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HomeMy WebLinkAbout; 2500 Navarra Drive Multi-Residential Units; Soils Report; 1973-01-11BENTON ENGINEERING, INC. PHlLlP HENKlNG BENTON CRE*IDLNT. ClYlL ENGIr4EEr( APPLIED ScJ,L MECHANICS -~~ FO”NDATIONS 6717 CONVOY COURT SAN DIEGO. CALIFORNIA 82111 January 11, 1973 ,EI.EP”ON~ ,,,A, 565.l9SJ Prover Bms. lnvestmenk 9744 Wilshire Blvd. Suite 203 Beverly Hills, California 90212 Attention: Mr. Stan Pmver Gentlemen: This Is to tmnsmit to you six copies of our report of Pmlect No. 72-l l-28A entitled, “Soils Investigation, Multi-residential Unik, 2500 Novarm Drive, La Costa Area of Son Diego County, California,” dated January 11, 1973. We are tmnsmitting under sepomte cover two copies to Walter Richardson Associates; two copies hand delivered January 12, 1973 to Toups Engineering, Inc., Attention: Mr. Ed Roberts; two copies to Title lnsumnce and Trust Company, Attention: Ruth Rogers; and two copies to Steinbrugge and Thomas, Incorpomted. If you should have any questions concerning any of the data presented in this report, please contact us. Very truly yours, BENTON ENGINEERING, INC. SOILS INVESTIGATION Multi-mddential Unik 2500 Navarm Drive La Costa Area of Son Diego County, California Pmver Bras. Investments Pmlsrt No. 72-l I-2BA January 11, lw3 BENTON EN.3INLERING. INC BENTON ENGINEERING, INC. APPLIED SOlL MECH*NICS -- FO”NDATIONS 6717 CONVOY COURT SAN DIEGO. C*LIFORNIA 82111 PHlLlP HENKING BEN-ION PRLOIDLNT CIY,L ENelNLFl SOILS INVESTIGATION Introduction TELLP”(oHE (7111, 685.1855 This is to present the resulk of CI soils investigation conducted at the site of the proposed mult-residential units and recreational facilities located at 2500 Navorm Drive, La Costa, California, brmerly Lots 46 to 52, inclusive, of La Costa South Unit No. 1, La Costo, Son Diego County, California. It is understood that the proposed residential structures will consist of concrete block and wood fmme construction with continuous footing loods varying from 2 to 8 kips per lineal foot ond with column loods up to approximately 135 kips. In addition there is to be on underground porking facility with the upper slob being utilized os o tennis court area. Column loads for this facility will be on the order of 80 kips. There is to be some cut and fill required according to the present grading plans. The obiectives of the lnvestigotion were to determine the existing subsurface conditions and physlcol proparties of the soils in order that recommendations could be presented for the design of economical and safe foundation support for the pmposed structures to be located on this site. In order to accomplish these oblectives, six borings were drilled ond representative undisturbed ond loose soil samples were obtained for laboratory testing. Prior gmdlng opemtions involved cutting to a fairly level grade on a portion of the front, streetaide of Lok 46 to 48, Inclusive, and o majority of the arem of the remalnlng lok. In addition, the eastern portion of Lot 46 was brought up to existing grade with compacted fill. Field lnvestigotion The six borings were drilled, each to a diameter of 24 inches, wlth a truck-mounted mtory b&et-type drill rig at the opproxlmote loccttlons shown on the ottached Dmwing No. 1, entitled “Location of Test Borings.” The borings were drilled to depths of 15 to 36 feet below the existing ground surface. A continuous log of the solls encountered ln the borings wos recorded ot the time of drilling and Is shown In detail on Dmwfng Nos. 2 to 10, Inclusive, each entitled “Summory Sheet. ‘I The solis were visually claolfied by field identitlcotion procedures in occordcmce with the Unified Soil ClossiRcatlon Chort. A simpllfled descrlptlon of this clossiflcotlon system is presenhd in the attached Appendix A at the end of this report, Undisturbed samples were obtained at frequent intenals, where possible, in the soils ahead of the drilling. The drop weight used for driving the sompllng tube into the rolls was the “Kelly” bar of the drill rig which weighs 1623 pounds, and the ovemge drop was 12 inches. The general procedures used in field sampling ore described under “Sampling” in Appendix B. Lobomtory Tesk Labomtory tesk were performed on all undisturbed samples of the soils in order to deter- mine the dry density, moisture content, and sheorlng strength. The resulk of these task ore presented on Dmwing Nos. 2 to 10, Inclusive. Consolidation tesk were performed on represent- otlve samples in order to detenine the lood-settlement chomcteristia of the soils ond the resulk of these tesk ore presented graphically on Dmwing Nos. 11 to 17, inclusive, each entitled “Consolidation Curves. ” In addition to the above lobomtory tesk, expansion tesk were performed on some of the clayey soils encountered to determlm their volumetric chowa chomcteristlcs wlth change in moisture content. The recorded expcpcnsions of the samples ore presented on the following poge. BENTON ENGINEERINO. INC. -3- fkcent Exponslon Under Unit Load of Depth of 150 Pounds per Square Borlng Sample Somple, So11 Foot from Alr Dry No. No. In Feet Description to Satumtlon 2 1 1 .O Fine to medium sondy cloy 0.30 3 2 12.0 Fine sandy cloy 1.48 4 2 4.0 Cloy and fine sandy cloy 2.44 4 4 11.0 Flne sandy clay 2.87 5 2 4.0 Fine to medium sandy cloy 4.74 6 2 6.0 Flne to medlum sandy cloy 1.91 The geneml procedures used for the obove loboratory task ore described brlefly In Appendix B. Compaction tests were performed on representative samples of the soils to be exarvoted to establish compaction criteria. The soils were tested occordlng to the A.S.T.M. D 1557-70 method of compoctlon which uses 25 blows of a 10 pound mmmer dropping 18 inches on each of 5 layers in a 4 inch dicrmater l/30 cubic foot mold. The raulk of the tests ore presented as follows: Maximum Optimum Mols- brh3 eoS Depth WI Dry Density turn Content No. Sample in Feet Description lb/c” ft %drywt 1 2 5.0 - 6.0 Clayey fine to medium 122.3 11.0 sond 1 3 9.0 - 10.0 Fine to medium sand 122.9 10.9 DISCUSSION, CONCLUSIONS AND RECOMMENDATIONS Soil Stmta The soil stmto encountemd at Boring 1 consisted~of a 1.2 feet layer of firm flne to medium sandy cloy overlying 0 0.4 faot layer of firm clay. Beneath this, from 1.6 to 4.0 feet, a firm fine to medium sondy cloy was found. From 4.0 to 5.8 feet o very flrm clayey fine to medium sand was encountemd. Below this, to the depth of explomtion of 16.0 hot, o fin to very firm fine to medlum sand wos found. BENTON ENGINEERING. INC. -4 At Boring 2, CI 1 .O foot layer of medlum soft, fine to medium sandy clay topsoil was found overlying o 1.2 feet thick layer of very firm fine to coarse sandy cloy. A slightly clayey fine to medium sand wus encountemd from 2.2 feet to 10.4 feet when, It merged to o very firm fine to worse sandy clayey gravel that was found to the depth of explomtion of 15.0 feet. At Boring 3, drilling penetmted approximately 4.0 feet of fill soil which Was gmde.d in order to locate the drill rlg on the existing sloping natuml ground. Notuml soil was encountered at o depth of 4.0 feet and consisted of 1.5 feet of very firm clayey fine to coorse sandy gravel. Below this o firm clay containing occasional lenses of f7ne sandy cloy was found to o depth of 11.2 feet where it merged to o very firm fine sandy cloy. From 13.9 to 16.6 feet o medium firm slightly clayey flne fr, medium sand was encountered. Underlying this to o depth of 18.5 feet a medium firm clayey fine to medium sand was found. From this depth ot 24.0 feet, the dapth of explomtion, CI very compact flne to medium sand was encountered. At bring 4, (I medlum firm flne to medium sandy cloy wus found to o depth of 1.6 feet. below this to a depth of 9.0 feet the soil consisted of interbedded layers of medlum firm cloy and ffne sondy cloy. At 9.0 feet the soil merged to a medium firm to firm flne sondy cloy contoinfng occasional thin lenses of fine and fine to medium sand. At 18.0 feet, the soil changed to Q medium soft, silty tTne to medium sand which