I6 L. 5 k 52 L-l SUMMARY SHEET ? t 22 52g gEs $2 i2z BORING NO. 10 7 ELEVATION 153.0’ 5 ,l 6- keen-gray and Light Brawn, rbirt, Medium Loase, Highly ‘oraus, Rootlets, Many Lenses If Light Gray-brown Fine to kdium Sand .- 1.6 3.2 6.1 6.5 91, keen-any, Medium Firm 1 - 06, SILTY CLAY 11.4 - 6.5 - reen-gray, Moist, Firm FINE TO MEDIUM SANDY CLAY 6.5 SILTY CLAY I DRAWING NO. BENTON ENGINEERING, INC. 17 PROJECT NO. 72-s-2BC L - - I - - - - SUMMARY SHEET BORING NO. 11 ELEVATION 14.0’ Medium Firm to Firm, Porous, Gray-bmwn, increase In Clay Contentta11.5Feet 2- 3- :r o 6- 7- 8- SILTY FINE SAND CLAYEY FINE SAND a. a. a. 6 9 8, 7. 7 --! .ai 00. - 98. 98.’ 33.1 93., - - PROJECT NO. I DRAWING NO. 72-B-2BC BENTON ENGINEERING, INC. ia - i - .,;, L L -A (J 0 u - c i : A ii 5 z z O- 1 2- 3- 4- 5- 6- 7- a- 9- lo- ll- 12- 1; ‘4; 15 16 IF 18- 19 zo- 21- SUMMARY SHEET BORING NO. ‘12 ELEVATION i aoe O’ htiy Moist, Very Firm CLAYEY FINE .ight Gray-brawn with Yellow, Mst, Very Fin, Slight imount of Vary Fine Sand L-l FINE SANDY CLAY SILTY CLAY CLAYEY FINE SAND Continued on Drawing No. 20 24 27 .6 1 6.5 i2.2 oa.! 08.: 15.i PROJECT NO. I DRAWING NO. 72-G2BC BENTON ENGINEERING, INC. 19 - - L E 5 I; ii 21- 22- 23- 26 25- 26- 27: 2a- 29- 30- SUMMARY SHEET BORING NO. 12 (Cont’d) =+-&ig; , - u ~ Gray with Red, Moist, Firm PROJECT NO. 72-8-2Bc CLAYEY FINE SAND 66. t 56.6 - 12.1 102.: BENTON ENGINEERING, INC. DRAWING NO. 20 .-” - .- - I 2 1 I : : ? i : c i : 1 SUMMARY SHEET BORING NO. 13 ELEVATlON 130.0’ Compact, Porous, Root lets SLIGHTLY CLAYEY FINE SAND 5 c/ &ii& Brown L.LlA.2 -LLlLA 5 Kl - s 7- ““’ I Light Brown a . . 9 1 Es- o-e ;jy I I I CLAYEY FINE SAND 6.t 13.c 14.t 2 .: - 6.5 6.8 1.3 1.6 - - > ;t =z iq >ii $’ - 90.: - 98.1 91.’ 01.: 97.z 33.1 - - - - PROJECT NO. 72-8-2BC DRAWING NO. BENTON ENGINEERING, INC. 21 ,- - - A 1 - i - ; - - .- +4’ +3 +2 +1 0 :: ii : 1 2 3 0 i 2 1 : z 2 8 E a. 3 EO E 0 ? 3 1 !! 2 3 CONSOLIDATION CURVES LOAD IN RIPS PER SQUARE FOOT I lb &;+g ; epth 11.5’ - 0 INOICATES PERCENT COYSOLIOATION AT FIELD YOISTURE . INDICATES PERCENT CONSOLIDATION AFTER SATURATION PROJECT NO. DRAWNNO NO. 72-B-2BC BENTON ENGINEERING, INC. 22 - ,! z. i /,s I 1 f:, -: ,- :. L - - CONSOLIDATION CURVES LOAD IN KlP8 PER SQUARE FOOT 0.6 , 1.0 1.0 2 2 4 6 PROJECT NO. R-6-2Bc 0 INDICATES PERCENT CONSOLIOATION AT FIELD YOlSTURE . INDICATES PERCENT CONSOLIDATION AFTER SATURATION DRAWIN% NO. BENTON ENGINEERING, INC. 23 .- - - - - I: -_ L -_ 2 - .+: - - - - t-8 Z E % CONSOLIDATION CURVES LOAD IN KIPS PER SQUARE FOOT 1p Depth a . INDICATES PERCENT CONSOLIDATION AT FIELD YOlSTURE INDICATES PERCENT CONSOLIDATION AFTER SATURATION PROJECT NO. 72-S-2BC DRAWINQ NO. BENTON ENGINEERING, INC. 24 -~ - 2 ~j L 1 - - ;,. - - - - +8 +7 E = +3 0 E CONSOLIDATION CURVES LOAD IN KIPS PER SQUARE FOOT PROJECT NO. 72-8-2BC 0.8 0.8 1.0 1.0 2 2 - - - - - - - - - - - - - 6 a INDICATES PERCENT CONSOLIDATION AT FIELD MOISTURE . INDICATES PERCENT CONSOLIDATION AFTER SATURATION I BENTON I DRAWINS NO. ENGINEERING, INC. 25 I - - z. 1 L ,a 1 2 :i $ 11 - - L - - CONSOLIDATION CURVES LOAD IN KIPS PER SQUARE FOOT +5 +3 +2 F3 2 i 54 E 5 a INDICATES PERCENT CONSOLIDATION AT FIELD MOISTURE . INDICATES PERCENT CONSOLIDATION AFTER SATURATION PROJECT NO. DRAWINQ NO. 72-8-2BC BENTON ENGINEERING, INC. 26 .- - - i” - 2 - i$ $, 3: L ,s A 1 - - I CONSOLIDATION CURVES LOAD IN KIPS PER SQUARE FOOT a INDICATES PERCENT CONSOLIDATION AT FIELD MOISTURE . INDICATES PERCENT CONSOLlOATlON AFTER SATURATION PROJECT NO. 72-S2BC I BENTON ENGINEERING, INC - BENTON ENGINEERING, INC. APPLIED SOIL MECHANICS - FOUND*TION6 6717 CONVOY COURT - BAN DIEGO. CALIFORNIA 9.?11, - PHlLlP HENKINO BENTON P”E*IonHI. CIY1L LHCIHEER APPENDIX AA TELEPHONE ,714, SBB-1~SS STANDARD SPECIFICATIONS FOR PLACEMENT OF COMPACTED FILLED GROUND - 1. 