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HomeMy WebLinkAboutCT 03-07; Romeria Pointe; Preliminary Geotechnical Evaluation; 2004-09-27·1 ·I I -1 I ,I_ I I I I I I I I I I I I. I PRELIMINARY GEOTECHNICAL EVALUATION ROMERIA POINTE, APNS 216-300-12 AND -1·3 CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA, FOR KARNAK PLANNING AND DESIGN, INC. 2802 STATE STREET CARLSBAD, CALIFORNIA 92008 W.O. 4460-A-SC SEPTEMBER 27, 2004 RECEIVED FEB 2 4 2005 l;NGINEERiNG DEPARTMENT I I I I I I I I I I I I I I I I . 1 :1 I Geotechnical • Geologic O Environmental 5741 Palmer Way • Carlsbad, California 92008 • (760) 438-3155 ° FAX (760) 931-0915 September 27, 2004 Karnak Planning and Design, Inc~ 2802 State Street Carlsbad, California 92008 Attention: Mr. Robert Richardson W.O. 4460-A-SC Subject: Preliminary Geotechnical Evaluation, Romeria Pointe, APNs 216-300-12 and -13, Carlsbad, San Diego County, California Dear Mr. Richardson: In accordance with your request, GeoSoils, Inc. (GSI) has performed a preliminary geotechnical evaluation of the subject site. The purpose of the study was to evaluate the onsite soils and geologic conditions and their effects on the proposed site development from a geotechnical viewpoint. · EXECUTIVE SUMMARY Based on our review of data (see Appendix A), field exploration, laboratory testing, and geologic and engineering analyses, the· proposed project appears suitable for its intended residential use, from a geotechnical viewpoint, provided the recommendations presented in the text of this report are properly implemented. The most significant elements of this study are summarized below: • Based on a conversation with the Client, proposed development is to consist of utilizing the existing graded lots for the construction of three, three-story, multi-family, residential structures with undergrounq parking and associated improvements. The residential structures would be supported by post-tension, mat slab, or drilled pier foundations with slabs-on-grade and wood frames. Building loads are assumed to be typical for this type of relatively light construction . • All existing undocumented fill (on the order of± 10 to ±24 feet thick) is non-uniforn:i in nature and therefore is generally considered to be unsuitable for the support of settlement-sensitive impmvements and/or additional fill in its existing state, and will require mitigation in the form of removal and recompaction. Ot~erwise, drilled concrete piers will be recommended to support the proposed buildings. I I I I I I I I I I I I I I I I I I I • • • Post-tension or mat slab foundations may be utilized for foundation support if the existing undocumented fill is to be completely removed and recompacted. If drilled piers are to be utilized for foundation support, it is recommended that the upper 5 feet of the existing fill soils be removed and recompacted for concrete slab and asphaltic/concrete pavement support, and the support of other settlement sensitive improvements (i.e., retaining walls, privacy walls, etc.). Such support, however, would not eliminate the potential for distress to such settlement-sensitive improvements, if complete removals are not performed and deep foundations are not utilized. Based on the available data and our slope stability analysis, the existing graded fill-over-cut slopes, along the northern and western margins of the site, are generally considered grossly stable in their present condition.-However, the analysis indicates that the existing fill-over-cut slopes are surficially unstable in their present condition. Therefore, the existing fill-over-cut slopes should either be reconstructed at 2:1 (horizontal:vertical [h:v]) gradients, or be reconstructed and reinforced with Mirafi 8XT, if the current gradients are to remain. It should be noted that increased maintenance to the slopes and/or settlement-sensitive improvements (i.e., po.ols, walkways, walls, driveways, patios, etc.), proposed to be constructed within 10 feet from the tops of these slopes, may be necessary for slopes constructed steeper than a 2:1 gradient. Therefore, all settlement-sensitive· improvements should be setback from the tops of the slope. The setback may be calculated by using H/3, where H is the height of the slope. H should not be less than 1 O feet. This may be accomplished by simply deepening the footings. Owing to the age of the fill and our limited sampling/testing, some failures and distress in the fill and associated improvements should be anticipated, should complete removal and recompaction not be performed. Maximum to minimum fill thickness below the foundation elements of the structures should not exceed a ratio of 3:1 (maximum:minimum) during any fill placement associated with complete removal and recompaction. Based on the presence of medium to highly expansive soils (Expansion Index [E.I.] = 51 to 130), and existing fill-over-cut slopes that were previously constructed steeper than code (per the Uniform Building Code ([UBC]. lnternational Conference of Building Officials [ICBO], 1997) and are anticipated to remain at their current gradients provided that they have been reinforced according to the recommendations offered in this report, a post-tension foundation or mat slab foundation is specifically recommended for the support of the buildings. Post-tension or mat slab foundations may only be utilized if the existing undocumented fill has been completely removed and recompacted. It should also. be noted that distress to flatwork and hardscape cannot be precluded from occurring in the future, owing to the expansion potential and nature of site soils. Mitigation will serve to reduce this potential, but not eliminate it. This will need to be disclosed to all owners. Karnak Planning and Design, Inc. File:e:\4400\4460a.pge W.O. 4460-A-SC Page Two I I 1· I I I I I I I I I I I I I I I I • • • • • • • • Site soils tested present a negligible sulfate exposure to concrete and are severely corrosive to ferrous metals when saturated. Consultation from a qualified corrosion engineer is recommended regarding foundations, piping, etc." Groundwater was not observed during the field investigation and is not expected to be a major factor in development of the site. However, due to the nature of the site materials, seepage and/or perched groundwater conditions may develop throughout the Site along boundaries of contrasting permeabilities (i.e., fill/bedrock contacts), and should be anticipated after development. This should be disclosed to all owners. Our evaluation indicates that the site has a very low potential for liquefaction . Therefore, no recommendations for mitigation are deemed necessary. . The sei~mic acceleration values and design parameters provided herein should be considered during the design of the proposed development. The existing retaining wall, located below the western slope, may not be suitable for its intended use, and/or not in accordance with current standards of practice. Thus, this wall may suffer distress and/or failure. This condition should be disclosed to all owners. Our evaluation indicates there are no known active faults crossing the site. Adverse geologic features that would preclude project feasibility were not encountered. The recommendations presented in this report should be incorporated into the design and construction considerations of the project. Karnak Planning and Design, Inc. File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC Page Three I I I I I I I I I 'I I I I I I I I I I The opportunity to be ·of service is greatly appreciated. If you have any questions concerning this report, or if we may be of further assistance, please do not hesitate to contact any of the .undersigned. Respectfully submitted, GeoSoils, Inc. ~-&2. Ryan Boehmer Staff Geologist RB/JPF /DWS/jk Distribution: (6) Addressee Karnak Planning and Design, Inc. File:e:\wp9\4400\4460a.pge David W. Skelly Civil Engineer, RCE W. 0. 4460-A-SC Page Four I I I I .1 I ··1 I I ,I I I I I I I I I I TABLE OF CONTENTS SCOPE OF SERVICES ................................................... 1 SITE CONDITIONS/PROPOSED DEVELOPMENT ............... .-............ · .. 1 PREVIOUS ................................... · .......................... 3 SITE EXPLORATION ..................................................... 4 REGIONAL GEOLOGY ...................................... ; ............ 4 SITE GEOLOGIC UNITS .................................................. 4 Artificial Fill -Undocumented (Map Symbol -Afu) ........................ 4 Tertiary Santiago Formation (Map Symbol -Tsa) ......................... 5 FAULTING AND REGIONAL SEISMICITY .................. ; .................. 5 Regional Faults .................................................... 5 Seismicity ......................................................... 7 Seismic Shaking Parameters ......................................... · 8 Seismic Hazards ...... ; .... · ........................................ 8 GROUNDWATER ....................................... , ................. 9 LIQUEFACTION POTENTIAL .............................................. 9 LABORATORY TESTING .................................................. 10 General ..................................................•...... 10 Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Moisture-Density Relations ....... ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Laboratory Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Expansion Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Direct Shear Test ................................................. 12 ·Atterberg Limits .................................................... 12 Consolidation Testing ............ · ................................. 12 Corrosion/Sulfate Testing ....... : .......... : ........................ 12 · SLOPE STABILITY ...................................................... 13 Gross Stability Analysis ............................................. 13 Surficial Slope Stability ......................... ~ ................... 13 Summary of Slope Stability ... _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS .................... 14 General ...................... , ................................... 14 I I I I I I I ·1 I I I I I I I I I I I EARTHWORK CONSTRUCTION RECOMMENDATIONS ....................... 16 General .......... : .............................................. 16 Site Preparation .... ; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Removals (Unsuitable Surficial Materials) ............................. 17 Fill Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Transitions/Overexcavation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Slope Considerations and Slope Design ......... · ..................... 18 Temporary Slopes ............................................. : . . 19 SUBDRAINS ........................................................... 19 PRELIMIMARY RECOMMENDATIONS -FOUNDATIONS ....................... 19 Preliminary Foundation Design ......................... · ............. 19 Bearing Value ... : ............... : .......................... 20 Lateral Pressure .................. -~ .......................... 20 Preliminary Foundation Settlement Evaluation .......................... 20 Post-tension or Mat Slab Foundations ........................... 20 Drilled Piers ................................................ 21 Footing Setbacks ................................................. 21 Construction .................. : .................................. 21 POST-TENSIONED SLAB SYSTEMS ....................................... 22 Post-Tensioning Institute Method .................................... 22 MAT SLAB FOUNDATIONS ............................................... 24 PRELIMINARY DRILLED PIER RECOMMENDATIONS ......................... 24 CORROSION ................... · .............................. · ......... 25 UTILITIES ...................................................... · ....... 25 WALL DESIGN PARAMETERS CONSIDERING EXPANSIVE SOILS ............... 26 Conventional Retaining Walls ........................ · ............... 26 Restrained Walls , ........................................... 26 Cantilevered Walls ........................................... 26 Retaining Wall Backfill-and Drainage .................................. 27 Wall/Retaining Wall ~ooting Transitions ............................... 27 TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS AND EXPANSIVE SOILS ...... 31 Expansive Soils and Slope Creep .................................... 31 Top of Slope Walls/Fences ......................................... 31 EXPANSIVE SOILS, DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS ...... 32 Karnak Planning and Design, Inc. File:e:\wp9\4400\4460a.pge Table of Contents Page ii I I I I I I I I I I I I I I I I I I I DEVELOPMENT CRITERIA ............................................... 34 Slope Deformation ............................................. · ... 