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HomeMy WebLinkAbout3308; Monroe St & Marron Rd; Monroe St & Marron Rd Geotechnical Investigation; 1989-02-23REPCMT OF QEXJIBCHNICMi INVESTIOTI(» FUTURE CCMMERCIAL SITES ICNRDE STREET AND MARRON ROAD CARLSBAD, CALIFORNIA PREPARED FOR: City of Carlsbad 1200 Elm Avenue Carlsbad, Califomia 92008 PREPARED BY: Southern Califomia Soil & Testing, Inc. Post Office Box 20627 6280 Riverdale Street San Diego, Califomia 92120 SOUTHERN C A L I F O R N SOIL 6280 RIVERDALE ST. SAN DIEGO, CALIF. 92120 • TELE 2BO-4321 67S ENTERPRISE ST. ESCONDIDO, CALIF. AND TESTING, INC. P.O. BOX 2D627 SAN DIEGD, CALIF. 921 2D g 2 • 2 5 TELE 7 4 G - 4 5 4 A February 23, 1989 City of Carlsbad 1200 Elm Avenue Carlsbad, Califomia 92008 ATTENnON: Mr. Alphonse Virgilio SCS&T 8821211 Report No. 2 SUBJECT: Geotechnical Investigation, Future Conmercial Sites, Itonroe St:reet and Marron Road, Carlsbad, Califomia. Gentlemen: In accordance with your request, we have performed an investigation of the soil conditions in the drainage area east and vest of Monroe Street and south of Marron Road in the City of Carlsbad, Califomia. Vfe are presenting herewith our findings and recommendations. In general we found that the soils below the site are moderately to highly compressible and are saturated. These conditions will require special grading and a consolidation period prior to constructing any settlement sensitive inprovements. If you have any questions after reviewing the findings and recommendations contained in the attached report, please do not hesitate to contact this office. This opportunity to be of professional service is sincerely appreciated. Respectfully submitted, SOUTHERN CALIFORNIA SOIL & TESTIITC, INC. Charles H. Christian, R.G.E. #00215 CHC:CRB:mw cc: (6) Subnitted (1) SCS&T, Escondido Curtis R. Burdett, C.E.G. #36037 SOUTHERN CALIFDRNIA SOIL AND TESTING I N C TABLE OF CMfTEMES PAGE Introduction and Project Description 1 Project Scope. 2 Findings -3 Site Description 3 Cfeneral Geology and Subsurface Conditions 4 (Geologic Setting and Soil Descriptions 4 Groundwater 5 Tectonic Setting 5 Geologic Hazards 6 Groundshaking. 6 Tsunamis and Seiches 7 Liquefaction 8 Conclusions 9 (feneral • 9 Recoimendations 10 Grading 10 Site Preparation 10 Imported Fill H Settlement Monitoring H Surface Drainage 11 Earthwork H Foundations 12 Cfeneral 12 Reinforcement 12 Concrete Slabs-on-Cirade 12 Settlement Characteristics 13 Expansive Characteristics 13 Lateral Resistance 13 Grading and Foundation Plan Review 13 Limitations 1'^ Review, Observation And Testing 14 Uniformity of Conditions 14 Change In Scope 14 Time Limitations 15 TABLE OF CCMTENTS (continued) PAGE Professional Standard 15 Client' s Responsibility 15 Field Explorations 16 Laboratory Testing 16 A3n30JMEWrS FI(30RE Figure 1 Site Vicinity Map, Follows Page 1 PLAOIS Plate 1 Plot Plan Plate 2 Subsurface Exploration Legend Plates 3-11 Boring and Trench Logs Plates 12-14 Grain Size Distribution Plates 15-18 Consolidation Load Test Results • APPENDIX Recomtrended (trading Specification and Special Provisions SOUTHERN CALIFORNIA SOIL AND TESTING, INC. 6ZBG RIVERDALE ST. SAN DIEGD, CALIF. 92120 • TELE ZBD-4321 • P.O. BOX 20627 SAN DIEGD, CALIF. 92120 e7S ENTERPRISE ST. ESCONDIDO, CALIF. 920Z5 • TELE 746-4544 \ GBOEBCHNICM. INVESTIG?m:ON FUTURE CQMMERCIAL SITES MDNROE STREET A^D MARRON ROAD CARLSBAD, CALIFORNIA INTODDUCnCN AND PROJECT' DESCRIPTICN This report presents the results of our geotechnical investigation for tvo proposed future comnercial sites in the City of Carlsbad, Califomia. Both sites are located soutJi of and adjacent to Marron Road, with Monroe Street separating the two parcels. The following Figiuje Number 1 shows the location of the site on a site vicinity map. It is our understanding that the two sites are owned by the City of Carlsbad and that they intend to eventually sell or lease the parcels. Future use will probably be for commercial/retail purposes, with one and/or two story- buildings of wood frame construction and shallow foxmdations being the probable type of const:ruction. Grading to develop the sites will require irtporting fill materials to bring the parcels up to street grade. This will require fills up to about 6 to 8 feet deep on the east parcel and 8 to 10 feet deep on the west parcel. lb assist in the preparation of this report, we have discussed the proposed construction with Mr. Virgilio, of City of Carlsbad, and have reviewed the improvement plans prepared for the construction of Monroe Street. In SOUTHERN CALIFDRNIA SOIL AND TESTING, INC. y\ SOUTHERN CALIFORNIA SOIL & TESTING, INC. MONROE STREET COMMERCIAL SITE y\ SOUTHERN CALIFORNIA SOIL & TESTING, INC. BY: CHC/WDW OATE: 2-16-89 y\ SOUTHERN CALIFORNIA SOIL & TESTING, INC. JOB NUMBER: 8821211 FIGURE //I SCS&T 8821211 February 23, 1989 Page 2 addition, we have reviewed a preliminary plan by BSI Consultants, Incorporated, dated June 13, 1989, that shows proposed street widening inprovements for Itonroe Street. Southem Califomia Soil and Testing, Inc. (SCS&T) prepared a geotechnical report for this widening project, dated January 26, 1989, and portions of said report are incorporated in this report. The plate included in the pocket of this report shows the sites, their approximate topography, and the locations of our subsurface explorations. PROJECT SCOPE This investigation consisted of: surface reconnaissance, subsurface exploration, obtaining representative undisturbed and bulk soil saitples, laboratory testing, analysis of the field and laboratory data. a) Ejqjlore the subsurface conditions to the depths influenced by the proposed construction. b) Evaluate, by laboratory tests, the pertinent engineering properties of the various strata which will influence the development of the site, or be influenced by the site development. c) Describe the general geology at the site including possible geologic hazards which could have an effect on the site development. d) Develop soil engineering criteria for site grading. e) Address potential construction , difficulties and provide recommendations concerning these problems. f) Recomnnend an appropriate foundation system for the type of structures anticipated and develop soil engineering design criteria for the recommended foundation design. SCS&T 8821211 February 23, 1989 Page 3 FINDINGS SnE EESCnOPTlCN , The two project sites are located south of Marron Road, at the south edge of the Buena Vista Lagoon Basin in Carlsbad, Califomia. The sites are at the mouth of one of the north draining canyons that feeds into the lagoon basin. Both sites are nearly triangular in area and are separated by Monroe Street, vAiich runs south from Marron Road through the natural invert of the canyon. The west parcel is presently being utilized as a desilting basin and is about eight to ten feet lower than MDnroe Street and Marron Road. This basin was created by filling for the adjacent streets above the valley floor. The basin is fed by the canyon and drains into a storm drain at the northwest comer of the parcel, that extends under Marron Road and eventually enpties into Buena Vista Lagoon. The desilting basin has gunite lined embankments and a relatively flat bottom that supports a thick growth of