contained occasional thin lenses of clay. The con- sistency of this soil changed to medlum firm to firm ot 21.5 feet. Below this from 31 .O to 33.5 feet a flrm slightly silty fine to medium sand was found. From 33.5 to 35.7 fact a firm flns sandy silt wos encountered. Underlying this, to the depth of explomtlon of 36.0 feet, a firm slightly clayey fine to medlum sand was found. At Boring 5, 0.7 foot of medium compact fine to medlum sand was found overlying o very firm slightly silty fine sand to 2.1 feet in depth. From 2.1 to 5.0 feet a very firm fine to medium sandy clay wus encountered which merged Into a medium firm slightly clayey fine te medium sand. Below this o very firm clayey fine to medium sand was encountered from 7.5 to 10.0 feet when, it BENTON ENGINEERING. 1NC. -5- merged to a fine to coarse sandy clayey gmvel which was found to the depth of explomtion of 21 .O feet except for a layer of clayey Rne to coarse sand found from 18.5 to 19.1 feet. At Boring 6, o 0.7 foot loyer of ff rm fine to medium sandy cloy was found overlying a very firm clayey fine to medium sand. At 3.5 feet this soil merged to (I firm fine to medium sandy clay. At 12.0 feet the consistency of this sandy clay changed to very firm until a depth of 18.0 feet whem the soil met& to a very firm clayey fine to medium sand. From 23.0 to 24.7 feet o very firm fine sandy cloy was fwrxi. Below this, to the depth of explomtlon of 25.0 feet, 0 firm clay was encountered. Ground water wos encountered at a depth of 24.0 feet in Boring 3 and below 18.0 feet In Boring 4. Conclusions It is conchrded from the fleld lnvestigotlon and the resulk of the lobomtory testing thatr 1. The on-site soils ore capable of supportIng the prOposed structural loads, provided that Footings ore designed in accordanus with the recommended bearing values which will be presented under “Recommerxkstions” in a subseque& sectlon of this report. 2. Some of the on-slh soils ore sufflclently expansive under condltlons of variations in moisture content to wurmnt the adopting of certain special design preccrutions, where these solls occur within 3 feet below flnlsh grode. 3. The load-settlement chamcterlstlcs of the soils am sufficiently fovomble to permit the use of spmod footings. Recomme.n&tions 1. Grading Prior to placing coyxlcted filled ground, it is mcommended that all soft or loose soils In areas that am to receive fill be excavated, to expose firm natural soils. iiorizontal benches BENTON ENGINEERING. INCA -6- should be excavated in the sloping hillside area into firm undisturbed soils, and the then exposed soils should be scarified to a depth of 6 inches, moistened to optimum, and then uniformly com- pacted to ot least 90 percent of maximum dry density. Thereofter approved fill material moy be placed and uniformly compacted to ot least 90 percent of maximum dry density. All of the soils that om to be excavated from cut omos am suitable for use os fill materials. However, it is moommended that the gmy-brow and yellow-brown fine to medium sandy cloy soils, such as was encountemd between the depths of 2.0 and 5.0 feet ot Boring 5, be used only crt depths of 3.0 feet or mom below Rnlsh gmde, or in non-building omas. it 1s also recommended that all gmding be accomplished in occordonce with the attached Appendix AA, entitled “Standard Specifications for Placement of Compacted Filled Ground.” 2. Footings Due to the variations in the physical properties of the soils at the various boring locations, mcommendations for allowable beorirlg values to be used in the design of footings for the several different categories of footlng loadings Indicated to us by Steinbrugge 8, Thomas, Structuml Engineers, on o dmwlng provided us by Walter Richardson Associates, Architects, will be presented sepomtely. These mcommendotions ore as followsr Geneml It is recommended that no footings be founded partly on filled ground and partly on notuml soils, and that footings be placed in fllled ground only where there is a thickness of such filled ground below the footing at least as great as the width of the footing. All of the recommended ollowoble bearing values given below am for deud plus live loads only, and may be Incmased one third for combined dead, live and seismic loads. 