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HomeMy WebLinkAboutCT 82-12; Cannon Road Reach 3; Soils Report; 1988-09-281550 Hotel Circfe North San Diego. Caii!ornia 92108 (619) 294-9400 Fax: ,619, 29:.-920 WoodwarcbClyde Consultants K ‘L ;1, +?p$ @JL, R LpcC.~ 2. Seprember 28.1988 Project No. 8851198R-SIOl -1 -! .- I P&D Technologies 401 West ‘A’ Street, Suite 2500 San Diego, California 92101 Attention: Mr. Lee Vance GEO’IECHNICAL INVESTIGATION FOR THE PROPOSED CANNON ROAD - REACH 3 CARLSBAD, CALIFORh?A Woodward-Clyde Consultants is pleased to provide the accompanying report, which presents the results of our geotechnical investigation for the project. This study was performed in accordance with our proposal dated May 19,1988, and your authorization of June 1,198s. This report presents our conclusions and recommendations pertaining to the project, as well as the results of our field explorations and laboratory tests. If you have any questions or if we can be of further service, please give us a call. Very truly yours, WOODWARD-CLYDE CONSULTAhTS Vera Berger R.E. 32810 G.E. 2054 David L. Schug C.E.G. 1212 - I Consmng E-2 -eers Gmlogms and El”,ro”r*-:al Scle”r.srs -I 1 - - -I i , DISCUSSIONS, CONCLUSIONS AND RECOMMENDATIONS 2 -1 -I Project No. 8851198R-S101 Woodward-Clyde Consultants TABLE OF CONTE&X PURPOSE AND SCOPE OF IWESTIGATION DESCRIPTlON OF THE PROJECT FIELD AND LABORATORY INVESTIGATIONS SITE, SOIL AND GEOLOGIC CONDITIONS Geologic Setting Surface Conditions Subsurface Conditions Landslides Faults Potential Geologic Hazards Groundwater Excavation Characteristics Soil Characteristics Slopes Grading and Earthwork Embankment Settlements Flexible Pavements UNCERTAJNTY AND LIMITATIONS Fieures ::6. Vicinity Map SitePlan and Geologic Map (under separate cover) Field Investigation Laboratory Tests Guide Specifications for Earthwork Guide for Oversized Rock Disposal PAGE NO. 8 8 10 10 10 11 12 13 14 15 clvb2 -I Project No. 885 1198R-SIOl Woodward~Clyde Consultants GEOTECHNICAL INVESTIGATIOX FOR THE PROPOSED CANNON ROAD - REACH 3 CARLSBAD. CALIFORNIA PURPOSE AND SCOPE OF INVESTIGATION This report presents the results of our geotechnical investigation for the proposed alignment of Reach 3 of Cannon Road which extends northeasterly from El Camino Real for approximately 0.9 miles. This report has been prepared exclusively for the Buie CorporationKarlsbad Development Company, Ranch0 De1 Cerro joint venture, P&D Technologies and their consultants for use in evaluating the property and in project design. This reports presents our conclusions and/or recommendations regarding: _, . The geologic setting of the site; . Potential geologic hazards; -i . General subsurface soil conditions; . General extent of existing fill soils; . Conditions of areas to receive fill; . General excavation characteristics; . Characteristics of proposed fill material; . Presence and effect of expansive and compressible soils; . Groundwater condirions wirhin rhe depths of our subsurface investigation; cfvb2 -1 - - i -! -1 - I - i -I Project No. 885 1198R-SIOl . Stability of proposed cut and fill slopes; . Grading and earthwork; . Settlements; and . Flexible pavement design. DESCRIPTION OF THE PROJECT WoodwardGyde Consukants For our study, we have discussed the project with Mr. Lee Vance of P&D Technologies and we have been provided with an undated, unsigned set of drawings entitled “Plans for the Improvement of Cannon Road”, prepared by P&D Technologies. In addition, we have also reviewed the following reports prepared by our firm; . “Geotechnical Investigation for the Proposed Cannon Road - Reach 1, Carlsbad, California,” dated September 26, 1988; and . “Draft Report, GeorechnicaI Investigarion, Macario Canyon Bridge, Carlsbad, California,” dated Seprember 7, 1988. We have also reviewed pertinent stereographic aerial photographs and available geologic maps. We understand that the project includes construction of a new roadway extending from the existing El Camino Real (approximate Sta. 10+50) for approximately 0.9 mile to the beginning of the Cannon Road - Reach 4 (approximate Sta. 59+.50). Based on the project plans available to us at this time, we understand that cuts and falls of up to 30 and 12 feet, respectively, will be required to consnuct the road. Maximum inclinations for cut and fill slopes of 2:l (horizontal to venicsl) are indicated on the plans. The project Vicinity Map is presented as Figure 1. The location and layout of the roadway alignment is shown on the Site Plan and Geologic Map (Figures 2 through 6) provided under separate cover. c/vb2 -2- WoodwardCtyde Consultants Project No. 8851198R-SIOl -1 i - I - I FIELD AXD LABORATORY INVESTIGATIONS Our field invesdgaion included making a visual geologic reconnaissance of the existing surface conditions, making t\vo exploratory borings on June 29 and 30, 1988, excavating nine backhoe test pits on July 18, 1988, and obtaining samples. The borings were advanced to depths ranging from 53 to 77 feet and the test pit depths ranged from 4 to 16 feet. The locadon of the borings and the test pits are shown on the Geologic Maps, Figures 2 through 6. We have used a consecutive numbering system for borings and test pits for Cannon Road - Reach 1 and Cannon Road - Reach 3 projects. The numbering for this project starts with Boring 4 and Test Pit 11. Borings 1 through 3 and Test Pits 1 through 10 are part of the Cannon Road - Reach 1 project and they are included in the above-mentioned September 26, 1988 report. A Key to Logs is Presented in Appendix A as Figure A-l. Final logs of the boring and test pits are presented in Appendix A as Figures A-2 through A-15. The descriptions on the logs are based on field logs, sample inspection, and laboratory test results. Results of laboratory tests are shown at the corresponding sample locations on the logs and in Appendix B. The field investigation and l&oratory testing pro,Qms are discussed in Appendices A and B. SITE, SOIL AAJ GEOLOGIC CONDITIONS Geolotic Setting The project alignment is sited in an area characteristically underlain by the erosional remnants of Pleistocene river terrace deposits and Eocene sedimentary units that line the edges of the Agua Hedionda Creek Valley. The alignment crosses portions of the valley itself and major tributary canyons which are characterized by thick accumulations of Holocene alluvial soils. Cretaceous granitic basement rock outcrops in areas east and north of the alignment and is present ar shallow depths in localized portions of the alignment. - clvb2 - Woodward+de Consultants - - - -, -I I-I - I -1 Project No. 855119SR-SIOI Surface Conditions Extending northeast from El Camino Real within Xgua Hedionda Creek Valley, the Reach 3 alignment stretches across the lower hillsides and drainages bordering the north side of the valley. After crossing a relatively wide side canyon drainage, the alignment continues up the lower flanks of the adjoining hillside and eventually enters the hard rock terrain in the end portion of the project area. Elevations through the Reach 3 alignment range from a low of approximately 35 feet (N.A.V. Datum) within the Agua Hedionda Creek Valley near El Camino Real to nearly 110 feet at the northeast end of the project. Natural vegetation along the alignment is limited to moderate to dense trees and brush bordering the valley near Station 19+50 and the side canyon near Station 48+50. Over the remainder of the alignment, the natural vegetation has generally been removed and the surface cultivated. Several of the fields were under crop at the time of our investigation; those areas not being used supported a sparse to moderate regrowth of weeds and gasses. ;Man-made construction within the alignment consists primarily of paved and unimproved access roads and the remnants of a building foundation near Station 50+00. Some shallow irrigation lines cross the alignment and a large underground municipal water line parallels the road near Station 48+80. Residences and packing facilities are present adjacent to the alignment within the Reach 3 area Subsurface Conditions The project alignment is underlain by fill soils, recent overburden soils including stnficial soils and alluvium, Pleistocene Fluvial