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HomeMy WebLinkAboutCT 72-20; La Costa Rancho Santa Fe; Soils Report; 1970-12-14BENTON ENGINEERING, INC. P”lLlP HENKIHCC mENTON PllSSIDSHI ClYlL I*GI*rL” December 14, 1970 *AN 1311ro: s*5-ses. LA MI**: .60-S(1S. Rancha La Costa Route 1, Box 2550 Encinitas, California 92024 Subject: Project No. 70-6-29F, Part II, and Proiect No. 70-8-18F, Part IV Prliminary.Jp~j&lnvestigotion La Costa Ranch0 West ot Kancho > and South of San Marcos Creek San Diego County, California Gentlemen: CONCLUSIONS It is concluded from the field investigation and laboratory test results that: 1. The medium firm to very firm notural soils are suitable for support of the proposed fills and/or residential structures. However, loose or porous compressible upper soils, similar to those encountered to a depth of 6.5 feet in Boring 2-11, to 5.5 feet in Pit lo-IV, and to 6.0 feet in Boring 18-W, may be expected to exist in certain low areas and it is recommended that these materials be removed ond that the compacted filled ground and/or footings be placed on the underlying natural’soils determined suitable for foundation support. Also potentially expan- sive clayey fine sand, sandy clay, silty clay and clay soils were found in certain areas and specially designed footings and slabs are recommended where these expansive soils are allowed to remain in place within the upper 3 feet below finished grade. 2. It is concluded from the results of the laboratory tests that the natural soils, suit- able far structural support, have a safe bearing capacity of at least 2000 pounds per square foot for one foot wide con0nuous footings placed one foot below the firm undisturbed natural ground surface. The settlement of a one foot wide continuous footing loaded to 2COO pounds per lineal foot and founded on suitable undisturbed notural soils is estimated to be less than l/8 inch. 3. The results of the laboratory expansion tests indicate that,certain of the clayey fine sand, silty clay, sandy clay, and cloy soils encountered in the investigation would be con- sidered as “expansive” soils. Therefore, in order to avoid the use of specially designed footings and slabs, it is recommended that, wherever practicable, the “expansive” sails be removed to a ENGINEERING DEPT. LIBRABY City of Carlsbad 2075 Las Palmas Drive Carlsbad CA92009-4859 Project No. 70-6-29F, Part II Proiect No. 70-8-18F, Port IV -2- December 14, 1970 depth of 3 feet below proposed finished grade and be replaced with nonexpansive soils uniformly compacted to at least 90 percent of maximum dry density. In filled ground areas, all “expansive” soils should be placed at least 3 feet below the final compacted fill surface. If “expansive” soils are allowed to remain in the upper 3 feet below finished grade, then it is recommended that footings and slabs be specially designed. The required special design will be dependent upon the degree of expansion potential of the soil, the thickness of the layer, and the location of the expansive layer with respect to the footings or concrete slabs. The lots requiring specially designed footings and slabs will be listed upon the completion of grading. 4. All of the soils may be satisfactorily compacted in the fill areas and, when com- pacted to at least 90 percent of maximum dry density, have a safe bearing capacity of at least 1470 pounds per square foot for one foot wide footings placed 1 foot below the compacted ground surface. The settlement of a one foot wide continuous footing placed on fill sails uniformly com- pacted to 90 percent of maximum dry density is estimated to be on the order of l/8 inch. It is recommended that oil soft, loose, or compressible sails existing in proposed compacted filled ground areas be removed as required by the soils engineer and the compacted filled ground be placed on firm natural soils. Recommendations for the placement of filled ground are presented in the attached “Standard Specifications for Placement of Compacted Filled Ground,” Appendix AA. Decomposed and weathered rock formations were encountered at relatively shallow depths in Pits 5, 6, 7, and 8 ond in Borings 9, 13, 20, 21,22, and 23. It is probable that excavation to greater depths is possible with heavy duty equipment at these locations; however, the extent of deeper excavation without blasting and the suitability of materials for use in com- pacted filled ground areas is questionable. 