reeds. Groundwater can be seen at the surface in the lower areas of this parcel. The area west of the parcel slopes moderately to steeply upward to a relatively flat lying westerly sloping mesa. A reconnaissance of this eucalyptus covered hillside above this site did not reveal any areas of potentially unstable soils or areas of excessive erosion, even though a trail has been cut into the hillside that in sone areas concentrates drainage that would normally sheetflow down the hillside. A large manmade hole about ten feet in diameter and ten feet deep was, hovv^er noted in one area that could be a safety hazard for children playing in the area. The east parcel, vhich is also nearly rectangular, is six to eight feet below the adjacent street grade. The adjacent streets also make this site a drainage basin that has a relatively flat-lying bottom. The parcel is drained via a culvert located at the northwest comer, that drains across the street to the desilting basin. This basin also supports a thick growth of reeds and has groimdwater standing throughout most of the low lying areas. Tree stunps were, however, noted throughout this area that indicate SCS&T 8821211 February 23, 1989 Page 4 that the water table at ground surface must have been created by the damming effect of the adjacent roads. The area east of this site is also a eucalyptus covered moderately sloping hillside that did not show any signs of instability or excessive erosion. GENERAL WJUJSl AND SUBSURFACE CCNDITICNS GBQUOGIC SETTING Jttff) SOIL DESCRIPTICiB: The two sites that are the si±>ject of this study are located in the Coastal Plains Physiographic Province of San Diego County and, as such are underlain by Tertiary-age sediments, terrace deposits. Quaternary-age alluvial deposits and artificial fill. The artificial fill consists of the embankments for the adjacent road beds and desilting basin. These materials basically consist of clayey sands, slightly silty sands, and fine to medium sands vhich are generally in a medium dense condition. The fill was relatively free of organic materials and debris; however, the contact between the fill material and alluvial soils had a slight organic content. This may be due to the mixing of some organic materials with the native soils prior to placement of the fill, or, having organic materials within the upper foot of alluvium vhich were not properly removed prior to placing the fills. The alluviimi that underlies the roads, and hence, the two parcels, consists of altemating strata of clayey sands, clayey silty sands, sandy silts and sandy silty clays. For the most part, the alluvium appears to be clayey, silty sands or clayey sands that are medium dense. These soils have low to moderate settlement characteristics. Some of the alluvium, however, consisted of soft to medium stiff clays that had low densities and that were highly conpressible. The alluviimi extended to a depth of 54 feet and 53 feet in Test Borings Number 1 and 4, respectively. These borings were located on the edge of Marron Road, vMch represents the north side of the parcels. Boring B-2 and B-3 were located on the west and east shoulders of Monroe Street near the south end of the two parcels. These borings encountered alluvium to a depth of 19 feet and 14 feet, respectively. SCS&T 8821211 February 23, 1989 Page 5 Underlying the alluvium and draping the lower portions of the hillsides are terrace deposits that are basically conprised of medium dense to dense silty sands and clayey sands. Some slopewash materials also drape the hillsides as identified in Test Trench Number 3. This material consists predominantly of medium dense, slightly silty sands. The Tertiary-age sediments are represented as dense, moderately cemented sandstones of the Santiago Formation. These materials basically make up the hills and bluffs south of the lagoon basin. GROUNDWATER: In the two borings on the south shoulder of Marron Road, groundwater was found at an elevation of about 12 feet MSL. This is slightly lower than the bottom of the basin created on the east parcel and very close to the elevation of the bottom of the desilting basin on the west parcel. Groundwater exists at the surface in both of these basins. Borings Number B-2 and B-3, vhich were located at the south end of the parcels, found the groundwater at elevations of about 16 and 18 feet MSL. TECTONIC SETTING: Nb faults are known to traverse the subject site but it should be noted that much of Southern California, including San Diego County, is characterized by a series of Quaternary-age fault zones which typically consist of several individual, en echelon faults that generally strike in a northerly to northwesterly direction. Some of these fault zones (and the individual faults within the zone) are classified as active while others are classified as only potentially active according to t±e criteria of the Califomia Division of Mines and Geology. Active fault zones are those vhich have shown conclusive evidence of faulting during the Hoiocene Epoch (the most recent 11,000 years) vMle potentially active fault zones have demonstrated movement during the Pleistocene Epoch (11,000 to 2 million years before the present) but no movement during Hoiocene time. A review of available geologic maps indicates that the,, Rose Canyon Fault Zone is located approximately five miles to the west. Recent earthquake activity along faults in the southem extension of the Rose Canyon Fault SCS&T 8821211 February 23, 1989 Page 6 Zone indicates that this zone could be classified as active. The recent seismic events along a small portion of the Rose Canyon Fault Zone generated earthquakes of magnitude 4.0 or less. Other active fault zones in the region that could possibly affect the site include the Coronado Banks and San Clenente Fault Zones to the west, the Elsinore and San Jacinto Fault Zones to the northeast, and the Agua Blanca and San Miguel Fault Zones to the south. GBODCDGIC HAZARDS GROUNDSHAKING: One of the most likely geologic hazards to affect the site is groundshaking as a result of movement along one of the fault zones nentioned above. The maximum bedrock accelerations that would be attributed to a maximum probable earthquake occurring along the nearest portion of selected fault zones that could affect the site are summarized in the following table. TABLE I Fault Zone Maximum Probable Distance Bedrock Design Acceleration Acceleration Rose Canyon 5 miles 6.0 magnitude 0.37 g 0 .25 g Elsinore 23 miles 7.3 magnitude 0.23 g 0 .15 g Coronado Banks 20 miles 6.0 magnitude 0.13 g 0 .09 g San Jacinto 43 miles 7.8 magnitude 0.14 g 0 .09 g San Clemente 55 miles 7.3 magnitude 0.08 g 0 .05 g Earthquakes on the Rose Canyon or Coronado Banks Fault Zones are expected to be relatively minor. Major seismic events are likely to be the result of mDvenent along the San Clemente or Elsinore Fault Zones, In addition, we have analyzed the fault zones vhich could affect the San Diego area in order to detennine the probability of groundshaking of any given level. The individual faults and different fault zones have slip rates vMch have been calculated to range from very low to very high rates of activity. SCS&T 8821211 Febmary 23, 1989 Page 7 The following chart summarizes our opinion of the probability of events vM-ch would result in associated maximum and "design" bedrock accelerations. 