Terrace Deposits, the Eocene Santiago Formation and Cretaceous granitic rock. These geologic units are described below. The approximate area1 extent of each unit, with the exception of thin or discontinuous units such as some fill and topsoils, are shown on the Site Plan and Geologic Map (Figures 2 through 6). The geologic map symbol for each mapped unit is given after the formal name of the unit. -I -. I c/vb2 -4. -i -i Woodward-Clyde Consultants Project No. 8S5 1 I9SR-SIOl - i -I -i Fill soils within the alignment include road Ells for El Camino Real and the access road near Station 39i-00. Fills for El Camino Real arc estimated from the grading plans to be up to 9 feet in thickness at the west end of Reach 3. Test Pit P-15. which was made in the access road, indicated that the fill is that area consisted of sandy clay to clayey sand and it was up to 4 feet thick. A till pad composed of similar soils supports the packing facility adjacent to the alignment near Station 36+00. Some small fills may be present near the concrete foundation located at Station 5O+CO. Surficial Soils (unmapped) Natural surficial soils which overlie formational soils at the site include topsoil and residual clay soil. Our field reconnaissance indicates that the topsoils have been disturbed over most of the site, primarily by cultivation. The topsoils, where present in our test excavations, generally consisted of silty to clayey sand and were up to approximately 1.5 feet in thickness. In most cases, the topsoils were observed to be underlain by a residual clay horizon composed of sandy clay that ranged up to 2.5 feet in thickness. -i Alluvium (Qd) - 1 ,- I Thick accumulations of natural alluvial soils are present within the Agua Hedionda Creek Valley and within the side canyon drainages crossed by the project alignment. Test Boring 5, drilled in the valley near its northern edge encountered approximately 43 feet of alluvial sediments. Alluvial deposits in the large side canyon crossed by the alignment were indicated in Test Boring 4 to he in excess of 77 feet in thickness. Our test excavations along the alignment indicate that the alluvial soils generally consist of interbedded loose to medium dense sands and soft to firm clays. -i Fluvial Terrace Deposits (Qt) -I -I - 4 -/ Fluvial terrace deposits are present along the lo\ver hillsides bordering the Aqua Hedionda Creek Valley and the large side canyon drainage near the east end of the site. These soils, as clvb2 -j. - Project No. 5851198RSIOl Woodward-Clyde Consultants indicated by our test excavations, consist primarily of medium dense, clean to clayey sand which locally contains some small gravels. Santiago Formation (Ts) .- -: -I - I Interbedded, very dense sands and hard clays characterize the Santiago Formation in the general site area. Based on our experience, concretions and cemented layers are not uncommon within the Santiago Formation. Observations in Test Pit 19 indicate that a weathered horizon consisting of firm clay soil may be locally present in the upper Santiago Formation sediments. Granitic Rock (Kgr) Observations made during our general site reconnaissance indicate that granitic rock outcrops in areas directly north and east of the eastern portions of Reach 3. In addition, our test explorations indicate that weathered granitic rock is present below a mantle of fill, surflcial soils and/or Terrace Deposits in the vicinity of Station 39+00 through 40+25. The granitic rock materials observed in the Test Pits P-15 and P-16 consisted of hard sandy clays which exhibited less weathering and have increasing sand content with depth. Our experience with graniric rock materials in the general site area indicates that the granite can range in composition from clay weathering products to fresh, unfractured rock. Smtctttre The large majority of sedimentary formational soils observed at the site appear to be massive or have poorly defined bedding. Available geologic literature indicates that approximated bedding attitude measurements, recorded within Santiago Formation soils in the general site area are variable and range in dip from zero up to 10 degrees in a north or south direction. Such variability in bedding is common in areas near a contact with underlying basement rock. - 1 - -I clvb2 -6- -I - Woodward-Clyde Consultants ( - I -I -1 Project No. 8851198RSIOl Groundwater Our test explorations encountered a shallow groundwater table within the alluvial soils in the major drainages along the alignment. Test Boring 5 and Test Pits P-12 and P-13 encountered a water table at depths of approximately 3 feet (elevation 32 feet), 11 feet (elevation 33 feet) and 13.5 feet (elevation 36.5 feet), respectively. Test Boring 4 made in a wide side canyon drainage encountered a perched groundwater table at approximately 10 feet (elevation 52 feet). Estimated permanent grottndwater table in that area is approximately 22 feet from the ground surface (elevation 40 feet). No other occurrences of groundwater, such as seeps, springs or unusually wet areas were observed on the surface or in our hillside test excavations during our field studies. Landslides Features suggesting the possible existence of landslides within or adjacent to the alignment were not indicated during our site investigation or review of air photos. Our review of available geologic literature indicates that no landslides have been mapped in the area of the alignment. - 1 - .I -1 --I - ! Faults or indications of faults were not observed in our site reconnaissance or in our test excavations. However, our review of geologic literature indicates that a concealed fault has been mapped (Weber, 1982) as trendin g north-south within the side canyon drainage at approximately Station 42+50. Several other short faults are mapped within the Santiago Formation in arcas west, north and south of the site. The majority of the faults in the general project area are mapped trending between N6OW and N20’E with dips north or south ranging from 40 degrees to near vertical. The dominant local fault system is the Rose Canyon Fault zone which, when projected offshore along the coast, is within approximately 8 miles south-southwest of the site. Although the Rose Canyon Fault zone has been historically seismically quiescent, a series of earthquakes with events up to Richter Magnitude 4.2 were attributed to the Rose Canyon Fault clvb2 -7. - - -1 ‘I -, J -, Project So. 8851198R-St01 Woodward-Clyde Consultants zone in San Diego Bay in 1985. Studies on the geologic history and characteristics of the Rose Canyon Fault zone indicate that it is capable of prod.ucing a moderate to large earthquake. Other known active fault systems where recurring seismic events of Richter Magnitude 4.0 or greater have been recorded are within the Elsinore Fault zone and the Coronado Bank Fault zone, located approximately 21 miles northeast and approximately 23 miles southwest (offshore) of the site, respectively. Both of these systems are also considered capable of producing a moderate to large earthquake. The most recent significant activity on local fault systems included a series of earthquakes registering up to Magnitude 5.3 on the Richter Scale which occurred on the nearest portions of the Coronado Bank Fault zone in July of 1986. DISCUSSIONS, CONCLUSIONS Ah?) RECOMMENDATIONS The discussions, conclusions and recommendations presented in this report are based on the information provided to us, results of our field and laboratory studies, analyses and professional judgemenr We have observed only a very small portion of the pertinent soil and groundwater conditions. The geotechnical recommendations made are based on the assumption that soil conditions do not deviate appreciably from those found during our field investigation. If the plans for site development are changed, or if variations or undesirable geotechnical conditions are encountered during construction, we should be consulted for further recommendations. Potential Geologic Hazards Faults and Seismicity Our field studies did not indicate the presence of faulting within the site area. A concealed fault has been mapped as trending north-south approximately at Station 42+50. The above fault, as well as the numerous fault