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HomeMy WebLinkAboutCT 80-09; Hidden Meadows Access Road; Soils Report Preliminary; 1981-01-08PRELIMINARY CEOTECHNICAL INVESTIGATION HIDDEN MEADOWS ACCESS ROAD CARLSBAD, CALIFORNIA W.O. 1165 January 8, 1981 c@ii ,--Lq ENGINEERING DEPT. LIBRARY City of Carlsbad 2075 Las Palmas Drive Carlsbact CA 92009-4859 - c2 - EBERHART-AXTEN and ASSOCIATES, INC. e n EBERHART-AXTEN and ASSOCIATES, INC. a9 GEOTECHNICAL CONSULTANTS 0 221, E. WlNSTON ROAO. SUITE F * ANAHEIM. CAuFORNlA 92806. (714,9910163 8353 EL CAMlNO REAL. SUITE c . CARLSBAO. CAUFORNIA 9ZWB. ,714)438-9418 DAN R. EBERHART. CEG GREGORY W. AXTEN. RCE GERALD L. STONE, RCE W.O. 1165 January 8, 1981 La Costa Land Company 2100 Costa Del Mar Road Carlsbad, California 92008 Attention: Subject: Mr. It-v Roston Preliminary Geotechnical Investigation for Hidden Meadows Access Road, Carlsbad, California. Gentlemen : Pursuant to your request, we have undertaken a geotechnical investigation of the subject road alignment. Herein it is our intention to provide general information as to the nature of the materials encountered, slope stability, feasibility of grading, as well as other conclusions and recommendations. SCOPE OF SERVICES The scope of services on this project was as follows: o Review of available published and unpublished soil and geologic reports o Aerial photographic interpretation o Site reconnaissance and geologic mapping o Excavation of 5 backhoe test pits o Laboratory testing of samples obtained from pits Q Seismic refraction survey of rock encountered onsite o Engineering and geologic evaluations o Preparation of this report PROJECT AND SITE DESCRIPTION The Hidden Meadows Access Road is a residential collector street which will service the proposed Hidden Meadows Development. It will trend in an over- all northwest direction, where it will terminate on Alga Road East. Cut slopes will be on the order of 25 feet in height and fill slopes approxi- mately the same order of magnitude. Maximum depth of cut is approximate- ly 17 feet. Maximum depth of fill to be placed is about 25 feet. La Costa Land Company -2- W.O. 1165 The proposed alignment is located south of Alga Road East. The site consists of a small valley or swale formed between the road fill of Alga Road East and an easterly to northerly facing knoll. Vegetation onsite is composed of thick growths of manzanita, trees, sage brush, and annual grasses and weeds. Slopes are relatively flat, on the order of 3:l or 4:l. Large granitic rock outcrops abound over 90% of the site. These rocks are from 2 feet to 8 feet or more in diameter. FIELD INVESTIGATION Our work on the project began with site reconnaissance. A geologist from our firm walked the site, and geologically mapped it, noting possible locations for future test excavations. We also noticed during this walkover that the site was studded with large granitic rocks, indicating that a seismic refraction survey might be required. Following site reconnaissance, five trenches were excavated utilising a backhoe. Visual and tactile identifications were made of the soil types encountered. Samples obtained with the test pits were transported to our laboratory for testing. The logs of these test pits accompany this report as Table II. While excavating with the backhoe, we found that many areas could not be excavated below 24 feet to 3 feet. Therefore, a seismic refraction survey was performed. Utilizing a signal enhancement seismograph, four survey lines were run to determine velocities and corresponding depths where changes in hardness occur. The results of these survey lines are presented on Plate A. ENGINEERING GEOLOGY The site is situated on the west flank of the Peninsular Ranqe Province and is composed of siltstones of the Del Mar Formation; and granttic rocks of the Southern California Batholith. Sedimentary rocks of the Del Ma~r Formation are primarily lagunal and near-shore deposits of Eocene time, while granitic rocks of the Southern California Batholith are much older, intrusive igneous rocks of Cretaceous age. Earth Materials Engineered Fill (Qafc) Near the intersection of the Hidden Meadows Access Road and Alga Road East there are deposits of engineered fill. These fills were placed under the observa- tion and testing services of Benton Engineering. Colluvium (Qcol) Near the same area as the engineered fill, there is a deposit of colluvium. This deposit is a build-up of soils from nearby bedrock. This soil is prima- rily composed of silty clays and sandy silts which are dark brown to gray, damp, firm to stiff and porous. These soils are not suitable to support addi- tional fill. Thicknesses are approximately 3 feet to 5 .feet in this area. - @ m EBERHART-AXTEN and ASSOCIATES, INC. La Costa Land Company -3- W.O. 1165 Del Mar Formation (Tdm) The Eocene age, near-shore and lagoon sediments which make up the De1 Mar Formation on the site, consist of light gray to yellowish, fine to medium grained sandstones interbedded with medium gray to olive green, arenaceous shales and claystones. Shales and claystones are well consolidated and con- tain concretionary beds with molluskan fossils. Granitic Rocks (Kgr) These Cretaceous age, plutonic, intrusive rocks of the Southern California Batholith were observed to crop out south of the site, and probably underly the De1 Mar Formation at depth. Geoloqic Structure Near the eastern end of the proposed alignment, the Del Mar Formation was encountered. This formation is composed of interbedded siltstones and sand- stones which are relatively flat-lying, except for local distortions in bedding. The typical structure in this formation varies from about 0 degrees to 5 degrees in a northerly direction, with local variations in a southerly direction. - Granitic rocks of the Southern California Batholith are typically very massive. These types of rock exhibit fracture patterns commonly referred to as joints. Except near minor faults, jointing was generally crudely developed. Many of the joints appear to be subparallel in nature at intervals from, 6 inches to 3 feet. No evidence of recent or active faulting was found during this investigation. No active faults are known to exist on or adjacent to the subject site. SEISMICITY Although no active or potentially active faults are known to cross the site, the proximity of the site to active faults in Southern California makes it reasonable to assume that the site will undergo moderate groundshaking as a result of an earthquake along an active fault. The most likely source of such an event is the Newport InglewoodlRose Canyon Fault System. Plate I shows the location of the site in relation to the most significant active faults in the region. Ground response at the site during a seismic event can be evaluated on the basis of previous ground motion studies, observations of other earthquakes, activity along selected faults and current “state-of-the-art” understanding of seismic forces. Such an evaluation forms the basis for the seismic parameters listed for major active and potentially active faults in Southern California (see Table I). These listings provide estimates of seismic conditions which are likely to occur at the site, including accelerations, predominant period, dura- tion of shaking, and possible recurrence of probable seismic events along the listed faults. Due to the underlying bedrock throughout the site, liquefaction is not con- sidered a problem. os, EBERHART-AXTEN and ASSOCIATES, INC. La Costa Land Company Groundwater -4- W.O. 1165 The permanent groundwater table is estimated to be at considerable depth. Water may collect along fracture or joint patterns and migrate laterally toward slopes and hillsides, creating more nuisance problems rather than any hazards. However, we do not anticipate this problem at depths of cuts planned. GENERAL CONCLUSIONS AND RECOMMENDATIONS Based upon our investigation and review, it is our opinion that this site is suitable for the proposed improvements, provided the recommendations and specifications presented in this report are incorporated into project design and construction practice. GRADING Except as specifically noted herein, all grading should confirm to the appli- cable local grading code requirements, our recommendations