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 an:! grubbing, removal of existing structures, preparation of land to be fillet !, 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 unsatisfactory conditions are observecl 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, ond burned or other- wise disposed of so as to leave 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 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 (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. k) Where fills are made 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 shall be at least 10 feet in width on firm undisturbed natural ground at the eleva- tion of the toe stoke placed at the natural angle of repose or design slope. The sails engineer shall determine the width and frequency of all succeeding benches which will vory with the soil conditions and the steepness of slope. - .- - - _- - - -. - - - - .- APPENDIX AA -2- (d) After the natural ground has been prepared, it shall then be brought to the proper moir- ture content and compacted to not less than ninety percent of maximum density in accordance with A.S.T.M. D-155766T method that uses 25 blows of a 10 pound hammer falling from 18 inches on each of 5 layers in a 4” diameter cylindrical mold of a 1/30th cubic foot volume. 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 pik of any other approved sources and by mixing 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 areas as shown on the plans or as directed by the soils engineer. 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 reports 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. Plociw, Spreading, and Compacting Fill Materials. (4 b) (4 (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 be.low 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 compacting process. When the moisture content of the fill material is above that specified by the soils erg i neer, the fill material shall be aerated by blading and scarifyiw or other satis- factory methods until the moisture content is near optimum as specified by the soils ergi neer . 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 soil types. Rollers shall be of such design that they will be able _... ---...- ..- - - - - - -- - - - - - - 5. 6. 7. a. (e) (0 kd APPENDIX AA -3- to compact the ff II material to the speclffed density. Rolling shall be accompllshed while the fill material is at the specified moisture content. Rolllw of each layer shall be contlnuws over Its entire oreo and the roller shall make sufficient trips to insure that the desired density has been obtalned. The entire oreas to be filled shall be compacted. FIII slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compacting operatlons shall be continued until the slopes are stable but not too dense for plantfng and until there is no appreciable amount of loose soil on the slopes. Compacting of the slopes shall be accomplished by backrolliw the slopes In increments of 3 to 5 feet In elevation gain or by other methods producing satisfactory results. Field density tests shall be taken by the soils engineer for approximately each foot In elevation gain after compaction, but nor to exceed two feet in vertical height between tesk. Field density tests may be taken at intervals of 6 inches in elevation gain if required by the soils engineer . 