segments mapped in the general site area are not considered active and they are typical of other faults observed in the Cadsbad area. It is our opinion that these faults do not represent a significant hazard to site development. However, if on-site faults are discovered during future site studies or site grading, their impact on site development should be evaluated by an engineering geologist. c/vb2 -8. Woodward-Clyde Consultants Project No. 8851198R-SIOl Known active fault systems exist to the northeast and southwest of the site. Therefore, it is not unreasonable to anticipate that the site, as well as the entire North County coastal area, could experience relatively strong ground shaking due to a nearby or distant earthquake. Liquefaction Potential -i I - I - ‘I -, i -I - I -i Based on the model developed by Youd and Perkins (1978). the liquefaction susceptibility of soils can be assessed in a very general way in accordance with the age and type of deposit. According to this model, the Holocene age (relatively young) alluvial deposits are expected to have moderate to high susceptibility for liquefaction. The Pleistocene age Fluvial Terrace Deposits may have low to very low susceptibility for liquefaction, and the Eocene Age Santiago Formation and granitic rock do not pose a liquefaction hazard. The liquefaction susceptibility of soils can vary substantially from one site to another, dependent on the amount of cohesionless sediient and its density in each geologic unit. According to the results of our field investigation, clays and clayey sands comprise the majority of the alluvium at the project site, however, some portions of the alluvial deposits are composed of clean or slightly silty sands. Such sands are known to pose much larger liquefaction hazard than, for instance, fine-grained soils (clays and plastic silts) of the same geologic age and type of deposition. Mixed nature of the alluvial soils encountered in our borings (frequent interbedding of sands, silts and clays) did not allow a meaningful analysis of penetration blow counts and use of quantitative procedures (such as those developed by Seed and Idriss) for evaluation of soil liquefaction potential. However, based on the geologic nature of subsurface soils and our review of the field and laboratory test data, it is our opinion that alluvial sands and silty sands located below the groundwater table at the project site are susceptible to soil liquefaction at the ground shaking level specified by the City of San Diego Building Code, Section 91.02-2905. Soil liquefaction, if it occurs at the project site, will most likely manifest itself in sand boils, ground subsidence and differential settlement. C/V52 -9- Project No. SS51198R-SIOl WoodwarcbClyde Consultants - Landslides - Landslides were not identified on or adjacent to the site during our investigation. No landslides are known to have been mapped in the general site area. Groundwater - A relatively~shallow ,mundwater table (approximate elevations 32 to 33 feet) was encountered in Agua Hedionda Creek Valley. Perched water zones within the local side canyons and drainages are likely to be present due to percolated irrigation water. Perched water levels within alluvial soils are unpredictable, but can be frequently related to irrigation rates. Our experience indicates that local zones of perched water may be found in fort-national and overburden soils where permeable granular sediments are underlain by impermeable fine grained soils. It is our opinion that a permanent ,mundwater table may be- present in the local side canyons and drainages at approximately 20 to 25 feet from the ground surface. Based on our experience, we expect that the permanent groundwater table will vary only slightly due to seasonal variations in precipitation and runoff. Excavation Characteristics -, / ) - -1 Based on the results of our field investigation and general experience, the soils on the site can generally be excavated by light to moderate effort with heavy duty excavation equipment. It should be expected, however, that local cemented zones within the Santiago Formation and possible zones of relatively fresh granitic rock may require heavier ripping, possibly blasting, and may result in some oversized materials. Recommendation for placing oversize materials are contained under “Grading and Earthwork.” Soil Characteristics We expect that till soils generated from cuts in the River Terrace deposits will primarily be nonexpansive to slightly expansive sands. The sands of the Santiago Formation, alluvial soils, decomposed gmnitic rock and some surficial soils will range from slightly to moderately -I - c/vb2 -IO- Project No. 8351 I9SR-SIOl WoodwardClyde Consultants - I L I -I I -1 expansive. Formational clays within the Santiago Formation and residual clays will be moderately to highly expansive. It is our opinion that most of the alluvial soils and surticial soils along the alignment are compressible and may generate settlement if subjected to loads. Compression of sands and silts within the above deposits is expected to occur generally during construction; clayey soils may generate long-term consolidation settlement. Treatment of these compressible soils and estimated settlement are discussed later in the report. The soil strength parameters for use in our slope stability analysis were evaluated by a consideration of the results of previous slow direct shear tests performed on similar formations in the vicinity of the project site and in the general San Diego area, and the geologic characteristics of the formations. Stability analyses of fill and cut slopes for deep-seated failure were performed using the Janbu method of analysis. The results of these analyses for slopes of up to 30 feet high with inclinations of 2 to 1 (horizontal to vertical) indicate calculated average factors of safety for deep-seated failure of 1.5 or greater for static conditions. The above analyses assumed.no adverse geologic conditions or, groundwater. No stability analysis has been made for a seismic or other dynamic event. Stability analyses require using average parameters selected from a range of possible values; thus, there is a finite possibility that slopes having calculated factors of safety as indicated above could become unstable. In our opinion, the probability of the slopes becoming unstable is low, and it is our professional judgment that the slopes can be constructed as indicated above. We have also perfomred analyses of surficial stability of till slopes using the infinite layer method. In these analyses, we have assumed that up to 4 feet of soil below the slope surface may become saturated during rainy seasons. heavy irrigation, and/or upslope surface runoff. clvb:! -11 -( .- - I - ,! .I .- I -1 - Project No. 8S51198R-SIOl Woodward-Clyde Consultants The results of these analyses indicate an average safety factor of 1.6 for surficial failure of a 2:1 slope. Periodic maintenance of slopes may be required, including rebuilding the outer 1 l/2 to 4 feet of the slope. Sloughing of fill slopes can be reduced by overbuilding at least 3 feet and cutting back to the desired slope. To a lesser extent, sloughing can be reduced by backrolling fill slopes at frequent intervals. As a minimum, we recommend that all fill slopes be trackwalked so that a dozer track covers all surfaces at least twice. We recommend that all cut and fill slopes be planted, drained, and maintained. We recommend that an engineering geologist examine all cut slope-s and sloping areas undercut for placement of compacted fill for possible adverse conditions during grading. Additional investigation and analyses may be required, if adverse geologic conditions or ground water, are encountered. Grading and Earthwork We recommend that all grading be performed in accordance with the attached Guide Specifications for Earthwork (Appendix C). We recommend that oversize rock fragments (fragments between 2 feet and 4 feet in maximum dimension) be placed in accordance with the attached “Guide for Oversize Rock Disposal” (Appendix D). We recommend that no rock fragments larger titan 4 feet in size be used in tills. We recommend that a pre-construction conference be held at the site with developer, civil engineer, contractor and soil engineer in attendance. Special soil handling and grading procedures can be discussed at that time. We recommend that all loose, porous surticial soils within the proposed fill areas be excavated or scarified as required, watered, and then compacted prior to placing any additional fill. We recommend that the soil engineer evaluate the actual depth of excavation of surftcial soils in the field at the time of grading. cJvb2 -12. Woodward-Clyde Consultants Project No. 8851198R-S101 - - I .