within this report, and the accompanying Standard Grading Specifications. Site Preparation Prior to grading, the subject site should be stripped of all deleterious material such as trash, debris, and vegetation. These materials should be wasted off- site. Very light growths of grasses may be incorporated within the fills, pro- vided they are thoroughly blended with the soils. However, concentrations of vegetal matter should be avoided. We recommend that vegetation be stripped and disposed of offsite. Incorporation of any vegetal materials in the fills should be considered subject to review by the soil engineer and the governing authority as field conditions dictate. Overexcavations Portions of the site are covered with a 2 foot to 3 foot mantle oft topsoil, and creep-affected bedrock. These soils are considered unsuitable for support of additional fill or structures, and overexcavation should be planned. Cut Slope Stabilization Proposed cut slopes should be constructed no steeper than 2:l (horizontal to vertical). Cut slopes within the granitic rock and the De1 Mar Formation are generally considered grossly stable. If cut slopes expose locally adverse conditions, as determined by the engineering geologist, overexcavation and replacement as compacted fill will be recommended as field conditions dictate. Under certain conditions, if stabilizations are required, alternatives such as flattening of the slope ratios to 3: 1 ~may also be considered as field conditions dictate. However, we do not anticipate these problems. Unless otherwise recommended, stabilizations fills should be constructed in accordance with the accompanying Standard Grading Specifications. Fill Slopes Fill slopes should be constructed no steeper than 2:l (horizontal to vertical). Fills should be keyed and benched into competent material as determined by the soil engineer or engineering geologist during construction. EBERHART-AXTEN and ASSOCIATES, INC. La Costa Land Company -5- W.O. 1165 In order to enhance the probability of future favorable performance, we recom- mend overfilling and cutting back of the slope face to the firm compacted inner core. Conventional backrolling techniques may also be utilized for slope face compaction, but are considered less desirable. In addition, appropriate landscaping and maintenance programs should be established as soon as possible. Ideally, slope planting should consist of deep-rooting vegetation requiring little watering. Fill Placement Prior to placement and compaction of fill materials, the condition of the exposed ground surface should be reviewed by the soil engineer, then scarified, brought to the proper moisture content and compacted to a minimum of 90% of the laboratory maximum dry density per ASTM Method of Test D1557-70. Fill should be brought up in thin lifts not exceeding 8 inches in thickness (prior to compaction). Moisture content should be adjusted to near optimum, and the material should be compacted to 90%. Oversize Rock Placement within Compacted Fill Where rocks or similar irreducible materials of greater than 12 inches but less than 3 feet of maximum dimension, are generated during grading, ‘or otherwise desired to be placed within an approved compacted fill, special handling will be required. Rocks greater than 12 inches (maximum dimension) should not be placed in the upper 10 feet of any fill, nor closer than 15 feet to any slope face. Oversized material should be placed in windrows on a cIean, overexcavated or otherwise firm, unyielding compacted fill surface or a firm natural ground sur- face. Select native or imported granular soil should be placed and/or thorough- ly flooded over and around all windrows such that no voids remain. Windrows of oversized material shculdbe staggered so that successive strata of oversized material are not in the same vertical plane. For planning purposes, rocks larger than 3 feet should be disposed of offsite or broken down and incorpora- ted into the deeper fill areas. As field conditions dictate, however, it may be possible to dispose of some large rocks onsite. Excavation Characteristics Based on seismic refraction data, it is our opinion that mass excavation within the cut areas may be accomplished by light to moderate ripping within the Del Mar Formation. In the granitics, the cut areas will be marginally rippable and may require blasting below 9 feet to 14 feet. Due to the manner in which weathering occurs around hard boulders, locally difficult to very difficult excavating and/or blasting may also be required at shallower depths. These estimates are based on performance specifications of a D-9 dozer traveling in low gear with a single-shank ripper tooth. See Plate A for a summary of velo- cities and depths of rippable materials. Shrinkage, Bulkinq and Subsidence In consideration of the in-place densities and anticipated densification, we would anticipate shrinkage of on the order of 15% to occur for removal and replacement of existing fill, topsoil, alluvium, colluvium and creep-affected materials. Where fill material is generated from the Del Mar Formation bedrock, we would anticipate bulking to be on the order of 0% to 5%. Even greater - @ m EBERHART-AXTEN and ASSOCIATES, INC. La Costa Land Company -6- W.O. 1165 bulking could occur in areas where hard granitics are blasted or otherwise broken down and incorporated into the compacted fill. Subsidence of bedrock materials as a result of placement of additional fill should be minimal. These numbers are order of magnitude estimates based upon our field observations and laboratory testing to date, as well as our experience with similar projects and material types. SPECIFIC CONCLUSIONS AND RECOMMENDATIONS The area along the alignment of the Hidden Meadows Access Road between lo+00 and 11+77 will require 2 feet to 3 feet of removals plus an additional processing of 12 inches in place. Colluvial materials here may contain large rocks. Between stations 11?77 and 14+75, large granitic rocks were visible along the alignment. Within this area, it was not possible to excavate pits with a back- hoe deeper than 1 foot to 2 feet. Cuts within this area range from about 4 feet to 17 feet +. It is our opinion that this area may require blasting. Velo- cities recorded in this area (Plate A) ranged from approximately 6,200 feet per second to 9,000 feet per second. It is also very likely that this area will generate excessive amounts of oversize rock. Some of this may be disposed of in the fill area between stations lO+OO and 11+77. However, we anticipate that the volume of rock generated in this cut will be too much to dispose of in this area. We therefore recommend that excess rock be used within deeper fills of the nearby :tijor r.oads project. From Station 14+75 to Station 17+75 cuts of up to 17 feet are anticipated. These cuts may expose the contact between the Del Mar Formation and the granitic basement rock. Cut slopes within the De1 Mar Formation are anticipated to be grossly stable. However, if stabilisations are required, as determined by the engineering geologist during grading, laying back of slope at ratios of 3:l or flatter, may be considered as an alternative to stabilization. Seismic velo- cities recorded in this area ranged from 1,200 feet per second to 4,500 feet per second to depths up to approximately 30 feet (Plate A-2 ) . These velo- cities suggest that the materials are rippable. PAVEMENTS Due to the generally granular nature of the soils underlying the site at depth, minimum pavement sections (2fAC/6AB) should be applicable provided these materials are utilised near finished grades and clayier materials are disposed of at depth. Actual pavement requirements should be verified as final grades are achieved. We appreciate the opportunity to work with you on this project. If you have any questions concerning this report, please do not hesitate to call. Respectfully submitted, EBERHART-AXTEN &. ASSOCIATES, INC. - cs a EBERHART-AXTEN and ASSOCIATES, INC. La Costa Land Company v#gY President CEC 965 RKJIGWAIDRElrp Enclosure: Appendix Distribution : (2) Addressee (5) La Costa Construction Office, Att: Bob Stork (2) Rick Engineering W.O. 1165 c3 .m EBERHART-AXTEN and ASSOCIATES, INC. La Costa’ Land Company APPENDIX @ e EBERHART-AXTEN and ASSOCIATES, INC. W.O. 