5. A. Past experience in making excavations in the silty clay and clayey,siIt formations in the La Costa area has indicated that the slopes should be cut on a slope ratio of 2 horizontal to 1 vertical or flatter. It should be noted that any cut slopes in areas such as the plastic clay and fractured claystone below 8.5 feet in Baring 5-11 should be no steeper than 3 horizontal to 1 vert- ical. It is concluded from the test data that cuts made in other types of soils and rock formations may be safely excavated on a slope ratio of 1 l/2 horizontal to 1 vertical for heights up to at least 60 feet. 8. The fill sails, when uniformly compacted to ot least 90 percent of maximum dry density in accordance with the approved specifications, will be stable with an adequate factor of safety when constructed on o 1 l/2 horizontal to 1 vertical slope for heights up to 50 feet. The above conclusions assume that suitable erosional control and proper drainage will be provided to prevent water from running over the top of exposed slopes. *ENTON ENGINEERING. INC. Project No. 70-6-29F, Part II Project No. 70-8-18F, Part IV -3- December 14, 1970 6. Geophysical and geologic studies in the volcanic rock formation indicated that oversized blocks and fragments may be encountered when excavating in these areas. Therefore, it is recommended that the maximum particle size discussed in paragraph 3, of Appendix AA be modified to 12 inches for all fills below three feet below finished gmde provided that the rocks are distributed in such a manner that adequate quantities of minus No. 4 material exists and compaction can be accomplished between the racks. It is also recommended that rock disposal areas outside the foundation prisms of the proposed buildings be established to accomadate the oversized material. The foundation prism is defined as that prism enclosed by planes intenect- ing the ground surface 15 feet outside the foundation line and sloping outward and downward at 1 l/2 horizontal to 1 vertical slope. 7. Both cutting and filling are required for development of the site. Residences may be constructed portly on cut and partly on fill provided the load-settlement characteristics of the natural soils and the compacted filled ground are comparable. If any sail types are encountered during the grading operations that were not tested in this invest- igation, additional laboratory tesh will be conducted in order to determine their physical charact- eristics and supplemental reports and recommendations will automatically become a part of the specifications. The data presented on pages 1 to 8, inclusive, and on Drawing Nos. 1 to 34, inclusive, as well as Appendices AA, A and B, are a part of this report. Respectfully submitted, BENTON ENGINEERING, INC. BY&L?&. R. C. Remer Distr: (4) Rmcho La Costa, Inc. (2) Roncho La Costa, Inc. Attention: Mr. Burton L. Kramer (2) Rick Engineering Company BENTON ENGINEERING. INC. Project No. 70-6-29F, Part II Project No. 70-8-18F, Part IV -4- December 14, 1970 DISCUSSION A preliminary sails investigation has been completed on the property presently known as La Costa Ran&o Santa Fe Parts II and IV located in Son Diego County, California. The area is bounded on the West by La Costa South Unit Nos. 5 and 8 and on the east by Rmcho Santa Fe Road. The obiectives of the investigation were to determine the existing sail conditions and physical properties of the soils in order that engineering recommendations could be pre- sented for the development of proposed residential sites and to provide information to comply with the requirements of the County of San Diego. In order to accomplish these objectives, twenty-seven borings and exploration pih were excavated on the site, undisturbed and loose bag samples were obtained, and labomtory tests were performed on the samples. Information was also obtalned from a geologic study of the area prepared by Mr. W. G. Libby, Geologist, dated July 22, 1970. The general topography of most of the southerly portion of the area may be described as gently to moderately sloping terrain while the northerly portion is generally moderate to steep sloping terrain. Dmlnage is primarily into the swales crnd ravines directing water to Son Marcas Creek on the north and northwest portions of the site. Future drainage will be into the streets and storm dmlns. According to the “Soil Map” prepared by the U. S. Department of Agriculture, the upper soils In the area are described as Las Posas stony fine sandy loam and Altamont clay. The soils encountered in the investigation consisted primarily of clayey sands, sandy clays, clay, silty