34 Slope Maintenance and Planting ...................................... 35 Drainage ...... , ................................................ · . 35 Toe of Slope Drains/Toe Drains ...................................... 36 Erosion Control ................................................... 37 Landscape Maintenance ........................................... 37 Gutters and Downspouts ........................................... 37 Subsurface and Surface Water ...................................... 40 Site Improvements ............................ · .................... 40 Tile Flooring ..................................................... 40 Additional Grading ................................................. 40 Footing Trench Excavation ......................................... 40 Trenching ....................................................... 41 Utility Trench Backfill .............................................. 41 SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND . ' TESTING ........................................................ 42 OTHER DESIGN PROFESSIONALS/CONSULTANTS .......................... 42 PLAN REVIEW .......................................................... 43 LIMITATIONS ...................................... · .................... 43 · FIGURES: Figure 1 -Site Location Map ......................................... 2 Figure 2 -California Fault Map .......................................... 6 Detail 1 -Typical Retaining Wall Backfill and Drainage Detail .............. 28 Detail 2 -Retaining Wall Backfill and Subdrain Detail Geotextile Drain ....... 29 · Detail 3 -Retaining Wall and Subdrain Detail Clean Sand Backfill ........... 30 Detail 4 -Schematic Toe Drain Detail ....... , ......................... 38 Detail 5 -Subdrain Along Retaining Wall Detail ......................... 39 ATTACHMENTS: Appendix A-References .................................... Rear of Text Appendix .B -Boring Logs .................................. Rear of Text Appendix C -EQFAULT, EQSEARCH, and FRISKSP ............. Rear of Text Appendix D -Laboratory Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rear of Text Appendix E -ECSCEI (2001) Boring.and Test Pit Logs ........... Rear of Text Appendix F -ECSCEI (2001) Laboratory Data .................. Rear of Text Appendix G -Slope Stability Analysis ......................... Rear of Text Appendix H -General Earthwork and Grading Guidelines . · ........ Rear of Text Plate 1 -Geotechnical Map ......................... Rear of Text in Folder Plate 2 -Schematic Geologic Cross Sections A-A' and B-B' Rear of Text in Folder Karnak Planning and Design, Inc. File:e:\wp9\4400\4460a.pge Table of Contents Page iii I I I I I I I I I I I I I I I I I I I PRELIMINARY GEOTECHNICAL EVALUATION ROMER/A POINTE TOWNHOMES, APNs 216-300-12 AND -13 CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA SCOPE OF SERVICES The scope of our services has included the following: 1. Review of the available geologic literature for the site (see Appendix A). 2. Geologic site reconnaissance, subsurface exploration with two large diameter borings (see Appendix 8), sampling, and mapping. 3. 4. 5. 6. 7. 8. General areal seismicity evaluation (see Appendix C). Appropriate laboratory testing of representative soil samples (see Appendix D). Review of ECSCEI {2001) boring and test pit logs, and laboratory data (see Appendices E and F, respectively). Slope stability analyses of the existing slopes (see Appendix G). Engineering and geologic analysis of data collected. Preparation of this report. SITE CONDITIONS/PROPOSED DEVELOPMENT The subject site is composed of two previously graded, vacant, relatively level building pads located on the southwest corner of the intersection of Gibraltar Street and Romeria Street in Carlsbad, San Diego County, _California (see Figure 1, Site Location Map). The property is bounded to the north by Gibraltar Street, residential development to the west and south, and Romeria Street to the east. The two building pads are separated by an approximately 13-foot high 2:1 (horizontal:vertical [h:v]) slope. Slopes, with maximum heights of approximately 20 and 25 feet, descend at a maximum, approximate gradient of 1.5:1 · (h:v) to Gibraltar Street and the existing development, located to the west, respectively. The western slope begins its ascent to the lots, above an existing ±8-foot high retaining wall. Vegetation consists ofweeds,.grasses, and sparse trees. Based on the preliminary site plan provided by JNL Consulting Civil Engineers, it appears that proposed development will consist of preparing the property for the construction of three, three-story, multi-family, residential structures with below grade parking and associated improvements, that would be supported by post-tension, mat slab, or drilled pier foundations with slabs-on-grade and wood frames. Building loads are assumed to be GeoSoiis, Inc .. -I I I I I I I I I I I I I I I I I I I Rancho Santa Fe Quadrangle, California--San Diego Co., 7.5 Minute Series Base Map: (Topographic), 1983, by USGS, 1":2000' · · 0 1/2 Scale 1 Miles • N Re.produced with permlulon vranted by Thomaa Stoa. Mapa. Th111 map la ·copyrighted by Thomas Bros. Mapa. It la unlawful to copy or reproduce all or any part thereof, whether for personal uae or resale, without permission. Alt rights reserved. W .0. 4460-,A-SC. SITE LOCATION MAP Figure 1 I I I I I I I I I I I I I I I I I I I to be typical for this type of relatively light construction. It is anticipated that sewage disposal will be tied into the regional municipal system. PREVIOUS WORK Based upon the observed site conditions, the parcels have been previously graded. Site earthwork was most likely conducted in the late 1970's or early 1980's. Since that time, the site was evaluated in 2001 by East County Soil Consultation and Engineering, Inc. (ECSCEI). For their limited investigation, ECSCEI conducted two exploratory borings to depths ranging between 16 and 17 feet below the existing grade. ECSCEI also conducted two exploratory test pit excavations to depths on the orde·r of 1 o feet below the existing grade. The logs of ECSCEI (2001) are presented in Appendix E. The location of ECSCEl's borings and test pits are indicated on Plate 1 (Geotechnical Map). ECSCEl's laboratory data is presented in Appendix F. A review of ECSCEI (2001) indicates that the site is mantled by approximately 1 o feet of moderately to highly expansive fill soils that are underlain by dense sandstones of the Tertiary Santiago Formation. Based upon the analysis of the data and· information gathe~ed from their soil investigation, ECSCEI concluded that the site is suitable for the proposed development provided that their recommendations were implemented during construction. However, during our review, GSI could not locate ECSCEl's analysis of slope stability for the existing slopes that were constructed steeper than the current code. It is the opinion of GSI, that the stability of the existing slopes is likely detrimental to site development due to the proximity of the proposed buildings to the tops of these slopes. It is also the opinion of GSI that ECSCEl's recommended 8-foot structural setback from the tops of these slopes would not mitigate distress to the structures owing to the occurrence of gross failure and or surfici_al creep. Furthermore, ECSCEI (2001) states that the existing fill soils have been certified with a relative compaction of 90 percent. However, ECSCEI (2001) does not reference any existing final compaction reports. In August of 2003, Soil Pacific, Inc. (SPI) issued an addendum report and clarification letter for the subject site based upon a review of ECSCEI (2001) and the current grading plans JNL Consulting Civil Engineers, Inc. (JNLCCEI, 2003). In their addendum report, SPI clarified an engineering review comment by the City with respect to Building "C" by providing pile foundation and grade beam recommendations for support of that building. Based upon a review of SPI (2003), SPI states, "Building pads 'A' and 'B' will be placed on_ a cut building pad." Based on our review of the current grading plans (JNLCCEI, 2003) and ECSCEI (2001), this statement is incorrect. According to JNLCCEI (2003), Building "A" is not entirely a cut pad. It appears that the garages for Building "A" will require cuts to grade, but the living areas will require fills on the order of 2 to 3 feet above the existing grade. Additionally, the western edge of Building "A" is located beyond (west of) the top of the western slope and was not provided with any mitigation recommendations by SPI, based upon a review of the literature made available to GSI. It is the opinion of GSI, that SPI (2003) does not indicate a clear understanding of JNLCCEI (2003). Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad Fjle:e:\wp9\4400\4460a.pge GeoSoiis, lne. W.O. 4460-A-SC September 27, 2004 Page 3 I I I I I I I I I I I I I I I I I I I SITE EXPLORATION Surface observations and subsurface explorations were performed on August 12, 2004, by a representative of this office. A survey of line and ·grade for the subject lot was not conducted by this firm at the time of our site reconnaissance .. Near surface soil conditions were explored with two large diameter borings, within the site, to evaluate soil and geologic conditions. The approximate locations of each boring are shown on the attached Geotechnical Map (see Plate 1). Boring Logs are presented in Appendix B. · REGIONAL GEOLOGY The subject property is located within a prominent natural geomorphic province in southwestern California known as ·the Peninsular Range. It is characterized by steep, elongated mountain ranges and valleys that trend northwesterly. The mountain ranges are underlain by basement rocks consisting of pre-Cretaceous metasedimentary rocks, Jurassic metavolcanic rocks, and Cretaceous plutonic rock~ of the southern California batho!ith. In the San Diego County region; deposition occurred -during the Cretaceous Period and Cenozoic Era in the continental margin of a forearc basin. Sediments, derived from Cretaceous-age plutonic rocks and Jurassic-age volcanic rocks, were deposited into the narrow, steep, coastal plain and continental margin of the basin. These rocks have been uplifted, eroded, and deeply incised. During early Pleistocene time, a broad coastal plain was developed from the deposition of marine terrace deposits. During mid to late Pleistocene time, this plain was uplifted, eroded, and incised. Alluvial'deposits have since filled the lower valleys, and young marine sediments are currently being deposited/eroded within coastal and beach areas. SITE GEOLOGIC UNITS . The site geologic units encountered during our subsurface investigation and site reconnaissan·ce included undocumented artificial fill underlain by the Tertiary Santiago Formation. The earth materials are generally described below, from the youngest to the oldest. The distribution of these materials is shown on Plate 1. Artificial Fill -Undocumented (Map Symbol -Afu) Artificial fill (undocumented) was observed to mantle the entire level portion and a majority of the sloping portions of the site. The artificial fill consists of brown to gray brown to dark brown to yellow brown to olive gray to gray sandy clays and yellow brown to gray brown silty sands. The artificial fill was observed to be dry and soft within the upper 2 feet, generally becorriing moist and medium stiff/medium dense with depth. Based on current Karnak Planning and Design, Inc. . Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page4 I I I I I I I I I I I I I I I I I I I industry standards, the undocumented artificial fill is unsuitable for the support of settlement-sensitive improvements/engineered fill in its existing state due to its non-uniformity. Although ECSCEI (2001) states that the fill soils, mantling the site, have been certified, no reference to the final compaction report was provided. Based on all of. the above, it is the opinion of GSI that mitigation in the form of removal and recompaction of the existing fill soils will be necessary. Tertiary Santiago Formation (Map Symbol -Tsa) Sediments, belonging to the Tertiary Santiago Formation, were observed to underlie the undocumented fill, and consists of dark gray brown to brown to gray to orange to brown sandy claystones to yellow brown to gray to dark gray brown to orange clayey sandstones to brown sandstones to gray to orange silty sandstones. Discontinuous, occasional to abundant angular to rounded pebble to cobble sized clasts were observed. The sedimentary bedrock is suitable for the support of settlement-sensitive structures or engineered fill in its existing state. Geologic structure, exposed within the bedrock, was generally massive to weak, and subhorizontal bedding was noted. FAUL TING AND REGIONAL SEISMICITY Regional Faults Our review indicates that there are no known active faults crossing this site within the area proposed for development, and the site is not within an Earthquake Fault Zone (Hart and Bryant, 1997; Jennings, 1994). However, the site is situated in an area of active as well as potentially active faulting. These include, but are not limited to: the San Andreas fault zone; the San Jacinto fault zone; the Elsinore fault zone; the Coronado Bank fault zone; and the Newport-Inglewood -Rose Canyon fault zone. The location of these, and other major faults relative to the site, are indicated on Figure 2 (California Fault Map}. The possibility of ground acceleration, or shaking at the site, may be considered as approximately similar to the southern California region as-a whole. Major active fault zones that may have a significant affect on the site, should they experience activity, are listed in the following table (modified from Blake, 2000a): . Rose Canyon Newport-Inglewood (Offshore) Coronado Bank Elsinore-Julian Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge 6.7 (10.8) 11.8(19.0) 21.6 (34.7) 24.2 (38.9) W.O. 4460-A-SC September 27, 2004 Page 5 I I I I I I I I I I I I ·1 I I I I I I 1000 900 800 700 600 500 400 300 200 100 0 CALIFORNIA FAULT MAP KARNAK -1 00. --f--L--L....Jc.....L...f-L-..L....L.