1165 La Costa Land Company TABLE OF CONTENTS References Laboratory Testing Location Map Seismicity Map Seismic Parameters Log of Test Pits Seismic Refraction Survey Plot Direct Shear Test Plots Slope Stability Evaluation R-Value; Pavement Section Design Geologic Explanation Standard Grading Specifications Grading Plan - Geologic Map W.O. 1165 Page A-l Page A-2 Plate I Plate II Table I Table II Plates Al. and. A-2 Plate B Plates C-l and C-2 Plate D Plate E Pages 1 through 9 Pocket Enclosure (Plate Ill) m EBERHART-AXTEN and ASSOCIATES, INC. L-a Costa Land Company (A-2) W.O. 1165 LABORATORY TESTING Laboratory tests were performed on samples for subsequent use in engineering evaluations. Brief descriptions of laboratory tests performed have been indicated below. Classification Field classifications were verified in the laboratory by visual and tactile identi- fication. Compaction A representative sample of onsite soil was tested for maximum density and’optimum moisture content in accordance with ASTM Method of Test D1557-70. R-Values Resistance value testing was performed on samples representative of the onsite materials. R-Values were determined in accordance with California Test Method No. 301. EBERHART-AXTEN and ASSOCIATES, INC. ‘La Costa Land Company (A-1) W.O. 1165 REFERENCES Greensfelder, R.W., 1974, Maximum Credible Rock Accelerations from Earth- quakes in California, C.D.M.G., MS-23. Housner, G.W., 1970, Strong Ground Motion, Earthquake Engineering, edited by R.W. Wiegel. Leeds, A.J., 1973, The Design Earthquake, A.E.G., Special Publication. Moyle, W.R. Jr., 1974, Geohyrologic Map of Southern California, U.S.G.S., Water Resources Investigations 48-73 open file. Ploessel, M.R. and Slosson, J.E., 1974. Repeatable High Ground Accelerations from Earthquakes, California Geology. September 1974. Rogers, T.H., 1966, Geologic Atlas of California, Santa Ana Sheet, C.D.M.G., scale 1 :250,000. Schnabel, P.B. and Seed, H.B., 1973, Accelerations in Rock for Earthquakes in Western United States, S.S.A., Vol. 63, No. 2. Weber, F.H. Jr., 1977, Seismic Hazards Related to Geologic Factors, Elsinore and Chino Fault Zones, Northwestern Riverside County, California, C.D.M.G., open file 77-4. AERIAL PHOTOS Flown by Rick Engineering: July 13, 1970, Flight #10-l through 10-6 June 12, 1972, Flight #l-4 and B SOIL RELATED REPORTS Final Report on Compacted Filled Ground,Extension of Alga Road from El Fuerte Street to Ranch0 Santa Fe Road, by Benton Engineering, Inc., dated March 9, 1972 (P.N. 72-l-30). Soils Investigation, by Benton Engineering, Inc., dated June 27, 1979 (P.N. 79-4-4F). Supplemental Soils Investigation by Benton Engineering, Inc., dated September 19, 1979 (revised November 16, 1979). (P.N. 79-4-4F). m EBERHART-AXTEN and ASSOCIATES, INC. LOCKTION fuJAP From U.S.G.S. Encinitas and Ranch0 Santa Fe Quadrangles 0 2000 4000 , . HIDbEN MEADOWS ACCESS RD; LA COSTA LAND COMPANY W.O. 1165 Plate I ,, rh”. I . I -... ,i,. MA’@3 ~ARTHOIJAKES AND RECENTLY *CTIVE FAULTS IN TIE SCUTHERN CALIFORNIA RW4ON ,-~~‘- 7 LI”,., b”r...43CWId.~CLd~~-,~ WI. -clG..“.d.-d- ~I.#..eD,a,,:rr-m..” -.-;b. ‘C. I / / 1 I , / / , 1 1 La Costa. Land Company TABLE I W.O. 1165 _ SEISMIC PARAMETERS FOR NORTHWESTERN SAN DIEGO COUNTY otential iausative Fault In Andrear ;outh 6 central) an Jacinto sinore * awport- lglewood I Rose Canyon 5 ,tes: 1) 0 Postulated Fault Rupture Lengths~: #Maximum Credible Earthquake = length/2 Maximum Probable Earthquake,= length/l0 2) Schnabel and Seed, 1972. For sites less than 20 miles from the fault, the peak accelerations may, further be reduced to repeatable high ground accelerations by using 65% of the peak acceleration (after Ploessel 8 Slosson, 1974). Distance from site to fault (miles) 68 46 22 7 tom a t I Length of fault (miles) 310 150 : to 200 135 to 162 between 50 6 120 Richter Magnitude of Historical Earthquakes 8.0 (1857) 6.5 (1948) 6.8 (191a)i 6.0 (1937) 6.2 (1954) 6.4 (1958) 6.0 (1910) 6.3 (1933) Age of Maximum - Credible Maximum Probable Earthquake (for desian aurooses) Most-Recent1 Earthquake 1 I Peak I L redominent .IDuration I tstimatec Surface Richter Richter Horizontal Period Ground of strong Recurrence at Site Xsplacement Magnitude Magnitude Acceleration shaking Interval (Seconds) at Site (years) ~j(approx.1 (Note 1) (Note 1) (Gravity) (Note 3) (Seconds) (Note 5) (Note 2) (Note 4) 1948 7.50 7.50 less than 0.58 34 40-100 to to 0.10 8.25 a. 00 Holocene 7.50 7.00 less than or 0.40 28 40-100 I-11,000 yes. equal to 0.10 Holocene’ l-11.000 yrs. 7.7 6.7 0.18 0.3 20 go-200 Ground failures, 7.5 6.5 0.38 0.28 18 200-300 but no definite- known rupture I I I 3) After Seed, ldriss and Kiefec, 1969. 4) After Housner (1970), Bolt (1973) 5) Recurrence intervals for maximum probable earthquake taken in part from Lamar and others (1973). La Costa Land Co. Test Pit No. (Station) Table II LOG OF TEST PITS Depth (ft.) Field Description Hidden Meadows Access Road (10 .‘77) (11 +277) (12 +360) (13 +440) 0. o-1.5 1.5-3.0 0.0-1.0 1.0-2.5 0.0-1.0 1.0-1.1 0.0-1.0 1.0-1.1 0. O-7.0 7.0-10.0 10.0-15.0 W.O. 1165 TOPSOIL: Silty Clay, dark gray brown to red brown, dry, hard; desiccated, roots, porous, rootlets in the upper 6-in. COLLUVIUM: Silty Clay, dark red brown, moist, stiff; with occasional cobbles of granitic rock Z-in. to S-in. in diameter, at 3.5-ft. ; several large granitic boulders 2-ft. to 3-ft. in diameter. TOPSOIL: Silty Clay to Sandy Clay, dark brown to slightly reddish brown, dry near surface, moist below. COLLUVIUM: Silty Clay, dark gray brown, moist, stiff; with large, numerous fragments of granitic rock, average size of granitic rock ranges from S-in. to 2 to 3-ft. TOPSOIL: Silty Clay, medium brown, dry, hard. BEDROCK : Granitic refusal. TOPSOIL: Silty Clay, medium brown to gray brown, dry, loose; desiccated. BEDROCK: Granitic refusal. FILL: Silty Sand, medium brown, damp, firm; containing large angular fragments of volcanics 3-in. to 1.5-ft. in diameter. ALLUVIUM: Silty Clay, dark brown to pale brown, slightly reddish, moist, firm, stiff. COLLUVIUM: Silty Clay, medium brown to pale gray, damp to moist, firm to stiff; possibly residual soil from the Delmar Formation, moderately stiff. - c3 - EBERHART-AXTEN and ASSOCIATES, INC. MAJC -\ . -\ T,. . ‘\ ! . ‘, l ., J i --eF -i.+” / ,a.. I -j ,.I ys /- 0 ;, 11,*.11,., . ; w T .I -f;si -- .I... . I I I. L. . Y cu ; ‘\ a* ir ~RTnQUAKES AND RECENTLY ACTIVE FAULTS IN l-M SOUTHERN CALIFORNIA REGION m ,uJ.n UnTHpuuE Lcwms . %.L-.W,kDn.l...C.wMoCrr~L ” I..-,.,y I..., ,,.,.“b...p”‘“““-“‘“” I,..,.e,#.“a,I .v”‘;‘..CrWoI.l ,.......“.-“*.l. ~-~‘,“‘tt”+.l” .#..drrsu~cd‘-.dbkxrr,u-q-- ,~~,-~,i~c,~~----~-.-i~‘.~. -- . 1 SEISts1IC REFRACTION SURVEY 1 Line Number sL ’ \Y.o. 1165 Date: 10-8-w By: RJ Location: Bearing [Hammer to Ceophone) : Length: loo ft. Notes:Large outcrops granitic rocks along alignment of roadway. csta. 1st Arrzal-MS ~- Gain tit._ lor_warbiRexerse_ P.orwardiRevers j 10 2. 7.4 6.3 7.2 5.1 1 1 __-- ; ’ 30 8.3 9.9 2 I 40 11.0 i 11.0 2 80 16.2 17.6. I 20 90 17.4 .~ 20.6 20 ~JlOO ) p-3 1 2. ...-__ 18.1 _.LLQ- I JSL-11 I - I 120 vl= 1500 ftlse O-3.0 - v GRAPHIC REPRE r ?- :S Range Delay Sta. F_qwardRevecseLorwacdReverse Reverse -----lo--- l@ 10 ZOR ___- ~-._ --..-. es--30R 25 4OR ,..,. 25 50R _.-..~~- ~.~ -_ 25 RR 25 70R 25 I,..- ---&OR ~_.,25, >OR 25- - 1 OOR SI 1R -- 1lOR. ‘I= 1960 ftlsec O-LO ..--120R. '2= 5200 ftlsec 3-9 -130R "3~6300 ftlsec 9 l&OR 150R ENTATION 4 50 60. DllT.YCl,~IEO - Plilt~ A=i ~--.--- rs?%xz-i?E~Rx~ION SURVEY1 ~ .-.~-__-_ .--__ Line Number SL-2 lv.0: 1165 Date: By: 12/24/8Q RKJ Location: Bearing (Hammer to Ceophone) : Notes : Length: 1001 Near contxi with PeLMar-Earmtion------.---~~-- .---_ ~. -~ 1st Arrival-MS / i I- T ,,! ! 1 -..- -50---.-~. so.._ ~-.s~.--~~-. 5 -~. ----- ~~~~. .-J9..~-~.-_lL -IQ---IQ :--I=_- 10_--~..-m20.. -.. ~_-_-~-_ _ -_-~~.-__ _--~- __~ ~-. ~~.. _-.-- -.. ;RAPHIC REPRESENTATION e 1 i 1 -I- I Sta. Levers 10R 20R -~ 30R 40R _. 50R j _ 60R : 70R _ ~.., .~ 8OR ’ 1 -~~90R- 100R ; IlOR- 120R -j 130R~ I 140R 150R~ I DIRECT SHEAR TEST PLOT W.O. II65 Date I O/27/80 Excavation No. TV-2 , Depth 1)-& ft. Sample Type: 0 relatively undisturbed, a remolded 92% C,c, BY 6W4 Test Moisture:U natural I Cl optimum , w saturated Shear Strength Test Type: B ultimate, Cl peak, w residual, 0 resheared AA, Inc. Normal Load - kipslsq. ft. plate B -- %PE %ABlLlTY EVALu4-TI 0 4 2:l Slope A- CI d.0. Dqf - / - : ~‘C i .