sand, gravelly clayey sand, silty clay, gravelly sandy clay, sand, sandy siltstone, claytone, and gravelly silty sand. Much of the northeasterly portion of the site is underlain by the Black Mountain Volcanic rock formation. Fleld Investigation Twenty-ven borings and pits were excavated with a truck-mounted rotary bucket-type drill rig and a D-8 tmctor at the approxlmate locations shown on the attached Drawing No. 1, entitled “Location of Test Borings and Pits.” Four borings were drilled initially on a portion of the area and these were designated as Nos. 1, 2, 4, and 5 of Part II. Boring 3 of Part II wus not drilled and therefore does not appear in this report. Subsequent to the initial investigation, twenty- three additional borings and pits were excavated and these were numbered from 1 ta 23, inclusive, of Part IV. Pit Nos. 2, 5, 6, 7, 8, 10, and 11 were excavated to depths of 5.0 to 22.5 feet using o D-8 tractor. The borings were drilled to depths of 3 to 31 feet below the existlng ground surface. A continuous log of the soils encountered in the borings and pits was recorded at the time of excavation and is shown in detail on Drawing Nos. 2 ta 30, inclusive, each entitled “Summary Sheet.” The sails were visually classified by field identification procedures in accordance with the U&fled Sail Classification Chart. A simplified description of this classification system is pre- sented in the attached Appendix A at the end of this report. Undisturbed samples were obtained at frequent intervals, where possible, in the rolls ahead of the drilling. The drop weight used for driving the sampling tube into 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 are described under “Sampling” in Appendix 8. BENTON ENGINEERING. INC. Prolect No. 70-6-29F, Part II Project No. 70-8-18F, Part IV -5- December 14, 1970 Labamtory Tests Laboratory tests were performed on all undisturbed samples of the soils in order to determine the dry density and moisture content. Direct shear tesh were also performed on certain samples. The results of these tests are presented on the Summary Sheets. Consolidation tests were performed on representative samples In order to determlne the load-settlement characteristics of the soils and the resulh of these tests are presented grophlcally on Drawing Nos. 31 to 34, inclusive, each entitled “Consolidation Curves.” In addition to the above loboratory tests, expansion tests were performed on some of the clayey soils encountered to determine their volumetric change characteristics with change in moisture content. The recorded expansions of the samples are presented as follows: Boring No. Sample No. Depth of Sample, in Feet 1 II 1 2 4 II 1 2 4 II 5 21 5 II 4 16 2 IV 1 3 3 IV 1 11.5 13 IV Bag 1 * 1.5-2.5 14 IV 15 IV 15 IV 16 IV 17 IV 17 IV 19 IV 1 2 1 6.5 3 15 1A 1.5 : : 1 3 Soil Description Fine sandy clay Clayey fine sand Claystone Claystone Fine to medium sandy clay Fine sandy clay Fine to coarse sandy clay (Weathered volcanic rock) Flne sandy cloy Silty very fine to fine sand Clay Fine sandy clay Fine sandy clay Clayey very fine sand Silty clay Percent Expansion Under Unit Load of 150 Pounds per Square Foot from Air Dry to Saturation 11.50 4.84 9.16 10.28 13.09 10.69 12.53 14.70 2.51 13.17 8.18 6.76 1.87 4.00 * indicates sample was malded to approximately 92 percent of maximum dry density The general procedures used for the preceding laboratory tests are described briefly in Appendix B. Compaction tests were performed on representative samples of the soils to be excavated to establish compaction criteria. The soils were tested according to a modified A.S .T.M. D 1557-66T method of wmpaction which uses 25 blows of a 10 pound hammer dropping 18 inches on each of 5 layers in a 4 inch diameter l/30 cubic foot mold. The results of the tests ore presented on the fallowing pow. BENTON ENGINEEHING. INC. Project No. 70-6-29F, Part II Project No. 70-8-18F, Port IV Boring or Pit No. l-11 2-11 4-11 2-IV 2-IV 3-W 3-IV 13-IV 14-IV 15-IV 15-W 19-IV Bag Sample 1 1 2 2 3 1 3 1 1 1 2 3 Depth Sol1 in Feet Description l- 2 2- 3 4-5 3- 4 18-20 0.c 1.5 10.5-11.5 1.5- 2.5 1 .o- 2.0 1 .O- 2.0 5.5- 6.5 14.0-15.0 Fine sandy clay Clayey fine to medium sand Silty very fine to fine sand Fine to medium sandy clay Silty clay Fine sandy clay Fine sandy clay Fine to worse sandy clay (Highly weathered volcanic rock) Fine sandy clay Clayey fine to medium sand Silty very fine to fine sand Slightly silty fine to medium sand -6- December 14, 1970 Maximum Optimum Mois- Dry Density ture Content