0.30 g 0.20 g 1 x 10 ~3 0.25 g 0.17 g 1 x 10 "2 0.20 g 0.13 g 1 X 10 -1 0.15 g 0.10 g 5 x 10 ~1 0.10 g 0.07 g 1 X 10 -0 Probability of occurrence is defined as the probability of any given event occurring during the assumed life of the proposed structures (50 years) vhich would occur in accelerations of that level. Ejq^erience has shown that structures that are constmcted in accordance with Uniform Building Code Standards are fairly resistant to seismic related hazards. It is, therefore, our opinion that structural damage is unlikely if such buildings are designed and constmcted in accordance with the minimum standards of the most recent edition of the Uniform Building Code. TSUNAMIS AND SEICHES: Historically, the San Diego County area has been free of tsunami related hazards, and tsunamis reaching San Diego County have generally been wall within the normal tidal range. It is thought that the wide continental margin off the coast acts to diffuse and reflect the wave energy of remotely generated tsunamis. The largest tsunami to reach San Diego Countys coast was 4.6 feet, generated by the 1950 earthquake in south Chile. No locally generated tsunamis are known to have occurred in the San Diego area. However, it is speculated that a major earthquake along one of the major offshore faults would have the potential of generating a tsunami capable of inflicting damage to the San Diego coastal region. In addition, seiches associated with the tsunami forces could cause moderate damage in lagoonal areas. SCS&T 8821211 February 23, 1989 Page 8 A lack of knowledge about the offshore fault systems makes it difficult to assess the risk due to locally generated tsunamis. Considering the fact that a major tsunami has not occurred in 170 years of recorded history, the risk of such an event occurring in the near future appears nominal. LIQUEFACnCW: Liquefaction is the phenomenon in vhich soils lose all shear strength for short periods of time during an earthquake, and may result in very large total and/or differential settlements for st:mctures founded in the liquefying soils. Liquefaction is generally confined to loose, saturated sands and silts vyhich are subject to sufficient groundshalcing during an earthquake. Groundshaking of sufficient duration results in the loss of grain-to-grain contact due to a rapid increase in pore water pressure, causing the soil to behave as a fluid for short periods of time. In order to have a potential for liquefaction, a soil must be cohesionless with a grain size distribution of a specified range; it must be loose to nedium dense; it must be below the groundwater table; and it must be subject to a sufficient magnitude and duration of groundshaking. In evaluating the liquefaction potential for the subject site, we have relied in-part upon the results of studies presented by Seed and Idriss, "A Sinplified Procedure for Evaluating Soil Liquefaction Potential", 1971, and Borchardt and Kennedy, "Liquefaction Potential in Urban San Diego", 1979. Seed and Idriss present a method in vhich estimates of the stresses likely to be induced by an earthquake and the stresses likely to initiate liquefaction are evaluated using Standard Penetration Test (SPT) blowcounts as an indication of relative density. Based upon the evaluation methods outlined above, it is our opinion that the risk associated with liquefaction at the site is marginal to relatively low. It should be recognized, however, that many of the parameters used in liquefaction evaluations are subjective and open to interpretation, and that much is yet unknown about both the seismicity of the San Diego County area and the phenomenon of liquefaction. Historically, liquefaction in the Southem Califomia region has been manifested as isolated sand boils and not as catastrophic ground failure. SCS&T 8821211 Febmary 23, 1989 Page 9 It should also be understood that much of Califomia, including the San Diego County area, is an area of moderate to high seismic risk and it is not generally considered economically feasible to build stmctures totally resistant to earthquake related damage. However, the current Standards of Practice for design and constmction should prevent major stmctural damage vdiich can result in loss of life. The recommendations presented in later sections of this report should prevent any catast:rophic stmctural failure that may be associated with liquefaction. CONCLUSKXe GENERAL Based on our findings, it is our opinion that the two subject parcels may be developed into commercial/retail development as proposed provided the recommendations presented herein are conplied with. Three conditions will, however, require special consideration. First, the alluvial deposits vary from moderately to highly conpressible. Due to their depth and a shallow groundwater table, removal of this material is not practical. Therefore, the development of this site will require placing structures on a mat of uniformly conpacted fill of a thickness that would allow stmctural loads to dissipate within the fill. For the type of stmctures anticipated, this mat should be at least eight feet thick. Since the sites will require about this much fill to bring them up to street grade, it appears this may be able to be acconplished without extensive dewatering. Stiffened foundations and slabs should also be used for buildings since the alluviums cannot be removed. Secondly, the shallow groundwater table and soft soils will make site preparation of the areas to receive fill difficult. We anticipate that even a swanp cat would not be able to clear the sites without some dewatering. Since the sites aire heavily vegetated, bridging the soft alluvium with dry soil in order to get equipment onto the site is not recommended without first removing the vegetation. Vie anticipate that it may irequire a drag line SCS&T 8821211 Febmary 23, 1989 Page 10 to clear the site to allow bridging with dry soils. Another option, howsver, would be to excavate a pit near the north boundary and punp out enough water to lower the groundwater to three or four feet below existing grade. This may dry out the bottoms enough to allow a swanp cat to operate. The third condition that should be considered is that the fill loads will induce tine-dependent settlements in the soft clayey alluvial deposits. Vfe anticipate that it may take about one year to conplete the settlements. However, since the sites may not be developed immediately, this may not present a problem. On the other hand, if iimiediate development is planned, this condition may require surcharging or the use of deep foundations. RBOCMMENDATKJNS SITE PREPARATION: Site preparation should start with removal pf all vegetation within the areas to receive fill. This may require clearing with a drag line or a dewatering program to lover the groundwater to a depth that would allow equipment to work in the basins. It should be noted that some of the near surface alluviums contains enough organic materials that make them unsuitable as stmctural materials and that this will require off-site disposal of such material. Once the vegetation is removed, all existing soils within eight feet of finish grade should be removed. Any