- 1 - 3 It is our opinion that excavation of deep alluvial soils located predominantly below the groundwater table within Ague Hedionda Creek Valley (approximately from Station lo+50 to Station 14+30 and from Station 17+30 to Station 30+00) and in the large side drainage extending from approximately Station 40+00 to Station 48+80 is not practical. Our ground surface settlement estimates and proposed construction schedule for the above areas are discussed in the section entitled “Settlement.” Highly expansive clayey soils could be encountered at grade in areas of shallow cuts and fills (daylight areas), or in deeper cuts in the Santiago Formation if siltstone or claystone is encountered. We recommend that these clayey soils be excavated to a minimum of 12 inches below rough road grade, and then be replaced with properly compacted, nonexpansive soils or slightly expansive soils available on the site. We recommend that the actual extent of excavation and replacement of clay soils be revaluated by the soil engineer at the time of grading. We recommend that general road fills be compacted to at least 90 percent relative compaction. The top 6 inches of sub--de material in the paved areas should also be compacted to a relative compaction not less than 95 percent. We recommend that all fill be compacted at least at optimum water content; the range of water content should be optimum to optimum plus 3 percent. Embankment Settlements It should be recognized that compacted fills will increase in moisture and consolidate during their lifetime. We estimate that road embankments placed directly on undisturbed formational soil and made of fill compacted in accordance with the recommendations of this report may develop total post-construction settlements on the order of up to 0.5 percent of the total fill height. Our experience indicates that tills with substantial amount of clayey soils are generally more settlement prone than fills composed of granular material. Fills and stressed natural soils subjected to the infiltration of water can consolidate and settle considerably more than indicated above. We recommend that drainage design incorporate the prevention of water entry into both tills and existin g natural soils loaded by tills. c/vb? -13- - Woodward-Clyde Consultants Project No. 885 1198R-SIOl -I - - - I - _I Long-term consolidation of saturated clays of the alluvial deposits underlying the proposed road embankment is also likely to occur. We estimate that the area of the fill embankment immediately northeast of El Camino Real (approximately from Station lo+50 to Station 14+30) may experience total post construction settlement ranging from 6 to 12 inches. Approximately 4 to 8 inches of total post construction settlements are estimated for the area approximately between Stations 40+00 and 48+OO. We estimate that it may take 3 to 6 months for approximately 80 to 90 percent of these settlements to occur. We recommend that embankment fills in the areas underlain by aIluvial soils not removed by gradiug be placed at least 6 months prior to road paving. Surcharge till may be placed in the above areas if it is desired to speed up the mad construction. We estimate that a surcharge of 5 feet will reduce the settlement period required to reach 80 to 90 percent consolidation approximately by a factor of 2. We recommend that settlement monuments be placed in the areas that have potential for consolidation settlement prior to placing new fill and the settlements be recorded by a licensed surveyor on a weekly basis during grading and for the first month upon completion of grading; readings may be made monthly thereafter. We recommend that settlement readings be forwarded to Woodward-Clyde Consultants for periodic evaluation. Flexible Pavements We understand that pavement design will be done in accordance with the City of San Diego Schedule I and that the asphalt section will consist of Asphalt Concrete over cement treated base. This schedule utilizes the subgrade soil R-value as the basis for design. An R-value test on a soil sample that appeared to have low subgrade resistance was performed and the results are reported on Figure B-3. It has been our experience that the R-values of the soil expected to be encountered along the proposed street alignment can vary widely. We recommend that R- value tests be performed on samples of actual subgrade soils after general grading and earthwork are complete. c/vb2 -14. Woodward43yde Consultants Project h’o. SS51198R-SIOl -1 I - I .) The subgrade should be compacted to a depth of at least 6 inches to a minimum 95 percent of maximum laboratory dry density in accordance with ASTM D1557-78. Cement treated base should confirm to Standard Specifications for Public Works Construction (1985), Section 301- 3.3. We recommend that asphalt concrete pavement be provided and placed in accordance with Section 302-5 of the above mentioned specifications. We recommend that mix design for asphalt concrete bz made by an engineering company specializing in this type of work, and the paving operations be inspected by a qualified testing laboratory. UNCERTAIXTY A&D LIMITATIONS We have observed only a very small portion of the pertinent soils and groundwater conditions. The recommendations made herein are based on the assumption that soil conditions do not deviate appreciably from those found during our field investigation. We recommend that Woodward-Clyde Consultants review the final grading plans to verify that the intent of the recommendations presented herein has been properly interpreted and incorporated into the contract documents. We further recommend that Woodward-Clyde Consultants observe the site grading and subgrade preparation under paved areas to verify that site conditions are. as anticipated or to provide revised recommendations if necessary. If the plans for site development are changed, or if variations or undesirable geotechnical conditions are encountered during consuucdon, we should be consulted for further recommendations. This report is intended for design purposes only and may not be sufficient to prepare an accurate bid. California, including San Diego, is an area of high seismic risk. It is generally considered economically unfeasible to build a totally earthquake-resistant project; it is, therefore, possible that a large or nearby earthquake could cause damage at the site. Geotechnical engineering and the geologic sciences are characterized by uncertainty. Professional judgements presented herein are based partly on our understanding of the proposed construction, and partly on our general experience. Our engineering work and judgements rendered meet current professional standards; we do not guarmntee the performance of the project in 2.7~ respect. -.J - c/vb2 -15. Woodward-Clyde Consultants Project No. 8851198RSIOI -I - - :) -I -’ - Inspection services allow the testing of only a small percentage of the fill placed at the site. Contractual arrangements with the grading connactor should contain the provision that he is responsible for excavating, placing, and compactin g fill in accordance with project specifications. Inspection by the geotechnical engineer during grading should not relieve the grading contractor of his primary responsibility to perform all work in accordance with tire specifications. This fmn does not practice or consult in the field of safety engineering. We do not direct tire contractor’s operations, and we can not be responsible for the safety of personnel other than our own on the site; the safety of others is the responsibility of the contractor. The contractor should notify the owner if he considers any of tire recommended actions presented herein to be unsafe. -. , -I - - / clvb2 -16- - - .