Ib/cu ft % dry wt 118.8 12.2 128.0 9.2 117.0 123.3 10.7 118.8 14.6 111.5 13.8 109.0 16.1 113.3 13.4 114.2 121 .o 117.5 118.5 12.0 13.1 15.0 10.3 10.0 In order better to classify the finer grained soils, Atterberg Limit tests were performed on certain samples in accordance with A.S.T.M. Designations D 423-61T and D 424-59. The resulk of these tests and the group symbols, for the soils finer than the No. 40 Sieve, are presented as follows: ,wl boring Sample No. No. 2-W 2 2-IV 3 3-IV 1 14-IV 1 15-IV 2 Depth Soil Liquid Plastic Plasticity Group in Feet Description Limit Limit Index Symbol 3- 4 Fine to medium 31.2 13.5 17.7 CL sandy clay 18-20 Silty clay 46.3 20.4 25.9 CL 0.5-l .5 Fine sandy cloy 55.1 18.3 36.8 CH l- 2 Fine sandy clay 54.2 17.1 37.1 CH 5.5-6.5 Silty very fine 30.0 26.2 3.8 ML to fine sand Direct shear tesk were performed on’ saturated and drained samples in order to determine the minimum angle of Internal friction and apparent cohesion of the various soils. The results of the tesk were as fallows on page 7. BENTON EN61NEERING. INC Project No. 70-6-29F, Part II Project No. 70-8-18F, Part IV Boring 4-11, Bag 2 * Depth: 4-5 feet Boring 5-11, Sample 2 Depth: 6 feet Pit 2-IV, Bag 3 * Depth: 18-20 feet Baring 3-IV, Bag 3 * Depth: 10.5-11.5 feet Boring 13-IV, Bag 1 * Depth: 1.5-2.5 feet Boring 14-IV, Sample 1 Depth: 2 feet Baring 16-IV, Sample 3 Depth: 8 feet Boring 19-IV, Sample 2 Depth: 7 feet Boring 19 IV, Bag 3 l Depth: 14-l 5 feet -7- December 14, 1970 Normal Load in kips/sq ft Maximum Shear Load kips/sq ft Angle of Internal 0.5 1.0 2.0 0.5 1 .o 2.0 0.5 1 .o 2.0 0.5 1.0 2.0 0.5 1.0 2.0 0.5 2.0 0.5 1.0 2.0 0.5 1.0 2.0 0.5 1 .o 2.0 0.70 1.20 1.83 Degrees 33 Apparent Cohesion Ib/sq ft 390 1.05 1.98 2.92 44 570 0.64 0.98 1.70 35 278 0.67 0.83 1 .lO 15 550 0.81 0.80 1.20 22 400 1.42 3.46 Greater than 45 Greater than 45 740 1 .14 1.65 3.74 6.40 1.07 3.33 1.84 27 820 0.52 0.86 1.41 34 190 * Indicates samples were remolded to approximately 90 percent of maximum dry density sENTON ENGINEERING. INC. Project No. 70-6-29F, Part II Project No. 70-8-18F, Port IV -a- December 14, 1970 Using the lower volues of internal angle of friction and opparent cohesion, and the Terzoghi Formula for local shear failure, the safe allowable bearing pressures for the sails are deter- mined as follows: Local Shear Formula: Q’d = y3 c N’, + y Df N’q + Y BN’y Assumptions: (1) Continuous footing 1 foot wide =2B (2) Depth of footing = 1 .O foot = Df Undisturbed natural soils @=27’ C = 820 Ib/sq ft y = 119 Ib/cu ft N’c = 16.5 N’q = 7.5 N’y=4.0 Q’d = (y3 x 820 x 16.5 + 119 x 1 .O x 7.5 + 119 x 0.5 x 4.0) = 10,161 Ib/sq ft Q’d Safe = Q’d f3 (Factor of Safety) = 3,387 Ib/sq ft f-ill soils compacted to 90 percent of maximum dry density @=22O c = 400 Ib/sq ft Y = 116 Ib/cu ft N’c = 13.5 N’q = 5.8 N’y=2.3 Q’d = (2/3 x 400 x 13.5 + 116 x 1 .O x 5.8 + 116 x 0.5 x 2.3) = 4,4O6 Ib/sq ft Q’d Safe = Q’d i3 (Factor of Safety) = 1,469 Ib/sq ft BENTON ENGINEERING. INC. : 1 d II , f L d : 1 d , 1 rl I @oirt,Medium Firm 3 Moist, Very Firm 1 -- - Red-Brown and Gray Light Gmy, Moist, Very Firm 7 8 __ LAYEYFIJNE SAr\ INE SANDY CLA’ CLAYSTONE 8.1 6.5 8.1 13.6 14.9 4.43 -. ,,.1- gi Z$& :gC! c ;< I ,_. - 14.5 19.7 - L 9.5 5.2 03.0 2.89 :8.4 4.74 ,i i -j 1 ; ! I cl Indicates loose bog sample 0 Indicates undistrubed drive sample * The elevations shown on these Summary Sheets were obtained by interpolating between the contours on a map provided by Rick Engineering Company of San Diega. t- - 1 c : , i - I! : I d , 1 - c < SUMMARY SHEET BORING N0.2-Il.. ELEVATION _ 197’ Clayey Fine to hdium Sand lne Sondy Clay, Scattered ~Ivbrges) 4 Gray-B rown, Medium Firm FINE SANDY I I CLAY / 3.2 Light Groy, Moist, Firm ‘CLAY, MERGING TO CLAYSTONE - - - - - - - - - 0.8 I 17.9 108.2 0.57 17.5 110.4 1.54 I: t&t Brown ond Lbht Gray J Midst, Vee Flnw ‘, ‘. ,,~ -.’ I, ” I C&AYEY < f+Jg ,.~:,. SAND ~ 3 s\ Sf LTY VERY FINE TO FtNE SAND .,, ,. ,;’ ,/. I- .1 it: i‘ ti! t - ix ; t’ I - 6.2 4.c !6. ( 2.5 2.; 16.1 ;li / 2 I 5_ IS I --1 I-. 11 .; w., 13.r $1 f, g: 2! -: .~-- .& !.B SUMMARY SHEET BORING NO..4-&t’d) Lfgfjt *own and Liiht Gmy, ht, Very Finn t@btWh Gmen, k&t, V~ryflrm, Highly Fractured Olive Green, ,#idt Massive . ,, ILTY VERY FINE 0 FINES SAND C LAYSTONE 16.: r:, i4.! I1 .; - 18.: 8.4 - ,;::,:: ‘_ ..y .,g f ‘ i ~~ .iy ,,J / ,!~ . g c~,‘:: ,~:‘~ ,‘$ ;, ,. ,‘, ,>. ‘/,: ‘,,. 5.10 1.33 - P~JECT NO. 7es-16F BENTOy :~. .~&~NEERING, INC. + ,. DIAWINC NO. 98 5 ‘i’ ‘, ,.::,; ; ,’ i f’:, i: - il ;; w i -> , g1 - - 22. 