dry materials aroimd the sides such as slopewash or colluvium should also be removed to firm groimd or to just above the saturated alluvial deposits. Firm natural ground is defined herewith as the terrace deposits or Santiago Formation sandstones, or to any other materials that in the opinion of the soils engineer are suitable to support the fills and settlement sensitive stmctures. On the west parcel, the gunite on the perimeter embankments should be removed. This material may be broken up into small pieces of hard debris that may be mixed with the fills as they are placed. I I SCS&T 8821211 Febmary 23, 1989 Page 11 The road embankments should be keyed into as the fills increase in height such that all loose soils on the face of these slopes are removed. IMPCREED SOUS: All inported soils should be free of deleterious materials and other materials determined to be unsuitable fill material by the soils engineer. Nb rocks or lunps of soil over six inches in diameter should be inported and at least 60 percent of the material should be smaller than 1/4 •inch. No nore than 30 percent by weight should be finer than the No. 200 sieve. All fill material within four feet of finish grade should be granular in nature and have an expansion index of less than 50. All inported soil should be approved by the soils engineer. SETELEMENT JfUnCRING: Due to the anticipated time dependent settlement characteristics of some of the alluvial soils, we recommend that the fill settlement be monitored. Upon conpletion of the grading, at least three nonunents should be established on each site and these monuments should be surveyed at least bi-monthly for four months and then at least once a montJi for six nonths or until it is determined that the settlements are in the secondary consolidation stage. SURFMi: imiNZ^: It is recommended that all surface drainage be directed away from the proposed structures. Ponding of water should not be allowed. EARTHWORK: All earthwork and grading contenplated for site preparation should be acconplished in accordance with the attached Recommended Grading . Specifications and Special Provisions. All special site preparation recommendations presented in the sections above will supersede those in the standard Recomtended Grading Specifications. All embankments, stmctural fill and fill should be conpacted to at least 90% relative conpaction at or slightly over optimum noisture content. Utility t:rench backfill within five feet of the proposed stmctures and beneath asphalt pavements should be conpacted to minimum of 90% of its maximum dry density. The upper twelve inches of subgrade beneath paved areas should be conpacted to 95% of its maximum dry density. This compaction should be obtained by the paving I SCS&T 8821211 Febmary 23, 1989 Page 12 contractor just prior to placing the aggregate base material and should not be part of the mass grading requirements. The maximum dry density of each soil type should be determined in accordance with A.S.T.M. Test Method D-1557-78, Method A or C. POUNDATICHS GENEIUVL: Provided the sites are prepared as recommended herein, one and two-story, wood frame st:mctures may be founded on shallow spread footings. Such footings should be founded at least 18 inches below lowest adjacent finish grade and should have a minimum width of 12 inches for continuous footings and 24 inches for square footing. For preliminary purposes, an allowable soil bearing pressure of 2500 psf may be assumed. This should be verified vhen the site grading is conpleted. RETNFCMIQlQtT: It is recommended that minimum reinforcement for shallow continuous footings consist of at least four continuous No. 4 reinforcing bars, two located near the top of the footings and two near the bottom. This reinforcenent is based on soil characteristics and is not intended to be in lieu of reinforcement necessary to satisfy stmctural considerations. CXICREIE SLRBS-CN-ORACE: Interior concrete on-grade slabs should have a thickness of four inches. Minimum slab reinforcement should consist of No. 3 reinforcing bars placed at 24 inches on center each way. The reinforcement should be placed near the middle of the slab. A' three-inch-thick layer of clean, coarse sand or cmshed rock should be placed under the slab. This layer should consist of material having 100 percent passing the one-half-inch screen, no more than ten percent passing sieve #100 and no nore than five percent passing sieve #200. Where moisture-sensitive floor coverings are planned, the sand or rock should be overlain by a visqueen noisture barrier. A one-inch-thick layer of silty sand should be provided above the visqueen to allow proper concrete curing. SCS&T 8821211 Febmary 23, 1989 Page 13 SETTLEMENT CHAR20£EIISI1CS: The anticipated total and/or differential settlements for proposed stmctures may be considered to be within tolerable limits provided the recommendations presented in this report are followed. This includes allowing the fill induced time dependent settlement to occur prior to constmction of settlement-sensitive stmctures. It should be recognized that minor hairline cracks on concrete due to shrinkage of constmction materials or redistribution of stresses are normal and may be anticipated. EXPANSIVE CHARidERISnCS: The inported fill soils within four feet of finish grade should be nondetrimentally expansive. The recommendations of this report reflect a this condition resulting from select grading operations. If this is not the case, revised slab and foundation design will be necessary. LAIERAL RESISTANCE: Resistance to lateral loads may be provided by friction at the t>ase of the footing and by passive pressure against the adjacent soil. For concrete footings on conpacted fill soil or firm formational soils, a coefficient of friction of 0.35 may be used. For calculating passive pressure, an equivalent fluid unit weight of 400 poimds per cubic foot may be used. Passive pressure should not exceed 2,500 poimds per square foot. When combining frictional and passive resistance, the former should be reduced by one-third. GRADING AND POUNDATICN PLAN REVIEW The grading and foimdation plans should be submitted to this office for review to ascertain that the recommendations of this report have been implemented and the assunptions utilized for its preparation are still appropriate. SCS&T 8821211 Febmary 23, 1989 Page 14 LIMITATIONS REVIEW, OBSERVZOITCN AND TESTING The recommendations presented in this report are contingent upon our review of final plans and specifications. Such plans and specifications should be made available to the soil engineer and engineering geologist so that they may review and verify the conpliance with this report and with Chapter 70 of the Uniform Building Code. It is recomiended that Southem Califomia Soil & Testing, Inc. be retained to provide continuous soil engineering services during the earthwork operations. This is to observe compliance with the design concepts, specifications or recommendations and to allow design changes in the event that subsurface conditions differ from those anticipated prior to start of constmction. UNIPORMITy OF CXUDmCHS The recommendations and opinions expressed in this report reflect our best estimate of the project requirements based on an evaluation of