~ j I I - - I - I -- - ~1 - -i 7 - : WUCONI-I-V MAP NO SCALE 1.: I C I I‘i I TY SAP C ‘..!.:l;W ROAD - REACH 3 IRAWN BY: cb CHECKED BY: v&, PROJECT r&85 I98R-S 101 DATE: g-1 5433 FlG”RE NO: I ~nnn~fittn~r~ Y~F i-nwtb T*UTP Woodward-Clyde Consultants - i .i .., 1 J - J Project No. 8851198R-SIOl APPENDIX A FIELD 1NVESTIGATlON Two exploratory borings and nine backhoe test pits were advanced at the approximate locations shown on the Geologic Maps, Figures 2 through 6. The drilling was performed on June 29 and 30, 1988, under the direction of a geologist from our firm, using an S-inch diameter hollow-stem auger. Test pits were excavated on July 18, 1988, using a Case 580E backhoe equipped with a 24inch bucket. Samples of the subsurface materials were obtained from the borings using a modified California drive sampler (2-inch diameter and 2-Winch outside diameter) with thin brass liners. The sampler was generally driven 18 inches into the material at the bottom of the hole by a 140-pound hammer falling 30 inches; thin metal liner tubes containing the sample were. removed from the sampler, sealed to preserve the natural moisture content of the sample, and returned to the laboratory for examination and testing. Additionally, bag and sack samples of the subsurface materials were obtained from the borings and test pits and returned to the laboratory for examination and testing. The location of each boring and test pit and the elevation of the ground surface at each location were estimated based on the available topographic maps. A Key to Logs is presented as Figure. A-l, Logs of Test Borings are presented as Figure Nos. A-2 through A-6. Logs of Test Pits are presented on Figure Nos. A-7 through A-15. -I -! -i clvb? A-l - - - .~. ..- .- - - - - - i .- - ) - - - Project: CANNON ROAD - REACH 3 KEY TO LOGS Date Drilled: Water Depth: Measured: Type of Boring: Type of Drill Rig: Hammer: 5 s f a 2 ;= r; gz F 2 zsae & b 0 ; m Material Description g-6 6’5% fz 2 0: Surface Elevation: 0 Id DISTURBED SAMPLE LOCATK)N Sample war obtained by collecting auger cuttings in a plastic bag. - Y4 DRIVE SAMPLE LOCATlON Sample with reoxded blows per foot war obtained with a ModSed CaMomM drive sampler (2’ inside diameter. 25’ 5- outside diameter) line with sample tubes. The sampler was driven into the soil at the bottom of the hole with a 140 pound hammer falling 30 inches. lo- Fill Sand Clay Silt 15- Silt/Sand Sand/Clay 20- %S - Grain Size Distribution Analysis PI - Plasticity Index LL - Liquid Limits CT - Consolidation Test ‘R’- R-value Test 25- 30, ‘reject No: 8851 lgSR-SO1 I Woodward-Clyde Consultants s Figure: A-l - - .~~ - - - - - - - - J .- - - .~ Project: CANNON ROAD - REACH 3 Date Drilled: 6-29-66 Water Depth: Perched water at 9’4 Type of Boring: 6’ HSA Type of Drill Rig: B-61 * see Key to Logs. Fig. A-l 25 f $+ 3 E s 0 ; ; Material Description Surface Elevation: Approximately 62’ (CL/CH), upper 12’cultivated Log of Boring No: 4 Measured: At time of drilling Hammer: 140 Ias at 30’drcq 2; g g ; ‘m s;$$-tg f;i $6 4 0: brown. sifty to poorfy graded medium sand (SM/sP) ALLUVIUM Firm, moist, gray brown, sandy fat clay (CH) with interbeds of light brown, silty to poorly gr+ded sand (SMiSP) ALLUVIUM lean to fat clay (CL/CH) ALLUVIUM ‘reject No: 6651196R.SlOl Woodward-Clyd$ Consultants e Figure: A-2 - ) 1 ; 2- .~ .- 1 .- ;I -, .- ! - 1 -4 Lo - ) - - -. Voject: CANNON ROAD REACH 3 I Log of Boring No: 4 (Cont’d) Material Description -----------. Interbedded. loose to medium dense, wet. yellowish brown, silty sand (SM) and firm, wet, yellowish brown, fine sandy Loose to medium dense, wet. yellowish brown, poorly graded sand (SP) with some layers of firm, wet. gray brown, sandy lean clay (CL) and medium dense, moist, yellowish brown. very clayey sand (SC) ALLUVIUM ‘reject No: 8851198R-SlOl Woodward-Clyde Consultants c 20 108 L 19 108 - - Figure: A-3 Woodward-Clyde Consultants Project No. 8851198R-SIOl -- )’ -~ I - I -1 11.5 Properly compacted till shall extend to the design surfaces of till slopes. The surface of till slopes shall be compacted in accordance with Section 11.1 of these specifications. 12. PLACING, SPREADING, AND CO~~~PACTIIIG PAVEMENT SUBGRADE 12.1 Subgrade materials shall be placed, spread, and compacted in accordance with Section 11 of these specifications, except that the top 6 inches of subgrade material shall be compacted to a relative compaction that is indicated by test to be not less than 95 percent. 13. PLACING AND COMPACTING TRENCH BACKFILL 13.1 Backfilling and compacting shall be in accordance with Section 306-1.3 of the Green Book, except that jetting or flooding shall not be aIlowed and that all backtill shall be compacted to a relative compaction that is indicated by test to be not less than 90 percent. 13.2 All trenches 5 feet or more in depth shall be sloped or shored in accordance with OSHA safety requirements. Trenches less than 5 feet in depth shall also be so guarded when examination indicates hazardous ground movement may be expected. 13.3 No compaction testing shall be required for portions of trenches backfilled with cement slurry. 14. PLACING AND COMPACTING WALL BACKFILL 14.1 Backfilling and compacting shall be in accordance with Section 300-3.5 of the Green Book, except that jetting or flooding shall not be allowed, and that relative compaction in the general till area shall not be less than 90 percent. 14.2 The Contractor shall be responsible for using equipment capable of compacting the backfill to the specified relative compaction without damaging adjacent walls or other existing improvements. 15. PROTECTION OF WORK 15.1 During construction, the Contractor shall properly grade all excavated surfaces to provide positive drainage and prevent ponding of water. When earthwork operations are interrupted, the Contractor shall reestablish specified compaction to the depth necessary before placing new fill. The Contractor shall control surface water to avoid damage to adjoining propenies or to finished work on the site. The Contractor shall take remedial measures to prevent erosion of freshly graded areas and until such time as permanent drainage and erosion control features have been installed. 15.2 After completion of the earthwork and \vhen the Geotechnical Engineer has finished obsenntion of the work, no further excavation or tilling shall be done except under the observation of the Geotechnicnl Engineer. clvb2 C-6 , Woodward4Zlyde Consultants Project xo. SS51198R-S101 APPESDIX D GUIDE FOR OVERSIZE ROCK DISPOSAL Oversize rocks larger than 12 inches may bz incorporated into the unclassified fill in accordance with the following guidelines. Also see Section 300-4 of the Standard Specifications for Public Works Construction. Refer to sketches above for classification of these guidelines. ZONE A: Shall be 15 feet measured horizontally from face of slope and 5 feet minimum measured venically from finished grade. In public rights-of-way and easements, Zone A shall be 10 feet minimum or must extend 3 feet below the deepest utility, whichever is greater. Zone A must consist of compacted soil only (no rock fragments over 12 inches in maximum dimension), must be in conformance with Section 300-4 of the Standard Specifications and shall contain at least 40% soil sizes passing the Winch sieve. ZONE B: Oversize rocks must either be individually placed or windrowed within this zone. For individual placement, rocks must be uniformly distributed and spaced so as to permit placement and compaction of soil conforming to Zone A material. For windrows, rocks shall be placed in excavations in well compacted soil conforming to Zone A requirements. Approved granular soil (SE > 30) must be flooded in the windrows to completely fill the voids around and beneath rocks. All windrows must be parallel and may be placed either parallel or perpendicular to face of slope depending on site geometry. All rock placement. fill placement and flooding of approved granular fill must be continuously observed by the Geotechniccll Engineer. Rock fills containing less thin 40% soil sizes p:tssin : W-inch sieve may be permitted in designated areas. Specific recommendntions sh:lll be m:lde by the Geotechnicnl Engineer and be subject to approval by [he City Engineer. c/vb2 D-l ~/ .