4 Concrete Garage with Tennis Courts Over One foot wide continuous footirqs located at a depth of one foot in the firm to very firm fine to medlum sand t&nd below 5.8 feet at Rorirg T (below Elevotlon 61.9 feet), may be BENTON ENGINEERING. INC -7- designed for on ollowoble beoring value of 2O@l pounds per squom foot. This value moy be increased at CI mte of 925 pounds per square foot for each foot of depth in excess of one foot, and ot on additionol mte of 450 pounds per square foot for each foot of width in excess of one foot, to a recommended moximum value of 4ooO pounds per square foot. Square footings that ore 3.0 feet wide and similarly located may be designed for on allow- able bearing value of 2700 pounds per squam f&t. This value moy be incmosed ot a mte of 925 pounds per squore foot for each foot of depth In excass of one foot, ond at on additional mte of 350 pounds per square foot for each foot of width In excess of 3.0 feet to a recommended moximum value of 5ooO pounds per square foot. b) Combinotion Wood Frame and Concmte Block, (Northwesterly) One foot wide continuous footings located at least one foot into the medium firm clayey fine to medium sand such OS MIS found below Elevvation 23 feet, (below 14 feet in depth) in Boring 3, or the medium firm c Ioy and fine sandy cloy loyers found between the depths of 1.6 and 9.0 feet ot Boring 4 moy be designed for on allowable bearing value of 4200 pounds per square foot. This v&e may be increased at o mte of 275 pounds per squom foot for each foot of depth in excess of one foot, ond at on additional mte of 75 pounds per square foot for each foot of width in excess of one foot, to o recommended maximum value of 4500 pounds per squam foot. 4 Combinotion Wood Frame and Concrete Block (Northeasterly) One foot wide continuous footings located at least one foot into the very firm slightly silty f7ne sand such as was found between the depths of 0.8 and 2.2 feet ot Boring 5 may be designed for on allowable beorlng value of 2OOU pounds per square foot. This value may be increased at a rote of 275 pounds per square foot for each foot~of depth in excess of one foot, ond at on odd]- tional mte of 75 pounds per square foot for each foot of width in excess of one foot, to a recommended maximum volue of 3000 pounds per square foot. BENTON ENGINEERING. INC. -B- 4 Concrete Gamge With Wood Fmme Unik Over (Adjacent to Navorm Drive) One foot wide continuous footings located one foot into the fim fine to medium sandy cloy found between 3.5 and 12 .O feet at Boring 6 moy be designed for on allowable bearing value of 2000 pounds per square foot. This value moy be increased at a mte of 350 pounds per square foot for each Foot of depth in excess of one foot, and at on additional rate of 100 pounds per square foot for each foot of width in excess of one foot, to a recommended maximum value of 3OOU pounds per square Foot. Square footings that ore 3.0 feet wide ond similarly located may be designed for on allow- able bearing value of 2650 pounds per square foot. This value may be lncreosed at CJ mte of 350 pounds per squam foot for each foot depth In excess of one foot, and ot on additional mte of 85 pounds per squom foot for each foot of width in excess of 3.0 feet, to a recommended maximum value of 3000 pounds per square foot. e) Footings in Compacted Filled Ground One foot wide continuous footings located ot o depth of one foot into properly compacted filled ground moy be designed for on ollowoble bearing value of 2700 pounds per square foot. Square footings that ore 3.0 feet wide and similarly located may also be designed for on allowable bearing value of 2700 pounds per square foot. Settlements Estimated toto! settlements, bosed on the resulk of the load-consolidation