The URL can be used to link to this page

Home My WebLink AboutCT 06-27; Muroya Subdivision; Geotechnical Investigation; 2009-07-14'tat I1 .«•» O GE<TE HNICAI. GEOTECHNICAL INVESTIGATION MUROYA PROPERTY CARLSBAD, CALIFORNIA PREPARED FOR TAYLOR MORRISON OF CALIFORNIA, LLC IRVINE, CALIFORNIA H d o UJ Xo JULY 14, 2009 PROJECT NO. 07671-52-01 GEOCON INCORPOBATED GEOTECHNICAL CONSULTANTS Project No. 07671-52-01 July 14, 2009 Taylor Morrison of California, LLC 15 Gushing Irvine, California 92618 Attention: Ms. April Tornillo Subject:MUROYA PROPERTY CARLSBAD, CALIFORNIA GEOTECHNICAL INVESTIGATION Dear Ms. Tornillo: In accordance with your authorization of our Proposal No. LG-06088 dated February 27, 2006, we have prepared this geotechnical investigation for the subject project. We performed our investigation to assess the underlying soil and geologic conditions and potential geologic hazards, and to assist in the design of the proposed development. The accompanying report presents the results of our study and conclusions and recommendations pertaining to the geotechnical aspects of the proposed project. The findings of this study indicate that geologic hazards are not present and the site is suitable for development provided the recommendations of this report are followed. Should you have any questions regarding this report, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED "*>,••V "Shawn Weedon GE 2714 SW:JH:dmc (2/del) Addressee (3/del) Hunsaker and Associates Attention: Mr. Chuck Cater (6/del) Jack Henthorn & Associates Attention: Mr. Jack Henthorn i Hoobs iG 1524 JOHN HOOBSNo. 1524 CERTIFIED ENGINEERING GEOLOGIST 6960 Flanders Drive • San Diego, California 92121-2974 • Telephone (858) 558-6900 • Fax (858) 558-6159 TABLE OF CONTENTS 1. PURPOSE AND SCOPE 1 2. SITE AND PROJECT DESCRIPTION 1 3. SOIL AND GEOLOGIC CONDITIONS 2 3.1 Debris Fill (Qdf) 2 3.2 Undocumented Fill (Qudf) 2 3.3 Topsoil (Unmapped) 3 3.4 Colluvium (Qcol) 3 3.5 Alluvium (Qal) 3 3.6 Lindavista Formation (Qln) 3 3.7 Santiago Formation (Tsa) 3 4. GROUNDWATER 4 5. GEOLOGIC HAZARDS 4 5.1 Faulting and Seismicity 4 5.2 Liquefaction 6 5.3 Landslides 7 5.4 Tsunamis and Seiches 7 5.5 Slope Stability 7 6. CONCLUSIONS AND RECOMMENDATIONS 8 6.1 General 8 6.2 Excavation and Soil Characteristics 9 6.3 Slope Stability Analyses 10 6.4 Grading 11 6.5 Slopes 13 6.6 Subdrains 13 6.7 Seismic Design Criteria 14 6.8 Temporary Excavations 15 6.9 Foundation and Slab-On-Grade Recommendations 15 6.10 Conventional Retaining Wall Recommendations 20 6.11 Lateral Loads 21 6.12 Mechanically Stabilized Earth Walls 21 6.13 Preliminary Pavement Recommendations 23 6.14 Site Drainage and Moisture Protection 26 6.15 Foundation and Grading Plan Review 27 LIMITATIONS AND UNIFORMITY OF CONDITIONS MAPS AND ILLUSTRATIONS Figure 1, Vicinity Map Figure 2, Geologic Map (Map Pocket) Figure 3, Geologic Cross-Sections Figures 4-5, Computer Output from GeoStudio2004 Figure 6, Surficial Slope Stability Analysis Figure 7, Cut and Fill Slope Stability Analysis Figure 8, Typical Canyon Subdrain Detail Figure 9, Typical Subdrain Cut-Off Wall Detail Figure 10, Typical Subdrain Outlet Headwall Detail Figure 11, Wall/Column Footing Dimension Detail Figure 12, Typical Retaining Wall Drain Detail TABLE OF CONTENTS (Continued) APPENDIX A FIELD INVESTIGATION Figures A-l - A-12, Logs of Trenches APPENDIX B LABORATORY TESTING Table B-I, Summary of Laboratory Maximum Dry Density and Optimum Moisture Content Test Results Table B-II, Summary of Laboratory Expansion Index Test Results Table B-III, Summary of Laboratory Direct Shear Test Results Table B-IV, Summary of Laboratory Water-Soluble Sulfate Test Results Table B-V, Summary of Laboratory Resistance Value (R-Value) Test Results APPENDIX C RECOMMENDED GRADING SPECIFICATIONS LIST OF REFERENCES •*,- .it GEOTECHNICAL INVESTIGATION 1. PURPOSE AND SCOPE This report presents the results of a geotechnical investigation for the proposed development of the Muroya Property in Carlsbad, California. The purpose of this report is to provide information related to the subsurface conditions at the site and to provide recommended grading specifications, slope stability evaluation, foundation and retaining wall design criteria, seismic design criteria, pavement design criteria, and excavation and remedial grading considerations for the proposed development. The scope of this investigation included a review of stereoscopic aerial photographs, topographic maps, and readily available published and unpublished geologic literature (see List of References). We performed a field investigation that included performing a geologic reconnaissance and excavating 12 exploratory trenches to a maximum depth of approximately 10 feet to assess the subsurface geologic conditions. We performed laboratory tests on selected soil samples obtained during the field investigation to evaluate pertinent physical and chemical properties for engineering analyses and to assist in providing recommendations for site grading and foundation design. The trench logs are presented in Appendix A and details of the laboratory tests and a summary of the test results are presented on the trench logs and in Appendix B. 2. SITE AND PROJECT DESCRIPTION The site consists of approximately 9!/2 acres of land located on the west side of Black Rail Road and south of Corte Orchidia in Carlsbad, California (see Vicinity Map, Figure 1). The property is currently occupied by a palm nursery with a single-story residence, greenhouses, and equipment sheds. A 150-foot-wide easement for SDG&E transmission lines extends through the central portion of the property. Topographically, the eastern portion of the site generally consists of a relatively level to gently sloping mesa at elevations ranging between approximately 325 and 345 feet above mean sea level (MSL). The western portion consists of moderately to steeply sloping natural and manufactured fill slopes extending toward the SDG&E easement into a large canyon drainage. Elevations within the proposed development range between approximately 300 and 360 feet above Mean Sea Level (MSL). Based on the grading plans prepared by Hunsaker & Associates, progress print date July 9, 2009, we understand that a 37-unit, single-family residential development with on-grade parking is planned for the property. Buildings are expected be one- to two-story, wood-frame and stucco structures with concrete slabs-on-grade and shallow foundations. The grading will create residential pads, roadways, and supporting infrastructure requiring cuts and fills of approximately 10 and 30 feet, respectively. Fill slopes with inclinations of 2:1 (horizontal:vertical) up to approximately 45 feet are planned along the western margins of the proposed development. A fill slope with a height of approximately 50 feet is Project No. 07671-52-01 -1- July 14, 2009 ^ planned at an inclination of VA'.l (horizontal:vertical) located southwest of Lots 22 through 27. * Retaining walls are planned throughout the site with a maximum height of approximately 10 feet. " The site location, descriptions, and proposed development discussed above are based on a site "** reconnaissance, review of the grading plans prepared by Hunsaker & Associates, and our discussions ••"' with you. ** 3. SOIL AND GEOLOGIC CONDITIONS ^ The site is underlain by surficial soil consisting of debris fill, undocumented fill, topsoil, colluvium, ^ and alluvium, and by formational materials of the Lindavista and Santiago Formations. The geologic "" units are discussed herein and the approximate lateral limits are depicted on the Geologic Map, "~" Figure 2 (map pocket). Geologic Cross-Sections depicting the planned development and subsurface * geologic conditions are presented on Figure 3. ••-••#? ' 3.1 Debris Fill (Qdf) We encountered fill material containing abundant agricultural and construction debris predominantly along the western slopes in exploratory Trenches T-l, T-3, T-5, and T-9. This material appears to have been end-dumped over the edge of the native slopes. The debris fill has a thickness of up to 9 feet in the areas explored; however, it is likely that this material is thicker beyond the areas of exploration. Debris fill is comprised of silty to clayey sand with plastic bags and pots, planter soil, and chunks of asphalt and concrete. The debris fill is considered unsuitable for support of additional fill and/or structural loads in its present condition and will require remedial grading. The material generated will * likely be unsuitable for reuse as compacted fill and should be cleaned of debris or exported from the site. 3.2 Undocumented Fill (Qudf) Undocumented fill exists in the northwestern comer of the site, along the upper slope areas in the western margin of the planned developed area, and in the area of the existing residence in the southeastern portion of the site. In addition, undocumented fill associated with the backfilling of a storm drain is located in the southeastern portion of the site and trends in an east-west direction. We observed undocumented fill to vary in thickness from approximately 3 to 9 feet. The fill is comprised of silty to clayey sand and silty to sandy clay, and contains minor amounts of debris. This material is considered unsuitable for support of additional fill and/or structural loads in its present condition and will require remedial grading in areas of planned development. This majority of this material will likely be suitable for reuse as compacted fill. Project No. 07671-52-01 -2- July 14, 2009 3.3 Topsoil (Unmapped) We encountered topsoil in Trench T-2 with a thickness of approximately l'/2 feet. The maximum thickness of the topsoil is expected to be approximately 3 feet across a majority of the property. The topsoil consists of loose, dark brown, silty sand with some organic material. The topsoil is unsuitable in its present condition and will require remedial grading. This material is suitable for use as compacted fill soil. 3.4 Colluvium (Qcol) We encountered colluvium on the northern and eastern portions of the property and in the open space area. The maximum thickness of colluvium encountered is approximately 3 feet. The colluvium consists of loose to medium dense, moist, brown, clayey and silty, fine to medium sand, sandy silt and clay. The colluvium is considered unsuitable for support of fill and/or structural loads in its present condition and will require remedial grading. This material is suitable for use as compacted fill. 3.5 Alluvium (Qal) Alluvium exists within the northwestern portion of the property within a canyon drainage to an observed depth of greater than 7'/2 feet and within open space areas not proposed to be graded. The alluvium is composed of loose, moist to wet, grayish brown, silty, fine to medium sand. The thickness of the alluvium could not be determined in Trench T-8 due to abundant seepage and caving. The alluvium is considered unsuitable for support of fill and/or structural loads and will require remedial grading. This material is suitable for use as compacted fill soil. 3.6 Lindavista Formation (Qln) The site is underlain by Quaternary-age Terrace Deposits correlative with the Lindavista Formation (Kennedy and Tan, 1996). The formational materials are exposed at the surface or underlie the surficial soil to the maximum depth explored. The Lindavista Formation consists of medium dense to very dense, brown to reddish brown and olive gray, clayey and silty sand and sandy clay. Bedding is expected to be relatively massive or flay-lying and localized gravel layers may be encountered during grading. The Lindavista Formation is considered suitable for the support of compacted fill and/or structural loads. This material is suitable for use as compacted fill. 3.7 Santiago Formation (Tsa) The site is mapped by Kennedy and Tan (1996) to be underlain at depth by the Santiago Formation. Exposures of the Santiago Formation are identified along the lower areas of the slopes to the south and west of the area of development below an approximate elevation of 275 feet above MSL. We did not encounter the Santiago Formation during our subsurface investigation and is not expected to be encountered during site development. This formation generally consists of interbedded dense to very Project No. 07671-52-01 -3- July 14, 2009 dense, damp to moist, light yellowish brown to light olive, silty to clayey, fine to medium sandstone, clayey siltstone, and claystone. Bedding within the Santiago Formation has been mapped dipping approximately 5 degrees toward the northwest. This unit typically exhibits stable natural slope conditions within the project area. 4. GROUNDWATER We encountered a perched groundwater condition in Trench T-8 in the northwestern portion of the site at a depth of approximately 5 feet. In addition, we encountered seepage in Trenches T-3 and T-4. Groundwater and seepage should be expected during remedial grading in these areas and in excavations for deeper utilities. The use of dewatering techniques may be necessary during remedial grading operations to facilitate excavation in the northwestern portion of the property. A permanent, shallow groundwater table is not expected at the site. It is not uncommon for groundwater or seepage conditions to develop where none previously existed. Groundwater elevations are dependent on seasonal precipitation, irrigation, and land use, among other factors, and vary as a result. Proper surface drainage will be important to future performance of the project. 