~. .~~, ..~.I I ,-1 I -~ -~I I -1 -I .- I I I / I Project: CANNON ROAD - REACH 3 Log of Boring No: 5 Date Drilled: 6-30-66 Water Depth: 3 Measured: At time of drilling Type of Baring: 6’ HSA Type of Drill Rig: B-61 Hammer: 140 Ibs at 30’ drop ’ see Key to Logs. Fig. A-l r‘ g E 2 2 s $= -g EL? Material Description 22 ; -ta _o 5 g $ g’s8 sj; 0 2 m 20 2 0g Surface Elevation: Approximately 35 ALLUVIUM fine to medium sand (SM) slightly clayey sand (SC) and firm. wet. gray lo gray brown. sandy lean to cat clay (CUCH) ALLUVIUM Firm. wet. olive gray with reddish brown mottles, sandy lean to fzt clay (CLCH) wiih local zones cf lime and interbeds of tedium dense. wet. gray. clayey medium to coarse sand (SC) ALLUVIUM Project: CANNON ROAD REACH 3 Log of Boring No: 5 (Cont’d) 35- 40- 5-10 45- 50- 5-12 55- 60- 65, 27 !9 ‘5J6 ‘reject No: 6651198R-SlOl Material Description (Continued) firm. wet. olive say with reddish brown mottles. sandy lean lo fat clay (CL/CH) with local zones of lime and intetieds 01 medium dense. wet. grey. clayey medium to coarse sand (SC) ALLUVIUM .----------. Gredi”gto -- -------- -- ------ Firm. moist, mottled, grey end reddish brown, fine sandy lean day (CL) ALLUVIUM Medium dense, moist. olive gray with yellowish brown mottles, clayey medium sand (SC) ALLUVIUM OR WEATHERED SANTLAGO ‘\ FORMATk3N I - ----- ---. Gradi”g to ----------------- Medium dense, moist. olive grey. silty medium to fine se.4 (SM) with local zonee of silty to poorb graded medium to coarse sand (SMISP) ALLUVIUM OR WEATHERED SANTIAGO FORMA-RON Very hard. moist, dark olive grey. lean clay (CL) ALLUVIUM OR WEATHERED SANTWX FORMATION .----------Gradi”gto .---------- -------- Very dense. moist, olive grey. silty fine sand (SM) and fine sandy sik (ML) SANllAGO FORMATION Layer of very hard. moist. dark olive gray. lean clay Bottom of Boring at 53 leet Woodward-Clyde Consultants s 23 103 - L-25 1.42 -. .~~ I .- i -: ! 7 ‘I .~ - I - jl .- ! I I .- 61, I Project: CANNON ROAD - REACH 3 Log of Test Pit No: P-11 Date Excavated: 7-16-66 Water Depth: Dry Measured: At time of drilling Type of Excavation: 24’ backhoe Type of Backhoe: Case 560E * see Key to Logs, Fig. A-l i $ f z< - p F 22 e &?j z ‘2 0 2 s * Material Description c60ga f$ ‘Z $ 0 Ok Surface Elevation: Approximately 60 feet A 0 _ 11-l z Medium dense, dry, grey brown. clayey medium sand (SC) ,.s.?jy$ TOPSOIL :@ Medium dense, moist, light brown. poorly graded medium to s**y,i .:x*>.:::: axrse sand (SP) with some gravels end local sihy zones :&q;;; y&q;.!; FLUVtALTERRACE DEPOSITS 5- 11-2 $2; g$ ,d@ gg .@ g$$ Fewer gravels i$$$$ >m$ :A#* 10- Bottom of Test Pit at 9.5 feet 15- 20- 25- 30, ‘roiect No: 6651196R-Slot 1 Woodward-Clyde Consultants c Figure: A-7 - -L - - - - A - -1 i 2 I -. -j -. -1 / Project: CANNON ROAD - REACH 3 Date Excavated: 7-t 8-88 Water Depth: 11.5 Type of Excavation: 24’ backhoe Type of Backhoe: Case 5ZE ’ see Key to Logs. Fig. A-l r‘ 3 s $z 2 s 0 $ 2 Material Description Surface Elevation: Approximats~ 43.5 feet Log of Test Pit No: P-12 hfeasur@Z: At time of drilling F f x.5 5 ; ;, zzap 6‘2% =yj ‘g 8 s 6: ALLUVIUM Firm. moist. olive brown with reddiih brown mottles. sandy ___________ Grading to _______-___________ Medium dense, moist to wet, light brown with reddish brown mottles. silly medium send (SM) ALLUVIUM 20- 25- 30, ‘reject No: 885tl98R.Slol Woodward-Clyde Consultants e Figure: A-8 - -- - i -i -1 .,.. -~ I ~-1 ..:, .- -f -~ .- ! Project: CANNON ROAD - REACH 3 Date Excavated: 7-18-88 Water Depth: 13.5 Type of Excavation: 2C- backhoe Type of Backhoe: Case 580E * see Key to Logs, Fig. A-1 x- 3 f s g:= E Material Description 0 ; 2 Surface Elevation: Approximately 50 feet Log of Test Pit No: P-13 Measured: At time of drilling 2 -g r: p*b.~~ z> c*bgp 5: .g 6 0 O+ Medium dense, moist. dark grey, clayey medium send (SC) ALLUVIUM lean clay (CL) with some gravels ALLUVIUM Medium dense, moist, olive grey. very sitty to clayey very fine send (St&SC) ALLUVIUM Water seepage 13Stot5 Bottom of Test Pit at 15 feet 20- 25- 30, ‘rojeCt No: 8851198R-SlOl Woodward-Clyde Consultants = Figure: A-9 -! \ i 2 -3 .-I I -I -/ 1 -j -I / - I - -1 , -3 .- 1, -1 -1 - ~1 j Project: CANNON ROAD - REACH 3 Da:e Excavated: 7-18-88 W&x Deplh: Dry Type of Excavation: 24’ backhoe Type of Backhoe: Case 58CE * see Key to Logs, Fig. A-l L Is F s $+;-= 2 2 Material Description P G m Surface Elevation: Appmximaraly 102 feet Log of Test Pit No: P-14 Measured: At time of drilling z< - ;rn< co $8 ; ;n S$ +ri s 0; CULTIVATED SOIL Bottom of Test Pit at 4 feet lo- 15- 20- 25- 30, ‘reject No: fJ851198R-SlOl Woodward-Clyde Consultants s Figure: A-10 -- -1 - .- - ! -! I - 1 -! -> - - - Project: CANNON ROAD - REACH 3 Log of Test Pit No: P-15 Date Excavated: 7-18-88 Water Depth: Dly Measured: At lime of drilling Type of Excavation: 24’ backhoe Type of Backhoe: Case 580E * see Key to Logs. Fig. A-l i z r’ z 5 r: F&z -e r L3 ; 2 Material Description 22 0 F’ZTj z -2 c*ogp 5: .; 6 D Of- Surface Elevation: Approximately 67 feel 0 Moist, brown to gray brown. sandy lean clay and clayey medium sand FILL 15-l Loose. dry. light gT;ra;o;F silty fine sand (SM) Medium dense. moist, mottled, light brown and light reddish brown. clayey medium sand with some gravels (SC) FLUV!AL TERRACE DEPOSITS WEATHERED GFfANfTlC ROCK ‘rojecf No: 8851 lQQR-SlOl Woodward-Clyde Consultants 3 Figure: A-l 1 - Project: CANNON ROAD - REACH 3 Log of Test Pit No: P-16 Dale Excavated: 7-18.88 WSer Depth: Dry Measured: Al time of drilling Type of Excavation: 24- backhoe Type of Backhoe: Case 580E * see Key lo Logs. Fig. A-l i FG e 0 < F$ z s -0 Material Description ;<g &.& 22 0 z * g$ $ 6$ Surface Elevation: Approximately 72 feet Very herd. moist. ol’we brown with reddish brown mottles. sandy lean lo fat clay (U/CH) WEATHERED GRANfTlC ROCK Bottom of Test Pii at 4 feet 25- ‘rojecl No: 8851 l98R-SO1 Woodward-Clyde Consultants s Figure: A-12 .- - I -1 - .- -, -I -.~j Project: CANNON ROAD - REACH 3 Log of Test Pit No: P-17 Date Excavated: 7-l 6-6.6 Waler Depth: Perched waler al 5.5 Measured: Al time of drilling Type of Excavation: 24-backhoe Type of Backhoe: Case 580E * see Key lo Logs, Fig. A-l r‘ Ji f s ..a s= i? s g g cl ;: z Material Description z;s 2‘ZZ 2; ‘2 s oga P 0: Surface Elevation: Approximately 62 feet 0’ Loose. moist lo wet. brown. silly medium to fine sand (SM) $g:$.~{ ALLUVIUM ~~~ 17-l @; &g 5- ,g# Strong water seeps at 5.5 .‘\‘\ ,I\‘\ Firm, wet. gray brown with gray mottles. very sandy lean :\: clay lo clayey sand (CL/SC) 17-2 ,;, ALLUVNJM 3: ,‘#’ ,\ 10 17-3 Medium dense. moist, light brown lo light olffe. dayey medium to Bottom of Test Pit al 10 feel 15- 20- 25- 30, ‘reject NCI 6851 I gaR-Slol Woodward-Clyde Consultants s Figure: A-13 .- - - - ii - - - i - - - - - ,~. Project: CANNON ROAD - REACH 3 Date Excavated: 7-18-88 Wzer Depth: Dry Type of Excavation: 24- backhoe Tyse of Backhoe: Case 580E * see Key lo Logs. Fig. A-1 5 i E C&E e _o F Material Description 0 G m Surface Elevaiion: Approximately 103 feet Log of Test Pit No: P-18 Measured: Al time of drilling z< - $S< co & k> 5” gs 2 OC Bottom of Test Pit at 7 feet lo- 15- 20- 25- 30, ‘rojecl No: 885119ERSiol Woodward-Clyde Consultants = Figure: A-14 Project: CANNON ROAD - REACH 3 Log of Test Pit No: P-19 Date Excavated: i-l 8-88 Water Depth: Dry Measured: At time 01 drilling Type of Excavation: 24’ backhce Type of Backhce: Case 580E ’ see Key to Logs. Fig. A-l r’ 4 E g:= ft 0 e Material Description 0 2 a Surface Elevation: Approximately 104 ieet -__- ______ -.Gradingto ________ ---- ______ Firm, moist. gray with reddish brown mottles, fine sandy to silty lean to fat cby (CINCH) SANTlAGO FOFtMATfON - - .