tab, hove been calculated for Q number of typical footings designed in accordance with the foregoing recommend- ations. These estimoted total settlemenk am presented on the following poge. Footing Type ond Size 1 foot wide continuous 3 feet wide sqwre 1 foot wide continuous 1 foot wide continuous 1 foot wide continuous 3 feet wide square 1 foot wide continuous 3 feet wide sqwre Comment Location -9- Deslgn Unit Load Wsq ff) Concrete Gomge with Tennis Courk Over Concmte Gomge with Tennis Courts Over Combination Wood Fmme and Concrete Block (Northwesterly) Comblnatlon Wood Fmme and Concnte Block (Northeasterly) Concrete Garage. with Wood Frame Units Over Concrete Gamge with Wood Frame Units Over Filled Ground Fi I led Ground 2000 2700 4200 2ooo 2000 2650 2700 2700 Estimated Totol Settlement Approximately l/4 inch Approximately l/2 inch Less than 3/B inch Approximately l/4 inch Approximately l/4 inch Approximately l/2 inch Less than l/B inch Less than l/4 imh It may be noted from the results of the expansion tesk that ot Ieost one somple of clayey soil (Somple 2 of Boring 5) was found to be exponsive. It is themfom probable thot simllor potentially exponslve soils exist within the upper 3.0 feet below finish grade, at locations other thon those at which the borings warn drilled. It is therefore recommended that, durlng groding, the inspecting soils technicion scmple any suspected expansive cloy soils to 3 feet below the proposed finished gmdes, in order to evaluate the potentiol expansiveness and in order thot appropriate mcommendotions moy be mode t%r the removal of expansive soils and the mplacament of these with nonexpansive soils. Respectfully submitted, ,_/‘~-- BENTON ENGINEERING, INC. Reviewed b G, &$yJ/~- I . > /- By x& && Philip H!Benton, Civil EGineer M. V. Rathier, Civil gglneer sENTON ENGINEERING. INC. AN P/PWR/aw E p-8 42 ;gs ic 0 - _i B = S - W c* w F 1*- I c z LzA.2 z c x z . . ;.... .‘. : :: PROJECT NO. DRAWING NO. 72-l I-2BA BENTON ENGINEERING, INC. 2 SUMMARY SHEET q ORlNG NO. ELEVATION 6:.7' * jroy-brown, Slightly Moist, irm, Rootlets tork Brown, Slightly Moist, Firm, Rootlets .lght Brown, Red-brown, lightly Moist, Firm, R&lets .ight Brown, Slightly Moist, irm to Very Fin, Rootlets ,ight Brown, Red-brown, Dry, irm to Very Firm, Some Zones ran Oxide Cemented, Some :ones Very Frioble kcosionol Lenses of Fine to ioorse Sond With Few Grovel, ilightly Moist :INE TO MEDlUh SANDY CLAY CLAY 4NE TO MEDIUN SANDY CLAY CLAYEY FINE TC MEDIUM SAND FINE TO MEDIUM SAND 8.1 9.7 , 6.5 - ,g! :zi ;$I - - - i7. - 0.1 4.' 8.1 5.t - - tb z” 5: c $ 0 - - 12. - I5 ?l. 95 - 5.81 I.11 1.1 - - u - Indicates Undlsturbed Drive Sample Cl - Indicates Loose Bog Sample * - Elevations Shown Wem Obtoined By interpolation of Contour Lines On Grading Plon For 2500 Novorro, doted November 22, 1972, Provided by Toupr, Eq$neers j ! 5 i 1 I . ! : . a B 5 SUMMARY SHEET BORING NO. my Firm, Occarionol Grbel FINE TO COARSE o 2 Inches, Rootlets SANDY CLAY 3 4- o E \L,ght I Brown, ye~lw~mn, _ 2 I%% Slightly Moist, Very Firm, 19.4 6.510B.5 4.52 S- IIZII Occasional kses of Clayey IIZIZZ Fine to Medium Sand, Fine to ,I@ 9 E~$2$!L!%~~~~. SLIGHTLY 6 c$;;;‘~;Jf 16.2 6.1100.2 2.27 B- 9- wwl4 Gray-brown, Yellow-brown, Slightly Moist, Very Firm, 14.61 10.4 l l + 60 Percent Gravel and Cobbles FINE TO COARSE SANDY CLAYEY GRAVEL l Too Rocky To Test PROJECT NO. DRAWlNa NO. 72-l l-2BA BENTON ENGINEERING, INC. 3 L 5 i?J. Y y$ 52 SUMMARY SHEET .gt ti =t 0:s Y riuz g ggs y;i $5 f$d : BORING NO. 3 ws i$; gq Lu+v) p 9: i “2 ELEVATION 37- O’ C~.o >u) Et $2 zx r$ :: 0 u 0 A l- 2- FILL GRADED FOR ACCESS ROADWAY =: 3- i; 4- 5- 6- 710 Light Gray, Yellow-brown, Slightly Moist, Firm, Occasional Lens of Fine Sandy a- Clay, Few Iron Oxide Cemented Pockets of Fine Sand 9- O- (~54 13.0 7.2 101.6 2.48 FINE SANDY CLAY v 4- I..,,:’ .,~;:.:;, Red-brown, Slightly Moist, 5- ~,.,~’ Medium Firm, Slight Clay FINE TO ‘,“~ ~: Binder, Occasional Pocket of ’ MEDIUM SAND 6 - ‘: : ,. ,’ ,’ Clay, Slightly Friable 7-@‘& A Groy, Slightly Moist, Madium cLAYEY FlNE TO 4.9 17.1 TOT.6 1.85 IZIZ.ZFI~~ s- MEDIUM SAND -x-LLL 9- . . Light Gray-brown, Slightly :::.:::.:!: Moist, Very Compact, FINE TO O- ‘::::::m.:~:‘,:‘. Occasloflal L4-s of Clayey MEDIUM SAND L.,‘.,.