5. GEOLOGIC HAZARDS 5.1 Faulting and Seismicity A review of geologic literature indicates that known active, potentially active, or inactive faults are not located at the site. The Rose Canyon Fault Zone, located approximately 5 miles west of the site, is the closest known active fault. An active fault is defined by the California Geologic Survey (CGS), as a fault showing evidence for activity roughly within the last 11,000 years. The CGS has included portions of the Rose Canyon Fault Zone within a State of California Earthquake Fault Zone. This site is not located within such an earthquake fault zone. A minor fault offsetting the Santiago Formation and Lindavista Formation is mapped by Tan and Kennedy (1996) several hundred feet south of the site. This fault does not offset Holocene-age units and is considered inactive. According to the computer program EZ-FRISK (Version 7.30), 11 known active faults are located within a search radius of 50 miles from the property. The nearest known active fault is the Rose Canyon Fault, located approximately 5 miles west of the site and is the dominant source of potential ground motion. Earthquakes that might occur on the Rose Canyon Fault Zone or other faults within the southern California and northern Baja California area are potential generators of significant ground motion at the site. The estimated deterministic maximum earthquake magnitude and peak ground acceleration for the Rose Canyon Fault are 7.2 and 0.35g, respectively. Table 5.1.1 lists the estimated maximum earthquake magnitude and peak ground acceleration for the most dominant faults in relationship to the site location. We calculated peak ground acceleration (PGA) using Boore-Atkinson (2008) NGA USGS2008, Campbell-Bozorgnia (2008) NGA USGS, and Chiou-Youngs (2008) NGA acceleration-attenuation relationships. Project No. 07671-52-01 -4- July 14, 2009 TABLE 5.1.1 DETERMINISTIC SPECTRA SITE PARAMETERS Fault Name Rose Canyon Newport-Inglewood (offshore) Coronado Bank Elsinore (Julian) Elsinore (Temecula) Elsinore (Glen-Ivy) Palos Verdes San Joaquin Hills Thrust Earthquake Valley San Jacinto (Anza) San Jacinto (San Jacinto Valley) Distance from Site (miles) 5 9 21 25 32 37 39 40 42 47 48 Maximum Earthquake Magnitude (Mw) 7.2 7.2 7.7 7.5 7.2 7.2 7.4 6.7 6.9 7.6 7.3 Peak Ground Acceleration Boore- Atkinson 2008 (g) 0.28 0.21 0.16 0.13 0.11 0.08 0.08 0.06 0.06 0.07 0.06 Campbell- Bozorgnia 2008 (g) 0.30 0.20 0.12 0.09 0.09 0.06 0.07 0.06 0.05 0.06 0.05 Chiou- Youngs 2008 (g) 0.35 0.24 0.15 0.11 0.09 0.06 0.07 0.05 0.04 0.06 0.05 We used the computer program EZ-FRISK to perform a probabilistic seismic hazard analysis. The computer program EZ-FRISK operates under the assumption that the occurrence rate of earthquakes on each mappable Quaternary fault is proportional to the faults slip rate. The program accounts for fault rupture length as a function of earthquake magnitude, and site acceleration estimates are made using the earthquake magnitude and distance from the site to the rupture zone. The program also accounts for uncertainty in each of following: (1) earthquake magnitude, (2) rupture length for a given magnitude, (3) location of the rupture zone, (4) maximum possible magnitude of a given earthquake, and (5) acceleration at the site from a given earthquake along each fault. By calculating the expected accelerations from considered earthquake sources, the program calculates the total average annual expected number of occurrences of site acceleration greater than a specified value. We utilized acceleration-attenuation relationships suggested by Boore-Atkinson (2008) NGA USGS, Campbell- Bozorgnia (2008) NGA USGS, and Chiou-Youngs (2008) in the analysis. Table 5.1.2 presents the site- specific probabilistic seismic hazard parameters including acceleration-attenuation relationships and the probability of exceedence. Project No. 07671-52-01 -5-July 14, 2009 TABLE 5.1.2 PROBABILISTIC SEISMIC HAZARD PARAMETERS Probability of Exceedence 2% in a 50 Year Period 5% in a 50 Year Period 10% in a 50 Year Period Peak Ground Acceleration Boore- Atkinson, 2007 (g) 0.49 0.35 0.27 Campbell-Bozo rgnia, 2008 (g) 0.50 0.36 0.26 Chiou-Youngs, 2008 (g) 0.57 0.41 0.30 The California Geologic Survey (COS) has a program that calculates the ground motion for a 10 percent probability of exceedence in 50 years based on an average of several attenuation relationships. Table 5.1.3 presents the calculated results from the Probabilistic Seismic Hazards Mapping Ground Motion Page from the COS website. TABLE 5.1.3 PROBABILISTIC SITE PARAMETERS FOR SELECTED FAULTS CALIFORNIA GEOLOGIC SURVEY Calculated Acceleration (g) Firm Rock 0.27 Calculated Acceleration (g) Soft Rock 0.29 Calculated Acceleration (g) Alluvium 0.32 While listing peak accelerations is useful for comparison of potential effects of fault activity in a region, other considerations are important in seismic design, including the frequency and duration of motion and the soil conditions underlying the site. Seismic design of the structures should be evaluated in accordance with the California Building Code (CBC) guidelines currently adopted by the City of Carlsbad. 5.2 Liquefaction Liquefaction typically occurs when a site is located in a zone with seismic activity, onsite soil is cohesionless, groundwater is encountered within 50 feet of the surface, and soil relative densities are less than about 70 percent. If the four previous criteria are met, a seismic event could result in a rapid pore-water pressure increase from the earthquake-generated ground accelerations. The potential for liquefaction occurring within the site soil is considered to be very low due to the dense nature of the proposed compacted fill and formational materials. Project No. 07671-52-01 -6-July 14, 2009 5.3 Landslides Examination of aerial photographs in our files and a review of referenced geologic maps (Tan and Kennedy, 1995 and 1996) indicate that landslides are not present at the property or at a location that could impact the site. 5.4 Tsunamis and Seiches A tsunami is a series of long period waves generated in the ocean by a sudden displacement of large volumes of water. Causes of tsunamis include underwater earthquakes, volcanic eruptions, or offshore slope failures. The first order driving force for locally generated tsunamis offshore southern California is expected to be tectonic deformation from large earthquakes (Legg, et al., 2002). Historically, tsunami wave heights have ranged up to 3.7 feet in the San Diego area (URS, 2004). The County of San Diego Hazard Mitigation Plan maps zones of high risk for tsunami run-up for coastal areas throughout the county. The site is not included within one of these hazard areas. The site is located several miles from the Pacific Ocean at an elevation of more than 300 feet above MSL; therefore, the risk of tsunamis affecting the site is negligible. A seiche is a run-up of water within a lake or embayment triggered by fault- or landslide-induced ground displacement. The site is not located in the near vicinity of, or down stream from, such bodies of water. Therefore, the risk of seiches affecting the site is negligible. 5.5 Slope Stability We evaluated the proposed slope configurations, as depicted on the referenced plans, for surficial and global stability based on the current geologic information. Based on the results of our geotechnical investigation, portions of the planned fill slopes will encroach within the unsuitable debris fill. Portions of the debris fill should be removed and replaced with properly compacted fill. Portions of the debris fill are located outside the planned limits of grading. Excavations outside the limits of debris fill would encroach into sensitive habitat and we understand remedial grading in the sensitive habitat can not occur. Where sensitive habitat exists and deep removals are required, the remedial grading for the planned fill slope should begin at the limits of grading and project down at a 1:1 inclination into formational materials as shown in the recommended grading specifications provided in Appendix C. The resulting keyway should be at least approximately 15 feet wide. Geologic Cross-Sections A-A' and B-B' (Figure 3) depict the planned remedial grading of the subject slopes. In addition, we performed slope stability analyses to address the conditions of the planned slopes located southwest of Lots 22 through 29 and west of Lots 35 through 37 at the subject site. The inclination of the planned slopes vary from approximately 2:1 (horizontal:vertical) up to approximately 1!/2:1 with a maximum height of about 50 feet. The Geologic Map, Figure 2, presents the lateral limits of the undocumented fill, debris fill, and alluvium overlying the Lindavista Formation. Project No. 07671-52-01 ~- July 14, 2009 6. CONCLUSIONS AND RECOMMENDATIONS 6.1 General 6.1.1 No soil or geologic conditions were encountered during this geotechnical investigation that would adversely impact the development of the property as presently proposed, provided the recommendations of this report are followed. 6.1.2 With the exception of possible strong seismic shaking, we did not observe significant geologic hazards and we do not know any to exist on the site that would adversely affect the proposed project. Special seismic design considerations other than those recommended herein are not required. The risk of geologic hazards due to fault rupture, liquefaction, landsliding, or tsunamis is considered negligible. 6.1.3 The site is underlain by surficial soil consisting of debris fill, undocumented fill, colluvium, alluvium, and topsoil, and by formational materials of the Lindavista and Santiago Formations. Remedial grading in the form of removal and compaction of the debris fill, undocumented fill, alluvium, colluvium, and topsoil should be performed. The debris fill should be cleaned of unsuitable material prior to placement as compacted fill or be exported offsite. The remaining surficial soil is suitable for use as compacted fill. The Lindavista and Santiago Formations are considered adequate for the support of compacted fill and/or structural loads. 6.1.4 We expect remedial grading will be required outside of the planned grading. The limits of the expected remedial grading operations are presented on the Geologic Map, Figure 2. Temporary excavations for remedial grading along the project margins should be initiated at permissible boundary locations and extend into the site at inclinations of 1:1 (horizontal:vertical). 6.1.5 We encountered a perched groundwater condition within the alluvium at a depth of approximately 5 feet in the northwestern portion of the site. In addition, seepage exists in the central and eastern portions of the site. Perched groundwater and seepage should be expected during remedial grading operations. 6.1.6 The buildings can be supported by conventional continuous and spread footings or a post-tensioned foundation system, provided the recommendations of this report have been incorporated into the design. 6.1.7 A canyon subdrain should be constructed at the bottom of the drainage in the northwestern portion of the site, with its proposed location shown on the Geologic Map, Figure 2. Project No. 07671-52-01 -8- July 14, 2009 6.2 Excavation and Soil Characteristics 6.2.1 We encountered soil during the investigation that is "non-expansive" (expansion index [El] of 20 or less) as defined by 2007 California Building Code (CBC) Section 1802.3.2. Table 6.2 presents soil classifications based on the expansion index. We expect a majority of the soil possesses a "very low" to "low" expansion potential (Expansion Index of 50 or less). Some of the surficial soil containing clay may possess a "very low" to "medium" expansion potential (Expansion Index of 90 or less). TABLE 6.2 SOIL CLASSIFICATION BASED ON EXPANSION INDEX Expansion Index (El) 0-20 21-50 51-90 91-130 Greater Than 130 Soil Classification Very Low Low Medium High Very High 6.2.2 We tested samples of the site materials to evaluate the percentage of water-soluble sulfate content. Results from the laboratory water-soluble sulfate content tests are presented in Appendix B and indicate that the on-site materials at the locations tested possesses "negligible" sulfate exposure to concrete structures as defined by 2007 CBC Section 1904.3 and ACI318. The presence of water-soluble sulfates is not a visually discernible characteristic; therefore, other soil samples from the site could yield different concentrations. Additionally, over time landscaping activities (i.e., addition of fertilizers and other soil nutrients) may affect the concentration. 6.2.3 Geocon Incorporated does not practice in the field of corrosion engineering. Therefore, further evaluation by a corrosion engineer may be performed if improvements that could be susceptible to corrosion are planned. 6.2.4 Based on the results of the field investigation and our experience in the general area, we expect the surficial soil and formational materials can generally be excavated with moderate to heavy effort using conventional heavy-duty excavation equipment. Cemented zones may be encountered at random locations in the formational materials; however, the extent is expected to be localized. Difficult ripping conditions and the generation of oversize material should be expected within these cemented zones. Project No. 07671-52-01 -9-July 14,2009 6.3 Slope Stability Analyses 6.3.1 We performed the slope stability analysis using a two-dimensional computer program GeoStudio2004 created by Geo-Slope International Ltd. We calculated the factor-of-safety using rotational-mode and an entry-exit mode analysis using Spencer's procedure. The output from the computer program including the calculated factor-of safety is presented in Figures 4 and 5. The soil parameters implemented in the slope stability analysis are based on the laboratory test results provided in Appendix B. Based on our study, the results of the analyses indicate the calculated factors-of-safety for the proposed fill slopes is 1.5 or greater. However, geogrid fabric should be used during the construction of the \1A:\ (horizontal:vertical) fill slope. The geogrid should start at the base of the slope and end approximately 5 feet from the top. The geogrid should be placed at least 3 feet vertically, extend a minimum of 10 feet horizontally into the slope and consist of Strata Grid 200 or equivalent. The grid should be placed on a flat compacted surface and pulled taut with no slack or folds in the grid. Each grid sheet should overlap a minimum of 12 inches. The future home owners should be made aware of the location of the reinforcement so damage can be avoided. 6.3.2 We used shear strength parameters for the existing geologic features from laboratory direct shear tests on soil samples obtained during our field investigation and on samples obtained from other investigations in the area. We performed direct shear tests on samples of the fill soil and the formational materials. The laboratory shear tests were performed in accordance with ASTM D 3080. The geologic units encountered and the shear strength properties used in the analyses are presented on Table 6.3.1. TABLE 6.3.1 SUMMARY OF SOIL PROPERTIES USED FOR SLOPE STABILITY ANALYSES Geologic Unit Compacted Fill (Qcf) Alluvium (Qal) Lindavista (Qln) Santiago Formation (Tsa) Density (pcf) 130 130 130 130 Cohesion (psf) 300 250 400 400 Friction Angle (degrees) 30 28 32 32 6.3.3 We selected cross-sections A-A' and B-B' to perform the computer slope stability analyses. Output from the analyses is presented in Figures 4 and 5. Table 6.3.2 provides a description of the cross-sections, their corresponding factors of safety and figure number, and the condition of the slope stability analyses. A factor of safety of at least 1.5 for static conditions is currently required by the City of Carlsbad for graded slopes. Project No. 07671-52-01 -10-July 14, 2009 TABLE 6.3.2 SUMMARY OF SLOPE STABILITY ANALYSES Cross Section A-A' B-B' Factor of Safety 1.58 1.60 Figure Number 4 5 Condition of Slope Stability Analyses Minimum rotational-mode factor of safety for 1 1A\ 1 (horizontakvertical) fill slope Minimum rotational-mode factor of safety for 2: 1 (horizontal:vertical) fill slope 6.3.4 The proposed cut and fill slopes within the project limits should be stable for both surficial and deep-seated conditions, provided the recommendations of this report are incorporated into site grading. We performed surficial slope stability calculations for a \1A:\ (horizontal:vertical) fill slope with maximum heights of approximately 50 feet. The results of the surficial slope stability analyses for the planned fill slopes at the site indicate the slopes possess a calculated factor-of-safety of at least 1.5 if constructed with geogrid. Surficial and cut and fill slope stability calculations are presented on Figures 6 and 7, respectively. 