--'--f.,,.._L....L..-L-+_._.,_--L....Jc...+-L....L....L....L.-f-L--L.....L-+-'--...L.....1.---"'-lc.....L....L..J...<D.-f-....L...1-'--'-+-..L....L....L.....I.~ -400 -300 -200 . -100 0 100 200 300 400 500 600 W .0. 4460..;A-SC Figure 2 I I I I I I I I I I I I I I I I I I I APPROXIMATE DISTANCE ABBREVIATED FAULT NAME MILES (KM) Elsinore-Temecula 24.2 (39.0) Elsinore-Glen Ivy 38.9 (62.6) Earthquake Valley 39.0 (62.8) Palos Verdes 42.4 (68.2) San Jacinto-Anza 46.9 (75.5) San Jacinto-San Jacinto Valley 49.0 (78.8) San Jacinto -Coyote Creek 49.8 (80.1) Seismicity The acceleration-attenuation relations of Bozorgnia, Campbell, and Niazi (1999) and Campbell and Bozorgnia (1997 Revised) have been incorporated into EQFAULT (Blake, 2000a). EQFAULT is a computer program developed by Thomas F. Blake (2000a), which performs deterministic seismic hazard analyses using digitized California faults as earthquake sources. The program estimates the closest distance between each fault and a given site. If a fault is found to be within a user-selected radius, the program estimates peak horizontal ground acceleration that may occur at the site from an _upper bound ("maximum credible")" earthquake on that fault. Site acceleration (g) is computed by one or more user-selected acceleration-attenuation relations that are contained in EQFAULT. Based on the EQFAUL T program, peak· horizontal ground accelerations frpm an upper bound event at the site may be on the order of 0.47g to 0.55g. The computer printouts of portions of the EQFAULT program are included within Appendix C. Historical site seismicity was evaluated with the acceleration-attenuation relations of Bozorgnia, Campbell, and Niazi (1999) and the computer program EQSEARCH (Blake, 2000b). This program performs a search of the historical earthquake records for magnitude 5.0 to 9.0 seismic events within.a 100-mile radius, between the years 1800 to December 2003. Based on the selected acceleration-attenuation relationship, a peak horizontal ground acceleration is estimated, which may have effected the site during the specific event listed. Based on the available data and the attenuation relationship used, the estimated maximum (peak) site acceleration during the period 1800 to December 2003 was 0.45g. Site specific probability of exceeding various peak horizontal ground · accelerations and a seismic recurrence curve are also estimated/generated from the historical data. Computer printouts of the EQSEARCH program are presented in Appendix C. Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page7 I I I I I I I I I I I I I I I I I I I A probabilistic seismic hazards analyses was performed using FRISKSP (Blake, 2000c}, which models earthquake sources as three-dimensional planes and evaluates the site specific probabilities of exceedance for given peak acceleration levels or pseudo-relative velocity levels. Based on a review of this data, and considering the relative seismic activity of the southern California region, a peak horizontal ground acceleration of 0.29g was calculated. This value was chosen as it corresponds to a 1 O percent probability of exceedance in 50 years (or a 475-year return period). Computer printouts of the FRISKSP program are included in Appendix C. Seismic Shaking Parameters Based on the site conditions, Chapter 16 of the Uniform Building Code ([UBC], International Conference of Building Officials [ICBO], 1997) seismic parameters are provided in the following table: ~-,,.~-... ,, ........ :·;," ·.·, .·, ... , .,, •,• ........ ,:,, .,·;,, ... . . . , . ~·-'l\;j;';, ·,s, . ,;~1~1991:UQC:.CHAPJER ,16::TABLE;NO;,.,;.~.,.,~ l~r.rsii1sM1c·:e'ARAMETER~ Seismic Zone (per Figure 16-2*) 4 Seismic Zone Factor (per Table 16-1*) 0.40 Soil Profile Type (per Table 16-J*) So Seismic Coefficient Ca (per Table 16-Q*) 0.44Na Seismic Coefficient Cv (per Table 16-R*) .. 0.64Nv Near Source Factor Na (per Table 16-S*) 1.0 Near Source Factor Nv (per Table 16-T*) 1.0 Distance to Seismic Source . 6.7 mi (10.9 km) Seismic Source Type (per Table 16-U*) 8 Upper Bound Earthquake (Rose Canyon) Mw6.9 I * Figure and Table references from Chaeter 16 of the USC {ICBO, 1997) . I Seismic Hazards The following list includes other seismic related hazards that have been considered during our evaluation of the site. The hazards, listed, are considered negligible and/or completely mitigated as a result of site location, soil characteristics, and typical site development procedures: • Tsunami • · Dynamic Settlement • Surface Fault Rupture Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File: e:\wp9\4400\4460a.pge · W.O. 4460-A-SC September 27, 2004 Page B I I I I I I I I I I I I I I I I I I I • • Ground Lurching or Shallow Ground Rupture Seiche It is important to keep in perspective that in the event of a maximum probable or credible earthquake occurring on any of the nearby major faults, strong ground shaking would occur in the subject site's general area. Potential damage to any structure(s) would likely be greatest from the vibrations and impelling force caused by the inertia of a structure's mass than from those induced by the hazards considered above. This potential would be no greater than that for other existing structures and improvements in the immediate vicinity. GROUNDWATER Subsurface water was not encountered, within the property, during field work performed in preparation of this report. Subsurface water is not anticipated to adversely affect site development, provided that the recommendations contained in this report are incorporated into final design and construction. These observations reflect site conditions at the time of our investigation and do not preclude future changes in local groundwater conditions from excessive irrigation, precipitation, or that were not obvious at the time of our investigation. The elevation of a perched groundwater table is estimated to range between 35 and 40 feet Mean Sea Level (MSL). This estimate is based upon the occurrence water, observed in a creek channel thattransects the nearby golf course, located to the northwest of the site. Therefore, the perched groundwater table is located approximately 15 to 20 feet below the toe of the northern slope that descends to Gibraltar Street and 35 to 40 feet below the proposed grade for Lot 393 (lower pad). The regional groundwater table is anticipated to be near MSL (approximately 55 feet below the toe of the northern slope that descends to Gibraltar Street). Perched groundwater conditions along fill/bedrock contacts, and along zones of contrasting permeabilities, may not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities, and should be anticipated. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide the· appropriate recommendations to mitigate the observed groundwater conditions. This potential should be disclosed to all owners. LIQUEFACTION POTENTIAL Seismically-induced liquefaction is a phenomenon in which cyclic stresses, produced by earthquake-induced ground motion, create excess pore pressures in soils. The soils may thereby acquire a high degree of mobility, and lead to lateral movement, sliding, sand boils, consolidation and settlement of loose sediments, and other damaging deformations. This phenomenon occurs only below the water table; but after liquefaction has developed, Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 9 I I I I I I I I I I I I I I I I I I I · it can propagate upward into overlying, non-saturated soil as excess pore water dissipates. Typically, liquefaction has a relatively low potential at depths greater than 45 feet and is virtually unknown below a depth of 60 feet. Liquefaction susceptibility is related to numerous factors and the following conditions should be concurrently present for liquefaction to occur: 1) sediments must be relatively young in age and not have developed a large amount of cementation; 2) sediments must generally consist of medium to fine grained relatively cohesion less sands; 3) the sediments must have low relative density; 4) free groundwater must be present in the sediment; and 5) the site must experience a seismic event of a sufficient duration and magnitude, to induce straining of soil particles. . The condition of liquefaction has two principal effects. One is the consolidation of loose sediments with resultant settlement· of the ground surface. The other effect is lateral sliding. · Significan, permanent lateral movement generally occurs only when there is significant differential loading; such as fill or· natural ground slopes within susceptible materials. No such loading conditions exist on the site since the site is underlain at depth · by very dense/very stiff bedrock sediments not considered to be liquefiable. In the site area, we found there is a potential for seismic activity and a perched groundwater table that is estimated to be approximately 15 to 20 feet below the toe of the western slope that descends to Gibraltar Street and 35 to 40 feet below the proposed grade for Lot393 (lower pad). However, the bedrock sediments that underlie the site were generally fine grained, and· become very dense/very stiff with depth and therefore, are not considered to be susceptible to liquefaction. Since at least three or four of these five required concurrent conditions discussed above do not have the potential to affect the site, our evaluation indicates that the potential for liquefaction and associated adverse effects within the site is very low, even with a future rise in groundwater levels. Therefore, based on the available data, it is our opinion that the liquefaction potential does not constitute a significant risk to site development. · LABORATORY TESTING General Laboratory tests were performed on representative samples of the onsite earth materials in order to evaluate their physical characteristics. GSl's laboratory data is presented below and in Appendix D. ECSCEI (2001) laboratory data is presented in Appendix F. The test procedures used and.results obtained in preparation of this report are presented below. Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 10 I I I I I I I I I I I I I I I I I I I Classification Soils were classified visually according to the Unified Soils Classification System. The soil classifications are shown on the Boring Logs in Appendix B. Moisture-Density Relations The field moisture contents and dry unit weights were determined for selected undisturbed samples in the laboratory. The dry unit weight was determined in pounds per cubic foot (pcf), and the field moisture content was determined as a percentage of the dry weight. The results of these tests are shown on the Boring Logs (GSI) in Appendix B. Laboratory Standard The maximum dry density and optimum moisture content was determined for the major soil type encountered in the exploratory borings. The laboratory standard used was ASTM D-1557. The moisture-density relationship obtained for this_ soil is shown below: Gray Brown, Sandy CLAY 8-1 @ 0-2 120.0 12.5 (Artificial Fill) Light Green Gray, CLAY 8-1 @ 5-10 119.0 14.0 (Artificial Fill) Gra CLAY with Sand B-2@ 10-15 114.0 15.5 Expansion Potential Expansion testing was performed on a representative sample of site soils in accordance with UBC Standard 18-2. The result of the expansion testing is presented in the following· table. · 8-1 @0-2 8-1 @ 5-10 Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge 65 57 Medium Medium W.O. 4460-A-SC September 27, 2004 Page 11 I I I I I I I I I I I I I I I I I I I Direct Shear Test Shear testing was performed on representative, "undisturbed" and "remolded samples of site soil in general accordance with ASTM Test Method D-3080 in a Direct Shear Machine of the strain control type. The shear test results are presented as follows and are provided in Appendix D: 8-1 @0-2 (remolded) 8-2@35 (undisturbed) Atterberg Limits 440 301 22 428 22 36 177 37 Testing was performed on a selected representative fine grained soil sample to evaluate · the liquid limit; plastic limit and plasticity index in general accordance with ASTM 04318-64. The test result is presented in the following table and in Appendix D. 8-1@ 0-2 43 20 8-1 @5-10 41 20 21 Consolidation Testing Consolidation testing was performed on relatively undisturbed soil samples in general accordance with ASTM Test Method D-2435-90. The consolidation test results are presented in Appendix D. Corrosion/Sulfate Testing A typical sample of the site material was analyzed by M. J Schiff and Associates, Inc., for corrosion/acidity and sulfate potential. The testing included determination of soluble sulfates, pH, and saturated resistivity. Results indicate that site soils are mildly alkaline (pH=7.6) with respect to acidity and have a saturated resistivity of 410 ohm-cm. Thus, the site soils are severely corrosive to ferrous metals when saturated. Severely corrosive soils are considered to be below 1,000 ohms-cm. Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page12 I I I I I I I I I I I I I I I I I I I Testing indicates that the site soils have a sulfate content of 0.0617 percentage by weight. This corresponds to a: negligible sulfate exposure to concrete (UBC range for negligible sulfate exposure is 0.00 to 0.1 O percentage by weight soluble [S04] in soil). Alternative testing methods and additional comments should be obtained from a qualified corrosion engineer with regard to foundations, piping, etc. Laboratory test results are presented in Appendix D. SLOPE STABILITY Conventional slope stability analyses were performed utilizing the PC version of the computer program GSTABL7 v.2. The program performs a two-dimensional limit equilibrium analysis to compute the factor of safety for a layered slope using the simplified Bishop or Janbu methods. Representative Geologic Cross Sections A-A' and 8-8' (see Plate 2) were prepared for analysis from the topographic base map, provided by the Client. Field and laboratory data were then applied to the analysis. The maximum 1.5: 1 (horizontal:vertical [h:v]) ±20-foot high fill-over-cut slope, along the northern property margin, is presented as Cross Section A-A'. The maximum 1.5:1 (h:v), ±25-foot high fill-over-cut slope above an 8-foot high retaining wall, along the western property margin, is presented as Cross Section 8-8'. The results of the analyses are included in Appendix E. Gross Stability Analysis A calculated factor-of-safety greater than 1.5 from a· static viewpoint and greater than 1.1 from a seismic viewpoint has been obtained for the existing fill-over-cut slopes, presented in Cross Sections A-A' and 8-8'. The results of the analyses. are included in Appendix E. Surficial Slope Stability The surficial stability of the existing fill-over-cut slopes have been analyzed. Our evaluation indicates a surficial safety factor less than 1.5, from a static viewpoint, for the existing fill-over-cut slopes. Mitigation measures will be necessary to reduce the potential for surficial instability. Mitigation recommendations are provided in the · "Earthwork Construction Recommendations" section of this report. Summary of Slope Stability Based on our analyses, the existing fill-over-cut ~lopes are calculated to be grossly stable in their present condition. However, as stated above, the existing fill-over-cut slopes are generally considered to be surficially unstable in their present condition, and will potentially be subject to failures and/or slope creep because they have been previously constructed at a gradient that is steeper than current code (per code fill slopes shall not be constructed at a gradient steeper than 2:1 [h:v]). Therefore, mitigation measures will be necessary to Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 13 I I I I I I I I I I I I I I I I I I I reduce the potential for surficial slope instability. Otherwise, conservative building setbacks and increased maintenance to the slopes and/or settlement-sensitive improvements (i.e., pools, walkways, driveways, patios, etc.), constructed within 1 O feet or so from the tops of these. slopes, and disclosure to all homeowners and Homeowners Association (if any) will be required. · PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS General Based on our field exploration, laboratory testing, and geotechnical engineering analysis, it is our opinion that the site appears suitable for the proposed development from a geotechnical engineering and geologic viewpoint, provided that the recommendations presented in the following sections are incorporated into the design and construction phases of site development. The primary geotechnical concerns with respect to the proposed development are: • Depth to competent bearing soils/suitability of existing artificial fill and remedial removals. • Potential for settlement and associated distress. • Slope stability of the existing graded slopes, including surficial stability. • Expansion and corrosion potential of site soils and their ongoing effects. • Potential for perched groundwater after development • Regional seismic activity. The recommendations presented herein consider these as well as other aspects of the site. The engineering analyses performed concerning site preparation and the recommendations presented herein have been completed using the information provided and obtained during our field work. In the event that any significant changes are made to proposed site development, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the recommendations of this report verified or modified in writing by this office. Foundation design parameters are considered preliminary until the foundation design, layout, and structural loads are provided to this office for review. 1. Soil engineering, observation, and tes~ing services should be provided during grading to aid the contractor in removing unsuitable soils and in his effort to compact the fill. 2. Geologic observations should be performed during grading to verify and/or further evaluate geologic conditions. Although unlikely, if adverse geologic structures are encountered, supplemental recommendations and earthwork may be warranted. Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 14 I I I I I I I I I I I I I I I I I I I 3. The existing undocumented fill soils are non-uniform in nature and therefore are considered unsuitable for the support of settlement-sensitive improvements and/at additional fill in their present condition, based on current industry standards. These materials are potentially compressible in their present condition, and may be subject to differential settlement. Mitigation in the form of removal and recompaction will be necessary. Based upon GSl's field investigation and a review of ECSCEI (2001), removal depths on the order of ±10 to ±24 feet should be anticipated at this time. However, localized, deeper removals cannot be precluded. If the recommended remedial earthwork is performed, the proposed buildings may be supported by post-tension or mat slab foundations. Otherwise, it is recommended that the proposed buildings be supported by drilled piers. If drilled piers are to be utilized for foundation support, it is recommended that the upper 5 feet of the existing· fill soils be removed and recompacted for concrete slab and asphaltic/concrete pavement support, and the support of other settlement sensitive improvements (i.e. retaining walls, privacy walls, etc.). Such support, however, would not eliminate th~ potential for distress to such settlement-sensitive improvements, if complete removals are not performed and deep foundations are not utilized. 4. In general and based upon the available data to date, groundwater is not expected to be a major factor in development of the site assuming shallow excavations. However, perched groundwater conditions along fill/bedrock deposit contacts, and along zones of contrasting permeabilities, may not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities, and should be anticipated. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. In addition, subdrainage systems for the control of localized groundwater seepage should be anticipated. The proposed locations of_ such drains can be delineatec;I at the grading plan review stage of planning. The potential for perched groundwater should be anticipated after development. This potential should be disclosed to all owners. 5. Due to the nature of some of the onsite materials, some caving and sloughing ·may be anticipated to be a factor in subsurface excavations and trenching. Therefore, current local and state/federal safety ordinances for subsurface excavations should be enforced. Temporary slopes should be constructed for Type "B" soils, and should be further evaluated during grading and/or the grading plan review stage.· 6. General Earthwork and Grading Guidelines are provided atthe end of this report as Appendix F. Specific recommendations are provided below. 7. A review of ECSCEI (2001) and our laboratory test results, indicate that soils with medium to high expansion indices generally underlie the site. This should be considered during project design. Preliminary post-tension and mat slab foundation design and construction recommendations are provided herein for medium to high Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 15 I I I I I I I I I I I I I I I I I I I expansion potential classifications, provided that the complete removal and recompaction of the existing fill soils is to be performed. Otherwise, the buildings should be supported by drilled concrete piers. Final foundation and design· and construction recommendations will be provided at the conclusion of grading. 9. Our slope stability analysis indicates that the existing, graded fill-over-cut slopes are grossly stable. However, analysis indicates that the existing fill-over-cut slopes are surficially unstable and will require reconstruction to a 2:1 (h:v) gradient during remedial earthwork or will require reconstruction with geogrid reinforcement if the current gradients of the slopes are to remain. Increased maintenance to the slopes and/or settlement~sensitive improvements constructed within 1 O feet from the tops of slope may be required if the proposed slope gradient are to remain steeper than 2:1 (h:v). Furthermore, disclosure, pertaining to increased maintenance, will be required to all homeowners and the Homeowners Association (if any). · 1 o. The seismicity-acceleration values provided in the "Faulting and Regional Seismicity" section of this report should be considered during the design of the proposed development. ' EARTHWORK CONSTRUCTION RECOMMENDATIONS General All grading should conform to the latest guidelines presented in Chapter A33 of the USC, the requirements of the City, and the Grading Guidelines presented in Appendix H, except where specifically superceded in the text of this report. Prior to grading, a GSI representative should be present at the preconstruction meeting to provide additional grading guidelines, if needed, and review the earthwork schedule. During earthwork construction, all site preparation and.the general grading procedures of the contractor should be observed and the fill selectively tested by a representative(s) of GSI. If unusual or unexpected conditions are exposed in the field, they should be reviewed by this office and, if warranted, modified and/or additional recommendations will be offered. All applicable requirements of local and national construction and general industry safety orders, the Occupational Safety and Health Act (OSHA), and the Construction Safety Act should. be met. Site Preparation All vegetation and/or deleterious materials should be remove·d from the site prior to the start of construction. Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 16 I I I I I I I I I I I I I I I I I I I Removals (Unsuitable Surficial Materials} If the proposed buildings are not planned to be supported by drilled piers, the complete removal of the existing fill soils should be performed. Based upon a review of ECSCEI (2001) and observations, conducted during GSl's subsurface investigation, removal depths on the order of ±10 to ±24 feet in depth should be anticipated. However, locally, deeper removals cannot be precluded .. If drilled piers are to be utilized for foundation support, it is recommended that the upper 5 feet of the existing fill soils be removed and recompacted for concrete slab and asphaltic/concrete pavement support, and the support of other settlement sensitive improvements (i.e., retaining walls, privacy walls, etc.). · Removals should be completed below a 1 :1 projection down and away from the edge of any settlement-sensitive structure and/or limit of proposed fill. Once removals are completed, the exposed bottom should be scarified in two perpendicular directions, moisture conditioned to at least optimum moisture content, and recompacted to 90 percent relative compaction prior to fill placement. It should be noted that the USC/CBC (ICBO, 1997 and 2001) specifically requires that removals of unsuitable soils be performed across all areas to be graded, not just within the influence of the residential structure. Relatively deep removals may also necessitate a special zone of consideration on perimeter/confining areas. This zone would be approximately equal to the depth of removals, if removals cannot performed offsite. Thus, any settlement-sensitive improvements (walls, curbs, flatwork, etc.) constructed within this zone may require deepened foundations, reinforcement, etc., or will retain some potential for settlement and associated distress. This will require proper disclosure to all homeowners and any homeowners association. Fill Placement Subsequent to ground preparation, onsite soils may be placed in thin (±6-to 8-inch) lifts, cleaned of vegetation and debris, brought to at least 1 · to 2 percent above the soils' optimum moisture content, and compacted to achieve a minimum relative compaction of 90 percent. If fill soil importation is planned, a sample of the soil import should be evaluated by this office prior to importing, in order to assure compatibility with the onsite soils and the recommendations presented in this report. At least three business days of lead time should be allowed by builders or contractors for proposed import submittals. This lead time will allow for particle size analysis, specific gravity, relative compaction, expansion testing, and blended import/native characteristics as deemed necessary. Import . soils for a fill cap should be very low to medium expansive (Expansion Index [E.l.] less than 91). The use of subdrains at the bottom of the fill cap may be necessary, and subsequently recommended based on compatibility. with onsite soils and other considerations. Transitions/Overexcavation Based upon a review of field data collected in preparation of ECSCEI (2001) and this report, and a review of the grading plans, transition conditions are not anticipated. Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 17 I I I I I I I I I I I I I I I I I I I However, if encountered, the cut portion of the building pads should be overexcavated a minimum of 4 feet below the proposed pad grade or to a depth where a minimum of 2 feet of compacted fill beneath the footing is provided. The maximum to minimum fill thickness should not exceed a ratio of 3: 1 (maximum:minimum) beneath the entire building pad. Overexcavation will not be necessary if the buildings are to be supported by drilled piers. Slope Considerations and Slope Design Our slope stability analysis indicates that the existing fill-over-cut slopes are generally grossly stable in their present condition. However, the analysis indicates that the existing fill-over-cut slopes are surficially unstable, based upon current industry standards and will require mitigation measures to reduce the potential for significant slope creep. Owing to their oversteepened condition, the potential for long-term maintenance may be necessary to mitigate surficial erosion, slumps, etc., if the slopes are to remain at a gradient that is steeper than 2:1 (h:v). This condition should be disclosed to all homeowners and the Homeowners Association (if any). All existing and proposed slopes should be designed and constructed in accordance with the minimum requirements of the City, and the recommendations in the General Earthwork and Grading Guidelines section of this report (see Appendix F)_, and the following: • If the existing slopes are to remain at their current gradients, in order to maximize building space, the outer 10 feet of the slopes should be removed, properly keyed and reconstructed with geogrid reinforcement as specified below: 1. 2. 3. As stated above, the outer 1 O feet of the existing graded slopes should be removed. A keyway should be constructed at the toe of the slope. The keyway width should minimally be 12 feet or H/2 where H is the maximum height of the slope. The toe of the keyway should be minimally excavated 2 feet into suitable bearing soils as determined by the ge·otechnical engin·eer. The bottom of the keyway should be constructed to slope at a 2 percent gradient from the toe to the heel. In order to reinforce the face of the slopes, Mirafi BXT geogrid should be placed 2 feet on center from the toe to the top of the slopes. The minimum length of the geogrid should be 7 feet. Moisture conditioned fill soils should be placed in thin 6-to 8-inch lifts above each layer of geogrid and be compacted to 90 percent relative compaction. The face of the slope should also be compacted to 90 percent relative compaction. It should be noted that the recommended mitigation measures have been developed to reduce the potential for surficial slope creep. However, disclosure to all homeowners and the Condominium Association (if any) Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 18 I I I. I I I I I I I I I I I I I I I I should be provided with respect to a potential for increased maintenance to the slopes and any settlement-sensitive improvements constructed within 1 a feet to the top of slopes. All proposed fill slopes should be designed and constructed at a 2:1 (h:v) gradient, or flatter, and should not exceed about 15 feet in height without further analysis. Fill slopes should be properly built and compacted to a minimum relative compaction of 90 percent throughout, including the slope surfaces. Guidelines for slope construction are presented in Appendix H. Temporary Slopes Unsupported excavations should be constructed in accordance with criteria established in Article 6 of the State of California, Construction Safety Orders (CALJOSHA) for Type "B" soils. On a preliminary basis, temporary slopes.for removals may be inclined at gradient of 1 :1 (h:v). Heavy equipment and/or stockpile should not be stored within 5 feet of any temporary. slope. Additionally, heavy equipment should not be operated within 5 feet from the top of any temporary slope. Temporary slopes should be further evaluated during site grading. The possibility of inclining temporary slopes to a flatter gradient may be recommended if adverse soil conditions are observed. If the required gradient of any temporary slope conflicts with property boundaries, shoring may be necessary. SUB DRAINS Subdrains may be required after development to control the effect of perched water conditions, and may not be precluded during grading. This condition should be disclosed to all owners. PRELIMIMARY RECOMMENDATIONS -FOUNDATIONS Preliminary Foundation Design In the event that the information concerning the proposed development plans is not correct, or any changes in the design, location, or loading conditions of the proposed structures are made, the conclusions and recommendations contained in this report are for the subject site only, and shall not be considered valid unless the changes are reviewed and conclusions of this report are modified or approved in writing by this office. The information and recommendations presented in this section are considered minimums and are not meant to supercede design(s) by the project structural engineer or civil engineer specializing in structural design. They are considered preliminary recommendations for proposed construction, in consideration of our field investigation, laboratory testing, and engineering analysis. Upon request, GSI could provide additional consultation regarding soil parameters, as related to foundation design. Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 19 I I I I I I I I I I I I I I I I I I I Our review, field work, .and recent laboratory testing indicates that onsite soils have a medium expansion potential (E.I. 51 to 90). However, a review of ECSCEI (2001) indicates that highly expansive soils (E.I. 90 to 130) also occur onsite. Therefore, it is the opinion of GSI that post-tension or mat slab foundations will be required to support the proposed buildings, owning to the moderate to high expansion potential of the onsite soils.· Post-tension or mat slab foundations may only be utilized if the complete removal and recompaction of the existing undocumented fill is performed. Otherwise, the proposed buildings should draw support from drilled piers. Preliminary recommendations for foundation design and construction, with respect to medium to high expansion classifications, are presented below. Final foundation recommendations will be provided at the conclusion of grading, based on laboratory testing of fill materials exposed at finish grade. Bearing Value 1. 2. The foundation systems should be designed and constructed in accordance with guidelines presented in the latest edition of the UBC. An allowable bearing value o.f 1,500 pounds per square foot (psf) may be used for design of continuous footings 12 inches wide and 12 inches deep, and for design of isolated pad footings 24 inches square· and 24 inche$ deep, founded entirely into compacted fill and connected by grade beam or tie beam in at least one direction. This value may be increased by 20 percent for each additional 12 inches in depth to a maximum value of 2,500 psf. The above values may be increased by one-third when considering short duration seismic or wind loads. No increase in bearing for footing width is recommended. Lateral Pressure 1. For lateral sliding. resistance, a 0.30 coefficient of friction may be .utilized for a concrete to soil contact when multiplied by the dead load. 2. Passive earth pressure may be computed as an equivalent fluid having a density of 250 pcf with a maximum earth pressure of 2,500 psf. 3. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. Preliminary Foundation Settlement Evaluation Post-tension or Mat Slab Foundations Provided that all existing undocumented fill has been properly removed and recompacted, the proposed buildings may be supported by post-tension or mat slab foundations. Preliminary settlement analysis indicates a post-development total settlement of 1-inch and Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 20 I I I I I I I I I I I I I I I I I I I a differential settlement of 0. 75-inch over a 40-foot horizontal span (angular distortion = 1 /640 for this scenario. Drilled Piers If the complete removal and recompaction of the undocumented fill is not feasible, the proposed buildings will be required to draw support from drilled piers. Preliminary settlement analysis indicates a post-development total settlement of 0.75-inch and a differential settlement of 0.5-inch over a 40-foot horizontal span (angular distortion = 1 /960) for this scenario. · Footing Setbacks All footings should maintain a minimum 10-foot horizontal setback from the base of the footing to any descending slope. This distance is measured from the footing face at the bearing elevation. Footings should maintain a minimum horizontal setback of H/3 {H = slope height) from the base of the footing to the descending slope face and no less than 1 O feet, nor need be greater than 40 feet. If the location of proposed footings conflicts with GSl's setback recommendations, proper setbacks may be maintained by simply deepening the footings. Footings adjacent t9 unlined drainage swales should be deepened to a minimum of 6 inches below the invert of the adjacent unlined swale. Footings for structures adjacent to retaining walls should be deepened so as to extend below a 1 : 1 projection from the heel fo the wall. Alternatively, walls may be designed to accommodate structural loads from buildings or appurtenances as described in the "Wall Design Parameters Considering Expansive Soils" section of this report. Construction The following foundation construction recommendations are presented as a minimum criteria from a soils engineering standpoint. The onsite soil expansion potential is generally medium {E.I. 51 to 90). However, a review of ECSCEI (2001) indicates that highly expansive soils {E.I. 91 to 130) exist onsite. Due to the medium to high expansion potential of onsite soils and fill slopes that are anticipated to be constructed steeper than code (per the current edition of the UBC), post-tension or mat slab foundation systems are specifically recommended for the support of the condominiums if the complete removal and recompaction of the existing fill is performed. If remedial earthwork is not proposed the buildings should be supported by drilled piers Preliminary recommendations for post-tensioned and mat slab foundation systems, and drilled piers are provided herein. Recommendations by the project's design-structural engineer or architect, which may exceed the soils engineer's recommendations, should take precedence over the following minimum requirements. Final foundation design will be provided based on the expansion potential of the finish grade soils encountered at the conclusion of grading. Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 21 I I I I I I I 1· I I I I I I I I I I I POST-TENSIONED SLAB SYSTEMS The recommendations presented below should be followed in addition to those contained in the previous sections, as appropriate. The information and recommendations presented below in this section are not meant to supercede design by a registered structural engineer or civil engineer familiar with post-tensioned slab design. Post-tensioned slabs should be designed using sound engineering practice and be in accordance with local and/or national code requirements and should only be used if the complete removal and recompaction of the existing undocumented fill soils have been performed. Upon request, GSI can provide additional data/consultation regarding soil parameters as related to post-tensioned slab design. - From a soil expansion/shrinkage standpoint, a common contributing factor to distress of structures using post-tensioned slabs is fluctuation of moisture in soils underlying the perimeter of the slab, compared to the center, causing a 11dishing11 or "arching" of the slabs. To mitigate this possibility, a combination of soil presaturation and construction of a perimeter "cut off' wall should be employed. Perimeter cut off walls should be a minimum of 18 inches deep for medium expansive soils and 24 inches deep for highly expansive soils. The cut off walls may be integrated into the slab design or independent of the slab. The concrete slab should be a minimum of 5 inches thick. Concrete, utilized, shall be Type V concrete with a maximum water-cement ratio of 0.45 and a minimum strength of 4,500 psi to mitigate the effects from post-development perched water and to impede water vapor transmission. Slab underlayment should consist of 2 inches of washed sand placed above a vapor barrier consisting of 15-mil polyvinyl chloride, or equivalent, will all laps sealed per the USC. The vapor barrier shall be underlain by 4 inches of pea gravel placed directly on the slab subgrade, and should be sealed to' provide a continuous water-proof barrier under the entire slab, as discussed above. All slabs shall be additionally sealed with a suitable slab sealant, and shall minimally be 5 inches thick. Specific soil presaturation is required for medium and highly·expansive soils .. The moisture content of the slab subgrade soils should be equal to, or greater than, 120 percent of the soil's optimum moisture content to a depth of 18. inches for medium expansive soils and 130 percent of the soil's optimum moisture content to a depth of 24 inches for highly expansive soils. · Post-Tensioning Institute Method Post-tensioned slabs should have sufficient stiffness to resist excessive bending due to non-uniform swell and shrinkage of subgrade soils. The differential movement can occur at the corner, edge, or center of the slab. The potential for differential uplift can be evaluated using the 1997 USC, Section 1816, based on design specifications of the Post-Tensioning Institute. The following table presents suggested minimum coefficients to be used in the Post-Tensioning Institute design method. Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 22 I I I I I I I I I I I I I I I I I I I Thornthwaite Moisture Index -20 inches/year Correction Factor for Irrigation 20 inches/year · Depth to Constant Soil Suction 7 feet Constant soil Suction (pf) 3.6 Modulus of Subgrade Reaction (pci) 75 Moisture Velocity . a.Tinch/month The coefficients are considered minimums and may not be adequate to represent worst case conditi_ons such as adverse drainage and/or improper landscaping and maintenance. The above parameters are applicable provided structures have positive drainage that is maintained away from structures. Therefore, it is important that information regarding drainage, site maintenance, settlements, and effects of expansive soils be passed on to future owners. Based on the above parameters, the following values were obtained from figures or tables of the 1997 UBC Section, 1816. The values may not be appropriate to account for possible differential settlement of the slab due to other factors. If a stiffer slab is desired, higher values of ym may be warranted. em center lift 5.5 feet 5.5 feet em edge lift 4.0 feet 4.5 feet Ym center lift 2.7 inches 3.5 inches 0.75 inch 1.2 inches Deepened footings/edges around the slab perimeter must be used to m1nrm1ze non:..uniform surface moisture rnigrat.ion (from an outside source) beneath the slab. An edge depth of 24 inches should be considered a minimum. The bottom of the deepened footing/edge should be designed to resist tension, using cable or reinforcement per the structural engineer. Other applicable recommendations presented under conventional foundation and the California Foundation Slab Method should be adhered to during the design and construction phase of the project. Should open bottom planters be planned directly adjacent to the foundation sys~em, the values in the above tables would need to be reviewed and/or modified to reflect more highly variable moisture fluctuations along the edges of the foundations. Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 23 I I I I I I I I I I I I I I I I I I I MAT SLAB FOUNDATIONS As an alternative to post-tension foundation systems mat slab foundations may be utilized to mitigate the effects of expansive soils. The structural mat should have a double mat of steel (minimum No. 4 reinforcing bars located at 12 inches on center each way, top and bottom) and a minimum thickness of 1 o inches. Mat edges should have a minimum edge footing of 12 inches wide and 18 inches deep for medium expansive soils and 24 inches deep for highly expansive soils below the lowest ijdjacent grade and be embedded into properly compacted fill. Mats may be designed by UBC Section 1815 (Div. Ill) methods using an Effective Plasticity Index of 40. · Mat slabs may be designed for a modulus of subgrade reaction (Ks) of 75 pci when placed on compacted clay. Concrete, utilized, · shall be Type V concrete with a maximum water-cement ratio of 0.45 and a minimum strength of 4,500 psi to mitigate the effects from post-development · perched water and to impede wate_r vapor transmission. Slab underlayment should consist of 2 inches of washed sand placed above a vapor barrier consisting of 15-mil polyvinyl chloride, or equivalent, will all laps sealed per the UBC. The vapor barrier shall be underlain by 4 inches of pea gravel placed directly on the slab subgrade and should be sealed to provide a continuous water-proof barrier under the entire slab, as discussed above. All slabs shall be sealed with a suitable slab sealant. Specific soil presaturation is required for medium to highly expansive soils. For medium expansive soils the slab subgrade moisture content should be at or slightly above 120 percent of the soil's optimum moisture content to a depth of 18 inches below pad grade. For highly expansive soils, the slab subgrade moisture content should be at or slightly above 130 percent of the soil's optimum moisture content to a depth of 24 inches below pad grade. 1. PRELIMINARY DRILLED PIER RECOMMENDATIONS· The entire buildings and structural foundations should be supported on a 24-inch wide grade beam and pier foundation system in lieu of the complete removal and recompaction of the existing undocumented fill. Piers should be at minimum, 24-inch in diameter, and should encounter and be minimally embedded 5 feet into suitable bearing formational sediments. Installed piers should be connected together by a "grade beam." Where the piers are to be located adjacent to a down-sloping ground, the following specified creep loads should be accounted for in the design. The piers should be designed by the structural engineer based on the applicable structural axial and lateral loads and the following geotechnical design parameters: Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004· Page 24 I I I I I .1 I I I I I I I I I I I I I Minimum Pier Diameter 24inches Creep Zone 5 feet measured vertically below the slope surface and projected upward parallel to slope face Lateral Creep Load 1,000 lbs/ft of pier depth, located within the creep zone Lateral Passive Resistance 500 lb/ft2 per foot of depth of pier, to a maximum value of (applicable below the point of fixity 5,000 lb/ft2 per foot of depth -increase by one-third for short only) duration wind and seismic loading Allowable Axial Capacity Tip Capacity: 5,000 lb/ft2 -increase by one-third for short duration wind or seismic loading Point of Fixity At least 2.0 times caisson diameter below the surface, or the creep zone, whichever applicable: · 2. ·The excavation and installation of the drilled piers should be observed and documented by the project geotechnical consultant to verify the desired depth. 3. The bottom of the drilled piers should be cleared of any loose or soft soils before concrete placement. 4. The exact depths of piers should be determined in the field based on conditions exposed during drilling. 5. · We recommend thatconcrete be placed through a tremie pipe immediately after the hole is drilled, the excavation is approved and the reinforcement is in place. Care should be taken to prevent striking the walls of the excavations with the tremie pipe during concrete placement. 6. All footing excavations should be inspected and approved by the geotechnical consultant prior to placement of concrete forms and reinforcements. CORROSION Upon completion of grading, additional testing of soils (including import materials) for corrosion to concrete and metals should be performed prior to the construction of utilities and foundations. UTILITIES Utilities should be enclose<;J within a closed utilidor (vault) or designed with flexible connections to accommodate differential settlement and expansive soil conditions. Due to the potential for differential settlement, air conditioning (A/C) units should be supported Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\446Da.pge W.O. 4460-A-SC September 27, 2004 Page 25 I I I I I I I I I I I I I I I I I I I by slabs that are incorporated into the building foundation or constructed on a rigid slab with flexible couplings for plumbing and electrical lines. NC waste waterlines should be drained to a suitable outlet. · WALL DESIGN PARAMETERS CONSIDERING EXPANSIVE SOILS Conventional Retaining Walls The design parameters provided below assume that either very low expansive soils (Class 2 permeable filter mate~ial or Class 3 aggregate base) or native materials are used to backfill any retaining walls, and that the retaining walls are founded in properly (removed and recompacted) fill, or on deep foundations. The type of backfill (i.e., select or native), should be specified by the wall designer, and clearly shown on the plans. Building walls, below grade, should be water-proofed or damp-proofed, depending on the degree of moisture protection desired. The foundation system for the proposed retaining walls should. be designed in accordance with the recommendations presented in this and preceding sections of this report, as appropriate. Footings should be embedded a minimum of 18 inches below adjacent grade (excluding landscape layer, 6 inches) and should be 24 inches in width. There should be no increase in bearing for footing width. Recommendationsforspecialtywalls (i.e., crib, earthstone, geogrid, etc.) can be provided upon reque_st, and would be based on site specific conditions. Restrained Walls Any retaining walls that will be restrained prior to placing and compacting backfill material or that have re-entrant or male corners, should be designed for an at-rest equivalent fluid pressure (EFP) of 65 pounds per cubic foot (pcf), plus any applicable surcharge loading. For areas of male or re-entrant corners, the restrained wall design should extend a minimum distance of twice the height of the wall (2H) laterally from the corner. Cantilevered Walls The recommendations presented below are for cantilevered retaining walls up to 1 O feet high. Design parameters for walls less than 3 feet in height may be superceded by City and/or County standard design. Active earth pressure may be used for retaining wall design, provided the top of the wall is not restrained from minor deflections. An equivalent fluid pressure approach may be used to compute the horizontal pressure against the waH. Appropriate fluid unit weights are given below for specific slope gradients of the retained material. These do not include other superimposed loading conditions due to traffic, structures, seismic events or adverse geologic conditions. When wall configurations are finalized, the appropriate loading conditions for superimposed loads can be provided upon request. Karnak Planning and Design, Inc. Romeria