~ p ~_ ,; E ,I OF 0.164 0.100. ,. 0.303 y0.-3os 0.130 - ~. 0.463 0.533 o-455 0.3ZO’ ~zs.5 45.5 - 15.5 33.5 .Gl.S - ,, 5.0 20.5 -37.0 55 .~ GleeId *\ Plate C-1 SUURFIC IAL SLOPE STABiLlT’f Aswmed Flow Lnes - YW-= +I! wel$h+ Or Wafer * 62.4 pLf _. F-d~.hvc~j ~orcc,-=~.d$~Sin&:~ ..: ” .” . . . >. ,“_ : ~. i _ ,b.* Rei& ii, Force = d(Y5Sx*~)toS;Tun~+=(~s;. ,, -- _ .‘., 2 .‘i...G.. . ..- F*++.. I ” .~:L _ ~;~-.,-:~ ;,:. ., _. i: ’ *. ;, ?, ;:- .~ l=i- d(fs-‘IU)&S; Ta;~i=/cosA R = F&t& ~uf Safe+y=g-’ ‘. : Iii’ ,., ._ dy&Slni ~. ‘.’ .,. FS = ‘d(Y,-‘dv)c&Tarl@+c d Ys 4cni b*t e &4-b+ v,,r I,< :’ .f Es.=-\.5 2C d= ‘ds co5%(3Tani-G&g -&3EiS”L&-,&E~ r &,oCIAT’=S, fNC. ,- . . -. . . I’ z , . Plate C-2 . ’ EBERHART-AXTEN AND ASSOCIATES, INC. Date Work Order f\bS PAVEMENT THICKNESS DETERMINATION BY R-VALUE - Material AC AC Street/Description e+de &I cbI14cw- R-Value = 40 A= L&. -- Traffic Index, T.I.= 5,s Required Gravel Equivalent : GE=0.0384 (TI) (100-R) = 12,6-l Inches Assumed Gravel Gravel Thickness Factor Equivalent .(inches) Gf GE tvt Z&42 6.4 6 1 I.1 6.6 Total = ' 12,K -L )Z,L7 :. 4c IF ONLY AC USED Th 1 = . . . . . . .ickness ='-- inches, say inches GEOLOGIC EXPLANATION - TP-5 Approximate location of pits 5L-2&) 4 Approximate location of seismic lines Approximate location of geologic contact , Colluvium overlying the Del Mar Formation Del Mar Formation l<w Ct-anitic rock of Southern California 3atholith Plate E ‘, 1.9 1.1 1.2 1.3 1.4 1.5 2.0 2.1 2.2 2.3 2.4 -l- STANDARD SPECIFICATIONS FOR GRADING PROJECTS GENERAL The specifications contained herein and the standard details attached hereto represent this firm’s minimum requirements for grading and other associated operations on construction projects. These specifications should be considered a portion of the pro- ject specifications. These recommendations should not be considered to preclude more restrictive requirements of the regulating agencies. The contractor, prior to any site preparation or grading, should arrange a meeting onsite among himself, the developer, the design engineer, the geotechnical consultant, and representatives of the appropriate governing authorities. All parties should be given at least 48 hours notice. The contractor shall be responsible for the satisfactory completion of all grading and other associated operations on construction projects, including, but not limited to, all earth work in accord- ance with the project plans, specifications and controlling agency requirements. All plates attached hereto shall be considered as part of these specifications. These.Standard Specifications for Grading Projects may be modified and/or superseded in part or all by recommendations contained ’ in flie text of” the preliminary geotechnical (report and/or sub- sequent reports as a result of engineering analyses and evalu- ations of laboratory data andlor grading plan changes, or con- ditions found during grading. DEFINITION OF TERMS BEDROCK a relatively solid, undisturbed or in-place rock existing at either the ground surface or beneath surficial deposits [old or recent alluvium, colluvium) of soils. Bedrock will be identified in the field by the engineering geologist. COL~LLJVIDM-loose, incoherent deposits usually found at the toe:of- slopes and brought there chiefly by gravity. RECENT:~ALLIJV-IUM-unconsolidated detrital deposits resulting from blj&at)ons .-of modern rivers, including sediments laid down in river beds, flood plains, lakes, fans at the foot of slopes and estuaries. C)&R‘A~lJVtl&~- sameorigin as recent ahuvium,except that it is older.&dIias been lithified. \ @ m EBERHART-AXTEN and ASSOCIATES, INC. -- . 2.5 2. 6, 2.7 2.8 2.9 2.10 2.11 2.12 2.13 2.14 2.15 2.16 2.17 -2- SLIDE DEBRIS - material (bedrock, colluvium,alluvium) produced from instability of natural or manmade slopes, usually fractured, porous and of low density. DEBRIS - all products of clearing, grubbing, demolition, contamin- ated soil material unsuitable for reuse as compacted fill. FILL - any deposits of soil, rock, soil-rock blends or other similar materials placed by man. IMPORTED OR BORROW MATERIAL - any fill material hauled to the project site from offsite areas. ENGINEERED FILL -. a fill of which the soil engineer or his repre- sentative during grading has made sufficient observations and taken sufficient tests to enable him to conclude that the fill has been placed in substantial compliance with these specifications and the governing agency requirements. RELATIVE COMPACTION - the degree of compaction (expressed as a percentage) of dry unit weight of a material as compared to the maximum dry unit weight of the material. Unless otherwise speci- tied, the maximum dry unit weight shall be determined in accordance with ASTM Method of Test D1557-70. GRADING - any operation consisting of excavation, filling or combinations thereof and associated operations. CLIENT - The .developer or his authorized representative shall have the responsibility of reviewing recommendations made by the geotechnical consultant and shall authorize or cause to have authorized the contractor to perform such work as required to comply with said recommendations. CONTRACTOR - a person or company under contract or other- wise retained by the client to perform demolition, grading, and other site improvements. TRACT ENGINEER - a licensed civil engineer experienced in sub- division planning design and preparation of construction plans and overall coordination of all engineering, surveying, and construction of the project. ENGINEERING GEOLOGIST - a geologist holding a valid certificate of registration in the specialty of engineering geology. SOIL ENGINEER - a’ licensed civil engineer experienced in soil mechanics. GEOTECHNICAL CONSULTANT - the soil engineering and engineer- ing geology consulting firm retained to provide technical ~services for the project. For the purpose of these specitTcations,including observations by the soil engineer, engineering geologist, and those performed’by persons employed by and responsible to the geotechnical consultant. @ CmCDYADI AYWC.. --> .CrA.m.as.r- . ..- . . . - 3.0 3.1 3.2 3.3 3.4 3.5 4.0 4.1 4.2 4.3 -3- SITE PREPARATION Clearing and grubbing should consist of the removal .of all vegetation such as brush, grass, woods, stumps, trees, roots of trees and all otherwise deleterious natural materials from the areas to be graded. Clearing and grubbing should extend to the outside of all proposed excavation and fill areas. Demolition should include removal of all buildings, structures, reservoirs, utilities [including septic tank, leach field, seepage pit, cisterns, mining shafts, tunnels,etc.), and all other manmade surface and subsurface improvements from the areas to be graded. Demolition of utilities should include proper capping or re-routing at the project perimeter and cutoff and capping of wells in ac- cordance with the requirements of the governing authorities and the recommendations of the soil engineer at the time of demolition. Trees, plants or manmade improvements not planned to be removed or demolished should be protected by the contractor from damage or injury. All deleterious material generated during clearing, grubbing and/or demolition operations should be wasted from areas to be graded and disposed offsite. All clearing, grubbing and demolition opera- tions should be performed under the observation of the geotechnical consultant. Where applicable, the contractor should obtain approval from the controlling authorities for the project, prior, during, and/or after demolition, site preparation, and removals, etc. The approprj- ate approvals should be obtained prior to proceeding with grading operations. SITE PROTECTION The contractor shall be responsible for the stability of all temporary excavations. Recommendations by the geotechnical consultant should not be considered to preclude those requirements of the regulating agencies. Precautions should be taken during the performance of all site clearing earthwork, excavations and grading to protect the work site from flooding, ponding or inundation by poor or improper surface drainage. Temporary provisions should be made during the rainy