-1 Project No. 8851198R-SIOl Woodward4Zlyde Consultants APPEXDIX B LABORATORY TESTS The materials observed in the borings and test pits were visually classified and evaluated with respect to strength, swelling, and compressibility characteristics; dry density; and moisture content. The classifications were substantiated by performing grain size analyses and evaluating plasticity characteristics of representative samples of the soil. The strength of the soils were estimated based on our past experience with similar soils in the area and by considering the density and moisture content of the samples. The suitability of soils for use as pavement subgrade was evaluated by performing an R-value test. The compressibility of soils were evaluated by performing a consolidation test The grain size distribution curves are shown in Figure B-l. The results of our consolidation test are presented in Figure B-2. The results of the R-value test, as submitted to us by Testing Engineers, are presented in Fi,me B-3. cJvb2 B-l i -I UNIFIED SOIL CLUSIFXAT~ON GRAVRL COBBLES - SAND RIlE - umuu FlME SILT OR CLAY "3. 3lBvE SDX Is mcaaa u.3. szu(DuID S&YE no. H-fuBoyBpgR 3 3/a 3/a 4 10 20 40 a0 14.0200 0 20 I I I I IlyI \ I 60 40 I I Ill IIIII II IFM 60 80 100 1O3 I-~~-"~ ' lo2 I"" 8 - ' ' ,~~"'~ 8 ' 11""' p j I~'*~'~- ' - 10 1 16 1U2 la9 GRAIN SIZE IN -R SYMBOL BORING "RF & &DESCRIPTION 0 5-3-4 POORLY GRADED SMO WKH SILT (SP-SM) 0 TPlZ-1 LEN CLAY (CL) A TP14-1 55 40 FINE SANDY FAT CLAY (CH) Remark : 1 8851198R 301 1 CANNON ROAD-REACH 3 I Hoodnerd Clyde Consultants San Dieeo. CA GRAIN SIZE DISTRIBUTION Figure No. B-l - i -1 -1 - I .- 1 1 CONSOLIDAION CRBPH X axis:Log OF Pressure,tsf; Y axis:Uoid Ratio, e to-1 Lll. i.3L 6.D r.,e 5.6% 5.w 5.w 5.07. *.*7. 1.6& 1.s , .*c 9e=j I , , , ) , ( , , , , , , , , , -0 7. .il . . -0 1c A no r, 1. co .I I ,a ” ., , I, Sample 1-2 INITIAL DRY DENSITY. pcf INITIAL WATER CCtlTENl. 5 INITIAL SATURATIDN. !. FINAL DRY DENSITY. pcf FINAL WATER CMENT. % FINAL SATURATION. b 102 SPECIFIC GRAVITY OF SOLIDS 2.69 21 INITIAL VOID RATIO. e0 0.66 85 CCUPRESSION INDEX. C, 0.19 118 SWELL INDEX. C1 --- 16 EFFECTIVE OVERRURDEN PRESS. P',. trf 0.2 loo+ MAX. PAST PRESSURE, PC. trf _-- I CONSOLIDATION TEST C.A::W\? ROAD - REACH 3 DRAWNBY: cb CHECKED sv: PROJECTNO:~R~~~~~R-SIO~ DATE: 9-26-88 1 FIGURE HO: B-2 WOODWARD-CLYDE CONSULTANTS -I : Testing Engineers-San Diego 3467 Ku”* s,reet. P.O. BOX 80985. San Die90 CA 92138 1619l225~96~1 ,* 2946 ii:ustry St.. Unit 6. Oceanside. CA 920% $19) 7584730 ! - I I I I -1 I - I .- ~1 q -/ I -/ - I - I - : 108 NO: 1285 WOODWARD/CLYDE CONSULTANTS DIRRIRUTED TO: JOI HM: I;SODUMD AND CLlDE CONSUTANTS ZND FLOOR UODBYARDlCLYDE UWSULTTPINTS JO) ADMESS : ALL LOG?TIMS l’JS0 HOTEL CIRCLE NORTH TESTING ENGINEE%SAN DIEGO SAN DIECO. b+ SAN DIEGO, CA 92108 ATTENTION: VERA BERGER FPOJECT: CiNYON ROAD #8851198R SIDI) ENCIuEEl : David Rendini REPUT NO: 15819 REPORT OF SOll TESTS DATE: 08125188 R VALUE DATA ================================== i====s+======== zl==========r===r=er A H C D ============================== ===z== ====== =====~ Efz=Im= compactor Press - P.S.I. Moist @ Compaction - % Density - P/Cu.Ft. R-Value - StabiloMeter Exud. Pressure - P.S.I. Stab, Thick - Feet Expan. Press. Thick - Feet T.I. (Assumed) Hv Stab. @ 300 P.S.I. Exud. Hu Expansion Pressure At Equilibrium Sand Equivalent Haterial sampled by: CLIENT 45.0 22,‘s 100.4 7.0 560.0 1.3 0.2 4 5 , < 5.0 N/A < 5.0 N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 , 0 0.0 0.0 NOTE: Due to high clay coneenf, unable to obtain exudation pressure below 300 PSI. Subnitted to laboratorv on: 08/16/88 Described as: TPSK 12-I DARK BROWN CLAY/R-VALUE #466 SanDled from: PROJECT SITE Figure B-3 - Woodward-Clyde Consultants Project No. 8851198RSIOl -- - .- - - - I - APPEKDIX C GUIDE SPECIFICATIOKS FOR EARTHWORK CANNOX ROAD - REACH 3 NOTE: These specifications are provided as a guide for preparation of the final grading specifications for the project, which with the plans constitute the project documents. These guide specifications are not intendedfor use as final grading specifications. 1. GENERAL 1.1 1.2 1.3 The work of the Contractor covered by these specifications consists of furnishing labor and equipment and performing all operations necessary to remove deleterious and undesirable materials from areas of grading, to properly prepare areas to receive fill, and to excavate and fill to the lines and grades shown on the plans or as directed in writing by the Owner. The Contractor shall perform the work in strict accordance with these specifications and the Contractor shall be responsible for the quality of the finished product notwithstanding the fact that the earthwork may be observed and tests made by a Geotechnical Engineer. Deviations from these specifications will be permitted only upon written authorization from the Owner. The data contained in the geotechnical report and in any following addenda indicating subsurface conditions are not intended as representations or warranties of the accuracy or continuity of subsurface conditions between soils borings. It shall be expressly understood that the interpretations or conclusions drawn from such data are the responsibility of the Contractor. 2. DEFINITIONS 2.1 2.2 2.3 2.4 Contractor shall mean the conuactor performing the earthwork Owner shall mean the owner of the property or the party on whose behalf the earthwork is being performed and who has contracted with the Contractor to have the earthwork performed. (Civil Enaineer) (Architect) shall mean the (engineer) (architect) who has prepared the grading plans and who is the Owner’s representative concerning the configuration, quantities and dimensions of the earthwork and who usually sets basic surveying data at the site for the Contractor’s conformance. Geotechnicnl Enaineer shall mean a licensed civil engineer authorized to use the title “Geotechnical Engineer” in accordance with Section 6736.1. Chapter 7, Division 3, Stare of Californta Business and Professions Code. The Geotechnical Engineer -I - c/vb2 C-l Woodward-Clyde Consultants Project No. 8851198R-SlOl shall be responsible for having representatives on site to observe and test the Contractor’s work for conformance with these specifications. 2.5 Green Book shall mean the most recent edition of the Standard Specifications for Public Works Construction, prepared by the Joint Cooperative Committee of the Southern California Chapter, American Public Works Association, and Southern California Districts, Associated Contractors of California. 2.6 Standard Suecial Provisions shall mean the most recent edition of the Standard Special Provisions, prepared by County of San Diego, Department of Public Works. 3. OBSERVING AND TESTING 2 3.1 3.2 3.3 Testing shall conform to the following standards as pertinent: The Geotechnical Engineer shalI be the Owner’s representative to observe and make tests during the foundation preparation, filling, and compacting operations. The Geotechnical Engineer shall make field density tests in the compacted fill to provide a basis for expressing an opinion as to whether the fill material has been compacted to at least the minimum relative compaction specified. The basis for this opinion shall be that no tests in compacted or recompacted areas indicate a relative compaction of less than that specified. Density tests shall be made in the compacted material below any disturbed surface. When these tests indicate that the density of any layer of fill, or portion thereof, is below the specified density, the particular layer or area represented by the test shall be reworked until the specified density has been achieved. l ASTM D2922-81, “Density of Soil and Soil-Aggregate in place by Nuclear Methods (Shallow Depth)” l ASTM D3017-78, “Moisture Content of Soil and Soil-Aggregate in place by Nuclear Methods (Shallow Depth)” l ASTM D1556-82, “Density of Soil in place by the Sand-Cone Method” l ASTIM D1557-78, “Moisture-Density Relations of Soils and Soil-Aggregate Mixtures Using a lo-lb. (4.54 kg) Rammer and 18-in. (457-mm) Drop,” Methods A, B. and C. l AASHTO T 224-86, “Correction for Coarse Particles in the Soil Compaction Test.” 4. CLEARING AND PREPARING AREAS TO BE FILLED 4.1 Clearin: and grubbing shall be in accordance with Section 300-l of the Green Book and, in addition. all trees, brush , grass. and other objectionable material shall be collected from areas to receive fill and disposed of off-site prior to commencement c/vb? C-2 -I . .- - I I -. .- -I Project h’o. 855119SR-SlOl WoodwardGlyde Consultants of any earth moving so as to leave the areas that have been cleared with a neat and finished appearance free from debris. 