6.4 Grading 6.4.1 Grading should be performed in accordance with the attached Recommended Grading Specifications contained in Appendix C. Where the recommendations of this section conflict with those of Appendix C, the recommendations of this section take precedence. Earthwork should be observed and fill tested for dry density and moisture content by Geocon Incorporated. 6.4.2 Prior to commencing grading, a preconstruction conference should be held at the site with the owner or developer, grading contractor, city representative, civil engineer, and geotechnical engineer in attendance. Special soil handling and/or the grading plans can be discussed at that time. 6.4.3 Site preparation should begin with demolition of the existing structures and utilities and the removal of deleterious material and vegetation. The depth of removal should be such that materials to be used in fill are generally free of organic matter. Material generated during stripping operations and/or site demolition should be exported from the site. 6.4.4 The potentially compressible surficial soil (debris fill, undocumented fill, topsoil, colluvium, and alluvium) should be removed to expose the underlying dense formational materials prior to placing fill and/or structural loads. The actual extent of removals should be evaluated in the field by a representative of Geocon Incorporated. The exposed material at the base of the Project No. 07671-52-01 -11-July 14, 2009 removal should then be scarified, moisture conditioned as necessary, and properly compacted. 6.4.5 Based on the results of our geotechnical investigation, portions of the planned slopes are composed of unsuitable debris fill. The debris fill should be removed and replaced with properly compacted fill. We understand the planned remedial grading within the slope areas will included the debris fill. Portions of the debris fill are located outside the planned limits of grading. Excavations outside the limits of debris fill will encroach into sensitive habitat and we understand remedial grading in the sensitive habitat can not occur. Where the sensitive habitat exists and deep removals are required, the remedial grading for the planned fill slope should begin at the limits of grading and projection down at a 1:1 inclination into formational materials as shown on the recommended grading specifications provided in Appendix C. The resulting keyway should be approximately 15 feet wide. Geologic Cross- Sections A-A' and B-B' as shown on Figure 3 depict the planned remedial grading of the subject slopes. 6.4.6 The debris fill and portions of the undocumented fill contain trash and construction debris that is unsuitable for reuse as compacted fill. Prior to reuse as compacted fill, the trash within the debris fill and undocumented fill units should be processed and the unsuitable material removed and exported offsite. A representative of Geocon Incorporated should evaluate the suitability of the material prior to its placement as compacted fill. 6.4.7 The existing surficial deposits contain high moisture contents in localized areas and we encountered a relatively shallow perched groundwater within the alluvial soil in the northwestern portion of the site. Special remedial grading operations may be required. Additional recommendations may be provided during the remedial grading operations to provide a stable bottom if excavations into groundwater areas cannot be performed. 6.4.8 The site soil is considered suitable for placement as fill provided it is generally free from vegetation, debris and oversize material. Layers of fill should be no thicker than will allow for adequate bonding and compaction. Fill, including trench and wall backfill and scarified ground surfaces, should be compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content as determined by ASTM Test Procedure D 1557. 6.4.9 To reduce the potential for differential settlement, cut-fill transition pads should be undercut at least 3 feet and replaced with properly compacted fill. The undercut should be sloped at least 1 percent toward the adjacent street or deep fill areas. Project No. 07671-52-01 -12- July 14,2009 6.4.10 Import fill soil, if necessary, should consist of granular materials with a "very low" to "low" expansion potential (El of 50 or less) free of deleterious material and rocks larger than 3 inches and should be compacted as recommended above. Geocon Incorporated should be notified of the import soil source and should perform laboratory testing of import soil prior to its arrival at the site to determine its suitability as fill material. 6.5 Slopes 6.5.1 Based on experience with similar site materials and our slope stability calculations, it is our opinion that cut and fill slopes have calculated factors-of-safety in excess of 1.5 under static conditions of both deep-seated and shallow sloughing conditions. Results of the slope stability analyses are shown in Figures 4 through 7. 6.5.2 We should observe cut slope excavations and remedial grading operations to check that soil and geologic conditions do not differ significantly from those expected. 6.5.3 The outer 15 feet (or a distance equal to the height of the slope, whichever is less) of fill slopes should be composed of properly compacted "granular" soil fill to reduce the potential for surficial sloughing. In general, soil with an expansion index of 50 or less and at least 35 percent sand size particles should be acceptable as "granular" fill. Soil of questionable strength to satisfy surficial stability should be tested in the laboratory for acceptable drained shear strength. The use of cohesionless soil in the outer portion of fill slopes should be avoided. Slopes should be overbuilt a horizontal distance of two feet and cut back to finished grade or compacted by backrolling with a loaded sheepsfoot roller at vertical intervals not to exceed 4 feet and should be track-walked at the completion of each slope such that the fill soil are compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content to the face of the finished sloped. 6.5.4 Slopes should be landscaped with drought-tolerant vegetation, having variable root depths and requiring minimal landscape irrigation. In addition, all slopes should be drained and properly maintained to reduce erosion. 6.6 Subdrains 6.6.1 The geologic units encountered on the site have permeability characteristics that could be susceptible under certain conditions to groundwater seepage. The location of a proposed subdrain in the northwestern portion of the site is presented on the Geologic Map, Figure 2. The use of canyon subdrains will be necessary to mitigate the potential for adverse impacts associated with seepage conditions. Figure 8 depicts a typical canyon subdrain detail. Project No. 07671-52-01 -13- July 14,2009 6.6.2 Prior to outletting, the final 20-foot segment of subdrain should consist of non-perforated drainpipe. At the non-perforated/perforated interface, a seepage cutoff wall should be constructed on the down gradient side of the junction in accordance with Figure 9. Subdrains that discharge into a natural drainage course or open space area should be provided with a permanent headwall structure in accordance with Figure 10. 6.6.3 The final grading plans should show the location of the proposed subdrains. Upon completion of remedial excavations and subdrain installation, the project civil engineer should survey the drain locations and prepare an "as-built" map depicting the existing conditions. 6.7 Seismic Design Criteria 6.7.1 We used the computer program Seismic Hazard Curves and Uniform Hazard Response Spectra, provided by the USGS to calculate the seismic design criteria. Table 6.7.1 summarizes site-specific design criteria obtained from the 2007 California Building Code (CBC), Chapter 16 Structural Design, Section 1613 Earthquake Loads. The short spectral response has a period of 0.2 second. TABLE 6.7.1 2007 CBC SEISMIC DESIGN PARAMETERS Parameter Site Class Spectral Response - Class B (short), Ss Spectral Response - Class B (1 sec), Si Site Coefficient, Fa Site Coefficient, Fv Maximum Considered Earthquake Spectral Response Acceleration (short), SMs Maximum Considered Earthquake Spectral Response Acceleration - (1 sec), SMi 5% Damped Design Spectral Response Acceleration (short), SDS 5% Damped Design Spectral Response Acceleration (1 sec), SDI Value C 1.218 0.459 1.0 1.341 1.218 0.616 0.812 0.411 D 1.218 0.459 1.013 1.541 1.234 0.708 0.823 .0472 IBC-06 Reference Table 1613.5.2 Figure 1613.5(3) Figure 1613.5(4) Table 1613.5.3(1) Table 1613.5.3(2) Section 1613.5.3 (Eqn 16-37) Section 1613.5.3 (Eqn 16-38) Section 1613.5.4 (Eqn 16-39) Section 1613.5.4 (Eqn 16-40) 6.7.2 Conformance to the criteria in Table 6.7.1 for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur if a Project No. 07671-52-01 -14-July 14, 2009 maximum level earthquake occurs. The primary goal of seismic design is to protect life and not to avoid all damage, since such design may be economically prohibitive. 6.8 Temporary Excavations 6.8.1 Temporary slopes should be made in conformance with OSHA requirements. The existing surficial materials should be considered Type B soil (Type C where groundwater or seepage is encountered) and the formational materials should be considered Type A soil (Type B where groundwater or seepage is encountered). In general, special shoring requirements will not be necessary if temporary excavations will be less than 4 feet in height. Temporary excavations greater than 4 feet in height, however, should be laid back in accordance with OSHA requirements and the soil types listed herein. These excavations should not become saturated or be allowed to dry out. Surcharge loads should not be permitted within a distance equal to the height of the excavation from the top of the excavation. The top of the excavation should be a minimum of 15 feet from the edge of existing improvements. Excavations steeper than those recommended or closer than 15 feet from an existing surface improvement should be shored in accordance with applicable OSHA codes and regulations. 6.9 Foundation and Slab-On-Grade Recommendations 6.9.1 The foundation recommendations herein are for proposed one- to three-story residential structures. The foundation recommendations have been separated into three categories based on the maximum and differential fill thickness and expansion index. The foundation category criteria are presented in Table 6.9.1. TABLE 6.9.1 FOUNDATION CATEGORY CRITERIA Foundation Category I II III Maximum Fill Thickness, T (feet) T<20 20<T<50 T>50 Differential Fill Thickness, D (feet) — 10<D<20 D>20 Expansion Index (El) EI<50 50<EI<90 90<EI<130 6.9.2 Table 6.9.2 presents minimum foundation and interior concrete slab design criteria for conventional foundation systems. Project No. 07671-52-01 -15-July 14, 2009 TABLE 6.9.2 CONVENTIONAL FOUNDATION RECOMMENDATIONS BY CATEGORY Foundation Category I II III Minimum Footing Embedment Depth (inches) 12 18 24 Continuous Footing Reinforcement Two No. 4 bars, one top and one bottom Four No. 4 bars, two top and two bottom Four No. 5 bars, two top and two bottom Interior Slab Reinforcement 6x6- 10/10 welded wire mesh at slab mid-point No. 3 bars at 24 inches on center, both directions No. 3 bars at 18 inches on center, both directions 6.9.3 The embedment depths presented in Table 6.9.2 should be measured from the lowest adjacent pad grade for both interior and exterior footings. The conventional foundations should have a minimum width of 12 inches and 24 inches for continuous and isolated footings, respectively. A wall/column footing dimension detail is presented on Figure 11. 6.9.4 Concrete slabs-on-grade should be underlain by 4 inches of clean sand (3 inches for a 5-inch- thick slab) to reduce the potential for differential curing, slab curl, and cracking. Slabs that may receive moisture-sensitive floor coverings or may be used to store moisture-sensitive materials should be underlain by a vapor retarder placed near the middle of the sand bedding. The vapor retarder used should be specified by the project architect or developer based on the type of floor covering that will be installed. The vapor retarder design should be consistent with the guidelines presented in Section 9.3 of the American Concrete Institute's (ACI) Guide for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials (ACI 302.2R-06). 6.9.5 As an alternative to the conventional foundation recommendations, consideration should be given to the use of post-tensioned concrete slab and foundation systems for the support of the proposed structures. The post-tensioned systems should be designed by a structural engineer experienced in post-tensioned slab design and design criteria of the Post-Tensioning Institute (PTI) Third Edition as required by the 2007 California Building Code (CBC Section 1805.8). Although this procedure was developed for expansive soil conditions, we understand it can also be used to reduce the potential for foundation distress due to differential fill settlement. The post-tensioned design should incorporate the geotechnical parameters presented on Table 6.9.3 for the particular Foundation Category designated. The parameters presented in Table 6.9.3 are based on the guidelines presented in the PTI, Third Edition design manual. Project No. 07671-52-01 -16-July 14, 2009 TABLE 6.9.3 POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS Post-Tensioning Institute (PTI) Third Edition Design Parameters Thornthwaite Index Equilibrium Suction Edge Lift Moisture Variation Distance, eM (feet) Edge Lift, yM (inches) Center Lift Moisture Variation Distance, eM (feet) Center Lift, VM (inches) Foundation Category I -20 3.9 5.3 0.61 9.0 0.30 II -20 3.9 5.1 1.10 9.0 0.47 III -20 3.9 4.9 1.58 9.0 0.66 6.9.6 If the structural engineer proposes a post-tensioned foundation design method other than the 2007 CBC: • The criteria presented in Table 6.9.3 are still applicable. • Interior stiffener beams should be used for Foundation Categories II and HI. • The width of the perimeter foundations should be at least 12 inches. • The perimeter footing embedment depths should be at least 12 inches, 18 inches and 24 inches for foundation categories I, II, and III, respectively. The embedment depths should be measured from the lowest adjacent pad grade. 6.9.7 Our experience indicates post-tensioned slabs are susceptible to excessive edge lift, regardless of the underlying soil conditions. Placing reinforcing steel at the bottom of the perimeter footings and the interior stiffener beams may mitigate this potential. Current PTI design procedures primarily address the potential center lift of slabs but, because of the placement of the reinforcing tendons in the top of the slab, the resulting eccentricity after tensioning reduces the ability of the system to mitigate edge lift. The structural engineer should design the foundation system to reduce the potential of edge lift occurring for the proposed structures. 