the subsurface soil conditions encountered at the subsurface exploration locations and the assumption that the soil conditions do not deviate appreciably from those encountered. It should be recognized that the performance of the foimdations and/or cut and fill slopes may be influenced by undisclosed or unforeseen variations in the soil conditions that may occur in the intermediate and unexplored areas. Any unusual conditions not covered in this report that may be encountered during site development should be brought to the attention of the soils engineer so that he may make modifications if necessary. CHANCS: IN SCOPE This office should be advised of any changes in the project scope or proposed site grading so that it may be determined if the recommendations contained herein are appropriate. This should be verified in writing or modified by a written addendum. SCS&T 8821211 Febmary 23, 1989 Page 15 TIME LIMITATICNS The findings of this report are valid as of this date. Changes in the condition of a property can, however, occur with the passage of time, v^ether they be due to natural processes or the vork of man on this or adjacent properties. In addition, changes in the State-of-the-Practice and/or (Government iCodes may occur. Due to such changes, the findings of this report may be invalidated vholly or in part by changes beyond our control. Therefore, this report should not be relied upon after a period of two years without a review by us verifying the suitability of the conclusions and reconmendations. PRQFESSICNAL STANDARD In the perfomance of our professional services, ve conply with that level of care and skill ordinarily exercised by members of our profession currently practicing under similar conditions and in the same locality. The client recognizes that subsurface conditions may vary from those encountered at the locations where our borings, surveys, and explorations are made, and that our data, interpretations, and recommendations are based solely on the information obtained by us. We will be responsible for those data, interpretations, and recommendations, but shall not be responsible for the interpretations by others of the information developed. Our services consist of professional consultation and observation only, and no warranty of any kind whatsoever, express or implied, is made or intended in connection with the work perfomied or to be performed by us, or by our proposal for consulting or other services, or by our fumishing of oral or written reports or findings. CLIENT'S RESPCNSIBILITY It is the responsibility of the City of Carlsbad, or their representatives to ensure that the information and reconmendations contained herein are brought to the attention of the engineer and architect for the project and SCS&T 8821211 February 23, 1989 Page 16 incorporated into the project's plans and specifications. It is furtJier their responsibility to take the necessary measures to insure that the contractor and his subcontractors carry out such recommendations during constmction. FIELD EXPEORKnCNS Seven subsurface explorations were made at the locations indicated on the attached Plate Nuntier 1 on December 30, 1988 through January 10, 1989. These explorations consisted of four borings drilled utilizing a hollow stem auger type drill rig and three test trenches using a backhoe. The field vork was conducted under the observation of our engineering geology personnel. The explorations were carefully logged vhen made. These logs are presented on the following Plates Number 3 through 11. The soils are described in accordance with the Unified Soils Classification System as illustirated on the attached sinplified chart on Plate 2. In addition, a verbal textural description, the wet color, the apparent moisture and the density or consistency are provided. The density of granular soils is given as either very loose, loose, medium dense, dense or very dense. The consistency of silts or clays is given as either very soft, soft, medium stiff, stiff, very stiff, or hard. Disturbed and "imdisturbed" samples of typical and representative soils were obtained and retumed to the laboratory for testing. LABORATORy TESTING Laboratory tests were performed in accordance with the generally accepted American Society for Testing and Materials (A.S.T.M.) test methods or suggested procedures. A brief description of the tests performed is presented below: SCS&T 8821211 Febmary 23, 1989 Page 17 a) CLASSIFICATICN: Field classifications were verified in the laboratory by visual examination. The final soil classifications are in accordance with the Unified Soil Classification System. b) JDISTURE-^KNSITX": Field noisture content and dry density vere determined for representative sanples obtained. This information was an aid to classification and permitted recognition of variations in material consistency with depth. The dry unit veight is determined in poimds per cubic foot, and the field moisture content is determined as a percentage of the soil's dry veight. The results are simmarized in the boring and trench logs. c) GRAIN SIZE DISTRIBLTI'ICN: The grain size distribution was determined for representative sanples of the native soils in accordance with A.S.T.M. Standard Test D-422. The results of these tests are presented on Plates Number 12 through 14. d) OCNSOLIDATION TEST: Consolidation tests were perfomied on selected "imdisturbed" sanples. The consolidation apparatus was designed to accommodate a 1-inch-high by 2.375-inch or 2.500-inch diameter soil sanple laterally confined by a brass ring. Porous stones were placed in contact with the top and bottom of the sanple to pemiit the addition or release of pore fluid during testing. Loads were applied to the sample in a geometric progression after vertical movement ceased, and resulting deformations vere recorded. The percent consolidation for each load cycle is reported as the ratio of the amoimt of vertical conpression to the original one-inch sanple height. The test sanple was inundated at some point in the test cycle to determine its behavior under the anticipated footing load as soil noisture increases. The results of this test are presented in the form of curves on Plates Number 15 through 18. LEGEND • BORING LOCATION H TRENCH LOCATION 15 EXISTING TOPOGRAPHY APPROXIMATE LOCATION OF t^fil ORIGINAL TOPOGRAPHY SCALE O AO r'=60' 80 120 SOUTHERN CAUFORNIA SOIL & TESTING, INC. CHC/WDW JOBNa 8821211 OATE 2-16-89 PLATE ^1 SUBSURFACE EXPLORATION LEGEND UNIFIED SOIL CLASSIFICATION CHART SOIL DESCRIPTION GROUP SYMBOL sieve size. CLEAN GRAVELS I. COARSE GRAINED, more than half of matenal is laraer than No. 200 GRAVELS More than half of coarse fraction is larger than No. 4 sieve size but smaller than 3". •GRAVELS WITH FINES (Appreciable amount of fines) SANDS More than half of coarse fraction is smaller than No. 4 sieve size. CLEAN SANDS SANDS WITH FINES (Appreciable amount of fines) II. FINE GRAINED, more than half of material is smaller than No. 200 sieve sTzeT SILTS AND CLAYS Liquid Limit less than 50 SILTS AND CLAYS GW GP GM GC SW SP SM SC ML CL OL MH Liquid Limit CH greater than 50 OH HIGHLY ORGANIC SOILS PT US - Water level at time of excavation or as indicated Undisturbed, driven ring sample or tube sample TYPICAL NAMES ^\ SOUTHERN CALIFORNIA SOIL A TESTING, INC. Well graded gr sand mixtures, fines. Poorly graded sand mixtures, fines. Silty gravels, gravel-sand-si Clayey gravels graded gravel- mixtures. •avels, gravel- 1 ittle or no gravels, gravel 1 ittle or no poorly graded 1t mixtures. , poorly sand, clay Well graded sand, gravelly sands, little or no fines. Poorly graded sands, gravelly sanas, little or no fines. Silty sands, poorly graded sand and silty mixtures. Clayey sands, poorly graded sand and clay mixtures. Inorganic silts and very fine sands, rock flour, sandy silt or clayey-silt-sand mixtures witH slight plas- ticity. Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays. Organic silts and organic silty clays or low plasticity. Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts. Inorganic clays of high plasticity, fat clays. Organic clays of medium to high plasticity. Peat and otiier highly organic soils. CK — Undisturbed chunk sample BG — Bulk sample SP — Standard penetration sample MONROE STRFFT rOMM BY: CRB ERCIAL SITE JOB NUMBER: 21211 DATE: 01-19-89 Plate No. 2 2 ^ 4 - 6 - BAG 18 i 20 22 24 -I US US 26 28 30 ML/ CL& SM CL SC Fill to 15.5 Feet, Grey Brown, CLAYEY SAND ALLUVIUM, Dark Grey. CLAYEY SILT, Interbedded With MEDIUM to COARSE SILTY SAND Dark Grey, SILTY CLAY Grey, CLAYEY SAND Continued Moist Satur- ated Moist/ Wet Satur- ated Satur- ted Satur- ted Med i um Dense Stiff/ ^ledium Dense Stiff oose/ *^edium Dense 11 10 106.0 85.3 105.4 22.2 36.6 23.5 SOUTHERN CALIFORNIA SOIL &TESTING, INC. SUBSURFACE EXPLORATION LOG LOGGED BY: CRB JOB NUMBER: 8821211 DATE LOGGED: 01-10-89 Plate No. 3 a. Ill o 30 32 - 34 - 36 38 H 40 42 44 - 46 - 48 - IU 0. > Ul _l a. S < z o < -J CJ o ^ < BORING NUMBER 1 ELEVATION 1 Con ' t DESCRIPTION NT RE NT fENC All IU 3 IU fENC CO oc t-oc CO z < (0 < CO Ui a. — a. CO Q a. o a. z < s < COI OR z o < < o « >- ^ H to — IU U z CO IU oc > H CO z IU ^ a u a >- — oc Q IU ^ a — I- z (O Ul 3 o O IU z > O H H < O -" < IU a. O O US us US 50 jus 52 - 54 - 56 - CL Dark Grey, SILTY CLAY Satur- ated Medium Stiff 10 ML/ CL Grey, SANDY SILT to SILTY CLAY Satur- ated Medium Dense/ Stiff 11 SC/ CL Grey, CLAYEY SAND to SILTY CLAY Satur- ated Loose/ Medium Dense 10 SC/ CL Grey, CLAYEY SAND to SILTY CLAY Satur- ated Med i um Dense/ Stiff 10 108.9 21.3 89.3 33.8 111.0 19.1 112.5 19.6 SC TERRACE DEPOSITS, Red Brown, CLAYEY SAND Satur- ated Medium Dense 17 102.8 23.8 Bottom at 56 Feet SOUTHERN CALIFORNIA SOIL &TESTING,INC. SUBSURFACE EXPLORATION LOG SOUTHERN CALIFORNIA SOIL &TESTING,INC. LOGGED BY: CRB DATE LOGGED: 01-10-89 SOUTHERN CALIFORNIA SOIL &TESTING,INC. JOB NUMBER: 8821211 Plate No. 4 a. IU a IU a 0. S < CO o (0 CO < BORING NUMBER 2 ELEVATION DESCR IPTION I- Ui z oc Ui 3 oc t- < CO a. — a O < 2 >• (A Ui 5 2 w a. CO Q ^ ^ •< o 5 Ui o z o < K _ H <0 — Ui — Ui a. Ui > CO UJ w a u a > ~ oc Q Ui a< OC ~ I- Z CO UJ 2 o u Ul > < o Ui CL fl= z o o 2 - 4 - us 8 10 12 - 14 - US 16 US 18 - 20 I US 22 - 24 - 26 28 - US 30 - SM/ SC FILL TO 8 FEET, Red Brown to Grey Brown, SILTY SAND to CLAYEY SAND Moist Medium Dense SM/ SC SM/ SC Grey Brown to Red Brown, SILTY SAND to CLAYEY SAND ALLUVIUM, Dark Grey, SILTY SAND to SANDY CLAY Moist Satur- ated SM/ SC Dark Grey, SILTY SAND to CLAYEY SAND Satur- ated SC TERRACE DEPOSITS, Red Brown, CLAYEY SAND Satur- ated Moist/ Wet SC Red Brown, CLAYEY SAND Bottom at 26 Feet Moist Medium Dense Loose 17 106.9 20.1 Loose 105.5 19.9 Medium Dense Medium Dense Medium Dense 20 18.4 17 15.0 15.4 17.0 SOUTHERN CALIFORNIA SOIL &TESTING,INC. SUBSURFACE EXPLORATION LOG LOGGED BY: CRB JOB NUMBER: 8821211 DATE LOGGED: 01-10-89 Plate No. 5 1-o. Ui a 0 2 4 6 8 -1 10 Ui a CO < -I u o CO OT CO BORING NUMBER 3 ELEVATION DESCR IPTION H Ui Z IT Ui 3 K h- < CO a. — Q. O < s o < S2 Q. CO 0- z < o O 2 S H Z < < H- CO IU — z S Ui J Q. flC O CO z Ui Z C3 o a V — oc a Ui oc 3 co Ul s o o > o < o -i < Ui a 0= Z O o 12 - 14 - 16 i US 18 H 20 22 - 24 - 26 - 28 - 30 SM/ SC FILL TO 10 FEET, Red Brown to Grey Brown, SILTY SAND to CLAYEY SAND Moist SM/ SC ALLUVIUM, Dark Grey, SILTY SAND to CLAYEY SAND Wet/ Satur- ated SC TERRACE DEPOSITS, Grey, CLAYEY SAND Moist/ Wet US SC Grey, CLAYEY SAND Bottom at 20 Feet Moist Medium Dense Satur- ated Loose/ Medium Dense Medium Dense Medium Dense 22 23 121.5 13.0 118.9 13.6 SOUTHERN CALIFORNIA SOIL &TESTING, INC. SUBSURFACE EXPLORATION LOG LOGGED BY: CRB JOB NUMBER: 8821211 DATE LOGGED: 01-10-89 Plate No. 6 a. Ui Q 0 - o CO OT CO O BORING NUMBER 4 ELEVATION DESCRIPTION NT RE NT rENC All Ul 3 Ui rENC K t-K CA z < CO < CA Ui a. — IL CO Q a. o a. z < z < COi OR 2 S 1- z < < K h- t- CO Ui — , cn Ui oc Ui 0. CO z Ui a u a >- — oc Q Ui CC 3 H co 5 z I-z Ui o o Ul > < z o O < a. Z O o 2 - 4 - 6 - 8 - 10 12 US 14 - 16 US 18 - 20 I US 22 - 24 - 26 28 H US 30 SC SM SM/ SC SC/ CL SM/ SC SM/ SC FILL TO 12 FEET, Light Grey to Brown, CLAYEY SAND Moist Medium Dense Grey, SILTY SAND Moist Medium Dense ALLUVIUM, Grey, SILTY SAND to CLAYEY SAND Wet Med i um Dense Dark Grey, CLAYEY SAND to SANDY CLAY Wet Medium Dense/ Stiff Grey, SILTY SAND to CLAY- EY SAND Satur- ated Medium Dense Grey, SILTY SAND to CLAY- EY SAND Saturr ated Medium Dense 11 16 113.7 17.6 82.0 29.3 114.0 19.5 112.8 105.4 SOUTHERN CALIFORNIA SOIL &TESTING,INC. SUBSURFACE EXPLORATION LOG LOGGED BY: CRB JOB NUMBER: 8821211 DATE LOGGED: 01-10-89 Plate No. 7 SOUTHERN CALIFORNIA SOIL &TESTING,INC. SUBSURFACE EXPLORATION LOG LOGGED BY: CR3 JOB NUMBER: 8821211 DATE LOGGED: 01-10-89 Plate No. 8 I I I CL Ul Q CL > 0. z < CO 0 -I 1 2 3 4 _ 5 _ 6 z o O t CO (0 CO SM/ SP TRENCH NUMBER 1 ELEVATION DESCRIPTION FILL, Light Brown, FINE to MEDIUM SAND I- lu ^ = < to a. — a. O < z Very Moist z Ul oc < a. it Ul OT I- co (0 z o u UJ a oc o Loose (0 z _ UJ >- oc Q IU CO U o ^ s o o UJ > z o < a Z o o 7 _ 8 SM ALLUVIUM, Dark Brown, SILTY SAND, Numerous Roots 3'-5' Seepage and Caving 3'-5' Wet Saturated Loose Wet Med i um Dense SC Dark Brown, CLAYEY SAND Very Moist to Wet Medium Dense 9 _ 10 11 CL/ CH SUBSOIL/TOPSOIL, Grey Green and Brown, SANDY CLAY Wet to Very Moist Stiff Bottom at 11 Feet /Q\ SOUTHERN CALIFORNIA ^WW^ SOIL A TESTING,INC. SUBSURFACE EXPLORATION LOG /Q\ SOUTHERN CALIFORNIA ^WW^ SOIL A TESTING,INC. LOGGED BY: jgR DATE LOGGED: 12-30-88 /Q\ SOUTHERN CALIFORNIA ^WW^ SOIL A TESTING,INC. JOB ''UMBER:gg2-^211 Plate No. 9 IL Ul Q 0 - 1 • 2 - 3 - 4 - 5 - 6 - 7 - 8 - UJ a >- Ul -I CL Z < CO I-< =i - o il: CO OT CO < TRENCH NUMBER 2 ELEVATION DESCRIPTION UJ oc I-z UJ K I- < CO t o < z Ul oc < a a. z L: UJ CO , I- z CO tu » o DC o >- H (0 z _ IU 1^ oc o oc CA U i ^ s o o Ul > Ul cc z o o < a. Z o o SM FILL, Dark Brown, SILTY SAND Very Moist Loose SC ALLUVIUM, Dark Brown, CLAYEY SAND, Numerous Root I'-S' Wet Saturated Loose CL/ CH SUBSOIL/TOPSOIL, Grey Tan, SANDY CLAY Very Moist to Wet Stiff SM/ SP TERRACE DEPOSITS, Rust Brown, SLIGHTLY SILTY SAND Very Moist Medium to Dense Bottom at 9 Feet /\ SOUTHERN CALIFORNIA SOIL A TESTING,INC. SUBSURFACE EXPLORATION LOG /\ SOUTHERN CALIFORNIA SOIL A TESTING,INC. LOGGED BY: JBR DATE LOGGED: 12-30-88 /\ SOUTHERN CALIFORNIA SOIL A TESTING,INC. JOB NUMBER:gg2j211 Plate No.10 a. Ul Q 0 - 1 • 2 • 3 • 4 . 5 . 6 . 7 . 8 . 