season to adequately direct surface drainage from all sources away from and off the work site. Where low areas cannot be avoided, pumps should be kept on hand to continually remove water during periods of rainfall. During periods of rainfall, plastic sheeting should be kept on hand to prevents unprotected slopes from becoming saturated. Where neces- sary during periods of rainfall, the contractor should install check- dams, desilting basins, riprap , sandbags or other devices or methods necessary to control erosion and provide safe conditions. m EBERHART-AXTEN and ASSOCIATES. INC. . . -4- 4.4 4.5 During periods of rainfall, the geotechnical consultant should be kept continually informed by the contractor as to the nature of any work being performed (e.g., pumping, placement of sandbags or plastic sheeting, other hand labor, dozing, etc.). Following periods of rainfall, the contractor should contact the geotechnical consultant and arrange a walk-over of the site in order to visually assess rain-related damage. The geotechnical consultant may also suggest supplemental testing in order to complete his assessments. At the request of the geotechnical consultant, the contractor shall make all excavations as necessary to evaluate the extent of rain -t-elated damage. 4.6 Rain-related damage should be considered to include erosion, silting, saturation, swelling, structural distress, and any other adverse condition delineated by the soil engineer. Soil adversely affected should be classified as unsuitable materials, referred to herein under Section 5.1, and should be subject to overexcavation and replacement as compacted fill or other remedial grading as directed by the soil engin- eer. a) b) Relatively level areas, where saturated soils .andlor erosion- gullies exist to depths of greater than 1.0 foot., should be over- excavated to unaffected, competent material. Where less than 1.0 foot in depth, unsuitable materials may be processed in place to achieve near-optimum moisture conditions, then thoroughly re- compacted in accordance with the applicable specifications. If the desired results are not achieved, the affected materials should be overexcavated, then replaced in accordance with the applicable specifications. In slope areas, where saturated soil and/or erosion-gullies exist to depths of greater than 1.0 footl, they should be overexcavated and replaced as compacted fill in accordance with the slope repair specifications herein. Where affected materials exist to depths of 1.0 foot or less below proposed finished grade, remedial grad- ing by moisture conditioning in place followed by thorough re-. compaction in accordance with the applicable specifications may be attempted. If the desired results are not achieved, all af- fected materials should be overexcavated and replaced as com- pacted fill in accordance with the slope repair specifications herein. As field conditions dictate, slope repair may be recommended by the soil engineer in accordance with the accompanying speciti- cations for stabilization fills. 5.0 EXCAVATIONS 5.1 a) Unsuitable Materials: Materials which are unsuitable should be excavated under observation and recommendations of the geo- technical consultant. Unsuitable materials include, but may not be limited to,dry, loose, soft, wet, compressible natural soils and fractured, weathered, soft bedrock and non-engineered or otherwise non-approved fill materials. EBERHART.AXTFN nnrl ACCO#-IATFC lhlr 5.1 5.2 *:.,;., 5.2 5.2 5.2 5.2 5.3 .~ 5.3 .~ a) W d e-1 al b) -5- Material identified by the geotechnical consultant as unsatis- factory due to its moisture conditions should be overexcavated, watered or dried,as needed,and thoroughly blended to a uniform near-optimum moisture condition (as per guidelines in these specifications) ,p+r, to placement as compacted fill. recommended by the geotechnical the regulating agencies, perma- nent cut slopes should not be steeper than 2:l (horizontal to vertical). .:., , ,, If excavations for cut slopes expose loose, cohesionless, sig- nificantly fractured or otherwise unsuitable material, overex- cavation and replacement of the unsuitable materials with a compacted stabilization fill should be accoqplis-be-4. S-ncJ recom- mended b ified by the oeotechnical consultant, Unl6s.s otherwise spec- t ii e geo&hnical,zcq+ultant, stabilization fill coristruction ~-@u!~.~~nfor,& tothe requirementaof Plate 3 of these specifications. _; -. ,.., L’:,; _ ,,,. z The enginee$ng geologist should inspect all cut slopes at ver- tical intervals not exceeding 10 feet end shall be notified by the contractor when cut slopes are started and when the lo- foot intervals are anticipated. If, during the &&se of grading, adverse or potentially ad- verse geotechnical conditions are encountered which were not anticipated in the preliminary report, the geotechnical consultant should investigate, analyze., and make recommendations to treat these’ problems. : ~. Foi cut s&es made in the direction of the prevailing drainage, a non-.erodlble diversion swale (brow ditch) should be provided at ,the tc$Gf-6ut.. ~~, . .._. ., Lot Pads: ’ All lot pad areas, including side yard terraces, above stabilization fills or buttresses should be overexcavated to pro- vide for a minimum of 3 feet (Plate 5) of compacted fill over the entire-bad area& Ceotechnicalcohditions ?a$ requiregeeater depth of overexcavation and should be delineated by the geo- technical consultant during grading. Pad areas with both fill and cut materials exposed and pad areas containing both very shallow (less~.than 3 feet) and deeper fill should be overexca- vated to provide for a uniform compscted fill blanket of a min- imum of 3 feet in thickness (Plate 5). Cut areas exposing. significantly varying material types should also be overexca- vated to,provide for at least a 34oot thick compacted fill blanket. ~.~ .:~. .~ _, :)_ ‘. . ..-. .: For pad areas crk&d above c;t br natural slopes, positive drainage should be established away from the top-of-slope. This may’be accomplished utilizing a berm and/or an appro- priate pad gradient. An overall gradient away from top-of-. Slope of 2% or :greater.should be maintained. -6- 6.0 COMPACTED FILL 6.1 Compaction : All fill materials should be compacted as specified below or by other methods specifically approved by the geotech- nical consultant. Unless otherwise specified, the minimum degree of compaction (relative compaction) should be 90% of the laboratory maximum density. .: ~. _ T -4: a) Placement: P,rior to placement of compacted fill, the contractor should request a review by the geotechnical consultant of the exposed ground, surface. Unless otherwise recommended, the exposed ground surface should then be scarified (6-inch minimum), watered or dried as needed, thoroughly blended to achieve near;optimum moisture conditions, then thoroughly compacted to a minimum of 90% of the laboratory dry density. The review by the geotechnical consultant should not be con- sidered to preclude .requirement of review and evaluation by the controlling agency?,. 6.2 6.2 b) 6.2. .cl 6.2 4 6.2 e) When placing fill in horizontal lifts adjacent to areas sloping steeper than 5:l (horizontal to vertical), horizontal keys and vertical benches should be excavated into the adjacent slope area. Keyipg and benching should be sufficient to provide at least five-foot wide benches and a minimum of three feet of vertical bench height within firm natural ground, firm bed: rock or approved compacted till. ‘No compacted fill should be placed in an area subsequent to keying and benching until the area has been evaluated by the geotechnical consultant. Typical keying and ~benching details have been included on the accompanying Plate 4.,- .:: . ,::; -~. .: Within a single till area where grading procedures dictate two nor more separate fills, temporary slopes (false slopes) may ‘beg created. When placing fill adjacent to a false slope, : ,.. ., t...,:; m EBERHART-AXTEN and ASSOCIATES, INC.. ~- . : Compacted fill should be placed in thin horizontal lifts not exceeding eight inches (bulk) in thickness prior to compaction. Each lift should be watered or dried as needed, thoroughly blended to achieve moisture conditions within the range of optimum moisture ,-content and optimum moisture content plus 3% (by dry soil weight), then thoroughly compacted by mechanical methods to a minimum of 90% of laboratory maximum dry density. Each lift should be treated’in a like manner until the desired finished grades are achieved. The contractor shall have suitable and sufficient compaction equipment and watering apparatus on the job site to handle the amount of fill being placed in consideration of moisture retention properties of the materials. If necessary, excavation equipment will be “shut down” temporarily in order to permit proper compaction of fills. -7- 6.4 .I ., 6.2 6.3 6.3 b) 6.3 ,. 