4.2 All loose or porous soils shall be removed or compacted as specified for fill. The depth of removal and recompaction shall be approved in the field by the Geotechnical Engineer. Prior to placing fill, the surface to be filled shall be free from uneven features that would tend to prevent uniform compaction by the equipment to be used. It shall then be piowed or scarified to a depth as required and in no case less than a minimum depth of 6 inches. 4.3 Where the exposed slope is steeper than 6 horizontal to 1 vertical, or where specified by the Geotechnical Engineer, the slope of the original ground on which the fill is to be placed shall be stepped or keyed by the Contractor as shown on the figure below. The steps shall extend completely into the underlying formational materials or, where fort-national material is not present, into previously compacted fill. Oriqinal q?OUnd or sliding eoes not occur NOTES: The outside edge of bottom key “A” shall be not less than 2 feet in depth into formational soil or no less than 5 feet into previously compacted fill. The minimum width of benches “B” shall be at least l-1/2 times the width of the compaction equipment, and not less than 10 feet. 4.4 After the foundation for the fill has been cleared, plowed or scarified, it shall be disked or bladed by the Contractor until it is uniform and free from large clods, brought to the specified moisture convent, and compacted as specified for fill. c/vb’ c-3 Woodward.Clyde Consultants Project No. 8851198R-SIOl -; 1 I -ii - 1 .-~ I .- :I 5. SUBGRADE PREPARATION IN PA\ZMEhT AREAS 5.1 Subgrade preparation shall be in accordance with Section 301-l of the Green Book, except that relative compaction of subgrade shall be in accordance with Section 12 of these specifications. Scarification and recompaction requirements may be waived by the Geotechnical Engineer in subgrade areas with naturally cemented formational soils. 5.2 All areas to be paved shall be. proofrolled in accordance with Section 301-1.3 of the Standard Special Provisions. 6. MATERIAL-S - GENERALFILL 6.1 6.2 6.3 6.4 Materials for compacted fill shall contain no rocks or hard lumps greater than 24 inches in maximum dimension and shall contain at least 40% of material smaller than l/4 inch in size. Material of a perishable, spongy, or otherwise improper nature shall not be. used in fills. Select soil, to be used at finish ,grade to the depths and at the locations specified on the grading plans, shall consist of material that contains no rocks or hard lumps greater than 6 inches in maximum dimension and that has an Expansion Index of 50 or less when tested in accordance with UBC Standard 29-2. Samples of materials to be used for fill shall be. tested in the laboratory by the Geotechnical Engineer in order to evaluate the maximum density. optimum moisture content, classification of the soil, and expansion index, as required. During earthwork operations, soil types other than those analyzed in the report of the geotechnical investigation may be encountered by the Contractor. The Geotechnical Engineer shall be consulted to determine the suitability of these soils. 7. MATERIALS - PAVEMENT SUBGRADE 7.1 Pavement subgrade shall be defined as the top 12 inches of soil, excluding aggregate base, in areas to be paved with asphalt concrete or Portland cement concrete. 7.2 Materials for pavement subgrade shall contain no rocks or hard lumps greater than 6 inches in maximum dimension, shall contain at least 40 percent of material smaller than l/4 inch in size, and shall have an Expansion Index of 50 or less when tested in accordance with UBC Standard 29-2. Material of a perishable, spongy or otherwise improper nature shall not be used in fills. 8. MATERIALS - TRENCH BACKFILL 8.1 Trench backfill mclterials above pipe bedding shall be in accordance with Section 306- 1.3 of the Green Book. cfvb2 C-4 Woodward-Clyde Consultants Project No. SS5119SR-SlOl -i - .- il - -1 1 I - -~ .! 11.5 Properly compacted fill shall extend to the design surfaces of fill slopes. The surface of fill slopes shall be compacted in accordance with Section 11.1 of these specifications. 12. PLACING, SPREADING, AND COMPACTING PAVEMENT SUBGRADE 12.1 Subgrade materials shall be placed, spread, and compacted in accordance with Section 11 of these specifications, except that the top 6 inches of subgrade material shall be compacted to a relative compaction that is indicated by test to be not less than 95 percent. 13. PLACING AND COMPACTING TRENCH BACKFILL 13.1 Backfilling and compacting shall be in accordance with Section 306-1.3 of the Green Book, except that jetting or flooding shall not be allowed and that all backfill shall be compacted to a relative compaction that is indicated by test to be not less than 90 percent. 13.2 All wenches 5 feet or more in depth shall be sloped or shored in accordance with OSHA safety requirements. Trenches less than 5 feet in depth shall also be so guarded when examination indicates hazardous ground movement may be expected. 13.3 No compaction testing shall be required for portions of trenches backfilled with cement slurry. 14. PLACING AND COMPACITNG WALL BACKFILL 14.1 Backfilling and compacting shall be in accordance with Section 300-3.5 of the Green Book, except that jetting or flooding shall not be allowed, and that relative compaction in the general fill area shall not be less than 90 percent. 14.2 The Contractor shall be responsible for using equipment capable of compacting the backfill to the specified relative compaction without damaging adjacent walls or other existing improvements. 15. PROTECTION OF WORK 15.1 During construction, the Contractor shall properly grade all excavated surfaces to provide positive drainage and prevent ponding of water. When earthwork operations are interrupted, the Contractor shall reestablish specified compaction to the depth necessary before placing new fill. The Contractor shall control surface water to avoid damage to adjoining propenies or to finished work on the site. The Contractor shall take remedial measures to prevent erosion of freshly graded areas and until such time as permanent drainage and erosion control features have been installed. 15.2 After completion of the earth\vork and when the Geotechnical Engineer has finished obscnation of the work, no further excavlition or tilling shall be done except under the observation of the Geotcchnical Engineer. c/vb2 C-6 - Woodward-Clyde Consultants Project No. 855119SR-SIOl I APPESDIS D . . . . . - I L ) .- I - I GUlDE FOR OVERSIZE ROCK DISPOSAL Oversize rocks IarSer than 12 inches may be incorponted into the unclassified fill in accordance with the followinS guidelines. Also see Section 300-4 of the Standard Specifications for Public Works Consmtction. Refer to sketches above for classification of these guidelines. Shall be 15 feet measured horizontally from face of slope and 5 feet minimum ZONE A: measured vertically from finished grade. In public rights-of-way and easements, Zone A shall be 10 feet minimum or must extend 3 feet below the deepest utility, whichever is greater. Zone A must consist of compacted soil only (no rock fragments over 12 inches in maximum dimension), must be in conformance with Section 300-4 of the Standard Specifications and shall contain at least 40% soil sizes passing the l/l-inch sieve. ZONE B: Oversize rocks must either be individually placed or windrowed within this zone. For individual placement, rocks must be uniformly distributed and spaced so as to permit placement and compaction of soil conformin, n to Zone A material. For windrows, rocks shall be placed in excavations in well compacted soil conforming to Zone A requirements. Approved granular soil (SE > 30) must be flooded in the windrows to completely fill the voids around and beneath rocks. All windrows must be pamllel and may be placed either parallel or perpendicular to face of slope depending on site geometry. All rock placement, till placement and floodin: of approved granular fill must be continuously observed by the Geotechnical Engineer. Rock fills containing less than 407~ soil sizes p:tssin S l/?-inch sieve may be permitted in designated areas. Specific recommendations sh:tll be m:tde by the Geotechmcol Engineer and be subject to approval b:: the City En:ineer. - c/vb2 D- I