6.9.8 The foundations for the post-tensioned slabs should be embedded in accordance with the recommendations of the structural engineer. If a post-tensioned mat foundation system is planned, the slab should possess a thickened edge with a minimum width of 12 inches and extend below the clean sand or crushed rock layer. Project No. 07671-52-01 -17-July 14, 2009 6.9.9 During the construction of the post-tension foundation system, the concrete should be placed monolithically. Under no circumstances should cold joints form between the footings/grade beams and the slab during the construction of the post-tension foundation system. 6.9.10 Category I, II, or III foundations may be designed for an allowable soil bearing pressure of 2,000 pounds per square foot (psf) (dead plus live load). This bearing pressure may be increased by one-third for transient loads due to wind or seismic forces. 6.9.11 Isolated footings, if present, should have the minimum embedment depth and width recommended for conventional foundations for a particular foundation category. The use of isolated footings, which are located beyond the perimeter of the building and support structural elements connected to the building, are not recommended for Category III. Where this condition cannot be avoided, the isolated footings should be connected to the building foundation system with grade beams. 6.9.12 For Foundation Category III, consideration should be given to using interior stiffening beams and connecting isolated footings and/or increasing the slab thickness. In addition, consideration should be given to connecting patio slabs, which exceed 5 feet in width, to the building foundation to reduce the potential for future separation to occur. 6.9.13 Foundation excavations should be observed by the geotechnical engineer (a representative of Geocon Incorporated) prior to the placement of reinforcing steel to check that the exposed soil conditions are similar to those expected and that they have been extended to the appropriate bearing strata. If unexpected soil conditions are encountered, foundation modifications may be required. 6.9.14 Special subgrade presaturation is not deemed necessary prior to placing concrete; however, the exposed foundation and slab subgrade soil should be moisturized to maintain a moist condition as would be expected in any such concrete placement. 6.9.15 Where buildings or other improvements are planned near the top of a slope steeper than 3:1 (horizontal:vertical), special foundations and/or design considerations are recommended due to the tendency for lateral soil movement to occur. • For fill slopes less than 20 feet high, building footings should be deepened such that the bottom outside edge of the footing is at least 7 feet horizontally from the face of the slope. • When located next to a descending 3:1 (horizontal:vertical) fill slope or steeper, the foundations should be extended to a depth where the minimum horizontal distance is Project No. 07671-52-01 -18- July 14, 2009 equal to H/3 (where H equals the vertical distance from the top of the fill slope to the base of the fill soil) with a minimum of 7 feet but need not exceed 40 feet. The horizontal distance is measured from the outer, deepest edge of the footing to the face of the slope. An acceptable alternative to deepening the footings would be the use of a post-tensioned slab and foundation system or increased footing and slab reinforcement. Specific design parameters or recommendations for either of these alternatives can be provided once the building location and fill slope geometry have been determined. • If swimming pools are planned, Geocon Incorporated should be contacted for a review of specific site conditions. • Swimming pools located within 7 feet of the top of cut or fill slopes are not recommended. Where such a condition cannot be avoided, the portion of the swimming pool wall within 7 feet of the slope face be designed assuming that the adjacent soil provides no lateral support. This recommendation applies to fill slopes up to 30 feet in height, and cut slopes regardless of height. For swimming pools located near the top of fill slopes greater than 30 feet in height, additional recommendations may be required and Geocon Incorporated should be contacted for a review of specific site conditions. • Although other improvements, which are relatively rigid or brittle, such as concrete flatwork or masonry walls, may experience some distress if located near the top of a slope, it is generally not economical to mitigate this potential. It may be possible, however, to incorporate design measures that would permit some lateral soil movement without causing extensive distress. Geocon Incorporated should be consulted for specific recommendations. 6.9.16 The concrete slab-on-grade recommendations are based on soil support characteristics only. The project structural engineer should evaluate the structural requirements of the concrete slabs for supporting expected loads. 6.9.17 Concrete slabs should be provided with adequate construction joints and/or expansion joints to control unsightly shrinkage cracking. The design of joints should consider criteria of the American Concrete Institute when establishing crack-control spacing. 6.9.18 The recommendations of this report are intended to reduce the potential for cracking of slabs due to expansive soil (if present), differential settlement of existing soil or soil with varying thicknesses. However, even with the incorporation of the recommendations presented herein, foundations, stucco walls, and slabs-on-grade placed on such conditions may still exhibit some cracking due to soil movement and/or shrinkage. The occurrence of concrete shrinkage cracks is independent of the supporting soil characteristics. Their occurrence may be reduced and/or controlled by limiting the slump of the concrete, proper concrete placement and curing, and by the placement of crack control joints at periodic intervals, in particular, where re-entrant slab corners occur. Project No. 07671-52-01 -19- July 14, 2009 6.9.19 Geocon Incorporated should be consulted to provide additional design parameters as required by the structural engineer. 6.10 Conventional Retaining Wall Recommendations 6.10.1 Retaining walls not restrained at the top and having a level backfill surface should be designed for an active soil pressure equivalent to the pressure exerted by a fluid density of 35 pounds per cubic foot (pcf). Where the backfill will be inclined at no steeper than 2:1 (horizontahvertical), an active soil pressure of 50 pcf is recommended. These soil pressures assume that the backfill materials within an area bounded by the wall and a 1:1 plane extending upward from the base of the wall possess an El of 50 or less. For those lots with finish grade soils having an El greater than 50 and/or where backfill materials do not conform to the criteria herein Geocon Incorporated should be consulted for additional recommendations. 6.10.2 Unrestrained walls are those that are allowed to rotate more than 0.001H (where H equals the height of the retaining portion of the wall in feet) at the top of the wall. Where walls are restrained from movement at the top, an additional uniform pressure of 7H psf should be added to the above active soil pressure. 6.10.3 The structural engineer should determine the seismic design category for the project. If the project possesses a seismic design category of D, E, or F, the proposed retaining walls should be designed with seismic lateral pressure. The seismic load exerted on the wall should be a triangular distribution with a pressure of 25H (where H is the height of the wall, in feet, resulting in pounds per square foot [psf]) exerted at the top of the wall and zero at the base of the wall. We used a peak site acceleration of 0.33g calculated form the 2007 California Building Code (Sos/2.5) and applying a pseudo-static coefficient of 0.5. 6.10.4 Unrestrained walls will move laterally when backfilled and loading is applied. The amount of lateral deflection is dependant on the wall height, the type of soil used for backfill, and loads acting on the wall. The retaining walls and improvements above the retaining walls should be designed to incorporate an appropriate amount of lateral deflection as determined by the structural engineer. 6.10.5 Retaining walls should be provided with a drainage system adequate to prevent the buildup of hydrostatic forces and waterproofed as required by the project architect. The soil immediately adjacent to the backfilled retaining wall should be composed of free draining material completely wrapped in Mirafi 140 (or equivalent) filter fabric for a lateral distance of 1 foot for the bottom two-thirds of the height of the retaining wall. The upper one-third Project No. 07671-52-01 -20- July 14, 2009 should be backfilled with less permeable compacted fill to reduce water infiltration. The use of drainage openings through the base of the wall (weep holes) is not recommended where the seepage could be a nuisance or otherwise adversely affect the property adjacent to the base of the wall. The recommendations herein assume a properly compacted granular (El of 50 or less) free-draining backfill material with no hydrostatic forces or imposed surcharge load. Figure 12 presents a typical retaining wall drainage detail. If conditions different than those described are expected, or if specific drainage details are desired, Geocon Incorporated should be contacted for additional recommendations. 6.10.6 In general, wall foundations having a minimum depth and width of 1 foot may be designed for an allowable soil bearing pressure of 2,000 psf, provided the soil within 4 feet below the base of the wall has an Expansion Index of 50 or less. The proximity of the foundation to the top of a slope steeper than 3:1 could impact the allowable soil bearing pressure. Therefore, Geocon Incorporated should be consulted where such a condition is expected. 6.10.7 The recommendations presented herein are generally applicable to the design of rigid concrete or masonry retaining walls having a maximum height of 8 feet. In the event that walls higher than 8 feet or other types of walls (such as crib-type walls) are planned, Geocon Incorporated should be consulted for additional recommendations. 6.11 Lateral Loads 6.11.1 For resistance to lateral loads, an allowable passive earth pressure equivalent to a fluid density of 350 pcf is recommended for footings or shear keys poured neat against properly compacted granular fill or formational materials. The allowable passive pressure assumes a horizontal surface extending away from the base of the wall at least 5 feet or three times the height of the surface generating the passive pressure, whichever is greater. The upper 12 inches of material not protected by floor slabs or pavement should not be included in the design for lateral resistance. An allowable friction coefficient of 0.35 may be used for resistance to sliding between soil and concrete. This friction coefficient may be combined with the allowable passive earth pressure when determining resistance to lateral loads. 6.12 Mechanically Stabilized Earth Walls 6.12.1 Mechanically stabilized earth (MSB) retaining walls are alternative walls that consist of modular block facing units with geogrid reinforced earth behind the block. The geogrid attaches to the block units and is typically placed at specified vertical intervals and embedment lengths. Spacing and lengths are based on the type and strength characteristics of soil used for the backfill. Proj ect No. 07671 -52-01 -21- July 14, 2009 6.12.2 Based on information obtained from the referenced geotechnical report, the geotechnical parameters provided in Table 6.12.1 can be used for design of the MSB walls. TABLE 6.12.1 GEOTECHNICAL PARAMETERS FOR MSE WALLS Parameter Angle of Internal Friction Cohesion Wet Unit Weight Reinforced Zone 30 degrees 300 psf 130pcf Retained Zone 30 degrees 300 psf 130pcf Foundation Zone 30 degrees 300 psf 130pcf 6.12.3 The soil parameters presented in Table 6.12.1 are based on our experience and direct shear- strength tests performed during the geotechnical investigation and previous grading operations and represent some of the on-site materials. The wet unit weight values presented in Table I can be used for design but actual in-place densities may range from approximately 110 to 145 pounds per cubic foot. Geocon Incorporated has no way of knowing whether these materials will actually be used as backfill behind the wall during construction. It is up to the wall designers to use their judgment in selection of the design parameters. As such, once backfill materials have been selected and/or stockpiled, sufficient shear tests should be conducted on samples of the proposed backfill materials to check that they conform to actual design values. Results should be provided to the designer to re-evaluate stability of the walls. Dependent upon test results, the designer may require modifications to the original wall design (e.g., longer reinforcement embedment lengths). 6.12.4 For walls founded on and retaining compacted fill, the angle of internal friction recommended for the reinforced zone should also be used for the retained zone and foundation zone. The foundation zone is the area where the footing is embedded, the reinforced zone is the area of the backfill that possesses the reinforcing fabric, and the retained zone is the area behind the reinforced zone. 6.12.5 An allowable soil bearing pressure of 2,000 psf (pounds per square foot) should be used for foundation design and calculations for wall bearing. This bearing pressure assumes a minimum foundation width and depth of 12 inches founded in compacted fill or formational materials. The allowable soil bearing pressure may be increased by 300 psf and 500 psf for each additional foot of foundation width and depth, respectively, up to a maximum allowable soil bearing pressure of 4,000 psf. 6.12.6 Backfill materials within the reinforced zone should be compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture Project No. 07671-52-01 -22-July 14, 2009 content in accordance with ASTM D 1557. This is applicable to the entire embedment width of the geogrid reinforcement. Typically, wall designers specify no heavy compaction equipment within 3 feet of the face of the wall. However, smaller equipment (e.g., walk- behind, self-driven compactors or hand whackers) can be used to compact the materials without causing deformation of the wall. If the designer specifies no compactive effort for this zone, the materials are essentially not properly compacted and the geogrid within the uncompacted zone should not be relied upon for reinforcement, and overall embedment lengths will have to be increased to account for the difference. 