6.4 f) gi a) beEchingshall be conductedin [he same manner as the above described. At least a three-foot vertical bench should be established within the firm core of adjacent approved com- pacted fill (i.e., ‘the material underlying the surficial loose material) prior to placement of additional fill. Benching should proceed in approximately 3-foot to 4-foot increments until the desired finished grades are achieved. .<. t: i All fill, should be tested for compliance with the required reh ative compaction and moisture conditions as recommended. Field density’testing should conform to ASTM Method of Test D1556, D2922 and/or D2937. Tests should be provided for about every 2 feet or 1,000 cubic yards of fill placed. Fill found not to be-in ,conformance with the specifications should be removed, then replaced in accordance with the specifications. i -.~.<;)jij’j:~ !~..~ :~ :~ : ;. *~: ., The contractor shall assist the geotechnical consultant and/or his representative in digging test pits for removal determin- ations and/or testing as compacted fill progresse?, and will remove from test area, or shut down temporarily, the equip- ment during “sand cone” testing. Moisture: For field testing purposes, ‘;near-optimum” moisture should be considered to mean optimum moisture to 3% above optimum moisture. ,,. ,, ,( Prior to placement of additional compacted fill following an overnight, or other grading delay, the exposed surface of previously compacted fill should be processed by scarification, watered or d<e.d as needed, thoroughly blended to near- optimum mbisture conditions, then recompacted to a minimum of 90% of laboratory maximum dry density. Where wet or dry or ot,her unsuitable materials exist to depths of greater than l.fo~L’ the unsuitable materials should be overexcavated. cl . ‘:; ~.~ ..,~. Follow!ng a period of flooding, rainfall or overwatering by other means, no additional fill should be placed until damage assessments have been made and remedial- grading performed as described under Section 4.0 herein. .i z...,;.: “._ a)- k-1 ‘i, ,.- Fill Material: Excavated onsite materials which are acceptable to the geotechnical consultant may be utilized as compacted. fill, provided all trash, vegetation and other deleterious materials are removed~prior to :-placement. .~ .:,.-:* 1 _.. :: ~.:‘. .,_. y-. ,. . Where impor,tmaterials are required for use onsite, the geo- t.echnical consultant should be notified at least 72 hours in advance of importing, in order to sample and test materials c . . _ ~~ Tram prOpOsea borrow sites. No import materials shall be 6.4 . r -a- Rocks 8 inches in maximum dimension and smaller may be utilized within the compacted fill, provided t.hey are placed in such a manner that nesting of the rock is avoided. Fill should be placed and thoroughly compacted to the minumum requirement over and around all rock. .r DuAng the’course of grading operations, rocks, or similar irreducible materials greater than 8 inches maximum dimension (oversized material), may be generated. These rocks should not be placed within the compacted fill unless placed as rec- ommended by. the geotechnical consultant. -;. I.. “:::;~‘: _’ .~: ,. Where rocks or similar irreducible materials of greater than 12 inches, but less than 3 feet,of maximum dimension are generated during grading, or otherwise desired to be placed within an approved compacted fill, special handling in accor- dance with the accompanying Plate 6 is recommended. Rocks greater than 3 feet should be broken down or disposed offsite. Rocks.up to 3 feet maximum dimension should be placed below the upper 13 feet of any fill a@ should not be closer than IS feet to any slope face. Where practical, ove’rsized material should not be .placed -below areas til-iere structures or deep utilities are proposed. Oversized material should be placed in windrows on a clean, overexcavated or unyielding compacted fill or firm natural ground surface. Select native or imported granular soil (S.E=30 or better)’ should~ be placed and/or . thoroughly flooded over and around all windrowed rock, such that no voids remain. Windrows of oversized material should be~stagg~red so that successive strata of oversized material are not In the s,ame vertical ‘plane. -.. ” ; .; ‘.~--,,l.~~~.-:.;I:‘-’ ._. .-. :. .zi i , ._~’ Material ~that is considered unsuitable by the geotechnical con- consultant._should.not be utilized in the compacted fill. .;. y.,. .::. f. :.:::q :~ f- ; ; ‘: ..1’--+ .f~.:, < .‘, During grading ope;ations;’ blacing’and %i?itia the materials from the cut (borrow) areas may result in soir mixtures which may possess different physical properties. Additional testing may be required of samples obtained directly from the fill . areas In order to verify conformance with the intentions of the recom~tiendations of the ~preliminary report. Processing of these additional samples may take two or more working days. . ., -:: ~.. The contractor. may elect to move the operati& to other areas within the projects, or may continue placing compacted tilJ,, pending’ laboratory~ test results. S~hould he elect this second alternative,. fill placed ‘is done~ &o at the contractor’s risk. ‘6.4 cl 6.4 dl . 6.4 4 -- ‘6.4 4’ 6.4 ‘~ 1 g) 6.4 ;’ h) ., ~z”~;.=r:.-~,~;,~;,. : ;,r;.~ ‘Z. .-.~a. I .~ z _ ;. ‘. > ::‘-.- ,. _~ Any fill placed in areas not previously reviewed and evaluated by the geotechnical consultant, a’nd’lor in other areas, with- out.prior notification to the geotechnical consultant of his in- ‘: ,~_ ~~ ;.:-: .,~‘..,.~‘~..~~.~ __ tenfions~. ~of placing ‘the compacted ,fill, may require removal and recompaction ‘at the contractor’s expense. Determination ” . .~~..,A :*; ~.‘,: :.,.-.‘. _ L1; ,) of overexcacations should be made upon review of field con- ‘consultant;“f. ,‘~ -i ’ ..:l,i” L -’ .~ -i~.--:;.F.T .___,. .>.. ..,i- .- 6.4 6.5 6.5 6.5 6.5 6.5 . cl dl 4 . il a) W -9- Plan locations of field density tests (horizontal and vertical) should only be considered approximate. The contractor shall provide sufficient grading stakes with elevations to serve as guidelines for test loc+ion identification; ,,‘~ : Slopes Compacted fill slopes should be limited to a ilope ratio of no steeper than 2:l [horizontal to vertical). ) ,_; J i *I All co&acted fill slopes shall be overbuilt and cttt back to grade, exposing the firm, Compacted fill inner core. The actual amount of overbuilding may vary as field conditions dictate. If the desired results are not achieved, the existing slopes Should be overexcavated and reconstructed under the guidelines of the geotechnical consultant. The’degree of over- building shall be increased until the desired compacted slope surface condition is achieved. Care sHoul3’be taken by the contractor to prbvide thorough mechanical compaction to the outer edge of the overbuilt slope surface. . . Beginning in the &rly stages of fill slope construction, the con- tractor shall, upon the request of the geotechnical consultant, make excavations through the overbuilt section to the proposed finished slope surface in order for the geotechnical consultant to test for conformance with these specifications. Care should be taken b,y the contractor not to excavate beyond the proposed finished slope surface. : Following the attainment of the desired slope height, the outer surface of overbuilt slopes should be cut back to a desired finished surface contour. Care should be taken by the con- tractor not t,o excavate beyond the desired finished slope surface., ::‘~;:,:-‘y j.:. s .~’ ,v. ..:.- ,- . ~~,’ : ..;:,.::;;:~~~t~c i_,. . z ~$$&$ _ _, ~.~ .: ‘, .y:. ‘:I.; Q-1;:; .’ . ; . .;<:‘L. ,.&& -~...