16.; - - E2.I - 9.7 7 1 11 L 1 11 6.8 105.9 1.41 * 6.4 106.2 ~2.10 7.6 106.2 2.29 ., B.9 107.2 7.35 SUMMARY SHEET # BORING N0d.d-m ELEVATION 298’ -,. - - - - $1 SILTY VERY FINE TO FINE SAND ;&ht &w-l and Light Gmy, 1 ~Molrt, ;yy Pfrm~ ~, * CLAY SILTY FINE SAND ‘OKVO G&en, Moist, .Very Firm, Fmctured CLAYSTONE ,t;$,;:,?‘:‘“‘..:’ ,: I, ,’ i: c :.*a ., \ :: :~ . :i 6: w,:,., ‘+.ps:,; <> ,~ ,, . . :.‘~Contl&t&j m Dmwing No. 7 ‘;:: P b; i., . & ? ‘ii! ,!F i, *t: Gp ,. SJ; ;$ $:I .:. Lb .x3. i.. : a .‘I I :, ,::. ,,:>, I / ,:::,, ,.. ::. .” : ;z ,‘I,! ,:, I:$: ‘, -,,>$t?RING NO.5-lllco~‘d) ? j : i&igstr .Voly Fh, Fwctured ,. : , ‘ **’ ,,,.., .’ -..,“;~;‘,,i I. ,: ;:: 7 ). .: + “’ .a~ ,“. ‘5. ,:j!~, I~, ,’ ,. C LAYSTONE ,,~.f ~’ ,. - 5; :t Er “ii ;c 3 - 16 48. .‘. 35. - ;,5 , 1~: ti - 7.t 0,.: !l .I - 3 Mi CA “:I ,. ~’ ::I. * &IO~ rosfstonw &&j&d ~.,Wk~p~pr~squo&bt, tha limit of shear~tyachln~. :‘,: ,$$,, i 4 ,..~ ‘> ~~~, ;’ ‘i:: ? i’,, :,‘:,I ‘,I-; 4;: ! 1’; ~. p{$: “Z :#A >,p? ” ,, ,T :’ %, ‘, .~,L. “. .( ,, 3 - - i ~~’ :‘. .. ,,~;.f,y”“y P ?hs!w; j ~~, ::;, :ji& _~ ‘;,;j+si*&SF, ,:_;I@& -: ,. ,,, ~,,,I . . . . ::, , ,1 ” SUMMARY SWET BORING NO.l-lV Loose, 10 to 15 Percent Rock j Fragments to 2 Inches FINE TO MEDIUM SANDY CLAY -~~-,-- .,-. -.--_,-. _ ---,,~.~.~~___ 4.9 10.1 89.0 - Light Olive-gray and Light Red-brown, Very Moist, i Medlum Soft, Contains Medium to Coarse Grains Between 6.6 and 7.2 Feet -~ _ _ Medium Firm 1 -Very Firm 1 MEDIUM SAND _ ~-+.- ~.. ._.~_ ..__, 1.6 19.4 107.8 1.94 SILTY 3.2 19.7 105.7 1.20 CLAY 1.!6.2 12.$113.0 4.05: L... __ 1. .A c2 - Indicates Undisturbed Drlve Sample * - The elevations shown an these Summary Sheets were obtalned by interpolating between the contours an a map provided by Rick Engineering Company of San Dlego. PROJECT NO. ENGINEERING, INC. DRAWING NO. 8 PIT NO. 2-Iv CLAY Cobbles to 12 inches Some Small Intrusions of Fractured, Volcanic Rock SILTY CLAY Continued on Drawing No. 10 cl - Indicates Loose Bag Sample PROJECT NO. I I --a..,...- ..^ !9-8-?~~ I BENTON ENGINEERING, INC. I YKAVVIN~ NU. 9 PIT NO. 2-IV (Cont.) Gray-red-brawn, Moist, Very Firm, Some Small intrusions of Fractured, Volcanic Rock SILTY CLAY Could have excavated to greater depth. .L ;, :tt t: “G :t 3 - -L i I -- PROJECT NO. 70-E-18F -7&A-70E DRAWING NO. BENTON ENGINEERING, INC. 10 . : 0 , ; t! : 1 d c SUMMARY SHEET BORING NO.3-IV GRAVELLY FINE vel and Cobbles to SANDY CLAY Could not excavate large boulders at 16 feet. PROJECT NO. ?tW BENTON ENGINEERING, DRAWING NO. INC. 11 SUMMARY SHEET BORING NO. 4 - Iv ~.~ _-~.--~-- Brown, Slightly Moist, Very Firm, 10 to 15 Percent Gravel to FINE SANDY 11.4 9.8 110.2 6.41 17.9 15.8110.3 3.74 _,,,___._ _,.___... _.__ ~__ .~ .._ .~ _,-..~..--.,--___~-.-_*.-_~~~-~~~-.~ -a- - ve-gray with Red-brown, I__~.. _- _---- FINE SANDY Scattered Gravel to 1 Inch CLAY 8 ---.~.--I_ __-_ With Red-brown’ 9 27.611Z.j24.9,2.92’ ._ --~~- --~~ ..-,. / r.-,.. I PROJECT NO. 70-8-18F BENTON DRAWING NO. ENGINEERING, INC. 70-6-29F 12 z tIEi SUMMARY SHEET I- :; 22 5-IV ; $3 PIT NO,- ELEVATION 262’ Ti in Large Fragments :LAYEY FINE TO MEDIUM SAND , FRACTURED VOLCANIC ROCK PROJECT NO. DRAWING NO. 70-8-18F BENTON ENGINEERING, INC. 7n 1 .-lc-.c 13 -c gkl z SUMMARY SHEET $6 z:: UC: c i $2 tic ‘32 .~ PIT NO. 6-1v g 2 22, ml 2 ’ zy Ly z Y%?m, Q . u Q 2s ELEVATION 370’ 2 i -0Q > vi LSO” Ifl : Red-brown, Dry, Loose, 30 to 40 Percent Gravel, Topsoil sa \-- Yellow-brown GRAVELLY FINE TO MEDIUM I I I SANDY CLAY A Greenish-black and Brown With Yellow-brown Silty Clays in Fractures-7 HIGHLY FRACTURED VOLCANIC ROCK ~ - PROJECT NO. 70-8-l 8F DRAWING NO. BENTON 70-6-29F ENGINEERING, INC. 14 fifi SUMMARY SHEET 1 z c El ki;” 2I” PIT NO.. 7 - IV ! L k Q 22 ELEVATION 380’ 1 ; I I Brawn, Dry, Loose, Scattered Gravel, Tospoil #H Greenish-brown CLAYEY FINE SAND FINE TO MEDIUM sANDV HIGHLY FRACTURED VOLCANIC ROCK t - J- j PROJECT NO. DRAWING NO. 7&S-18F BENTON 7h*-9OC ENGINEERING, INC. 15 PIT NO. R-IV ELEVATION 243’ Yellow-brown and Gray --- Difficult to Rip at 16 Feet PROJECT NO. BENTON DRAWING NO. !s?-9-m ENGINEERING, INC. 16 . SUMMARY SHEET BORING NO. 9 - lV Slightly Moist, Medium Firm -~._- -_- a-groy, Moist, Medium rm, Scattered Medium Sand ~ - ~,.---- With Red-brown Olive-gray With 1 Moist, Very Firm, Wlth Small Chunks of Sandstone CLAY FINE SANDY CLAY ~~~,~~~~ ~~.~ 1. -~ Red-b,,,-‘-~~l,w-brown and Olive, Slightly Moist,. Very j ~ Firm, Highly Weathered WEATHERED VOLCANIC ROCK __~.~. .----- ~.~~~___. - .~ -..- Becoming Less Weathered With ~ ._ Increase in Depth...~.. ...~~~ .~ .