6.12.7 The wall should be provided with a drainage system sufficient to prevent excessive seepage through the wall and the base of the wall, thus preventing hydrostatic pressures behind the wall. 6.12.8 Geosynthetic reinforcement must elongate to develop full tensile resistance. This elongation generally results in movement at the top of the wall. The amount of movement is dependent upon the height of the wall (e.g., higher walls rotate more) and the type of geogrid reinforcing used. In addition, over time geogrid has been known to exhibit creep (sometimes as much as 5 percent) and can undergo additional movement. Given this condition, the owner should be aware that structures and pavement placed within the reinforced and retained zones of the wall may undergo movement. 6.13 Preliminary Pavement Recommendations 6.13.1 The following preliminary pavement design criteria are based on expected soil conditions. Minimum resistance values (R-Value) of 30 for subgrade soil and 78 for aggregate base materials have been assumed, based on the results of our laboratory testing and experience with similar materials. R-Value testing should be performed on materials present at subgrade elevation after grading and on base materials in order to develop final pavement recommendations. 6.13.2 The flexible pavement section was calculated in general conformance with the Caltrans Method of Flexible Pavement Design (Highway Design Manual, Section 608.4) using three possible Traffic Indices (TI). The project architect, civil engineer, and owner should review the pavement designation to determine appropriate locations for pavement thickness. Recommendations for flexible pavement sections are presented on Table 6.13.1. Project No. 07671-52-01 -23- July 14, 2009 TABLE 6.13.1 PRELIMINARY FLEXIBLE PAVEMENT RECOMMENDATIONS Location Proposed Roadways Traffic Index 4.5 5.0 5.5 Asphalt Concrete (inches) 4.0* 4.0* 4.0* Class 2 Aggregate Base (inches) 4.0* 4.0* 5.0 *City of Carlsbad Minimum Pavement Section 6.13.3 Asphalt concrete should conform to Section 203-6 of the Standard Specifications for Public Works Construction (Greenbook). Class 2 aggregate base materials should conform to Section 26-1.02A of the Standard Specifications of the State of California Department of Transportation (Caltrans). 6.13.4 The upper 12 inches of pavement subgrade soil should be scarified, moisture conditioned as necessary, and compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content as determined by ASTM D 1557. Base course materials should be moisture conditioned to near or slightly above optimum moisture content and compacted to a dry density of at least 95 percent of the laboratory maximum dry density. Asphalt concrete should be compacted to a density of at least 95 percent of the Hveem density as determined by ASTM D 2726. 6.13.5 A rigid Portland Cement concrete (PCC) pavement section should be placed in driveway entrance aprons, trash bin loading/storage areas and loading dock areas. The concrete pad for trash truck areas should be large enough such that the truck wheels will be positioned on the concrete during loading. We calculated the rigid pavement section in general conformance with the procedure recommended by the American Concrete Institute report ACI 330R-01 Guide for Design and Construction of Concrete Parking Lots using the parameters presented in Table 6.13.2. TABLE 6.13.2 RIGID PAVEMENT DESIGN PARAMETERS Design Parameter Modulus of subgrade reaction, k Modulus of rupture for concrete, MR Traffic Category, TC Average daily truck traffic, ADTT Design Value lOOpci 500 psi A-landC 10 and 100 Project No. 07671-52-01 -24-July 14, 2009 6.13.6 Based on the criteria presented herein, the PCC pavement sections should have a minimum thickness as presented in Table 6.13.3. TABLE 6.13.3 RIGID PAVEMENT RECOMMENDATIONS Location Automobile Parking Areas (TC=A-1) Heavy Truck and Fire Lane Areas (TC=C) Portland Cement Concrete (inches) 6 7 6.13.7 The PCC pavement should be placed over subgrade soil that is compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content. This pavement section is based on a minimum concrete compressive strength of approximately 3,000 pounds per square inch (psi). 6.13.8 A thickened edge or integral curb is recommended on the outside of concrete slabs subjected to wheel loads. The thickened edge should be 1.2 times the slab thickness with a minimum thickness increase of 2 inches at the slab edge and tapered back to the recommended slab thickness 3 feet behind the face of the slab (e.g., a 7-inch-thick slab would have a 9-inch- thick edge). Reinforcing steel will not be necessary within the concrete for geotechnical purposes with the possible exception of dowels at construction joints as discussed herein. 6.13.9 To control the location and spread of concrete shrinkage cracks, crack-control joints (weakened plane joints) should be included in the design of the concrete pavement slab. Crack-control joints should not exceed 30 times the slab thickness with a maximum spacing of 15 feet (e.g., a 7-inch-thick slab would have a 15-foot spacing pattern) and should be sealed with an appropriate sealant to prevent the migration of water through the control joint to the subgrade materials. 6.13.10 To provide load transfer between adjacent pavement slab sections, a trapezoidal-keyed construction joint is recommended. As an alternative to the keyed joint, dowelling is recommended between construction joints. As discussed in the referenced ACI guide, dowels should consist of smooth yg-inch-diameter reinforcing steel 14 inches long, embedded a minimum of 6 inches into the slab on either side of the construction joint. Dowels should be located at the midpoint of the slab, spaced at 12 inches on center, and lubricated to allow joint movement while still transferring loads. Other alternative recommendations for load transfer should be provided by the project structural engineer. Project No. 07671-52-01 -25-July 14, 2009 6.14 Site Drainage and Moisture Protection 6.14.1 Adequate drainage is critical to reduce the potential for differential soil movement, erosion, and subsurface seepage. Under no circumstances should water be allowed to pond adjacent to footings. The site should be graded and maintained such that surface drainage is directed away from structures and the top of slopes into swales or other controlled drainage devices. Roof and pavement drainage should be directed into conduits that carry runoff away from the proposed structure. 6.14.2 In the case of basement walls or building walls retaining landscaping areas, a water proofing system should be used on the wall and joints, and a Miradrain drainage panel, or similar, should be placed over the water proofing. A perforated drainpipe of schedule 40 or better should be installed at the base of the wall below the floor slab and drained to an appropriate discharge area. Accordion type pipe is not acceptable. The project architect or civil engineer should provide detailed specifications on the plans for all waterproofing and drainage. 6.14.3 Underground utilities should be leak free. Utility and irrigation lines should be checked periodically for leaks for early detection of water infiltration and detected leaks should be repaired promptly. Detrimental soil movement could occur if water is allowed to infiltrate the soil for a prolonged period of time. 6.14.4 We understand water infiltration devices (e.g. detention basins, bioswales, retention basins, pervious pavement) or are being considered for the project. Distress may be caused to planned improvements and properties located hydrologically downstream. The distress depends on the amount of water to be detained, its residence time, soil permeability, and other factors. We have not performed a hydrogeology study at the site. Downstream properties may be subjected to seeps, springs, slope instability, raised groundwater, movement of foundations and slabs, or other impacts as a result of water infiltration. Drainage and detention devices should be designed with an impermeable liner and connected to the storm drain system to reduce to potential of water infiltration. 6.14.5 Landscaping planters adjacent to paved areas are not recommended due to the potential for surface or irrigation water to infiltrate the pavement's subgrade and base course. We recommend that subdrains to collect excess irrigation water and transmit it to drainage structures, or impervious above-grade planter boxes be used. In addition, where landscaping is planned adjacent to the pavement, we recommend construction of a cutoff wall along the edge of the pavement that extends at least 6 inches below the bottom of the base material. Project No. 07671-52-01 -26- July 14,2009 6.14.6 Geocon Incorporated should be retained to provide additional recommendations pertaining to the geotechnical aspects of possible impacts and design, if required. 6.15 Foundation and Grading Plan Review 6.15.1 Foundation and grading plans should be reviewed by Geocon Incorporated to check that the plans have been prepared in substantial conformance with the recommendations of this report and to provide additional analyses or recommendations, if necessary. Project No. 07671-52-01 -27- July 14, 2009 LIMITATIONS AND UNIFORMITY OF CONDITIONS 1. The recommendations of this report pertain only to the site investigated and are based upon the assumption that the soil conditions do not deviate from those disclosed in the investigation. If any variations or undesirable conditions are encountered during construction, or if the proposed construction will differ from that anticipated herein, Geocon Incorporated should be notified so that supplemental recommendations can be given. The evaluation or identification of the potential presence of hazardous or corrosive materials was not part of the scope of services provided by Geocon Incorporated. 2. This report is issued with the understanding that it is the responsibility of the owner, or of his representative, to ensure that the information and recommendations contained herein are brought to the attention of the architect and engineer for the project and incorporated into the plans, and the necessary steps are taken to see that the contractor and subcontractors carry out such recommendations in the field. 3. The findings of this report are valid as of the present date. However, changes in the conditions of a property can occur with the passage of time, whether they be due to natural processes or the works of man on this or adjacent properties. In addition, changes in applicable or appropriate standards may occur, whether they result from legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review and should not be relied upon after a period of three years. The firm that performed the geotechnical investigation for the project should be retained to provide testing and observation services during construction to provide continuity of geotechnical interpretation and to check that the recommendations presented for geotechnical aspects of site development are incorporated during site grading, construction of improvements, and excavation of foundations. If another geotechnical firm is selected to perform the testing and observation services during construction operations, that firm should prepare a letter indicating their intent to assume the responsibilities of project geotechnical engineer of record. A copy of the letter should be provided to the regulatory agency for their records. In addition, that firm should provide revised recommendations concerning the geotechnical aspects of the proposed development, or a written acknowledgement of their concurrence with the recommendations presented in our report. They should also perform additional analyses deemed necessary to assume the role of Geotechnical Engineer of Record. Project No. 07671-52-01 July 14, 2009 SOURCE: 2007 THOMAS BROTHERS MAP SAN DIEGO COUNTY, CALIFORNIA "Map © Rand McNaily, R.L.08-S-100, reproduced with permission. It is unlawful to copy or reproduce, whether for personal use or resale, without permission" N NO SCALE GEOCON ^ INCORPORATED ^fflr GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 ME IRA \ DSK/GTYPD VICINITY MAP MUROYA PROPERTY CARLSBAD, CALIFORNIA DATE 07 - 14 - 2009 J PROJECT NO. 07671 - 52 - 01 I FIG. 1 Vicinity Mop o A1 r—370 : — 320 225 — — 270 250 300 DISTANCE (Feet) GEOLOGIC CROSS - SECTION A-A SCALE: 1" = 50' (Horiz. = Vert.) 350 I I I I I ^220 500 350 — Q 300 — 250 — — 350 300 O — 250 250 DISTANCE (Feet) GEOLOGIC CROSS - SECTION SCALE: 1" = 50' (Horiz. = Vert.) MUROYA PROPERTY CARLSBAD, CALIFORNIA Qcf Qudf Qdf Qal Qln Tsa "1- LEGEND COMPACTED FILL (Proposed) UNDOCUMENTED FILL DEBRIS FILL ALLUVIUM LINDAVISTA FORMATION SANTIAGO FORMATION APPROX. LOCATION OF EXPLORATORY TRENCH APPROX. REMOVAL AREA APPROX. LOCATION OF GEOLOGIC CONTACT (Queried Where Uncertain) GEOCON INC ORPORATED GEOTEOHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 PROJECT NO. 07671 -52-01 FIGURE 3 DATE 07-14-2009 Y7RAA/DWG.Y:\R14TEMR1_GEOTECHM_GEOTECH_RUBEN\GEOCON2009\07671-52-01 MUROYA PROPERTY\X-SECTNS\ME_r671 X-SECTNS (UPDATED 07-1 CW>9) - CDCD LJ_ g Ia> LU MUROYA PROPERTY CARLSBAD, CALIFORNIA Muroya Property Project No. 07671-52-01 Section: A-A' Name: M-1 a.gsz Date: 7/13/2009 Time: 11:33:09 AM Description: Qcf C: 300psf Phi: 30deg. Wt: 130pcf Description: Qal C: 250psf Phi: 28deg. Wt: 130pcf Description: Q!n C: 400psf Phi: 32deg. Wt: 130pcf Description: Tsa C: 400psf Phi: 32deg. Wt: 130pcf 375 - 300 275 250 225' 1.5:1 Slope 1:1 Prelection t^ establish toe Qal Tsa Tsa Tsa 275 300 Distance, Feet GEOCON INCORPORATED GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 PROJECT NO. 07671 - 52 - 01 SLOPE STABILITY ANALYSIS COMPUTER OUTPUT 0^07-14-2009 Y:/RAA/OWG. ooo MUROYA PROPERTY CARLSBAD, CALIFORNIA Muroya Property Project No. 07671-52-01 Section: B-B' Name: BB-1a.gsz Date: 7/14/2009 Time: 9:09:18 AM Description: Qcf C: 300psf Phi: 30deg. Wt: 130pcf Description: Qal C: 250psf Phi: 28deg. Wt: 130pcf Description: Qdf C: 200psf Phi: 22deg. Wt: 130pcf Description: Qln C: 400psf Phi: 32deg. Wt: 130pcf Description: Tsa C: 400psf Phi: 32deg. Wt: 130pcf 375 r— 1.60 Proposed Retaining Wall 1:1 projection - Existing Slope Tsa Tsa Tsa 225 250 275 300 Distance, Feet GEOCON INCORPORATED GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 PROJECT NO. 07671 - 52 - 01 SLOPE STABILITY ANALYSIS COMPUTER OUTPUT SS?E 0f. 14-2009 Y:/RAA/DWG.Y:\R14TEMP\1_GEOTECH\1_GEOTECH_RUBENVGEOCON 2009\07671-52-01 MUROYA PROPERTY\DETAILS\SLOPE STAB.ANALYSIS.dwg ASSUMED CONDITIONS : SLOPE HEIGHT DEPTH OF SATURATION SLOPE INCLINATION SLOPE ANGLE UNIT WEIGHT OF WATER TOTAL UNIT WEIGHT OF SOIL ANGLE OF INTERNAL FRICTION APPARENT COHESION H = Infinite Z = 3 feet 2 : 1 (Horizontal : Vertical) i = 26.5 degrees "Y = 62.4 pounds per cubic foot yt = 130 pounds per cubic foot <j) = 32 degrees C = 400 pounds per square foot SLOPE SATURATED TO VERTICAL DEPTH Z BELOW SLOPE FACE SEEPAGE FORCES PARALLEL TO SLOPE FACE ANALYSIS : FS =Z cos2 * tan = 3.2 yt Z sin i cos i REFERENCES: 1 Haefeli, R. The Stability of Slopes Acted Upon by Parallel Seepage. Proc. Second International Conference, SMFE, Rotterdam, 1948,1, 57-62 2 Skempton, A. W., and F.A. Delory, Stability of Natural Slopes in London Clay, Proc. Fourth International Conference, SMFE, London, 1957, 2, 378-81 SURFICIAL SLOPE STABILITY ANALYSIS GEOCON <@> INCORPORATED ^^ GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 ME/RA || DSK/GTYPD MUROYA PROPERTY CARLSBAD, CALIFORNIA DATE 07-14-2009 | PROJECT NO. 07671-52-01 j FIG. 6 Y:/RUTEMP/1_AUTOCAD PLATE TEMPUTE/1_MTAH/SLOPE STABILITY ANALYSiySFSSADWG ASSUMED CONDITIONS : SLOPE HEIGHT SLOPE INCLINATION TOTAL UNIT WEIGHT OF SOIL H = 45 feet 2 : 1 (Horizontal : Vertical) *fy =130 pounds per cubic foot ANGLE OF INTERNAL FRICTION cj> = 32 degrees APPARENT COHESION NO SEEPAGE FORCES C = 400 pounds per square foot ANALYSIS : FS = C NcfC Ncf = FS = 9.1 28 1.9 EQUATION (3-3), REFERENCE 1 EQUATION (3-2), REFERENCE 1 CALCULATED USING EQ. (3-3) DETERMINED USING FIGURE 10, REFERENCE 2 FACTOR OF SAFETY CALCULATED USING EQ. (3-2) REFERENCES: 1 Janbu, N., Stability Analysis of Slopes with Dimensionless Parameters, Harvard Soil Mechanics, Series No. 46,1954 2 Janbu, N., Discussion of J.M. Bell, Dimensionless Parameters for Homogeneous Earth Slopes, Journal of Soil Mechanics and Foundation Design, No. SM6, November 1967. CUT AND FILL SLOPE STABILITY ANALYSIS GEOCON <£* INCORPORATED ^vSr GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 ME IRA 1 | DSK/GTYPD MUROYA PROPERTY CARLSBAD, CALIFORNIA DATE 07 - 14 - 2009 I PROJECT NO. 07671 - 52 - 01 IFIG. 7 Y:/R14TEMP/1_AUTOCAD PIATE TtMPtATE/1_DETAIL/S.OPE STABIUTY ANALYSIS/5SAF .DWG NATURAL GROUND BEDROCK SEE DETAIL BELOW NOTE: FINAL 20' OF PIPE AT OUTLET SHALL BE NON-PERFORATED. 