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. Tesk shall be taken on corner and terrace lok for each two feet In elevation gain. The soils egineer may take additional tests as considered necessary to check on the uniformity of compaction. Where sheepsfwt rollers are used, the tests shall be taken in the com- pacted material below the disturbed surface. No additional layers of RII shall be spread until the ffeld density tests indicate that the specified density has been obtained. The fill operation shall be continued In six Inch (6”) compacted layers, as specified above, until the ff II has been brought to the finIshed slopes and grades as shown on the accepted plans. Inspection. SuffIclent inspection by the soils e~inneer~shall be maintained during the fllliw and compoctlw operations so that he can certify that the fill wos constructed in accordance with the accepted specifications. seasonal Limtk. No RI1 material shall be placed, spread, or rolled If weather conditions increase the moisture content above permissible limits. When the work Is interrupted by rain, fill operations shall not be resumed until field tests by the soils eglneer indicate that the moisture content and density of the fill are as previously specified. Limitlm Values of Nonexpansive Soils. Those soils that expand 2.5 percent or less from air dry to saturatron under a unit load of 500 pounds per square foot are considered to be nonexpansive. All recommendations presented in the “Conclusions” section of the attached report are a part of these specifications. , q LwroN LNmNLLIINO. INC. BEbhON ENGINEERING, INC. APPLIED Boll. MEC”ANICS - FOUNDATIONS 6717 CONVO” COURT SAN DIEGO. CALIFORNIA 8211, - PHlLlP HENKING BENTON P”l.101111. C,“Il. LNGIHIE” - APPENDIX A Unified Soil Classification Chart* SOIL DESCRIPTION GROUP SYMBOL I. COARSE GRAINED, More than half of - material is h than No. 200 sieve size.** - GRAVELS CLEAN GRAVELS m half of coarse fraction is - larger than No. 4 sieve size but smallerGRAVELSWITH FINES than 3 inches - (Appreciable amount of fines) - SANDS More than half of coarse fraction is - smaller than No. 4 sieve size CLEAN SANDS SANDS WITH FINES (Appreciable amount of fines) II. FINE GRAINED, More than half of - material is smaller than No. 200 sieve size.** SILTS AND CLAYS .- - Liquid Limit Less than 50 SILTS AND CLAYS - Liquid Limit Greater than 50 - III. HIGHLY ORGANIC SOILS PT GW GP GM GC SW SP SM SC ML CL OL MH CH OH TYPICAL NAMES TELEPHONE (714) S8%19SS Well graded grovels, gravel-sand mixtures, little or no fines. Poorly graded gravels, gravel-sand mixtures, little or no fines. Silty gravels, poorly graded gravel- sand-silt mixtures. Clayey gravels, poorly graded gravel- sand-clay mixtures. 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. Inorganic silts and very fine sands, rock flour, sandy silt or clayey-silt-sand mixtures with slight plasticity. Inorganic clays of low to medium plas- ticity, gravelly cloys, sandy clays, silty clays, lean clays. Organic silts and organic silty-clays of low plasticity. Inorganic silts, micoceous or diatomaceous fine sandy or silty soils, elastic silts. Inorganic cloys of high plasticity, fat clays. Organic clays of medium to high plasticity Peat and other highly organic soils. * Adopted by the Corps of Engineers and Bureau of Reclamation in January, 1952. ** All sieve sizes on this chart are U. 5. Standard. BENTON ENGINEERING. INC. .- _- - - - - - APPLIED SOlL MECHANICS - FOUND*T,ONs 6717 CONVOY CO”R(T SAN D&EGO. CALIFORNIA 82111 PHILIP HENKIND BENTON nls,oEnr ClYlL LNG,*rL” TELLP”ONE ,71*, 5BS-IDWS APPENDIX B Sampling 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 token to the laboratory in close fitting waterproof containers in order to retain the field moisture until completion of the tests. The driving 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 point 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 soil 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/10000 inch per hour.