~., 1 6.5 ~21 jO4.7; 27.6 18.7,107.0, A- PROJECT NO. 70-8-18F BENTON DRAWING I ENGINEERING, INC. 17 - 2; ]& :gc =d - - - 1 + - - - ,~ ;; :t zs ,= ; e’ a - - - - SUMMARY SHEET PIT NO. IO-IV ELEVATION 168’ Gmy-bmwn, Shghtiy Moist, Lw FINE SAND &&WI!. Ablst, ‘Medium Leo- &~.wlurn’ Ff+n; lop&!; 20 t0 : 30 Petwnt Grad GRAVELLY FINE TO MEDIUM SANDY CLAY - - Fkm PIT NO. ll4V ELEVATION 275’ Dry, Loos+Toprofl I CLAYEY FINE SAND , FINE SANDY ,. CLAY ,.,‘#, ” . 4, -Lb;:!;<&;, .:.,‘I; : ~’ j ,,: ,%I ,: Continued on piuwing 80. I.9 iI :,, ,” , . . . . . -m . . , .* . . SUMMARY SHEET PIT NO. Il-Iy (Cont.) Yellow-gmy, Very Moist, :i FINE SANDY CLAY SILTY CLAY - - ES z: ‘2” il - : i : I ;7 I ’ > ! ’ ‘ - ;1: z 24 G: z; - - Could have~excwatd. tg greotet depth:, ‘, - .I ,; ,,z: i!S,~ ,‘,S. ,+ :‘j ‘* ,I SUMMARY SHEET BORING NO. 12 - IV ‘, ELEVATION 272’ Brownish-gray, Dry, Lo&e Brown, Moist, Firm to Very Firm Ollve-gmy With Red-brown, Moist, Very Firm, Sama Saattered Medium Grains FINE SANDY ciAv CLAY CLAYSTONE 9‘ .d 7.5 16.C - : 9 c : z t ii 6 : I : 7 I ’ 2 1 2 ,g :z;: 3: . 23.9 - 27.6 18.9 - !I .9 !2.2 - CM.! - 31.2 33.E - I .81 2.52 - 1.49 1.74 - - - ..( .:, ,, i. ,: ” ,: PROJEC; NO. 70-8-18F BENTON DRAWIN@ .NO. 70-6-291: ENGINEERING, INC. 30 ,’ \, : L’ “;;p ;, t ,; q$ “? ,’ ,t:;,: I* ,,;;,:y; ‘, y W’ 2,. i :,: ‘.! ,& .; ;’ E! i$~: ~(~~ .!I,~ ,:: 2 i , L .I , d 9 ~,, ., 8, ., 1,. ;I,‘, I!~’ tit $.‘, g, .~/’ ,, ; ~, F: 2 R~ t e’ ’ : LJ ,,~. SUMMARY SHEET BORING NO i&l’/ ELEV*,,ON ’ 2298 Light Brown, Dry, Modlum , Firm, 15 to 18 Porcont ~Gtavel to 2 In&es 2 Rod-brown, Light Brown ond Ollvm, Dry, Fin, Highly With S@ma Pockois of Mullurn ‘Pfifnt I%* ,*,dy Cloy ~~ &conilng.Less Woathwod with Incrooso In Depth ( 1 GRAVELLY :LAYEY FINE TO MEDIUM SAND WEATHERED VOLCANIC ROCK i 1 I A - 12.7 19.5 13.2 - i 1 I - I1 .: 4.1 18.1 7.! - R ] ;li ’ , 3 1’ 3 1, - 07.L 38.: 39.1 28.4 - -- 2.71 /! .’ * ;*, ,.* : *, ~?i: i,, ,, 1 ! / 1 ! i 1 i ? 1 b SUMMARY SHEET BORING NO.14-IV ELEVATION 256’ 1 bark Gmy, Dry, Loose fi rzhtly M&t, Finnto Very 3 Olive-gmy and Red-btiwn, Mokt, voty Arm Light Yellow-b&ni Moist, Very Compact -7 FINE SANDY CLAY FINE TO MEDIUM SAND 1 1 I i 4.8 5.2 1.6 8.4 09.1 13.0 7.4 4.19 l Test exceeded 7.50 kipr pet *are foot, llmlt of shear machlna ., ,. .:,- ,,A ._ _,’ i,* ‘:PIOJECT NO. ~I ‘~70-8.18F; ~” : I-. ’ ’ BEN?QN ;’ Ef!lGINEERING,~, INC. DRAWING NO. ad-29F I c: i ,i ,s ,: :: ,:; y I. ,/ I s !: Mali!.: ;i;r SUMMARY SHEET BORING NO.- ELLVATION 363’ Llght Brwn, Dry, Laose, 20 ta 30 Parcont Gravel and Cobbles \ to 4 In&s \g- Very flrm Slightly Moist, - A : Light Gmy-bnwn, Slightly ;I: Molrt, very fltm, cemented ktween 4.0 and 5.5 Feat ii&t Red-brown to Light Gray- brown, Sltghtly Moist GRAVELLY CLAYEY FINE TO MEDIUM SAND - 97.: I-+ 00.: - 93., SILTY VERY FINE TO FINE SAND 16.2 17.9 - 14;6 Light Gray, Moist, Very Firm, With Slight Cloy Btnder 3 Llght C$vo-gmy and Red- brown; Moist, Very Firm CLAY i ,“’ ,,, ,~, ,’ ~.,. .~ * ‘., “I: ,,,‘f’, # 1 .: ,$ ‘z’:,, & uwlng Na. 24 C@nud on : : .., PROJECT NO. .’ 342% BENTON ‘,-ENGINEERING, INC., DRAWING NO. 2.3 ,: ,_ 1 I Ii T SUMMARY SHEET BORING NO.15-IV (ht.) -. - and Yeliow-brawn, Moist, 3.24 25.C - 1 ., ‘~’ .” > c,_. ‘. 8 j i .,. :,( ,- ,, .;:,~ ., ,. ,, ;. f 1 P$gii&& DlAWlNG NO. 70-6-29F .:,~ BENTON MGINEEI$ING, INC. .~ ,.,- 24 ! :, a 2; SUMMARY SHEET L i! ,,2 E z BORING NO.- a *s ELEVATION 295’ -0 1 Slightly Moirt, Firm ,2 3 4 5 ,6 7 ad &own, With Zones of Vety FINE ,SANDY CLAY SILTY VERY FINE SAND ZLAYE~Y VERY FI~:SAND 16.2 8.1 !4.3 Ml* 1 m3 ; i ;g: :sic ’ > I,! r I - 17.1 - m - 12.e I1 15.4 I1 14.6 - 98.: - 09.: 04.: 11 .t - - tit 35s ! $2; ; “,! -a L - - - - 2.1( 1 I.% , 1.13 I - L . . PROJECT NQ. i&i22!:~~ .~<;.A, ~~~.~ ~.?Y'N~ 1:, ENGINEERIbk, INC. ,OlAWlNG NO. ;c i i; 22.; 7 i 12.6 5 1 9 .! - 4.6 - 15.0 - i 2 !O.B - / - iii E3 ‘> ;s 3 d ;g 1-i is, gi - w 1 .7( 2.71 - ).4; vi.:, s., pi:-‘! ;@: 1. !,. I, j ‘“I 36% ;,P, i;; I, 5: ‘:., : ,( :. j p~:i SUMMARY SHEET BORING N0.L IV ELEVATION z ] Brown With Ollve-gmy, Dry, Loose - Moist, Firm - -r 11.! 12.; 11 .I - 36.5 - FINE SANDY CLAY 1 Light Gray With Yellow-brown, Moist, Very Firm, With Zones of Very Fine S&dy Clay, Loan With Red-brown CLAYEY VERY FINE SAND Gmy, Oilvqand Red-brown, Gmy, Oilvqand Red-brown, ” ” Moist,, Very Firm, With Some Moist,, Very Firm, With Some Fine Sandy Cloy Fine Sandy Cloy CLAY : ; 6‘, PROJECT NO. @$J!