‘~‘~:F,~ Sad .:~ !I - I,::: .: ‘, Continued on Drowirg No. 5 PROJECT NO. DRAWNG NO. 72-l 1-2BA BENTON ENGINEERING, INC. 4 L Y tt z i 21- 22 23 24 - - - - - SUMMARY SHEET BORING NO. 3 (Cont’d) 8.1 asionol Lenses of Clayey FINE TO MEDiUM SAND PROJECT NO. 72-ll-28A ; Verv Moist 1 I I \Soturated 1 / 1.65 I DRAWING NO. BENTON ENGINEERING, INC. 5 L SUMMARY SHEET BORINO NO. Occasional Lenses o;FIne and Fin to bdium Sand, Few iron Oxide Cemented Pockets 72-l 1-28A I BENTON ENGINEERING, INC. I 6 SUMMARY SHEET BORING NO. 4 (Cont’d) rown, Satumtd, h4edium Occasional Thin Lanses Medium Firm to Firm SILTY FINE TO MEDIUM SAND Red-brown, Saturated, Firm, Occasional Lnnses of Fine to SILTY FINE TO MEDIUM SAND CLAYEY FINE TO PROJECT NO. ORAWNG NO. BENTON ENGINEERING INC. SUMMARY SHEET BORING NO. 5 ELEVATlON 65*o’ 1 2 : 5 7 , 0 l;‘:‘::::‘:‘:..iDark Brown, Moist, Medium - - - - - - - :INE TO MEDiUh SAND SLIGHTLY SILTY FINE SAND Rootlets Brown, Slightly Moist, Very ,Fiml M.7 13.t - 97. : - i.oc - 7.21 - 3.9 Gmy-bmwn, Yeliow+mwn, Slightly Moist, Very Finn :iNE TO MDIUF SANDY CLAY SLIGHTLY :LAYEY FINE TO MEDIUM SAND :LAYEY FINE TO MEDIUM SAND Mws) II : , A 8 El Light Gray, Very Firm Slightly Moist, ‘...‘I -LLLL’ lzil I 1 ! I Gmy-bmwn Brown, Moist, Very Firm, f 50 Percent Gravel and Cobbles to 5 inches 4.0 6.2 5.2 . X.8 + 2.55 l FINE TO COARSE SANDY CLAYEY GRAM L 7 inch Layer Clayey Fine to ~Coorse Sand II I l Tao Rocky to Test PROJECT NO. 72-l l-28A I BENTON ENGINEERING, INC. I DRAWING NO. 8 r 2- 3- 4- 5- 6- 7: 8- 9: IO- 11: 2- 3: 4- 5- 6- 7- 8: 9- :0 - :1 - Ed YE i;o SUMMARY SHEET zg g$J $2 g BORING NO. 6 22 ELEVATION 67.4 I G 1 m Brown, Slightly Moist, Firm, :.,. .:. INE TO h4EDiUN SANDY CLAY , :LAYEY FINE TO MEDIUM SAND (Merses) c* E =F :::j:;. :~. 6’ . . 8.1 IO.1 0' . . 95. 00.1 3.82 FINE TO MEDIUM SANDY CLAY ,.~,:~ ,.,.. p ..~~.. Light Gray, Red-brown, Slightly Moist, Very Firm, 1.4 - - 4.6 8.2 - - 34.1 - 05.; - FINE SANDY CLAY CLAYEY FINE TO AEDIUM SAND 3.73 - - Continued on Dr&ing No. 10 PROJECT NO. 72-ll-28A I BENTON ENGINEERING, INC. DRAWING NO. 9 I 3 . . i , E ! 3 . ; i i ; ; : 2 ; ; I-- ,- i- I- i-( J 0 -2L.l L -LLL L-LL Z-LL ;;:” 4 - .., a * - - PROJECT NO. 72-l l-28A SUMMARY SHEET BORING NO. 6 (Cont’d) .ight Green-ray, Slightly &St, Very Firm FINE SANDY CLAY ky, Red-brown, Slightly Moist, Firm b CLAY I BENTON ENGINEERING, INC. CONSOLIDATION CURVES LOAD IN KIPI PER SQUARE FOOT moided to 90% of ,: ,‘,,, ,~ Boring I Bog3 Depth 9’-10’ Remolded to 9@4 of Maximum Dry Densit) 0 INDICATES PERCENT CONSOLIDATION Al FIELD NOISTUKE . INDICATES PERCENT CONSOLIOATIOW AFTER SATURATION PROJECT NO. I DRAWING NO. 72-l l-28A BENTON ENGINEERING, INC. 11 4 !! 3 5 0 z 6 Y 5 f 7 E 8 z Y 5 9 0 F3 0 5 5 :: 1 9 2 3 4 5 t CONSOLIDATION CURVES LDAD IN KIPS PER SOUARL FOOT 0 INDICATES PERCENT CONSOLIDATION AT FIELD MOISTURE . INDICATES PERCENT CONSOLIDATION AFTER SATURATION PROJECT NO. 72-l l-28A I BENTON ENGINEERING, INC. DRAWINS NO. 12 CONSOLIDATION CURVES LOAD IN KIPS PER SQUARE FODT 0 INDICATES PERCENT CONSOLIDATION AT FIELD MOISTURE . INDICATES PERCENT CONS0LIOATl0N AFTER SATURATION PROJECT NO. DRAWINS NO. 72-l I-28A BENTON ENGINEERING, INC. 13 CONSOLIDATION CURVES LOAD IN KIPS PER 8)PUARE FOOT 3.6 . 