(_.;_. ., :-_ ‘; :- Where-economrccansideratidn~8n-dl~r-bth~r’pertinent consider- ations.preclude overfilling and cuttilg back, alternative con- ventional~ construction procedures may be attempted. If other methods, including backrolling, are adopted, it should be recognized, by all interested parties that the slopes cannot be expected to perform as well as slopes which are overbuilt and cut back.~ Unless slopes are overfilled and cut back to grade, the otitei faces of all fill,slopes shall be at least back- rolled, utilizing’.a sheepsfoot roller at intervals not exceeding 4 feet of vertical slope height. Vibratory methods may be required;. ~During construction of the fill slopes, care should be taken to maintain~~near-optimum moisture conditions over ‘the entire slope’ height: Following achievement of the desired slope height, the, entire slope face may require thorough com- : paction, utiliiing a vibratory sheepsfoot roller. Upon completion of the above procedures, the faces of all filly slopes should . . . . . . ,~. ~. - . 6.5 6.5 6.5 6.8 6.6 i.6 6.6 7.0 7.1 7.2 8.0 8.1 f) cl) h) a) b) cl 4 -lO- Following slope construction in the manner described above, if the desired uniformly compacted fill slope condition is not achieved, overfillinu.and~utting back, as set forth in these- specifications;~should be adopted. Completed slopes found by the-geotechnical consultant to be below the standards [moisture and density) should be’overexcavated a minimum of 12 feet [horizontal) and replaced by the overfilling and cutting back procedure described above. .::. 7 c ‘i ,: / ,c I Where placementtof’.fill abovi a ‘natural slope ‘or above a cut slope is proposed, the fill slope configuration presented on the accompanying Plate 4, Figures 1 and 2, reipectively, should be adopted. :;- : ;~ ..’ For pad areas above fill slopes,. positive drainage shall be established away from the top-of-slope. This may be ac:, complished utilizing a berm and an overall pad gradient of at least 2%: .- Offsite Fill: Offsite fill, in general, should be treated in the same manner as recommended in these specifications for site preparation, excavation, drains, compaction, etc. .,. i. Offsite. canyon fill should be placed in preparation for future additional fill, as shown on Plates 7 and 8.. Offsite fill subdrains, temporarily terminated (up canyon) should be carefully surveyed for future relocation and.connecfian. - Surface-drainage of offsite fill areas should be planned to be collected and $kcharged by convenient storm drain devices. ~’ ,;, : <+ :’ . “. : ,. STAKING.;‘~ ,; ~~;‘;~;-~~I ~.~ : ,.WS ,,. - -, .- .~, In all fill areas, the fill should be compacted prior to the placement of the stakes. This’is particularly important on fill slopes. Slope stakes should not be~placed until then ~slope is thoroughly compacted (backFoIled) : .~ ~~~.. ‘;‘. ,’ 7 . In order to allow. for. remedial grading operations, which could include overexcavations or slope stabilization,~ appropriate staking offsets should be provided. For finished slope and stabilization backcut areas, we recommend at least a lo-foot setback from pro- posed toes and ~toos-of-cut:: 1 . . ~: : ._.,.. ‘Y-g’: ~ .: -: ., ’ II,. ..,., ,~:~I ~:,,” ,. iLOPE MAINTENANC~~~~~~..:I.~-..~:::I~~~~:l_i;: .* :. .’ -A-,~: _ ,. .njs. . , j ,: _:.. -.;,:y i ” . . .i. .~ Landscaping : In order to enhance surficial slope stability, . slope planting’ should ~consist of deep-rooted vegetation requiring : , -ll- and plants relative to native p1ant.s are generally desirable. Plants native to other semi-ari’d and arid areas may also be appropriate. A landscape architect would be the best party to consult regarding actual types of plants and planting configuration. al Irrigation: Slope irrigation should be minimized. If auto- matic timing devices are utilized on irrigation systems, pro- visions should be made for interrupting normal irrigation during periods of rainfall. .~ ) . ,,;,.‘.I ,,: ., . 5 ._ .,.. 1, ,>i Drip-irrigation systems may be utilized as ‘an alternative to con- ventional irrigation systems. .~ : .., .: : 8.2 8.2 .~ b) 8.2 cl 8.2 d) a. 3 al 8.3 b) 8.3 cl a.3 4 8.4 al 8.4 bl Though not a requirement, consideration should be given to the installation of near-surface moisture monitoring control devices. Such devices can aid in the maintenance of relatively uniforms and reasonably constant moisture conditions. -.~:e.-T, Property ow’ners should be ma&‘&are that’ overwatering of / slopes is detri.mental to slope stability. Maintenance: Periodic inspections of landscaped slope areas should be planned and appropriate measures, consistent with the provisions of these Standard Specifications, should be taken ‘. to control weeds and enhance growth of the landscape plants. . Some areas may require occasional replanting and/or reseeding. Terrace drains and downdrains should be periodically inspected and maintained free of debris., Damage to drainage improve- ments should be repaired immediately. .:~ -...1. ,;..-I.~ by ; ,~ .._, y -_.. ...-:;, +.:;~,. i, - ,,. :f .y .~ ..: ‘. Property owners should be”made aware than burrowing animals can be detrimental to slope stability.. A preventative program should be established to control burrowing animals. 1. ,. .: .,. .~ .y;:-; ; ;,. ,i :s;;,<“. : : As a precautionary~‘mea’sure;. ptasti$ sh:eting should be’ readily. ‘. available, or kept on hand, to protect all slope areas from~ saturation by periods of heavy or prolonqed rainfall. This. measure is strongly recommended, beginning with the period of time prior to’~landscape planting and before becoming well established.,:~ ,~‘..-,.~ Ed .- ~: ..( f*. .,‘.j.‘. :. Repairs:- If slope failures ‘occur, the geotechnical consultant should be contacted for a field review of site conditions. .~ . . If slope failures occur, apparently as a result of exposure to per@ds.!oF heavy rainfall, the ~failure area and currently unaffected areas should be covered with plastic sheeting to ; protect against additional ~rdin.:‘~~~;,:-:.“~--:- .. -‘.~ ” ,.,, ~,;; 1; .., t .~) .~. ‘_ .‘.~ :. ~ EFRHART.AXTEN and ASSOCIATES, INCA :‘;“:~,I~‘~1;~~~-~- ;:,+‘: : ~.~ .~ ’ ; ,’ -‘!’ . 8.4 9.0 9.1 9.2 9.3 9.4 10.0 10.1 10.2 10.3 -12- c) Plate 9 illustrates appropriate repair procedures for super- ficial slope failures (i.e., occurring typically within the outer 1 foot to 3 feet? of a slope face) during grading. These failures generally occur as a result of failure to comply with the in- tentions of Specification Sections 8.0 and/or 9.0 herein, DRAINAGE ‘, Canyon subdrain systems specified by the’geotechnical consultant should be installed in accordance with the specifications on. the ~~ accompanying ,Plate 1. : _ ‘. ~. : . ._, 7 Typical subdrains for compacted fill buttresses, slope stabiiizations, or sidehill masses, should be installed in accordance with the specifications on the accompanying Plate 2. :.,, _ ~. ‘. ,‘. All roof, pad and slope drainage should be directed away from slope area structures to approved disposal areas by way of non- erodible devices, (i.e., gutter, down spout, concrete swales). For drainage immediate& away from structures, a minimum 5% gradient should be maintained. Overall pad drainage of at least 2% should be maintained. Overall, pad drainage may be reduced to at least 1% for projects where no slopes exist, either natural or manmade, of greater than 10 feet in height and where no slopes are planned, either natural or manmade, steeper than 2:l (her: izontal to vertical slope ratio).; Trench Backfill:’ ,. . . . -~I ‘.l., .~ Utility trench backfill can be b&placed by mechanical compaction. Unless otherwise specified, degree of com- paction shall, be a minimum of 90% of,the laboratory maximum density. .y~ ;;.i,.;. :.‘,I- . ,~ .;,<y:- :. - .( As an alternattve,~ wher;! specificali~‘gippr~~~;e:d“b~~~ti;~~~~soil engineer, granular ,mateiial (sand equivalent greater than 30) may be thoroughly’.. jetted in-place. Jetting should only~ be considered to apply to~..:~ .