$#f I,__~ RENTON CNGlNEERlNG: ,# IIS,’ DRAWING, No., 1 ,e; ,,,,,,, _~ 3’ ::, .i SUMMARY SHEET BORING N0.J.h.b’ ELEVATtON 223’ Brown, Dry, Loose, Porous, Pockets of Clay and Scmd Sllght1.y .Moirt, Firm M&t Oilvb, Molri; Very Firm ” ,. I’ ‘, ,“~. ,. ,:, ,,.,J”+ ~:I: CLAYEY FINE TO MEDIUM SAND SILTY CLAY 8.1 13.r 12.1 - 2.4 - 77, 82, - 04. ,6 ,8 - - - L: ,A$ 3 ; ::$ I; 2s SUMMARY SHEET z it! 4: BORING NO.19-1y zs ELEVATION 236’ 2 Olive, Molrt, ~IEii ,:,“: ~. I 2 _’ ::, ” :, ,~ i 7 Oilve, Molrt, .Very Firm QJlvi; M&t; Very Firm ,Lighi &own, Moist, Very Firm CLAY ZLAYEY FINE TO D SILTY CLAY FINE SANDY SILTSTONE CLAYSTONE LENS SLIGHTLY SiLTY FINE TO MEDIUM SAND .:,/. 7;s 9.; - 2.7 T- ‘4 z ) ; ’ i !o.: !l .I - - 2.1 7.8 i :k ! is ‘> ;z 1 -I - - - 98.1 98.’ - - 19.: 17.1 ‘ia - Et ‘$5 ,si zj - - - - - - i mo. ,..,~ : ’ ;;- &,JTa ENGINEERING, INC. :- DRAWING NO. .we, I~ .r,r ,,’ : :, ,:,j ,z;,i; ,,28 .~. : I d .-. -- Brown, Dry, Loose, Topsoil, 20 Percent Rock Fragments to FINE TO MEDIUM : 1 3 Inches SAND _~-~_-..~_-.-.--.~~-_ L.-- Brown, Dry, Very Firm, Highly ~ 2 Fractured, Black Mountain i Volcanic, Becomes Firmer ~ _~. ~_~.__~ / FRACTURED VOLCANIC ROCK Too firm to excavate with drill rig. BORING NO. 21 - IV ELEVATION 46.5’ 0 Brown, Dry, Loose, Topsoil ~~~-~~ r GRAVELLY 1 20 Percent Rock Fragments ( SILTY FINE TO I MEDIUM SAND __--- J 2 rown, Dry, Very Firm, I Slightly Fractured, Black Mountain Volcanic ) FRACTURED - VOLCANIC ROCK 3 Too firm to excavate with drill rig. Too firm to excavate with drill rig. ;=! ‘.,_ rj rl” zL.2 2:s ‘ikl* . r zf:“Gx I 4 , :i ; - - - - -- --- T-l --- ‘1 r- 1 / ! 1 --J- --J- h---k --~~-- : --~~-- : / j i j +I.I 1 ! ’ 1 Ii .~-,---.-I_- .~-,---.-I_- LL - - BORING NO. 22 - IV ELEVATION 426’ Dry, Loose, Topsoil, ~~--GRAGiL& y -- -~~-- ~-~-~-~~----- ilLTY / ! j ercent Rock Fragments to 0 1 -- - - - - PROJECT NO. 70-6-29F 7,, Q,ldC DRAWING NO. BENTON ENGINEERING, INC. 29 BORING NO. 23 - Iv Brown, Dry, Loose, Scattered Brown, Dry, Firm, Highly ctured, Block Mountain Very Firm, Fractured FRACTURED .~-....-L -__ Hard to excavate but could drill deeper. PROJECT NO. 70629F BENTON DRAWING NO. ENGINEERING, INC. 7n-P-,*c 30 1 2 3 a :: r z 5 ', 5 t- 6 5 5 a~+1 2. 0 z :: ,g1 :: 2 3 &" c) CONSOLIDATION CURVES LOAO IN 1(lPS PER SOUARE FOOT 0 INDICATSS PERCCNT COW8OLIDATION AT FlELO MOISTURE . INDICATES PCRC~E,M~ ,$OMS$W~ATION ~AkTtiR SATURATION PROJCCT NO. t3ENFti ‘~: ..:~~~~t+3+ER’NG, INC. .,, ‘olir*lni NO;, I ,‘; ‘. 81 CONSOLIDATION CURVES LOAD IN KIPS PER SQUARE FOOT +9 0.4 0.6 0.6 1.0 2 4 +l Lo 0. L~~__~._..~ 4 I>;-‘;- V , 1 ...~~ nl I I I I I I I I:! E 0 o,, z ‘a.- .~~.,~ ~. -~~. -: ,,, ~. .~~ ,,. ,~ h.~ . I- ---a. !!i 2 ‘\ ‘I\ 3 2 .~ _ $ 3 ,,, 5 :, : E +2 ,. -I- t - - - - - - A -. - - - - - - 0 INDICATES PERCENT CONSOLIOATION AT FIELD Yo,ST”RE * INDICATES PERCENT CONSOLIDATION AFTER SATURATION PROJECT NO. 70-8-18F 7n L ,x-.c DRAWlNO NO. BENTON ENGINEERING, INC. 32 CONSOLIDATION CURVES LOAD IN KIPS. pm I~ouARC FOOT ;;y.;. l.,% ,, ~, i :. r?:,:3, 2,, :lII - ~. ;, ‘y ‘*~ : ,~, ,, ,, -,,::,: -,I~* :, 0, IIIIII I :r, I,~ 0 INOlCATf(C &CENT CONSOLIDATION AT FlELb UOISTURE i’~:~;.$gp& I:, . lNDic*tiS, ‘,PLRCLNT CONS~OLIDATlON AFTL’h~ SATURATION ‘, .,:I’ ~’ :;ISENtW : ~~.E~!#ht&hCj~~, jy$ . + . ..:,,, _: .c(. .,< ., iii.; ,, . ‘,?, ,* ,,.i’;, $ I:; ,$;i: !$: ,,I I:’ \, ,$,; / \ t ,.,, .’ ( / g;, ~J ; i”l, c CONSOLIDATION CURVES LDAD ,N RIPS PER SOUARL FOOT ;I 7- Y 0 t "olo-~ 5 5 11 \ I Et 12,------, , \ - --r,' 13 - . 14 e, BENTON ENGINEERING, INC. APPLIED BOIL MECHANICS - FO”NDATIONO 6717 CONVOY COURT SAN DIEGO. CALIFORNII\ S21!1 PHILIP HENKINO BENTON CILIIDENI Cl”lL CNCIHECR APPENDIX AA TELEPHONE ,714, S8S-!86S 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 immediately if any unsatisfactory conditions ore 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 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. (c) 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 o horizontal base so that each layer is placed and compacted on r~ 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 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 maxlmum density in accordance with A.S.T.M. D-1557-66T method that uses 2.5 blows of a 10 pound hammer failing from 18 inches on each of 5 layers in a 4” diameter cylindrical meld 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 pits 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 ;naterials 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. (a) 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. (b) When the moisture content of the fill material is below that specified by the soils erlgineer, 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. (c) When the