0.8 1.0 2 4 6 0 INDICATES PERCENT CONSOLIDATION AT FIELD NOISTURE . \NOlCATES PERCENT CONSOLIOATION AFTER SATURATION PROJECT NO. DRAWINQ NO. 72-l l-28A BENTON ENGINEERING, INC. 14 CONSOLIDATION CURVES LOAD IN KIPS PER SQUARE FOOT 4 4 :: :: w w 55 55 0 0 z z 6 6 2 2 w w a7 a7 k k :: :: 8 8 t t i9 i9 0 INDICATES PERCENT CONSOLIDATION AT FIELD NOISTURE . INOICATES PERCENT CONSOLIDATION AFTER SATURATION PROJECT NO. 72-l l -28A I BENTON ENGINEERING, INC. I DRAWINS NO. 15 2 3 4 & 5 5 u z 6 5 (L a 7 k 8 5 i k 9 CONSOLIDATION CURVES LOAD IN KIPS PER SQUARE FOOT 0.6 0.8 I.0 2 4 6 0 I1111 I I I I I I 0 INDICATES PERCENT CONSOLIDATION AT FIELD NOISTURE . INDICATES PERCENT CONSOLIDATION AFTER SATURATION t PROJECT NO. DRAWlNfJ NO. 72-l 1-28A I BENTON ENGINEERING, INC. I 16 1 CONSOLIDATION CURVES LOAD IN NIPS PER IWARE FOOT 0.6 ! I.6 PROJECT NO. 72-l l-28A ORAWINQ NO. BENTON ENGINEERING, INC. 17 0 INDICATES PERCENT CON6OLlOATlON AT FIELD YOl6TURE . INDICATE6 PERCENT CONSOLIDAtlON AFTIZR SATURATION BENTON ENGINEERING, INC. APPLIED SOIL MECHANICS - FO”NDATlONS 6711 EL CAJON BOULEVARD *AN DIE00. CALIFORNIA P2115 PHlLlPHENKING BENTOf r”L~IDI*T. ClVlL LNGlUCL” APPENDIX AA 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 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 immediotely if any unsatisfactory 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 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 (6’7, 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. (4 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 pro- vide both lateral and vertical stability. This is to provide a horizontal base so that each layer is placed and compacted on o horizontal plane. The initial bench at the toe of the fill shall be at least 10 feet in width on firm undisturbed natvral ground at the elevation of the toe stake 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. (4 APPENDIX AA -2- 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 falli% from 18 inches on each of 5 layers in a 4” diameter cylimlrical 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 olher approved sources and by mixirg 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 ewineer. 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. Placing, 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 below that specified by the soils ewineer, water shall be added until the moisture content is near optimum as specified by the soils engineer to assure thorough bonding duriw the compactiw process. When the moisture content of the fill material is above that specified by the soils eqineer, 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 eqineer . 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. 8. (4 APPENDIX AA -3- to compact the RII material to the specified density. Rolling shall be accomplished while the All material is at the specified moisture content. Rolling of each layer shall be contlnucus over ik entire area and the roller shall make sufficient trips to insure that the desired density has been obtained. The entire areas to be filled shall be compacted. Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compacting operations shall be continued until the slopes are stable but not too dense for plantiw and until there is no appreciable amount of loose soil on the slopes. Compacting of the slopes shall be accomplished by backrolliq the slopes in Increments of 3 to 5 feet in elevation gain or by other methods producing satisfactory resutk. Field density tests shall be taken by the solls engineer for approximately each foot in elevation galn after compaction, 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 engineer. The location of the tests in plan shall be so spaced to give the best posslble coverage and shall be taken no farther apart than 100 feet. Tests shall be taken on corner and terrace Iok for each two feet In elevation gain. The soils erglneer may take additional tests as consldered necessary to check on the uniformity of compaction. Where sheepsfoot rollers are used, the tests shall be taken In the com- pacted material below the disturbed surface. No additional layers of fill shall be spread until the field density tests indicate that the specified density has been obtained. The fi II operation shall be continued In six inch (6”) compacted layers, as specifTed above, until the fill has been brought to the finlshed slopes and grades as shown on the accepted plans. 