9 . Ui CL > I- Ui -I CL Z < CO < O o t CO CO < CO TRENCH NUMBER 3 ELEVATION DESCRIPTION I- Ul z oc < CA t o < z - ^ z z - IU Ui OT 4( CO Ul o. m O 0. < o u oc o >-I- (A z _ Ul >• OC a Ul 5^ OC CA U> i ^ s o u z Ui o > p I- <J < < -J Q. Ui 2 O o SM/ SP SLOPEWASH, Brown, SLIGHTLY SILTY SAND Moist Loose to Medium Dense SM ALLUVIUM, Green Grey, SILTY SAND, Caving and Seepage 8'-9' Saturated Loose Bottom at 9 Feet y\ SOUTHERN CALIFORNIA ^•Wfe^ SOIL A TESTING,INC. SUBSURFACE EXPLORATION LOG y\ SOUTHERN CALIFORNIA ^•Wfe^ SOIL A TESTING,INC. LOGGED BY: JBR DATE LOGGED: 12-30-88 y\ SOUTHERN CALIFORNIA ^•Wfe^ SOIL A TESTING,INC. JOB NUMBER:8821211 Plate No. ll > N m o H QD c H O O OD 5 03 00 ro 1—» ro 00 CD ro m ro I 1—' o I 00 ID n a* m mZ nz o m tn —\ TO o o m o I—I I—I —I m Bl & 21 B4 @ 36 (12 in.) 3 in. 3/4 in. No.4 No. 10 No. 40 No. 200 U.S. STANDARD SIEVE SIZE 1440 I'SO Om.) 100 .1^ PARTICLE SIZE LIMITS 1 1 BOULDER 1 COBBLES 1 1 GRAVEL SAND SILT OR CLAY 1 1 BOULDER 1 COBBLES 1 1 Coarse Fine Coarse Medium Fine SILT OR CLAY CD > N m g O) H CD c «_ o w z p CO 00 ro 5 a 00 cn CJO m ro I o I 00 (D n s* m mZ » n nz O OO —I ;^ m m -H o O m o I—I r- I—I -H m Bl (3 41 9876543 2 I (Pro/^ Size (mm) Bl @ 31 (12 in.) 3in. 3/4in. No.4 No.lO No.40 No.200 U.S. STANDARD SIEVE SIZE 440 (SO Gm.) 100 I44Q. (100 am.) PART ICLE SIZE Ll MITS 1 1 BOULDER I COBBLES 1 GRAVEL SANO SILT OR CLAY 1 1 BOULDER I COBBLES 1 Coarse Fine Coorse Medium Fine SILT OR CLAY > cn N m o H GO c H o z o 5 00 00 ro a DO 3> -a cu c-l- ru ro I I—' o I CO U3 ID fi* m mZ « n nz 70 o —I TO m m o o TO o r— oo B4 @ 21 36" 18" 24" 12 ^.S. standard Sieves Vi' *I0 *20 M40 t*60 3^" i»4 «8 . *I6 »30 *50 / *I00 *200 /hydrometer (t^inutes) 5 30 180 1440 (SO om.) •100 987654 3 2 I Grain Size (mm) PARTICLE SIZE Ll MITS 1 1 BOULDER 1 COBBLES 1 GRAVEL SAND SILT OR CLAY 1 1 BOULDER 1 COBBLES 1 Coarse Fine Coarse Medium Fine SILT OR CLAY (12 in.) 3in. 3/4in. No.4 No.lO No.40 No. 200 U.S. STANDARD SIEVE SIZE I I I SOUTHERIM CALIFORIMIA SOIL & TESTING LAB, INC. BBBO RIVERDALE STREET SAN OIEQO, CALIPORNIA BBieO MONROE STREET COMMERCIAL SITE BY DBA DATE 2-23-89 JOBNO. 8821211 Plate No. 15 I LOAD kips/sq.ft. 1 SOUTHERN CALIFORNIA SOIL & TESTING LAB, INC. SaSO RIVEROAUE STREET SAIM OIEGO, CALIFORNIA SBieo MONROE STREET COMMERCIAL SITE BY DBA DATE 2-23-89 JOB NO. 8821211 Plate No. 16 LOAD kIps/sq.ft. MONROE STREET COMMERCIAL SITE DBA DATE 2-23-89 JOBNO. 8821211 Plate No. 17 SOUTHERN CALIFORNIA SOIL & TESTING LAB, INC. SaSO RiVEROALE STREET SAN oiEcao, CALIFORNIA seieo LOAD kips/sq.ft. SOUTHERN CALIFORNIA SOIL & TESTING LAB, INC. BBSO RIVEROALE STREET SAN OIEQO, CALIFORNIA BBieo MONROE STREET COMMERCIAL SITE DBA DATE 2-23-89 JOB NO. 8821211 Plate No. 18 FUTURE CXWMERCIAL SITES, M3NR0E STTOET AND MZVRRCN ROAD, CARESBAD RECXWMENraD (3RADING SPBCIFICflTICNS - GENERAL PROVISICNS (SHERAL UnENT The intent of these specifications is to establish procedures for clearing, compacting natioral ground, preparing areas to be filled, and placing and conpacting fill soils to the lines and grades shown on the accepted plans. The recomiendations contained in the preliminary geotechnical investigation report and/or the attached Special Provisions are a part of the Reconmended Grading Specifications and shall supersede the provisions contained hereinafter in the case of conflict. These specifications shall only be used in conjunction with the geotechnical report for vdiich they are a part. No deviation from these specifications will be allowed, except where specified in the geotechnical soil report or in other written communication signed by the Soil Engineer. CfiSERVAnON ANQ TESTING Southem Califomia Soil and Testing, Inc., shall be retained as the Soil Engineer to observe and test the earthwork in accordance with these specifications. It will be necessary that the Soil Engineer or his representative provide adequate observation so that he may provide an opinion that the work was or was not accomplished as specified. It shall be the responsibility of the contractor to assist the soil engineer and to keep him appraised of work schedules, changes and new information and data so that he may provide these opinions. In the event that any unusual conditions not covered by the special provisions or preliminary soil report are encountered diiring the grading operations, the Soil Engineer shall be contacted for further recommendations. If, in the opinion of the Soil Engineer, substandard conditions are encountered, such as; questionable or unsuitable soil, unacceptable moisture (R-8/87) SCS&T 8821211 February 23, 1989 Appendix, Page 2 content, inadequate conpaction, adverse weather, etc., construction should be stopped until the conditions are remedied or corrected or he shall recommend rejection of this vrork. Test nethods used to determine the degree of conpaction should be performed in accordance with the following American Society for Testing and Materials test methocds: Maximum Density & Cptiraum Moisture Content - A.S.T.M. D-1557-78. Density of Soil In-Place - A.S.T.M. D-1556-64 or A.S.T.M. D-2922. All densities shall be expressed in terms of Relative Compaction as determined by the foregoing A.S.T.M. testing procedures. PREPARffTION OF AREAS TO RECEIVE FILL All vegetation, brush and debris derived from clearing operations shall be reiroved, and legally disposed of. All areas disturbed by site grading should be left in a neat and finished appearance, free from unsightly debris. After clearing or benching, the natural ground in areas to be filled shall be scarified to a depth of 6 inches, brought to the proper moisture content, conpacted and tested for the minimum degree of conpaction in the Special Provisions or the recommendation contained in the preliminary geotechnical investigation report. All loose soils in excess of 6 inches thick should be rent3ved to firm natural ground v^ch is defined as natural soils vAiich possesses an in-situ density of at least 90% of its maximum dry density. When the slope of the natural ground receiving fill exceeds 20% (5 horizontal imits to 1 vertical unit), the original ground shall be stepped (R-8/87) SCS&T 8821211 February 23, 1989 i^pendix. Page 3 or benched. Benches shall be cut to a firm conpetent soil condition. The lower bench shall be at least 10 feet wide or 1 1/2 times the the equipment width which ever is greater and shall be sloped back into the hillside at a gradient of not less than two (2) percent. All other benches should be at least 6 feet wide. The horizontal portion of each bench shall be conpacted prior to receiving fill as specified herein for conpacted natural ground. Ground slopes flatter than 20% shall be benched vhen considered necessary by the Soil Engineer. Any abandoned buried structures encountered during grading operations must be totally renoved. All underground utilities to be abandoned beneath any proposed structure should be removed from within 10 feet of the structure and properly capped off. The resulting depressions from the above described procedures should be backfilled with acceptable soil that is conpacted to the requirements of the Soil Engineer. This includes, but is not limited to, septic tanks, fuel tanks, sewer lines or leach lines, storm drains and water lines. Any buried structures or utilities not to be abandoned should be brought to the attention of the Soil Engineer so that he may detennine if any special recommendation will be necessary. All