6" DIA. PERFORATED SUBDRAIN PIPE 9 CUBIC FEET/FOOT OF OPEN GRADED GRAVEL SURROUNDED BY MIRAFI 140N (OR EQUIVALENT) FILTER FABRIC NOTE: 1 6-INCH DIAMETER, SCHEDULE 40 PVC PERFORATED PIPE NO SCALE TYPICAL CANYON SUBDRAIN DETAIL GEOCON O INCORPORATED XKr GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 ME/RA j | DSK/GTYPD MUROYA PROPERTY CARLSBAD, CALIFORNIA DATE 07-14-2009 | PROJECT NO. 07671-52-01 |FIG. 8 fc/l DETAIL/CYNDTAll/DWG. FRONT VIEW • 6- MIN. CONCRETE CUT-OFF WALL 6" MIN. ' MIN. NO SCALE SIDE VIEW 12" MIN. CONCRETE ^ _. CUT-OFF WALL 1 A SOLID SUBDRAIN PIPE U VKW; sLi - '•'-• " ' - . . a. 4«-« _ *^ ^ 6" MIN. fTYP) PERFORATED SUBDRAIN PIPE 6" MIN. (TYP) ; c\ViJ <^^~ NO SCALE TYPICAL SUBDRAIN CUT-OFF WALL DETAIL GEOCON <^ INCORPORATED ^8r GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 ME/RA | | DSK/GTYPD MUROYA PROPERTY CARLSBAD, CALIFORNIA DATE 07 - 14 - 2009 | PROJECT NO. 07671 - 52 - 01 FIG. 9 X:/R14TEMP/1_AUrOCAD PLATE TEMPLATE/lDeTAMJSOOW FRONT VIEW 24" 18" 12" SIDE VIEW NOTE: HEADWALL SHOULD OUTLET INTO CONTROLLED SURFACE DRAINAGE NO SCALE TYPICAL SUBDRAIN OUTLET HEADWALL DETAIL GEOCON <®> INCORPORATED ^SS^ GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 ME/RA 1 | DSK/GTYPD MUROYA PROPERTY CARLSBAD, CALIFORNIA DATE 07-14-2009 j PROJECT NO. 07671-52-01 j FIG. 10 X:/RUTEMP/LAUTOCAD PLATE TEMPIATE/LDETAII/SOHD WALL FOOTING CONCRETE SLAB [>^ SAND MOISTURE INHIBITOR (WHERE REQUIRED) PAD GRADE COLUMN FOOTING CONCRETE SLAB SAND MOISTURE INHIBITOR (WHERE REQUIRED) ••*»:'••..•:$^.--v*A-*;;/ •>. ;•* "«••':;-*-r'SV?*-^:-s'4-. :*,'--*:i.v*!•*?:•"*.- '.\•-.;•.*,-•«..'••••••* *4; •••' A'-'-i«'^^j^pftiia ....SEE REPORT FOR FOUNDATION WITDH AND DEPTH RECOMMENDATION NO SCALE WALL/COLUMN FOOTING DIMENSION DETAIL GEOCON <g& INCORPORATED ^wSr GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 ME/RA || DSK/GTYPD MUROYA PROPERTY CARLSBAD, CALIFORNIA DATE 07 - 14 - 2009 I PROJECT NO. 07671 - 52 - 01 I FIG. 1 1 Y:/RUTEMP/1 AUTOCAD PLATE TEMPUTE/l.DETAIiyCOLUMN FOOTING/CCXFOOTZDWG ,«*, 'if GROUND SURFACE CONCRETE BROWDITCH PROPOSED RETAINING WALL TEMPORARY BACKCUT PER OSHA GROUND SURFACE MIRAFI140N FILTER FABRIC (OR EQUIVALENT) OPEN GRADED 1" MAX. AGGREGATE Vl 4" DIA. PERFORATED SCHEDULE 40 PVC PIPE EXTENDED TO APPROVED OUTLET • GROUND SURFACE CONCRETE BROWDITCH " RETAINING WALL" 2/3H PROPOSED GRADE WATER PROOFING " PER ARCHITECT DRAINAGE PANEL (MIRADRAIN 6000 OR EQUIVALENT) — 12"H 3/4" CRUSHED ROCK (1 CU.FT./FT.) FILTER FABRIC ENVELOPE M1RAFI 140N OR EQUIVALENT _, Jr*""4" DIA. SCHEDULE 40 PERFORATED PVC PIPE OR APPROVED TOTAL DRAIN EXTENDED TO APPROVED OUTLET FOOTING NOTE: DRAIN SHOULD BE UNIFORMLY SLOPED TO GRAVITY OUTLET OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING TYPICAL RETAINING WALL DRAIN DETAIL GEOCON <£* INCORPORATED ^ff^ GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 ME/RA || DSK/GTYPD MUROYA PROPERTY CARLSBAD, CALIFORNIA DATE 07 - 14 - 2009 I PROJECT NO. 07671 - 52 - 01I FIG. 12 Y:/RUTEMP/1_AUTOCAD PUT! TEMPLArt/l_DETAJL/liETAINING WALL DRAINAGE/RET WALL DRAM DETAILS_20WG APPENDIX APPENDIX A FIELD INVESTIGATION The field investigation was performed on March 24, 2006 and consisted of the excavation of 12 exploratory trenches to depths varying between 3 to 10 feet below the existing ground surface using a Bobcat 863 equipped with a 12-inch-wide bucket. The approximate locations of the trenches are shown on the Geologic Map, Figure 2. Disturbed bulk samples were obtained at selected locations in the trenches. Logs of the backhoe trenches are presented on Figures A-l through A-12. The logs depict the soil and geologic conditions encountered and the depth at which samples were obtained. The soil encountered in the backhoe trenches were visually examined, classified, and logged in accordance with ASTM D 2488-00. Project No. 07671-52-01 July 14, 2009 PROJECT NO. 07671-52-01 DEPTH IN - 2 - - 4 - SAMPLE NO. Tl-1 >-ood 1— ••!• •)•••}.• $•#p ;i|| #}$ :M ;:|:j:;|: ^r. k . .r. UJ )occCO SOIL CLASS SM SM TRENCH T 1 ELEV. (MSL.) 334' DATE COMPLETED 03-24-2006 EQUIPMENT BOBCAT 863 w/ 1 2" BUCKET BY: N. ASH MATERIAL DESCRIPTION DEBRIS FILL Loose, moist, dark brown to olive brown, Sihy, fine to medium SAND; abundant organic material and plant debris from nursery operations LINDAVISTA FORMATION Dense, damp, reddish to yellowish brown, Silty, fine-grained SANDSTONE; moderately cemented; difficult excavation ^ -Becomes very dense ^ TRENCH TERMINATED AT 5 FEET No groundwater Zuj_ l| i7i li-l fpa.*-" - - I gQ Q£a LU oS II 5 O0 Figure A-1, Log of Trench T 1, Page 1 of 1 07671-52-01. GPJ SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL 13 ... DISTURBED OR BAG SAMPLE B ... STANDARD PENETRATION TEST B ... CHUNK SAMPLE • ... DRIVE SAMPLE (UNDISTURBED) I ... WATER TABLE OR SEEPAGE NOTE: IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. GEOCON PROJECT NO. 07671-52-01 DEPTH IN FEET - - 2 - SAMPLE NO. >-OO O (_ :;|vH: ' } "K"'i*.M.V*.r.vl*. l*J* '. '•[• • P* *vr rl a: I z -i :•) SOIL CLASS (USCS) SM SM TRENCH T 2 ELEV. (MSL.) 3351 DATE COMPLETED 03-24-2006 EQUIPMENT BOBCAT 863 w/ 1 2" BUCKET BY: N. ASH MATERIAL DESCRIPTION TOPSOIL Loose, moist, dark brown, Silty, fine to medium SAND; some organic material LINDAVISTA FORMATION Dense to very dense, damp, reddish brown to olive gray, Silty, fine to medium-grained SANDSTONE; some jointing REFUSAL AT 3 FEET No groundwater o /^ ^ r Pzt LLJ n*iO.Q: — - £ z^ a! cc.a Hi g?II ^s Cj° ^ Figure A-2, ; Log of Trench T 2, Page 1 of 1 07671-52-01. GPJ SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL & ... DISTURBED OR BAG SAMPLE D ... STANDARD PENETRATION TEST B ... CHUNK SAMPLE I ... DRIVE SAMPLE (UNDISTURBED) 5 -. WATER TABLE OR SEEPAGE NOTE: IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. D. IT GEOCON PROJECT NO. 07671-52-01 DEPTH IN FEET - 2 - - 4 - - 6 - - 8 - 1O SAMPLE NO. >- CDO O :':JyN-V '•v^"".V- :';!vf;-V; W< if || 1 II vfcfif • r *j *!• *lMl*l• HI • t 4 *i QL 1Q Z>-1 01 f SOIL CLASS (USCS) SM SM TRENCH T 3 ELEV. (MSL.) 324' DATE COMPLETED 03-24-2006 EQUIPMENT BOBCAT 863 w/ 12" BUCKET BY: N. ASH MATERIAL DESCRIPTION DEBRIS FILL Loose, damp to moist, brown to reddish brown, Silty, fine to medium SAND; common trash and nursery debris; fill in overall poor and uncompacted condition -Layer of plastic trash and debris -Some seepage at base of fill LINDA VISTA FORMATION Dense, damp, reddish brown to olive gray, Silty, fine- to medium-grained SANDSTONE, moderately cemented TRENCH TERMINATED AT 10 FEET Minor seepage at 9 feet f5 f4 ~j" l<«i t|| o.Q:~ - - - — >-P Z\i. °sl O tu g. O "Z."5. Oo Figure A-3, Log of Trench T 3, Page 1 of 1 07671-52-01.GPJ SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL ... DISTURBED OR BAG SAMPLE ... STANDARD PENETRATION TEST CHUNK SAMPLE .. DRIVE SAMPLE (UNDISTURBED) .. WATER TABLE OR SEEPAGE NOTE: IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. D. IT GEOCON ., PROJECT NO. 07671-52-01 DEPTH IN ~™ - 2 - - 4 - 6 - SAMPLE NO. T4-1 CDO ^ ::|-.-f:-V '}%' I1!fl -.1 • j -I • • V'j'-l- * "l * r" V" tl 1st:m\.•i-r.r. ::!;£f: cc.HI § zJo (T I SOIL CLASS SM SM SM TRENCH T 4 ELEV. (MSL.) 3321 DATE COMPLETED 03-24-2006 EQUIPMENT BOBCAT 863 w/ 12" BUCKET BY: N. ASH MATERIAL DESCRIPTION UNDOCUMENTED FILL Loose, moist, brown, Silty, fine to medium SAND; backfill for storm drain LINDA VISTA FORMATION Medium dense, moist, yellowish to light olive brown, Sifty, fine to medium SAND; uncemented -Becomes loose and saturated with abundant seepage at 6 feet Dense, moist, yellowish to reddish brown, Silty, fine-grained SANDSTONE; weakly to moderately cemented TRENCH TERMINATED AT 8 FEET Seepage at 6 feet Z[i|_ Fzt *" — o ^ LU m Q.* — ~ — zuT 8?a:a ^ II 5 O0 Figure A-4, Log of Trench T 4, Page 1 of 1 07671-52-01.GPJ SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL S ... DISTURBED OR BAG SAMPLE ... STANDARD PENETRATION TEST ... CHUNK SAMPLE • ... DRIVE SAMPLE (UNDISTURBED) I ... WATER TABLE OR SEEPAGE NOTE: IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. GEOCON PROJECT NO. 07671-52-01 DEPTH IN FEET - - 2 - - - 4 - - SAMPLE NO.THOLOGY— xTy^K *$/{• mi m m :M: 'Irltv $$UNDWATER |nOLCT SOIL CLASS (USCS) SC/SM SM TRENCH T 5 ELEV. (MSL.) 326' DATE COMPLETED 03-24-2006 EQUIPMENT BOBCAT 863 w/ 12" BUCKET BY: N. ASH MATERIAL DESCRIPTION DEBRIS FILL Loose, moist, brown, Clayey to Silty, fine to medium SAND; scattered trash and nursery debris; fill in poor and uncompacted condition LINDAVISTA FORMATION Dense to very dense, damp, olive to reddish brown, Silty, fine-grained SANDSTONE; moderately cemented REFUSAL AT 5'/2 FEET No groundwater JETRATIONSISTANCELOWS/FT.)Uj LLJ rna.K~ - - - . -Y DENSITY(P.C.F.)KQ OISTURENTENT (%)s oO Figure A-5, Log of Trench T 5, Page 1 of 1 07671-52-01.GPJ SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL E3 ... DISTURBED OR BAG SAMPLE B ... STANDARD PENETRATION TEST B ...CHUNKSAMPLE .. DRIVE SAMPLE (UNDISTURBED) .. WATER TABLE OR SEEPAGE NOTE: IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. D. IT GEOCON PROJECT NO. 07671-52-01 DEPTH IN FEET - 2 • - 4 - SAMPLE NO. T6-1 LITHOLOGY::|yf:}:; VL-f-.y.n:•}.% •Iflil'l*. 1*4 .'. ""If* IP H-K^I GROUNDWATER |SOIL CLASS (USCS) SM SM TRENCH T 6 ELEV. (MSL.) 321* DATE COMPLETED 03-24-2006 EQUIPMENT BOBCAT 863 w/ 12" BUCKET BY: N. ASH MATERIAL DESCRIPTION COLLUVIUM Medium dense, damp, brown to reddish brown, Silty, fine to medium SAND; few gravel LINDAVISTA FORMATION Dense, damp, yellowish to reddish brown, Silty, fine- to medium-grained SANDSTONE; weakly cemented TRENCH TERMINATED AT 6 FEET No groundwater PENETRATIONRESISTANCE(BLOWS/FT.)- - -DRY DENSITY(P.C.F.)— -MOISTURECONTENT (%)Figure A-6, Log of Trench T 6, Page 1 of 1 07671-52-01.GPJ SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL 81 ... DISTURBED OR BAG SAMPLE B ... STANDARD PENETRATION TEST H ... CHUNK SAMPLE .. DRIVE SAMPLE (UNDISTURBED) .. WATER TABLE OR SEEPAGE NOTE: IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. D. IT GEOCON PROJECT NO. 07671-52-01 DEPTH IN FEET 4 SAMPLE NO.LITHOLOGY::J-;-N-}: ftf :-)-%: SvXX m • +S+* -If */* ^•>* • y« /• • 'GROUNDWATER |SOIL CLASS (USCS) SM SM/SC TRENCH T 7 ELEV. (MSL.) 336' DATE COMPLETED 03-24-2006 EQUIPMENT BOBCAT 863 w/ 12" BUCKET BY: N. ASH MATERIAL DESCRIPTION COLLUVIUM Loose, damp, dark reddish brown, Silty, fine SAND LINDAVISTA FORMATION Dense to very dense, damp, reddish brown to olive gray, Clayey and Sifty, fine-grained SANDSTONE; weakly cemented TRENCH TERMINATED AT 4 FEET No groundwater PENETRATIONRESISTANCE(BLOWS/FT.)-DRY DENSITY(P.C.F.)MOISTURECONTENT (%)Figure A-7, Log of Trench T 7, Page 1 of 1 07671-52-01.GPJ SAMPLE SYMBOLS D SAMPLING UNSUCCESSFUL 0 ... DISTURBED OR BAG SAMPLE D ... STANDARD PENETRATION TEST B ... CHUNK SAMPLE .. DRIVE SAMPLE (UNDISTURBED) .. WATER TABLE OR SEEPAGE NOTE: IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. D. IT GEOCON PROJECT NO. 07671-52-01 DEPTH IN FEET - - 2 - - 4 - - 6 - . SAMPLE NO. T8-1 LITHOLOGYyjy^ '*$%m 1 * V *' *"k"i.* '"J*--. 1* •r.-i*. •*.l • Jt''1 - * V "i "*t* V.i *.f"-l • • !•* *"f • ""•1 "•• *"l " .-.j.-'-J'-t *".' '-f **l " i tr GROUNDWATEI SOIL CLASS (USCS) SC/SM SM TRENCH T 8 ELEV. (MSL.) 309' DATE COMPLETED 03-24-2006 EQUIPMENT BOBCAT 863 w/ 12" BUCKET BY: N. ASH MATERIAL DESCRIPTION UNDOCUMENTED FILL Loose, moist, dark grayish brown, Clayey and Sihy, fine to medium SAND; scattered trash and vegetation ALLUVIUM Loose, moist to wet, grayish brown, Sihy, fine to medium SAND -Groundwater encountered at 5 feet; abundant caving of trench; saturated soil -Unable to excavate further due to caving TRENCH TERMINATED AT 7'/2 FEET Groundwater at 5 feet PENETRATIORESISTANCE(BLOWS/FT.- - - - - >-DRY DENSIT(P.C.F.)MOISTURECONTENT ("AFigure A-8, Log of Trench T 8, Page 1 of 1 07671-52-01.GPJ SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL Ei ... DISTURBED OR BAG SAMPLE B ... STANDARD PENETRATION TEST B ••• CHUNK SAMPLE I ... DRIVE SAMPLE (UNDISTURBED) y. ... WATER TABLE OR SEEPAGE NOTE: IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. D. IT GEOCON PROJECT NO. 07671-52-01 DEPTH IN FEET - 2 - - 4 - - 6 - - - 8 - SAMPLE NO. >-LITHOLOCi1n i*t nijl I |iij OL GROUNDWASOIL CLASS (USCS) SM SM TRENCH T 9 ELEV. (MSL.) 332' DATE COMPLETED 03-24-2006 EQUIPMENT BOBCAT 863 w/ 1 2" BUCKET BY: N. ASH MATERIAL DESCRIPTION DEBRIS FILL Loose, damp to dry, olive to grayish brown, Silty SAND; abundant trash and debris; scattered chunks of asphalt concrete; fill in overall poor, uncompacted condition -Plastic bags and asphalt chunks LINDA VISTA FORMATION Dense to very dense, damp, yellowish to reddish brown, Silty, fine-grained SANDSTONE; moderately cemented TRENCH TERMINATED AT 10 FEET No groundwater Oo£"PENETRATRESISTAN(BLOWS/F- - - - >- b DRY DENS(P.C.F.)m sS MOISTURCONTENTFigure A-9, Log of Trench T 9, Page 1 of 1 07671-52-01.GPJ SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL S ... DISTURBED OR BAG SAMPLE B ... STANDARD PENETRATION TEST B ... CHUNK SAMPLE I ... DRIVE SAMPLE (UNDISTURBED) y. ... WATER TABLE OR SEEPAGE NOTE:D. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. GEOCON PROJECT NO. 07671-52-01 DEPTH IN FEET - - 2 - - - 4 - SAMPLE NO.HOLOGY1- *ffi%'- *$/&ititft m *i*j* f* r *L* 'vfcfl NDWATER |_i0 O SOIL CLASS SC/SM SM TRENCH T 10 ELEV. (MSL.) 333' DATE COMPLETED 03-24-2006 EQUIPMENT BOBCAT 863 w/ 1 2" BUCKET BY: N. ASH MATERIAL DESCRIPTION UNDOCUMENTED FILL Loose, dry to damp, brown to reddish brown, Silty and Clayey, fine to medium SAND; common trash and debris LINDA VISTA FORMATION Dense to very dense, damp, reddish brown, Silty, fine to medium-grained SANDSTONE; moderately cemented TRENCH TERMINATED AT 5'A FEET No groundwater ETRATIONISTANCEDWS/FT.)