moisture content of the fill material is above that specified by the soils engineer, the fill material shall be aerated by blading and scarifyins or other satis- factory methods until the moisture content is near optimum as specified by the soils ergi neer . (d) 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 VI kl) APPENDIX AA -3- to compact the fiii material to the specified density. Rolling shall be accompllshed while the fill materlaf is at the specified moisture content. Rolli~ of each layer shall be contlnuws over Its 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 piantirg and until there is no appreciable amount of loose soil on the slopes. Compacting of the slopes shall be accomplished by backrollirg 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 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 galn If required by the soils engineer. The location of the tests in plan shall be so spaced to give the best posstble 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 elevation galn. The soils er\glneer may take additional tests as considered necessary to check on the uniformity of compactlon. Where sheepsfcot rollers are used, the tests shall be taken In the com- pacted material below the dlsturbed surface. No additlonal layers of fill shall be spread until the Reid demlty tesk 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 fill has been brought to the fTnlshed slopes and grades as shown on the accepted plans. ?I=%- Sufflclent Inspection by the soils engineer.shaII be maintained during the ff 1~ an compactlrrg operations so that he can certify that the flil was constructed in accordance wlth the accepted specificotlons. Seasonal Limits. No fill material shall be placed, spread, or rolled if weather conditions increase the moisture content above permisslble limits. When the work Is Interrupted by rain, ffll operations shall not be resumed until field tests by the soils engineer indicate that the moisture content and density of the fill are as previously specified. Limltirg Values of Nonexpansive Soils. Those soils that expand 2.5 percent or less from alr dry to saturation under a unt t load of 500 pounds per squore foot are considered to be nonexpanslve. All recommendations presented in the “Conclusions” section of the attached report are a part of these speclflcatlons. BE&TON ENGINEERING, INC. APPUED SOlI. MECHANIC* - FO”NO*T,ONs 6117 CONVO” COURT *AN OIEGO. CALIFORNIA 82111 PHlLlP HENKING BENTON C”I.IOIYT CIVIL LHGIHLEI APPENDIX A Unified Soil Classification Chart* SOIL DESCRIPTION GROUP SYMBOL I. COARSE GRAINED, More than holf of material is w than No. 200 sieve size.** GRAVE LS CLEAN GRAVE LS s half of coarse fraction is larger than No. 4 sieve size but smaller GRAVELS WITH FINES than 3 inches (Appreciable amount of fines) SANDS CLEAN SANDS More than holf of coarse fraction is smaller than No. 4 sieve size SANDS WITH FINES (Appreciable amount of fines) Il. FINE GRAINED, More than holf of materiol is smaller 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- sond-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. Inorganic clays of low to medium plas- ticity, gravelly clays, sandy clays, silty clays, lean clays. Organic silts and organic silty-clays of low plasticity. Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts. Inorganic clays of high plasticity, fat clays. Organic clays of medium to high plasticity PT Peat and other highly organic soils. TYPICAL NAMES TELEPHONE ,714) SBS.lSS~ * Adopted by the Corps of Engineers and Bureau of Reclamation in January, 1952. ** All .:n\m e:.rcac r-.n th:r chnrt nrp 11~ 2. Ftnnrlnrrl. BENTON ENGINEERING. INC. APPLIED BOIL MEC”ANIC8 - FOUND*T,ON* 8717 CONVOY COURT SAN DIEGO. CALIFORNIA 82111 PHlLlP HENKlNG BENTON P”l*Ic.m*T. ClYlL LNTI*IIL” TELEPHONL ,714, ?18i3-,OS8 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 o 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. 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 sheor 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 mode without removing the samples from the brass liner rings in which they are secured, Each somple 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 ore 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 OS 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 somple 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 permltted to contact both the top and bottom of each sample through porous stones. Continuous observations are mode 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.