water wells vMch will be abandoned should be backfilled and capped in accordance to the requirements set forth by the Soil Engineer. The top of the cap should be at least 4 feet below finish grade or 3 feet below the bottom of footing vAiichever is greater. The type of cap will depend on the diaiteter of the well and should be determined by the Soil Engineer and/or a qualified Structural Engineer. FILL MATERIAL Materials to be placed in the fill shall be approved by the Soil Engineer and shall be free of vegetable matter and other deleterious svibstances. (R-8/87) SCS&T 8821211 February 23, 1989 i^pendix. Page 4 Granular soil shall contain sufficient fine material to fill the voids. The definition and disposition of oversized rocks, expansive and/or detrimental soils are covered in the geotechnical report or Special Provisions. Expansive soils, soils of poor gradation, or soils with low strength characteristics may be thoroughly mixed with other soils to provide satisfactory fill material, but only with the explicit consent of the soil engineer. Any inport material shall be approved by the Soil Engineer before being brought to the site. PLACING AND OOMPiO^ICN OF FILL improved fill material shall be placed in areas prepared to receive fill in layers not to exceed 6 inches in conpacted thickness. Each layer shall have a uniform moisture content in the range that will allow the conpaction effort to be efficiently applied to. achieve the specified degree of conpaction. Each layer shall be uniformly conpacted to a minimum specified degree of conpaction with equipment of adequate size to economically conpact the layer. Conpaction equipment should either be specifically designed for soil conpaction or of proven reliability. The minimum degree of conpaction to be achieved is specified in either the Special Provisions or the reconmendations contained in the preliminary geotechnical investigation report. When the structural fill material includes rocks, no rocks will be allowed to nest and all voids must be carefully filled with soil such that the minimum degree of compaction recommended in the Special Provisions is achieved. The maximum size and spacing of rock permitted in structural fills and in non-structural fills is discussed in the geotechnical report, v^en applicable. Field observation and conpaction tests to estimate the degree of conpaction of the fill will be taken by the Soil Engineer or his representative. The (R-8/87) SCS&T 8821211 February 23, 1989 i^spendix. Page 5 location and frequency of the tests shall be at the Soil Engineer's discretion. When the conpaction test indicates that a particular layer is less than the required degree of conpaction, the layer shall be reworked to the satisfaction of the Soil Engineer and until the desired relative conpaction has been obtained. Fill slopes shall be conpacted by means of sheepsfoot rollers or other suitable equipment. Conpaction by sheepsfoot rollers shall be at vertical intervals of not greater than four feet. In addition, fill slopes at ratios of two horizontal to one vertical or flatter, should be trackrolled. Steeper fill slopes shall be over-built and cut-back to finish contours after the slope has been constructed. Slope conpaction operations shall result in all fill material six or more inches inward from the finished face of the slope having a relative conpaction of at least 90% of maximum dry density or that specified in the Special Provisions section of this specification. The conpaction operation on the slopes shall be continued until the Soil Engineer is of the opinion that the slopes will be stable in regards to surficial stability. Slope tests will be made by the Soils Engineer during construction of the slopes to determine if the required conpaction is being achieved. Where failing tests occ\ar or other field problems arise, the Contractor will be notified that day of such conditions by written communication from the Soil Engineer or his representative in the form of a daily field report. If the method of achieving the requixed slope conpaction selected by the Contractor fails to produce the necessary results, the Contractor shall rework or rebuild such slopes until the recjuired degree of conpaction is obtained, at no cost to the Owner or Soils Engineer. (R-8/87) SCS&T 8821211 February 23, 1989 i^pendix. Page 6 CUT SLOPES The Engineering Geologist shall inspect cut slopes excavated in rock or lithified formational material during the grading operations at intervals determined at his discretion. If any conditions not anticipated in the preliminary report such as perched water, seepage, lenticular or confined strata of a potentially adverse natiire, imfavorably inclined bedding, joints or fault planes are encounte2:ed during grading, these conditions shall be analyzed by the Engineering Geologist and Soil Engineer to determine if mitigating measures are necessary. Unless otherwise specified in the geotechnical report, no cut slopes shall be excavated higher or steeper than that allowed by the ordinances of the controlling govemmental agency. ENGINEERING OBSERVTmiGN Field observation by the Soil Engineer or his representative shall be made during the filling and conpacting operations so that he can ejq^ress his opinion regarding the conformance of the grading with acceptable standards of practice. The presence of the Soil Engineer or his representative or the observation and testing shall not release the Grading Contractor from, his duty to conpact all fill material to the specified degree of conpaction. SEASCN LIMITS Fill shall not be placed during unfavorable weather conditions. When work is interrupted by heavy rain, filling operations shall not be resumed until the proper moisture content and density of the fill materials can be achieved. Damged site conditions resulting from weather or acts of God shall be repaired before acceptance of wDrk. (R-8/87) SCS&T 8821211 February 23, 1989 Appendix, Page 7 RECXWMENDED OWDING SPECIFICATICNS - SPECIAL PROVISIONS RELATIVE OOMPACnCN: The minimum degree of conpaction to be obtained in conpacting natural ground, in the conpacted fill, and in the conpacted backfill shall be at least 90 percent. For street and parking lot subgrade, the upper six inches should be compacted to at least 95% relative conpaction. EXPANSIVE SOILS: Detrimentally expansive soil is defined as clayey soil which has an expansion index of 50 or greater when tested in accordance with the Uniform Building Code Standard 29-C. OVERSIZE) MATERIAL: Oversized fill material is generally defined herein as rocks or luitps of soil over 6 inches in diameter. Oversize materials should not be placed in fill unless recommendations of placement of such material is provided by the soils engineer. At least 40 percent of the fill soils shall pass through a No. 4 U.S. Standard Sieve. •reANSinCN LOIS: Where transitions between cut and fill occur within the proposed building pad, the cut portion should be undercut a minimum of one foot below the base of the proposed footings and reconpacted as structural backfill. In certain cases that would be addressed in the geotechnical report, special fcxDting reinforcement or a combination of special footing reinforcement and undercutting may be required. (R-8/87)