|^ UJ QQ Q.^^ - - - -DENSITYP.C.F.)£Q UJ g. 5 b 2 O ° Figure A-10, Log of Trench T10, Page 1 of 1 07671-52-01. GPJ SAMPLE SYMBOLS . SAMPLING UNSUCCESSFUL . DISTURBED OR BAG SAMPLE B ... STANDARD PENETRATION TEST B ...CHUNKSAMPLE ... DRIVE SAMPLE (UNDISTURBED) ... WATER TABLE OR SEEPAGE NOTE: IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. GEOCON .PROJECT NO. 07671-52-01 1 DEPTH IN FEET 0 - - 2 - - 4 - J I 1 f SAMPLE NO. >-LITHOLOGiI!II ••[•]**P*•>.1.v '&$'• :¥&; OL £GROUNDWASOIL CLASS (USCS) SM SM/SC TRENCH T 11 ELEV. (MSL.) 3471 DATE COMPLETED 03-24-2006 EQUIPMENT BOBCAT 863 w/ 12" BUCKET BY: N. ASH MATERIAL DESCRIPTION COLLUVIUM Loose to medium dense, moist, dark brown to reddish brown, Silty SAND; some pores; locally clayey LINDA VISTA FORMATION Medium dense to dense, damp, yellowish to reddish brown, Silty and Clayey, fine-grained SANDSTONE; weakly to moderately cemented REFUSAL AT 5 FEET No groundwater O t •% i_J PENETRATIRESISTANC(BLOWS/Fl- £.DRY DENS(P.C.F.)UJS?MOISTURCONTENT^Figure A-11, *Log of Trench T11, Page 1 of 1 07671-52-01.GPJ j SAMPLE SYMBOLS O ... SAMPLING UNSUCCESSFUL S ... DISTURBED OR BAG SAMPLE B ... STANDARD PENETRATION TEST EH ... CHUNK SAMPLE . DRIVE SAMPLE (UNDISTURBED) .. WATER TABLE OR SEEPAGE NOTE: IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. D. IT GEOCON ., PROJECT NO. 07671-52-01 DEPTH IN FEET " ~ • 2 - - SAMPLE NO.THOLOGY—. •*f*1**t*•*M**[*viiiv :••}•>:•t«*f •£vi*:-M:•*L*J*»f« *'t'i**f-• #j* *UNDWATER |O OL(T SOIL CLASS (USCS) SM TRENCH T 12 ELEV. (MSL.) 3451 DATE COMPLETED 03-24-2006 EQUIPMENT BOBCAT 863 w/ 12" BUCKET BY: N. ASH MATERIAL DESCRIPTION LINDA VISTA FORMATION Medium dense to dense, damp, yellowish to reddish brown, Silty, fine-grained SANDSTONE; highly weathered in upper l'/2 feet -Becomes very dense, difficult excavation; some jointing and moderately cemented -Refusal at 3 '/2 feet TRENCH TERMENATED AT 3'/2 FEET No groundwater JETRATIONSISTANCE.OWS/FT.)yj LU [Q a.K^ ~ - -Y DENSITY(P-C.F.)a:o OISTURENTENT (%)^ O0 Figure A-12, Log of Trench T12, Page 1 of 1 07671-52-01. GPJ SAMPLE SYMBOLS O ... SAMPLING UNSUCCESSFUL S ... DISTURBED OR BAG SAMPLE ... STANDARD PENETRATION TEST ... CHUNK SAMPLE .. DRIVE SAMPLE (UNDISTURBED) .. WATER TABLE OR SEEPAGE NOTE: IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. D. IT GEOCON APPENDIX APPENDIX B LABORATORY TESTING We performed laboratory tests in accordance with generally accepted test methods of the American Society for Testing and Materials (ASTM) or other suggested procedures. We selected soil samples and tested them for their maximum dry density and optimum moisture content, expansion index, shear strength, water-soluble sulfate, and Resistance value (R-Value) characteristics. The results of our laboratory tests are presented on Tables B-I through B-V. TABLE B-I SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TEST RESULTS ASTM D 1557 Sample No. Tl-1 T4-1 Description Dark brown, Silty, fine to medium SAND Brown, Silty, fine to medium SAND Maximum Dry Density (pel) 119.9 127.9 Optimum Moisture Content (% dry wt.) 12.0 9.0 TABLE B-ll SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS ASTM D 4829 Sample No. Tl-1 T4-1 Moisture Content Before Test (%) 12.0 8.5 After Test (%) 20.3 12.7 Dry Density (pcf) 103.0 114.9 Expansion Index 5 0 UBC Classification Very Low Very Low TABLE B-lll SUMMARY OF LABORATORY DIRECT SHEAR TEST RESULTS ASTM D 3080 Sample No. Tl-1 T4-1 Dry Density (pcf) 108.5 115.6 Moisture Content (%) Initial 11.4 8.6 Final 18.2 14.0 Unit Cohesion (psf) 75 400 Angle of Shear Resistance (degrees) 40 32 Samples remolded to a dry density of approximately 90 percent of the maximum dry density at or near optimum moisture content. Project No. 07671-52-01 -B-l-July 14, 2009 TABLE B-IV SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULTS CALIFORNIA TEST NO. 417 Sample No. Tl-1 T4-1 Water-Soluble Sulfate (%) 0.001 0.004 Classification Negligible Negligible TABLE B-V SUMMARY OF LABORATORY RESISTANCE VALUE (R-VALUE) TEST RESULTS ASTM D 2844 Sample No. Tl-1 R-Value 60 Project No. 07671-52-01 -B-2-July 14, 2009 APPENDIX APPENDIX C RECOMMENDED GRADING SPECIFICATIONS FOR MUROYA PROPERTY CARLSBAD, CALIFORNIA PROJECT NO. 07671-52-01 RECOMMENDED GRADING SPECIFICATIONS 1. GENERAL 1.1 These Recommended Grading Specifications shall be used in conjunction with the Geotechnical Report for the project prepared by Geocon Incorporated. The recommendations contained in the text of the Geotechnical Report are a part of the earthwork and grading specifications and shall supersede the provisions contained hereinafter in the case of conflict. 1.2 Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be employed for the purpose of observing earthwork procedures and testing the fills for substantial conformance with the recommendations of the Geotechnical Report and these specifications. The Consultant should provide adequate testing and observation services so that they may assess whether, in their opinion, the work was performed in substantial conformance with these specifications. It shall be the responsibility of the Contractor to assist the Consultant and keep them apprised of work schedules and changes so that personnel may be scheduled accordingly. 1.3 It shall be the sole responsibility of the Contractor to provide adequate equipment and methods to accomplish the work in accordance with applicable grading codes or agency ordinances, these specifications and the approved grading plans. If, in the opinion of the Consultant, unsatisfactory conditions such as questionable soil materials, poor moisture condition, inadequate compaction, adverse weather, result in a quality of work not in conformance with these specifications, the Consultant will be empowered to reject the work and recommend to the Owner that grading be stopped until the unacceptable conditions are corrected. 2. DEFINITIONS 2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading work is being performed and who has contracted with the Contractor to have grading performed. 2.2 Contractor shall refer to the Contractor performing the site grading work. 2.3 Civil Engineer or Engineer of Work shall refer to the California licensed Civil Engineer or consulting firm responsible for preparation of the grading plans, surveying and verifying as-graded topography. GI rev. 04/2009 2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm retained to provide geotechnical services for the project. 2.5 Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner, who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be responsible for having qualified representatives on-site to observe and test the Contractor's work for conformance with these specifications. 2.6 Engineering Geologist shall refer to a California licensed Engineering Geologist retained by the Owner to provide geologic observations and recommendations during the site grading. 2.7 Geotechnical Report shall refer to a soil report (including all addenda) which may include a geologic reconnaissance or geologic investigation that was prepared specifically for the development of the project for which these Recommended Grading Specifications are intended to apply. 3. MATERIALS 3.1 Materials for compacted fill shall consist of any soil excavated from the cut areas or imported to the site that, in the opinion of the Consultant, is suitable for use in construction of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock fills, as defined below. 3.1.1 Soil fills are defined as fills containing no rocks or hard lumps greater than 12 inches in maximum dimension and containing at least 40 percent by weight of material smaller than % inch in size. 3.1.2 Soil-rock fills are defined as fills containing no rocks or hard lumps larger than 4 feet in maximum dimension and containing a sufficient matrix of soil fill to allow for proper compaction of soil fill around the rock fragments or hard lumps as specified in Paragraph 6.2. Oversize rock is defined as material greater than 12 inches. 3.1.3 Rock fills are defined as fills containing no rocks or hard lumps larger than 3 feet in maximum dimension and containing little or no fines. Fines are defined as material smaller than % inch in maximum dimension. The quantity of fines shall be less than approximately 20 percent of the rock fill quantity. GI rev. 04/2009 3.2 Material of a perishable, spongy, or otherwise unsuitable nature as determined by the Consultant shall not be used in fills. 3.3 Materials used for fill, either imported or on-site, shall not contain hazardous materials as defined by the California Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9 and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall not be responsible for the identification or analysis of the potential presence of hazardous materials. However, if observations, odors or soil discoloration cause Consultant to suspect the presence of hazardous materials, the Consultant may request from the Owner the termination of grading operations within the affected area. Prior to resuming grading operations, the Owner shall provide a written report to the Consultant indicating that the suspected materials are not hazardous as defined by applicable laws and regulations. 3.4 The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of properly compacted soil fill materials approved by the Consultant. Rock fill may extend to the slope face, provided that the slope is not steeper than 2:1 (horizontahvertical) and a soil layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This procedure may be utilized provided it is acceptable to the governing agency, Owner and Consultant. 3.5 Samples of soil materials to be used for fill should be tested in the laboratory by the Consultant to determine the maximum density, optimum moisture content, and, where appropriate, shear strength, expansion, and gradation characteristics of the soil. 3.6 During grading, soil or groundwater conditions other than those identified in the Geotechnical Report may be encountered by the Contractor. The Consultant shall be notified immediately to evaluate the significance of the unanticipated condition 4. CLEARING AND PREPARING AREAS TO BE FILLED 4.1 Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of complete removal above the ground surface of trees, stumps, brush, vegetation, man-made structures, and similar debris. Grubbing shall consist of removal of stumps, roots, buried logs and other unsuitable material and shall be performed in areas to be graded. Roots and other projections exceeding l'/2 inches in diameter shall be removed to a depth of 3 feet below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to provide suitable fill materials. GI rev. 04/2009 4.2 Any asphalt pavement material removed during clearing operations should be properly disposed at an approved off-site facility. Concrete fragments that are free of reinforcing steel may be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3 of this document. 4.3 After clearing and grubbing of organic matter and other unsuitable material, loose or porous soils shall be removed to the depth recommended in the Geotechnical Report. The depth of removal and compaction should be observed and approved by a representative of the Consultant. The exposed surface shall then be plowed or scarified to a minimum depth of 6 inches and until the surface is free from uneven features that would tend to prevent uniform compaction by the equipment to be used. 4.4 Where the slope ratio of the original ground is steeper than 5:1 (horizontal:vertical), or where recommended by the Consultant, the original ground should be benched in accordance with the following illustration. TYPICAL BENCHING DETAIL Finish Grade Original Ground Finish Slope Surface Remove All Unsuitable Material As Recommended By Consultant Slope To Be Such That Sloughing Or Sliding Does Not Occur See Note 1 See Note 2. No Scale DETAIL NOTES: (1) (2) Key width "B" should be a minimum of 10 feet, or sufficiently wide to permit complete coverage with the compaction equipment used. The base of the key should be graded horizontal, or inclined slightly into the natural slope. The outside of the key should be below the topsoil or unsuitable surficial material and at least 2 feet into dense formational material. Where hard rock is exposed in the bottom of the key, the depth and configuration of the key may be modified as approved by the Consultant. GI rev. 04/2009 4.5 After areas to receive fill have been cleared and scarified, the surface should be moisture conditioned to achieve the proper moisture content, and compacted as recommended in Section 6 of these specifications. 5. COMPACTION EQUIPMENT 5.1 Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented-steel wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of acceptable compaction equipment. Equipment shall be of such a design that it will be capable of compacting the soil or soil-rock fill to the specified relative compaction at the specified moisture content. 5.2 Compaction of rock fills shall be performed in accordance with Section 6.3. 6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL 6.1 Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with the following recommendations: 6.1.1 Soil fill shall be placed by the Contractor in layers that, when compacted, should generally not exceed 8 inches. Each layer shall be spread evenly and shall be thoroughly mixed during spreading to obtain uniformity of material and moisture in each layer. The entire fill shall be constructed as a unit in nearly level lifts. Rock materials greater than 12 inches in maximum dimension shall be placed in accordance with Section 6.2 or 6.3 of these specifications. 6.1.2 In general, the soil fill shall be compacted at a moisture content at or above the optimum moisture content as determined by ASTM D 1557-02. 6.1.3 When the moisture content of soil fill is below that specified by the Consultant, water shall be added by the Contractor until the moisture content is in the range specified. 6.1.4 When the moisture content of the soil fill is above the range specified by the Consultant or too wet to achieve proper compaction, the soil fill shall be aerated by the Contractor by blading/mixing, or other satisfactory methods until the moisture content is within the range specified. GI rev. 04/2009 6.1.5 After each layer has been placed, mixed, and spread evenly, it shall be thoroughly compacted by the Contractor to a relative compaction of at least 90 percent. Relative compaction is defined as the ratio (expressed in percent) of the in-place dry density of the compacted fill to the maximum laboratory dry density as determined in accordance with ASTM D 1557-02. Compaction shall be continuous over the entire area, and compaction equipment shall make sufficient passes so that the specified minimum relative compaction has been achieved throughout the entire fill. 6.1.6 Where practical, soils having an Expansion Index greater than 50 should be placed at least 3 feet below finish pad grade and should be compacted at a moisture content generally 2 to 4 percent greater than the optimum moisture content for the material. 