9=%- Sufffclent Inspection by the soils engineer shall be maintalned during the fl 1~ an compacting operations so that he can certify that the fill was constructed in accordance with the accepted specifications. seasonal Llmlk. No fill 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 tleld tests by the soils engineer indicate that the moisture content and density of the fill are as previously specified. Limitlrg Values of Nonexpansive Soils. Those soils that expand 2 5 percent or less from air dry to saturation under a unl t 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 speclflcations. BENTON m4G,NLLRING. WC, BENTON ENGINEERING, INC. APPLIED SOIL HECIIANICS -~~ rOUNoAT,ONS 6744 EL CAJON ~O”LE”ARD SAN DlEGO. CALIFORHIA 87.115 PHILIP HENKING BENTON l ICc.IDIHI Cl”lL IYCTINIII APPENDIX A Unified Soil Classification Chart* SOIL DESCRIPTION GROUP SYMBOL I. COARSE GRAINED, More than half of material IS larger than No. 200 sieve size.** - GRAVELS CLEAN GRAVELS w half of coarse fraction is larger than No. 4 sieve size but smallerGRAVELS WITH FINES (Appreciable amount than 3 inches SANDS -than holf of coarse fraction is smaller than No. 4 sieve size of fines) CLEAN SANDS SANDS WITH FINES (Appreciable amount of fines) II. FINE GRAINED, More than half of material is smaner than No. MO sieve size.** SILTS AND CLAYS Liquid Limit Less than 50 SILTS AND CLAYS Liquid Limit Greater thon 50 Ill. HIGHLY ORGANIC SOILS GW GP GM GC Well graded gravels, gravel-sand mixtures, little Q no fines. Poorly graded grovels, gmvel-sand mixtures, little or no fines. Silty gravels, poorly graded grovel- sand-silt mixtures. Clayey gmvels, poorly graded gravel- sand-cloy mixtures. SW SP SM SC Well graded sand, gravelly sands, little or no fines. Poorly graded sands, gravelly sands, little cr no fines. Silty sands, pocrly graded sand-silt mixtures. Cloyey sands, poorly graded sand-clay mixtures. ML CL OL MH Inorganic silts and very fine sands, rock flour, sandy silt or clayey-silt-sand mixtures with slight plasticity. Inorganic cloys of low to medium plas- ticity, gmvelly clays, sandy clays, silty cloys, lean clays. Organic silts and aganic silty-clays of low plasticity. lncrgonic silts, micoceous cr diotoma- ceous fine sandy or silty soils, elastic silk. CH OH Inorganic clays of high plasticity, fot clays. Organic clays of medium to high plasticity. PT Peat and other highly organic soils. TYPICAL NAMES *A” DISCO S.S.,~~‘ L. *rs1: 4(1S.S6S. * Adapted by the Carps of Engineers and Bureau of Reclamation in January, 1952. ** All C~LYP minx m thic rhnrt nra II-S. Ctnnrhrd. BENToN ~NGINEIxING. INC. APPLIED 501L MECHANlCS FOUNDATIONS 6741 EL CAIJON BOULEVARD *AN DIEGO. CALIFORNIA 92115 PYlLlP HENKING eENTON wlCSIOC”T C\“>L E”GIULE* APPENDIX B SAW DILGO. 5113.566. L. ML%*: 469.,654 Sampling The undisturbed soil samples ore 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 cut- ting 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 mois- ture until completion of the tests. The driving energy is calculated as the overage 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 SheOr machine of the strain control type in which the rote of deformation is approximately 0.05 inch per minute. The machine is so designed that the tests ore made without removing the samples from the brass liner rings in which they are se- cured. 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 off friction and cohesion. Where considered necessary, samples are saturated and drained before shearing in order to simulate extreme field moisture conditions. Consolidation Tesk 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 ore 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 ore placed in contact with the tap ond bottom of each specimen to permit the ready addition or release of water. Expansion Tests One inch high samples confined in the brass rings ore permitted to oir dry at 105°F for at least 48 hours prior to placing into the expansion apparatus. A unit load of 500 pounds per squore 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 ond 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 1/10000 inch per hour.