~_ _. : ( trenches no greater. than 2 feet in width and 4 feet in depth. : ~4, Following jetting operations, trench backfill should be thoroughly and mechanically compacted and/or wheelrolled from the surface. ,, Exterior and interior trenches extending below a 1: 1 projection from the outer edge of foundations should be mechanically corn- pacted to a minimum of 90% of the laboratory maximum density. Within slab areas, but outside the influence of foundations, trenches up to 1 foot wide and 2 ,feet~ deep may be backfilled with sand and consolidated by jetting, flooding, or by mechanical means, If qn- site materials are utilized, they should’be wheelrolled, tamped or . otherwise compacted to a firm condition.:~ For- these minor interior trenches; density testing may be deleted or, spot testing may be elected if deemed necessary, based upon review of backfill oper- ations during construction. j. ‘_. .,,; .-;::.Y :$.J, .,+.:-, :-r?: : r. I .~ : .~... I ~.. -.:;p. :. . . If ,tilit,‘;coni;a~~~~s..indicate.r‘ ;. .,<;+.;>:, .:.-;;i’.4 v>...;. ;.:,::. . . .” .._ I:. .~.T: ..,. ::,,.l. ;.~ that it-is’ undesirable to use&m- .~ _ .*..:,‘ paction equipment’ inclose proximity’to’~‘buried conduit, the con<.. :‘,‘?I. : 1. tractor may elect the utilization of lightweight mechanical ‘:(. -~~~~;~:~:~~, “~‘~-“.:~?: I , .;,. .,.. \,.~ I -.;: ..,i: ‘? .ri~*,.i ‘+ ..&, ; I _: :‘:I .;:.y ‘, .;. .y :~.. ;i: i, ._l~i~~-l-:;;i:~~~~~;;:~~~‘i~~~~:~’~ ;. ; i j. jiy’,+ -f,: ‘. ..: j . ~:.~ -,~1* .~I.- ._ .: ‘i: . -: ..,, ~. 1: ,i- . I: ‘:. ::,:;..s ‘.L<<. :;y:..,::,.,;, ‘,,;..:;I.;s,/ ..,, - ) ~. .:’ .) :. ‘,‘. : ., _’ e EEERHART-AXTEN and ASSOCIATES, INC ‘*~ 1-.’ :~“;; :’ jic~j.~:::j..;~,’ -.:t. :2.;,:;~‘-;,,:..‘;. ..~~ ‘, : 11.0 11.1 11.2 12.0 -13- compaction equipment and/or shading of the conduit with clean, granular material, which could be thoroughly jetted in-place above the conduit, prior to initiating mechanical compaction procedures. Other methods of utility trench compaction may also be appropriate, upon review by the geotechnical consultant at the time of con- struction. STATUS OF GRADING Prior to proceeding with any grading operation, the geotechnical consultant should be notified at least 2 working days in advance in order to schedule the necessary observation and testing services. Prior to any significant expansion or cut back in the grading op- eration, the geotechpical consultant should be provided with zi adequate notice (i.e., 2 days) in order to make appropriate adjustments in observation and testing services. ,: .~ a., Following completion of grading operations and/or between phases of a grading operation, the geotechnical consultant should be pro- vided with at least 2 working days notice in advance of commence- ment of additional grading operations. VARIANCES FROM SPECIFICATIONS .*. The contractor should not vary from these specifications without prior written recommendation by the geotechnical consultant- and the approval of the client and/or his authorized representative. The above~ should not be considered to preclude’ requirements for approval by the controlling a*n,cy.prior -to the_excecution of any changes. _.-. .- .~,__ . . . - .~., .;, _, ..‘. :~ I ~., ~~.~ ;.: ‘. : ;i’ r-‘ L ~1 “g t.+ r;.T.‘:.;:.-:I~-,-::-:‘..,;~~:-;-::i.:. :,’ ‘, ~,:~ I .,.. ! _,.~ ~,:. -~. :. - * , _.. ‘. i ,: ;;:,,. : j~l ..T,’ -.. h ,*. 1 ..-‘- :.I _ . . ,. >. : ; ,,Y’. I~” -: & ~~. :~“. -‘Y-.. ;.c.~--?.;‘- . . :~ $ ‘~ ‘i. ..*+;:‘& $-~ t .r_ ‘:“. :‘~yg’;;‘$.y ,:., _: ;; ..,. L’- +y _‘I.‘. .a:- -’ . ~-’ ,. ,, . . ..~ : : . _ ~. - . . . : f :pi i ,. , ~~: . . . . 7. ” ,, * I . . .a , . . ~, c3 :_ m EBERHART-AXTEN and ASSOCIATES, ,NC “-~ I~:,,:~;’ y:“,;.~ :<‘I :,:.‘.‘: .: , ,.-.r : ;.:: ..,- 1, > ..~ I I I I I I I I I I TYPICAL CANYON SUBDRAIN ALTERNATIVE A- PREFERED BACKHOE TRENCH- CANYON PROFILE ALTERNATIVE C DOZER V- TRENCH ~s?i,%sl~~ - I=- -2 1. CWAL EOft OFPPZ SIlqULD AE Acw-A7Eo PoIn-,“L c*NxLcT/av-~uLo aa P.uw,D.EB bl,Usz.v 2P ey” -#v-r QT Nr: w S/4” ROCX- 2. %?,wRA7zws J/fO”LD as ai- w r(NBLb % ,Nca HAr. 0/.4prrER wow Pyl,v. a= s U.v/~~LY -5TAc.50 P.cufn.e*w ALTERNATIVE ‘6 FE? Pzlar~/N LOrYM Ayczxw o,=AIP.c. ZNMY CJSS L%ayazTrn OF C1IR.=o/uT,oM SlrWLD BE L ow a= .=,LTLcI .+wrWIL. BACKHOE TRENCH 3. gf-E&4~~~~L”“” ~oTwti* .iPPrn~D, SAKWLD 4 tiL7z/c .y.4T.Gv.L SYOULD CONSIST- a= ST&q OF /.&$&@& . c&L/FORMA. CL&D .? fEx.-s*a&5 F,LTER #y,*. 5 l-o* ALTLR”“T,YL b q4* ROCK /.r A NLTLR +-..MK (.Eos= 70) -Lo dc “SIC. GRADING DETAIL (3 EBERHART-AXTEN and ASSOCIAiES. INC. a GEOTECHNICAL CONSULTANlS 22311 EAST Yu6Ton Mus.stJm F-Ae4A”EIY. ULWOR”ll.3(D6 STANDARD GRADINGS SPECIFICATIONS IPLATE 1 1 I TYPICAL SUBORAIN FOR BUTTRESS , STABILIZATION OR SIDEHILL FILL MASSES . I a/rUT.5 7vLcE SPLchD 47 ‘oo&wA~;~~~” “.~ 2 I I , Bu7n?Ess, .sTld,“z”Tm” -A. OR S/LuLMIL F//x f- 7’ -m-I? ISly f I L N CD-ES. 1. FALTER ryAT‘E8,AL SMo”LD BE 6Tm-E’OF CAUFORN,A CLASS 2 P.ER#y,AaLs FILTER. GRADING DETAIL @ EBERHART-iXTEN and ASSOCIATES. INC. a GEOTECHNICAL CONSULTANTS 1311 EAST *INsToN RoAD.WTE ~-*NI”EtY.cALIFcmNI* smm STANDARD GRADING SPECIFICATIONS J TYPICAL STABILIZATION FILL FIG. I TYPICAL BUTTRESS FILL FIG. 2 i GRADING DETAIL EBERHAdT-AXTEN and ASSOCIATES. INC. a GEOTECHNICAL CONSULTANTS : RII IASTWIMKJW RO*D.IUlrrF.~N*H~I”.C~LPORIII**~ STANDARD GRADING SPECIFICATIONS I PI ATF 7 TYPICAL FILL OVER NATURAL SLOPE TYPICAL FILL OVER CUT SLOPE N OTbs.- 1. IF o#u.e- A..!42 Curr~Aw - 7u GRaDA 4s AooR‘=D, ksf t WAY br RW 7w R f.? ,y,M. $9 no us.% ,uDmk-, Y*LL T”.s s=zL )Ybn#Ds SquaL 7w- 7xu.M “UC 7mc F,U YrviYT R+K+J.#Md. GRADING DETAIL EBERHART-AXTEN and ASSOCIATES. INC. GEOTECHNICAL CONWLTANTS ’ 223, ms,v,Ns,0w ROID.ZUITl‘-IHIHEI”.ULI~OR*I*~ .- GRADING SPECIFICATIONS TYPICAL REMOVAL OF TRANSITION LOTS NATURAL MATEMA GE0TECHNlCAL~CONSllLTANlS -: I, :J.;-, _... rn9 EmwINsToN “019.SU(rr*-I~HEIU,ULI~OR*I*- : .- PLATE 5 1 1 TYPICAL ROCK TYPICAL ROCK I WINDROW WINDROW PROpoJdD P-/,wse%D LiRlPI PROpoJdD P-/,wse%D LiRlPI Q 0 0 0 0 0 0 TYPICAL WINDROW DETAIL (edge viiew) -\L_,~-~, GRADING DETAlL N PUcro WD XI HD 07EJ: &u-r NUTI @I EBERHART-AXTEl’i’and ASSOCIATES, INC. L #OLLory/,v~ 7w.E cc.y-rrvr cv Txe a&w* AEwcyian7J,dyT Am 723 PrTocdPlsci avw,” .4Leuz~N4L FnL, E*LI a&amSiV bwyybdl @J GEOTECHNICAL CONSULTANTS 7w=?4?c.uewLYco3rpI.sLD /=aw,y TNb suR,uti 2. T e. 7%% CO”?-x4.zTo~ sHa,za P7az.*~ wFF/c/m am/ CT.=, Te PDW.ye7 LOdTxo.M~~OF~b”7t,sD’nQz#~ i.:- I-.ier :..< 3 DzK-asA z ,” ST-.-7 R -M =“c.LPm M CLIAR Mm MTT- 1 STANDARD GRADING SPECIFICATIONS ??,a u2.T*INsmN ruuo,slu*rr.~rilu,er~aol.,r..3*1 .--~ -‘-‘-r .7:. 4 .‘ .~ kAus,-y4. ..,. _&.._. ~,.._~. ~ - . . I.-~----- --- -~-- IPU\TE 6 . ADDITIONAL COMPACTED FILL ON EXISTING CANYON FILL (VIEW UP CANYON AXIS) --- PJ?OPDS~D ENGINEERED F,Lc ADDIT/ON*L ~O,~PACT.D F/%.,2 ;.. .T L8~-K aS WATER/AL ACCEPTABLZ- 7-o GeoTLrHN/c*L CCYYSU 17wT / * BEFORE pUc,rvB ADD/TXXWL W+WACTa F,L.& GRADING DETAIL @ EBERHART-AXTEN and ASSOCIATES, INC. a GEOTECHNICAL CONSULTANTS 1111 E*wINsTM RouJ.slnTE F-ANA”LtY.cALlFORWIA Pm . STANDARD GRADING SPECiFICAT& IPLATE 7 , -I I I I I f- - ADDITIONAL COMPACTED FILL ON EXISTING CANYON FILL (VIEW OF CANYON SIDE) . N..7-“iv11 CSROUND ON C*NlvN .s,DL NEl.# or( “YSYT U”,?z 7 7 dEDR- rvl +r&-.u?‘AL AccEP~A- 7m G.cor=CH”,cAL CaeLuL7av7 4 E.=mRa PIAC,NO ArvxrmNAL cafPAC7s‘a F/U GRADING DETAIL EBERHART-AXTEN ond ASSOCIATiS, INC. GRADING SPECIFICATIONS I -. --- ---_ _ ,TYPlCAL MINOR SLOPE FAILURE REPAIR DETAIL Mlnlmum 3ft. wlds by 2ft high~borltontat;., . end vertical benches lntc~flrm undisturbed l&ace sxcovated area with fill In b-ln.(max.I lcc~ ~. _ 11th adlusted to near optimum mol~ture and compocte to a mfnlmum of 90% of the laboratory maxlmum Excavate key Into firm undsrlylng denstty as dstsrmlned In accordoncs wlth method unaffected materlal of teat Dl557-70. Slope wrface cc” ba best __._ ___.___ ----_--~ .--.--. -_.-- constructed by overfllllng and cutting back to the ..~. firm compactsd Inner core. . __ . T_YPIC~L~.SLOPE~REPAIR~ BACKDRAIN DETAIL~-.-~~~~~._ --- -.-~ geotechnkol consultant during construction. -” * __~. _.. ..-_ ( ~.~. ~__ ._~.~ .~ ._ ~._. -.L.-~ _ ! . _.. .~.. -. ..z ._ ,- ..~ .., ~:...-~--.A . . (.... ~. AL ..__.... ._~.. ~... _ _~~_._ _~~.._ ~_~ : .( . . _~ .-a- -.- ------- -~. - .--_~--. NOTE1 Sack dralnr are oftsn cmlttsd fmm slope repalrs. Where Installed, 1~ _-... - I ._ . ~~ .~ ~. _~.~.._~.. ,.- _...... ~. ~._ _.._ howeb?r, they serve to mltlg~ts tha pctsntlal for reoccurlng .falluras. “. .~_~.. :y &: ----.-.yi ._A.. T. .___ - ___._... ~ ._,- -.. . _rr:._rr,_~~~~!z_:_:, _._-._ 1 . . _ _ :;:L. : . , ..-_. :- . . ..- ~-.~. -. .._~.. ..~ . ..1 ____. ! ‘/ I 4 -~; I I 1 I ; ii ! ! ! I ’ 1 .: i I i ./ t 1