6.1.7 Properly compacted soil fill shall extend to the design surface of fill slopes. To achieve proper compaction, it is recommended that fill slopes be over-built by at least 3 feet and then cut to the design grade. This procedure is considered preferable to track-walking of slopes, as described in the following paragraph. 6.1.8 As an alternative to over-building of slopes, slope faces may be back-rolled with a heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height intervals. Upon completion, slopes should then be track-walked with a D-8 dozer or similar equipment, such that a dozer track covers all slope surfaces at least twice. 6.2 Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance with the following recommendations: 6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be incorporated into the compacted soil fill, but shall be limited to the area measured 15 feet minimum horizontally from the slope face and 5 feet below finish grade or 3 feet below the deepest utility, whichever is deeper. 6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be individually placed or placed in windrows. Under certain conditions, rocks or rock fragments up to 10 feet in maximum dimension may be placed using similar methods. The acceptability of placing rock materials greater than 4 feet in maximum dimension shall be evaluated during grading as specific cases arise and shall be approved by the Consultant prior to placement. GI rev. 04/2009 6.2.3 For individual placement, sufficient space shall be provided between rocks to allow for passage of compaction equipment. 6.2.4 For windrow placement, the rocks should be placed in trenches excavated in properly compacted soil fill. Trenches should be approximately 5 feet wide and 4 feet deep in maximum dimension. The voids around and beneath rocks should be filled with approved granular soil having a Sand Equivalent of 30 or greater and should be compacted by flooding. Windrows may also be placed utilizing an "open-face" method in lieu of the trench procedure, however, this method should first be approved by the Consultant. 6.2.5 Windrows should generally be parallel to each other and may be placed either parallel to or perpendicular to the face of the slope depending on the site geometry. The minimum horizontal spacing for windrows shall be 12 feet center-to-center with a 5-foot stagger or offset from lower courses to next overlying course. The minimum vertical spacing between windrow courses shall be 2 feet from the top of a lower windrow to the bottom of the next higher windrow. 6.2.6 Rock placement, fill placement and flooding of approved granular soil in the windrows should be continuously observed by the Consultant. 6.3 Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with the following recommendations: 6.3.1 The base of the rock fill shall be placed on a sloping surface (minimum slope of 2 percent). The surface shall slope toward suitable subdrainage outlet facilities. The rock fills shall be provided with subdrains during construction so that a hydrostatic pressure buildup does not develop. The subdrains shall be permanently connected to controlled drainage facilities to control post-construction infiltration of water. 6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock trucks traversing previously placed lifts and dumping at the edge of the currently placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the rock. The rock fill shall be watered heavily during placement. Watering shall consist of water trucks traversing in front of the current rock lift face and spraying water continuously during rock placement. Compaction equipment with compactive energy comparable to or greater than that of a 20-ton steel vibratory roller or other compaction equipment providing suitable energy to achieve the GI rev. 04/2009 required compaction or deflection as recommended in Paragraph 6.3.3 shall be utilized. The number of passes to be made should be determined as described in Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional rock fill lifts will be permitted over the soil fill. 6.3.3 Plate bearing tests, in accordance with ASTM D 1196-93, may be performed in both the compacted soil fill and in the rock fill to aid in determining the required minimum number of passes of the compaction equipment. If performed, a minimum of three plate bearing tests should be performed in the properly compacted soil fill (minimum relative compaction of 90 percent). Plate bearing tests shall then be performed on areas of rock fill having two passes, four passes and six passes of the compaction equipment, respectively. The number of passes required for the rock fill shall be determined by comparing the results of the plate bearing tests for the soil fill and the rock fill and by evaluating the deflection variation with number of passes. The required number of passes of the compaction equipment will be performed as necessary until the plate bearing deflections are equal to or less than that determined for the properly compacted soil fill. In no case will the required number of passes be less than two. 6.3.4 A representative of the Consultant should be present during rock fill operations to observe that the minimum number of "passes" have been obtained, that water is being properly applied and that specified procedures are being followed. The actual number of plate bearing tests will be determined by the Consultant during grading. 6.3.5 Test pits shall be excavated by the Contractor so that the Consultant can state that, in their opinion, sufficient water is present and that voids between large rocks are properly filled with smaller rock material. In-place density testing will not be required in the rock fills. 6.3.6 To reduce the potential for "piping" of fines into the rock fill from overlying soil fill material, a 2-foot layer of graded filter material shall be placed above the uppermost lift of rock fill. The need to place graded filter material below the rock should be determined by the Consultant prior to commencing grading. The gradation of the graded filter material will be determined at the time the rock fill is being excavated. Materials typical of the rock fill should be submitted to the Consultant in a timely manner, to allow design of the graded filter prior to the commencement of rock fill placement. 6.3.7 Rock fill placement should be continuously observed during placement by the Consultant. GI rev. 04/2009 7. OBSERVATION AND TESTING 7.1 The Consultant shall be the Owner's representative to observe and perform tests during clearing, grubbing, filling, and compaction operations. In general, no more than 2 feet in vertical elevation of soil or soil-rock fill should be placed without at least one field density test being performed within that interval. In addition, a minimum of one field density test should be performed for every 2,000 cubic yards of soil or soil-rock fill placed and compacted. 7.2 The Consultant should perform a sufficient distribution of field density tests of the compacted soil or soil-rock fill to provide a basis for expressing an opinion whether the fill material is compacted as specified. Density tests shall be performed in the 'compacted materials below any disturbed surface. When these tests indicate that the density of any layer of fill or portion thereof is below that specified, the particular layer or areas represented by the test shall be reworked until the specified density has been achieved. 7.3 During placement of rock fill, the Consultant should observe that the minimum number of passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant should request the excavation of observation pits and may perform plate bearing tests on the placed rock fills. The observation pits will be excavated to provide a basis for expressing an opinion as to whether the rock fill is properly seated and sufficient moisture has been applied to the material. When observations indicate that a layer of rock fill or any portion thereof is below that specified, the affected layer or area shall be reworked until the rock fill has been adequately seated and sufficient moisture applied. 7.4 A settlement monitoring program designed by the Consultant may be conducted in areas of rock fill placement. The specific design of the monitoring program shall be as recommended in the Conclusions and Recommendations section of the project Geotechnical Report or in the final report of testing and observation services performed during grading. 7.5 The Consultant should observe the placement of subdrains, to verify that the drainage devices have been placed and constructed in substantial conformance with project specifications. 7.6 Testing procedures shall conform to the following Standards as appropriate: GI rev. 04/2009 7.6.1 Soil and Soil-Rock Fills: 7.6.1.1 Field Density Test, ASTM D 1556-02, Density of Soil In-Place By the Sand-Cone Method. 7.6.1.2 Field Density Test, Nuclear Method, ASTM D 6938-08A, Density of Soil and Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth). 7.6.1.3 Laboratory Compaction Test, ASTM D 1557-02, Moisture-Density Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound Hammer and 18-Inch Drop. 7.6.1.4. Expansion Index Test, ASTM D 4829-03, Expansion Index Test. 7.6.2 Rock Fills 7.6.2.1 Field Plate Bearing Test, ASTM D1196-93 (Reapproved 1997) Standard Method for Nonreparative Static Plate Load Tests of Soils and Flexible Pavement Components, For Use in Evaluation and Design of Airport and Highway Pavements. 8. PROTECTION OF WORK 8.1 During construction, the Contractor shall properly grade all excavated surfaces to provide positive drainage and prevent ponding of water. Drainage of surface water shall be controlled to avoid damage to adjoining properties or to finished work on the site. The Contractor shall take remedial measures to prevent erosion of freshly graded areas until such time as permanent drainage and erosion control features have been installed. Areas subjected to erosion or sedimentation shall be properly prepared in accordance with the Specifications prior to placing additional fill or structures. 8.2 After completion of grading as observed and tested by the Consultant, no further excavation or filling shall be conducted except in conjunction with the services of the Consultant. GI rev. 04/2009 9. CERTIFICATIONS AND FINAL REPORTS 9.1 Upon completion of the work, Contractor shall furnish Owner a certification by the Civil Engineer stating that the lots and/or building pads are graded to within 0.1 foot vertically of elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot horizontally of the positions shown on the grading plans. After installation of a section of subdrain, the project Civil Engineer should survey its location and prepare an as-built plan of the subdrain location. The project Civil Engineer should verify the proper outlet for the subdrains and the Contractor should ensure that the drain system is free of obstructions. 9.2 The Owner is responsible for furnishing a final as-graded soil and geologic report satisfactory to the appropriate governing or accepting agencies. The as-graded report should be prepared and signed by a California licensed Civil Engineer experienced in geotechnical engineering and by a California Certified Engineering Geologist, indicating that the geotechnical aspects of the grading were performed in substantial conformance with the Specifications or approved changes to the Specifications. GI rev. 04/2009 LIST OF REFERENCES 1. Anderson, J. G., T. K. Rockwell, and D. C. Agnew, Past and Possible Future Earthquakes of Significance to the San Diego Region: Earthquake Spectra. 1989, V.5, No. 2, p.299-333. 2. Boore, D. M., and G. M Atkinson (2006), Boore-Atkinson NGA Ground Motion Relations for the Geometric Mean Horizontal Component of Peak and Spectral Ground Motion Parameters, Report Number PEER 2007/01, May 2007. 3. Brain S. J. Chiou and Robert R. Youngs, A NGA Model for the Average Horizontal Component of Peak Ground Motion and Response Spectra, preprint for article to be published in NGA Special Edition for Earthquake Spectra, Spring 2008. 4. California Department of Conservation, Division of Mines and Geology, Probabilistic Seismic Hazard Assessment for the State of California, Open File Report 96-08, 1996. 5. California Geological Survey, Seismic Shaking Hazards in California, Based on the USGS/CGS Probabilistic Seismic Hazards Assessment (PSHA) Model, 2002 (revised April 2003). 10% probability of being exceeded in 50 years. http://redirect.conservation.ca.gov/cgs/rghm/pshamap/pshamain.html 6. Campbell, K. W., Y. Bozorgnia, NGA Ground Motion Model for the Geometric Mean Horizontal Component of PGA, PGV, PGD and 5% Damped Linear Elastic Response Spectra for Periods Ranging from 0.01 to 10 s, Preprint of version submitted for publication in the NGA Special Volume of Earthquake Spectra, Volume 24, Issue 1, pages 139-171, February 2008. 7. Geology and Mineral Resources of San Diego County, California, California Division of Mines and Geology Publication, 1963. 8. Legg, M. R., J. C. Borrero, and C. E. Synolakis (2002), Evaluation of Tsunami Risk to Southern California Coastal Cities, 2002 NEHRP Professional Fellowship Report, dated January. 9. Risk Engineering, EZ-FRISK, 2008. 10. Sadigh, et al. (1997), Attenuation Relationships for Shallow Crustal Earthquakes Based on California Strong Motion Data, Seismological Research Letters, Vol. 68, No. 1, January/ February, pp. 180- 189. 11. Tan, S. S. and D. G. Giffen, 1995, Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County, California, Landslide Hazard Identification Map No. 35, California Division of Mines and Geology, Open File Report 95-04. 12. Tan, S. S. and M. P. Kennedy, 1996, Geologic Map of the Encinitas and Rancho Santa Fe Quadrangle, San Diego County, California, DMG Open-File Report 96-02. Proj ect No. 07671 -52-01 July 14, 2009 LIST OF REFERENCES (Continued) 13. Treiman, Jerome A., The Rose Canyon Fault Zone Southern California, California Division of Mines and Geology Publication, 1993. 14. USGS computer program, 2002 Interactive Deaggregation, http://eqint.cr.usgs.gov/deaggint/2002/index.php. 15. USGS computer program, Seismic Hazard Curves and Uniform Hazard Response Spectra. 16. United States Geological Survey, 7.5 Minute Quadrangle Series, Encinitas Quadrangle, 1967, photo revised 1975. 17. United States Department of Agriculture, 1953 Stereoscopic Aerial Photographs, Flight AXN- 8M, Photos Nos. 98 and 99, dated May 2. 18. Unpublished reports, aerial photographs, and maps on file with Geocon Incorporated. 19. URS, 2004, San Diego County Multi-Jurisdictional Hazard Mitigation Plan, San Diego County, California, dated March 15, (URS Project No. 27653042.00500). Project No. 07671-52-01 . July 14,2009