P~inte, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 26 I I I I I I I I I I I I I I I I I I I SURFACE SLOPE OF EQUIVALENT EQUIVALENT RETAINED MATERIAL FLUID WEIGHT P.C.F. FLUID WEIGHT P.C.F. (HORIZONTAL:VERTICAL) (SELECT BACKFILL) · (NATIVE BACKFILL) I Level* I 38 I 50 I 2 to 1 55 65 * Level backfill behind a retaining wall is defined as compacted earth materials, properly drained, without a slope for a distance of 2H behind the wall, where H is the height of the wall. Retaining Wall. Backfill and Drainage Positive drainage must be provided behind all retaining walls in the form of gravel wrapped in geofabric and outlets. A backdrain system is considered necessary for retaining walls that are 2 feet or greater in height. Details 1; 2, and 3, present the backdrainage options discussed below. Backdrains should consist of a 4-inch diameter perforated PVC or ABS pipe encased in either Class 2 permeable filter material or %-inch to %-inch gravel wrapped in approved filter fabric (Mirafi 140 or equivalent). For low expansive backfill, the filter material should extend a minimum of 1 horizontal foot behind the base of the walls and upward at least 1 foot. For native backfill that has up to medium expansion potential, continuous Class 2 permeable drain materials should be used behind the wall. This material should be continuous (i.e., full height) behind the wall, and it should be constructed in accordance with the enclosed Detail 1 (Typical Retaini.ng Wall Backfill and Drainage Detail). For limited access and confined areas, (panel) drainage behind the wall may be constructed in accordance with Detail 2 (Retaining Wall Backfill and Subdrain Detail Geotextile Drain). Materials with an expansion index (E.I.) potential of greater than 90 should not be used as backfill for retaining walls. For more onerous expansive situations, backfill and drainage behind the retaining wall should conform with Detail 3 (Retaining Wall And Subdrain Detail Clean Sand Backfill). Outlets should consist of a 4-inch diameter solid PVC or ABS pipe spaced no greater than ± 100 feet apart, with a minimum of two outlets, one on each end. The use of weep holes in walls higher than 2 feet should not be considered. The surface of the backfill should be sealed by pavement or the top 18 inches compacted with native soil (E.I. ~ 90). Proper surface drainage should also be provided. For additional mitigation, consideration should be given to applying a water-proof membrane to the back of all retaining struct'ures. The use of a waterstop should be considered for all concrete and masonry joints. Wall/Retaining Wall Footing Transitions Site walls are anticipated to be founded on footings designed in accordance with the recommendations in this report. Should wall footings transition from cut to fill, the civil designer may specify either: Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 27 I I I I I I I I I I I I I I I I I I I DETAILS N . T . S . 2 Native Backfill Provide Surface Drainage ~·- Slope or Level (!)waterproofing Membrane (optional) ® Weep Hole Finished Surface ±_12" Native Backfill 12" @ Filter Fabric Native Backfill @ Pipe Q) WATERPROOFING MEMBRANE (optional): Liquid boot or approved equivalent. @ ROCK: 3/4 to 1-1/2" (inches) rock. @ FILTER FABRIC: @ PIPE: Mirafi 140N or approved equivalent; place fabric flap behind core. 4" (inches) diameter perforated PVC. schedule 40 or approved alternative with minimum of 1 % gradient to proper outlet point. @ WEEP HOLE: Minimum 2" (inches) diameter placed at 20' (feet) on centers along the wall, and 3" (inches) above finished surface. (No weep holes for basement walls.) • TYPICAL RETAINING WALL BACKFILL AND DRAINAGE DETAIL DETAIL 1 Geotechnical • Geologic • Environmental I I I I I I I I I I I I I I I I I I I DETAILS N . T . S . 2 Native Backfill Slope or Level Native Backfill ®waterproofing Membrane (optional)· @ Weep Hole @ Filter Fabric Finished Surface @ Pipe . · (!) WATERPROOFING MEMBRANE (optional): Liquid boot or approved equivalent. @ DRAIN: Miradrain 6000 or J-drain 200 or equivalent for non-waterproofed walls. Miradrain 6200 or J-drain 200 or equivalent for waterproofed walls. @ FILTER FABRIC: @ PIPE: Mirafi 140N or approved equivalent; place fabric flap behind care. 4" (inches) diameter perforated PVC. schedule 40 or approved alternative with minimum of 1 % gradient to proper outlet point. @WEEP HOLE: Minimum 2" (inches) diameter placed at 20' (feet) on centers along the wall, and 3" (inches) above finished surface. (No weep holes for basement walls.) • RETAINING WALL BACKFILL AND SUBDRAIN DETAIL GEOTEXTILE DRAIN DETAIL 2 Geotechnical • Geologic • Environmental I I I I I 1. I I I I I I I I I I I I I H DETAILS N . T . S . 2 Native Backfill Provide Surface Drainage .±12" ® Weep Hole Finished Surface H / 2 min . <D Waterproofing Membrane (optional) @ Filter Fabric : © Roe Heel Width (i) WATERPROOFING MEMBRANE (optional): Liquid boot or approved equivalent. @ CLEAN SAND BACKFILL: Slope or Level Must have sand equivalent value of 30 or greater; can be densified by water jetting. @ FILTER FABRIC: Mirafi 140N or approved equivalent. © ROCK: 1 cubic foot per linear feet of pipe or 3/4 to 1-1/2" (inches) rock .• @ PIPE: 4" (inches) diameter perforated PVC. schedule 40 or approved alternative with minimum of 1 % gradient to proper outlet point. · @WEEP HOLE: Minimum 2" (inches) diameter placed at 20' (feet) on centers along the wall, and 3" (inches) above finished surfa~e. (No weep holes for basement walls.) • RETAINING WALL AND SUBDRAIN DETAIL CLEAN SAND BACKFILL DETAIL 3 Geotechnical • Geologic • Environmental I I I I I I I I I I I I I I I I I I I a) A minimum of a 2-foot overexcavation and recompaction of cut materials for a distance of 2H, from the point of transition. b) Increase of the amount of reinforcing steel and wall detailing (i.e., expansion joints or crack control joints) such that a angular distortion of 1 /360 for a distance of 2H on either side of the transition may be accommodated. Expansion joints should be placed no greater than 20 feet on-center, in accordance with the structural engineer's/wall designer's recommendations, regardless of whether or nottransition conditions exist. Expansion joints should be sealed with a flexible, non-shrink grout. c) Embed the footings entirely into native formatibnal material (i.e., deepened footings). If transitions from cut to fill transect the wall footing alignment at an angle of less than 45 degrees (plan view), then the designer should follow recommendation "a" (above) and until such transition is between 45 and 90 degrees to the .wall alignment. TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS AND EXPANSIVE SOILS Expansive Soils and Slope Creep Soils at the site are likely to be expansive and therefore, become desiccated when allowed to dry. Such soils are susceptible to surficial slope creep, especially with seasonal changes in moisture content. Typically in southern California, during the hot and dry summer period, these soils become desiccated and shrink, thereby developing surface cracks. The extent and depth of these shrinkage cracks depend on many factors such as the nature and expansivity of the soils, temperature and humidity, and extraction of moisture from surface soils by plants and roots. When seasorial rains occur, water percolates into the cracks and fissures, causing slope surfaces to expand, with a corresponding loss in soil density and shear strength near the slope surface. With the passage of time and several moisture cycles, the outer 3 to 5 feet of slope materials experience a very slow, but progressive,··outward and downward movement, known as slope creep. For slope heights greater than 10 feet, this creep related soil·movement will typically impact all rear yard flatwork and other secondary improvements that are located within about 15 feet from the top of slopes, such as swimming pools, concrete flatwork, etc., and in particular top of slope fences/walls. This influence is normally in the form of detrimental settlement, and tilting of the proposed improvements. The dessication/swelling and creep discussed above continues over the life of the improvements, and generally becomes progressively worse. Accordingly, the developer should provide this information to any homeowners and homeowners association. Top of Slope Walls/Fences Due to the potential for slope creep for slopes higher than about 1 O feet, some settlement and tilting of the walls/fence with the corresponding distresses, should be expected. To Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 31 I I I I I I I I I I I I I I I I I I I mitigate the tilting of top of slope walls/fences, we recommend that the walls/fences be constructed on a combination of grade beam and caisson foundations. The grade beam should be at a minimum of 12 inches by 12 inches in cross section, supported by drilled caissons, 12 inches minimum in diameter, placed at a maximum spacing of 6 feet on center, and with a minimum embedment length of 7 feet below the bottom of the grade beam. The strength of the concrete and grout should be evaluated by the structural engineer of record. The proper ASTM tests for the concrete and mortar should be provided along with the slump quantities. The concrete used should be appropriate to mitigate sulfate corrosion, as warranted. The design of the grade beam and caissons should be in accordance with the recommendations of the project structural engineer, and include the utilization of the following geotechnicaf parameters: Creep Zone: 5-foot vertical zone below the slope face and projected upward parallel to the slope face. Creep Load: The creep load projected on the area of the grade beam should be taken as an equivalent fluid approach, having a density of 60 pcf. For the caisson, it should be taken as a uniform 900 pounds per linear foot of caisson's depth, located above the creep zone. Point of Fixity: Located a distance of 1.5 times the caisson's diameter, below the creep zone. Passive Resistance: Passive earth pressure of 300 psf per foot of depth per foot of caisson diameter,. to a maximum value of 4,500 psf may be used to determine caisson depth and spacing, provided that they meet or exceed the minimum requirements stated above. To determine the total lateral resistance, the contribution of the creep prone zone above the point of fixity, to passive resistance, should be disregarded. Allowable Axial Capacity: Shaft capacity: 350 psf applied below the point of fixity over the surface area of the shaft. Tip capacity: 4,500 psf. EXPANSIVE SOILS, DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS The soil materials on site are likely to be expansive. The effects of expansive soils are cumulative, and typically occur over the lifetime of any improvements. On relatively level areas, when the soils are allowed to dry, the dessication and swelling process tends to Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 32 I I I 1. I I I I I I I I I I I I I I I cause heaving and distress to flatwork and other improvements. The resulting potential for distress to improvements may be reduced, but not totally eliminated. To that end, it is recommended that the developer should notify any homeowners or homeowners association of this long-term potential for distress. To reduce the likelihood of distress, the following recommendations are presented for all exterior flatwork: 1. 2. 3. 4. 5. The subgrade area for concrete slabs should be compacted to achieve a minimum 90 percent relative compaction, and then be presoaked to 2 to 3 percentage points above (or 125 percent of) the soils' optimum moisture content, to a depth of 18 inches below subgrade elevation. The moisture content of the subgrade should be verified within 72 hours prior to pouring concrete. Concrete slabs should be cast over a relatively non-yielding surface, consisting of a 4-inch layer of crushed rock, gravel, or clean sand, that should be compacted and level prior to pouring concrete. The layer should wet-down completely prior to pouring concrete, to minimize loss of concrete moisture to the surrounding earth materials. Exterior slabs should be a minimum of 4 inches thick. Driveway slabs and approaches should additionally have a thickened edge {12 inches) adjacent to all landscape areas, to help impede infiltration of landscape water under the slab. The use of transverse and longitudinal control joints are recommended to help control slab cracking due to concrete shrinkage or expansion. Two ways to mitigate such cracking are: a) add a sufficient amount of reinforcing steel, increasing tensile strength of the slab; and, b) provide an adequate amount of control and/or expansion joints to accommodate anticipated concrete shrinkage and expansion. In order to reduce the potential for unsightly cracks, slabs should be reinforced at mid-height with a minimum of No. 3 bars placed at 18 inches on center, in each direction. The exterior slabs should be scored or saw cut, % to 3/a inches deep, often enough so that no section is greater than 1 O feet by 1 o feet. For sidewalks or narrow slabs, control joints should be provided at intervals of every 6 feet. The slabs should be separated from the foundations and sidewalks with expansion joint filler material. No traffic should be allowed upon the newly poured concrete slabs until they have been properly cured to within 75 percent of design strength. Concrete compression strength should be a minimum of 2,500 psi. 6. Driveways, sidewalks, and patio slabs adjacent to the house-should be separated from the house with thick expansion joint filler material. In areas directly adjacent to a continuous source of moisture (i.e., irrigation, planters, etc.), all joints should be additionally sealed with flexible mastic. Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 33 I I I I I I I I I I I I I I I I I I I 7. Planters and walls should not be tied to the house. 8. Overhang structures should be supported on the slabs, or structurally designed with continuous footings tied in at least two directions. 9. Any masonry landscape walls that are to be constructed throughout the property should be grouted and articulated in segments no more than 20 feet long: These segments should be keyed or doweled together. 10. Utilities should be enclosed within a closed utilidor (vault) or designed with flexible connections to accommodate differential settlement and expansive soil conditions. 1-1 . Positive site drainage should be maintained at all times .. Finish grade on the lots should provide a minimum of 1 to 2 percent fall to the street, as indicated herein. It should be kept in mind that drainage reversals could occur, including post-construction settlement, if relatively flat yard drainage gradients are not periodically maintained by _the homeowner or homeowners association. 12. Due to expansive soils, air conditioning (NC) units should be supported by slabs that are incorporated into the building foundation or constructed on a rigid slab with flexible couplings for plumbing and electrical lines. NC waste water lines should be drained to a suitable non-erosive outlet. 13. Shrinkage cracks could become excessive if proper finishing and curing practices are not followed. Finishing and curing practices should be performed per the . Portland Cement Association Guidelines. Mix design should incorporate rate of curing for climate and time of year, sulfate content of soils, corrosion potential of soils, and fertilizers used on site. DEVELOPMENT CRITERIA Slope Deformation Compacted fill slopes designf3d using customary factors of safety for gross or surficial stability and constructed in general accordance with the design specifications should be . expected to undergo some differential vertical heave or settlement in combination with differential lateral movement in the out-of-slope direction, after grading. This post-construction movement occurs in two forms: slope creep, and lateral fill extension (LFE). Slope creep is caused by alternate wetting and drying of the fill soils which results in slow downslope movement. This type of movement is expected to occur throughout the life of the slope, and is anticipated to potentially affect improvements or structures (i.e., separations and/or cracking), placed near the top-of-slope, up to a maximum distance of approximately 15 feet from the top-of-slope, depending on the slope height. This movement generally results in rotation and differential settlement ofimprovements located Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460~A-SC September 27, 2004 Page 34 I I I I I I I I I I I I I I I I I I I within the creep zone. LFE occurs due to deep wetting from irrigation and rainfall on slopes comprised of expansive materials. Although some movement should be expected, long-term movement from this source may be minimized, but not eliminated, by placing the fill throughout the slope region, wet of the fill's optimum moisture content. It is generally not practical to attempt to eliminate the effects of either slope creep or LFE. Suitable mitigative measures to reduce the potential of lateral deformation typically include: setback of improvements from the slope faces (per the 1997 UBC and/or California Building Code), positive structural separations (i.e., joints) between improvements, and stiffening and deepening of foundations. All of these measures are recommended for · design of structures and improvements. The ramifications of the above conditions, and recommendations for mitigation, should be provided to each homeowner and/or any homeowners association. Slope Maintenance and Planting Water has been shown to weaken the inherent strength of all earth materials. Slope stability is significantly reduced by overly wet conditions. Positive surface drainage away from slopes should be maintained and only the amount of irrigation necessary to sustain plant life should be provided for planted slopes. Over-watering should be avoided as it can adversely affect site improvements, and cause perched groundwater conditions. Graded slopes constructed utilizing onsite materials would be erosive. Eroded debris may be minimized and surficial slope stability enhanced by establishing and maintaining a suitable vegetation cover soon after construction. Compaction to the face of fill slopes would tend to minimize short-term erosion until vegetation is established. Plants selected for landscaping should be light weight, deep rooted types that require little water and are capable of surviving the prevailing climate. Jute-type matting or other fibrous covers may aid in allowing the establishment of a sparse plant cover. Utilizing plants other than those recommended above will increase the potential for perched water, staining, mold, etc., to develop. A rodent control program to prevent burrowing should , be implemented. Irrigation of natural (ungraded) slope areas is generally not recommended. These recommendations regarding plant type, irrigation practices, and rodent control should be provided to each homeowner. Over-steepening of slopes should be avoided during building construction activities and landscaping .. Drainage Adequate lot surface drainage is a very important factor in reducing the likelihood of adverse performance offoundations, hardscape, and slopes. Surface drainage should be sufficient to prevent ponding of water anywhere on a lot, and especially near structures and tops of slopes. Lot surface drainage should be carefully taken into consideration during fine grading, landscaping, and building construction. Therefore, care should be taken that future landscaping or construction activities do not create adverse drainage conditions. Positive site drainage within lots and common areas should be provided and maintained at all times. Drainage should not flow uncontrolled down any descending slope. Water Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 35 I I I I I I I I I I I I I I I I I I I should be directed away from foundations and not allowed to pond and/or seep into the ground. In general, the area within 5 feet around a structure should slope away from the structure. We recommend that unpaved lawn and landscape areas have a minimum gradient of 1 percent sloping away from structures, and whenever possible, should be above adjacent paved areas. Consideration should be given to avoiding construction of planters adjacent to structures (buildings, pools, spas, etc.). Pad drainage should be directed toward the street or other approved area(s). Although not ~ geotechnical requirement, roof gutters, down spouts, or other appropriate means may be utilized to control roof drainage. Down spouts, or drainage devices should outlet a minimum of 5 feet from structures or into a subsurface drainage system. Areas of seepage may develop due to irrigation or heavy rainfall, and should be anticipated. Minimizing irrigation will lessen this potentiaL If areas of seepage develop, recommendations for minimizing this effect could be provided upon request. Toe of Slope Drains/Toe Drains Where significant slopes intersect pad areas, surface drainage down the slope allows for some seepage into the subsurface materials, sometimes creating conditions causing or contributing to perched and/or ponded water. Toe of slope/toe drains may be beneficial in the mitigation of this condition due to surface drainage. The general criteria to be utilized by the design engineer for evaluating the need for this type of drain is as follows: • • • • • • Is there a source of irrigation above or on the slope that could contribute to saturation of soil at the base of the slope? Are the slopes hard rock and/or impermeable, or relatively permeable, or; do the slopes already have or are they proposed to have subdrains (i.e., stabilization fills, etc.)? Was the lot at the base of the slope overexcavated or is it proposed to be overexcavated? Overexcavated lots located at the base of a slope could accumulate subsurface water along the base _of the fill cap. · Are the slopes north facing? North facing slopes tend to receive less sunlight (less evaporation) relative to south facing slopes and are more exposed to the currently prevailing seasonal storm tracks. · What is the slope height? It has been our experience that slopes with heights in excess of approximately 1 O feet tend to have more problems due to storm runoff and irrigation than slopes of a lesser height. Do the slopes "toe out" into a residential lot or a lot where perched or ponded water may adversely impact its proposed use? Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 36 I I I I I I I I I I I I I I I I I I I Based on these general criteria, the construction of toe drains may be considered by the design engineer along the toe of slopes, or at retaining walls in slopes, descending to the rear of such lots. Following are Detail 4 (Schematic Toe Drain Detail) and Detail 5 (Subdrain Along Retaining Wall Detail). Other drains may be warranted due to unforeseen conditions, homeowner irrigation, or other circumstances. Where drains are constructed during grading, including subdrains, the locations/elevations of such drains should be surveyed, and recorded on the final as-built grading plans by the design engineer. It is recommended that the above be disclosed to all interested parties, including homeowners and any homeowners association. Erosion Control Cut and fill slopes will be subject to surficial erosion during and after grading. Onsite earth materials have a moderate to high erosion potential. Consideration should be given to providing hay bales and silt fences for the temporary control of surface water, from a geotechnical viewpoint. Landscape Maintenance Only the amount of irrigation necessary to sustain plant life should be provided. Over-watering the landscape areas will adversely affect proposed site improvements. We would recommend that any proposed open~bottom planters adjacent to proposed structures be eliminated for a minimum distance of 1 O feet. As an alternative, closed-bottom type planters could be utilized. An outlet placed in the bottom of the planter, could be installed to direct drainage away from structures or any exterior concrete flatwork. If planters are constructed adjacent to structures, the sides and bottom of the planter should be provided with a moisture barrier to prevent penetration of irrigation water into the subgrade. Provisions should be made to drain the excess irrigation water from the planters without saturating the subgrade below or adjacent to the planters. Graded slope areas should be planted with drought resistant vegetation. Consideration should be given to the type of vegetation chosen and their potential effect upon surface improvements (i.e., some trees will have an effect on concrete flatwork with their extensive root systems). From a geotechnical standpoint leaching is not recommended for establishing landscaping. If the surface soils are processed for the purpose of adding amendments, they should be recompacted to 90 percent minimum relative compaction. Gutters and Downspouts As previously discussed in the drainage section, the installation of gutters and downspouts should be considered to collect roof water that may otherwise infiltrate the soils adjacent to the structures. If utilized, the downspouts should be drained into PVC collector pipes or non-erosive devices that will carry the water away from the house. Downspouts and gutters are not a requirement; however, from a geotechnical viewpoint, provided that positive drainage is incorporated into project design (as discussed previously). Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 37 I I I I I I I I I I I I I I I I I I I DETAILS N . T . S . SCHEMATIC TOE DRAIN DETAIL Drain Pipe Drain May Be Constructed into, or at, the Toe of Slope • 12" Minimum 24" Minimum NOTES: 1.) Soil Cap Compacted to 90 Percent Relative Compaction. 2.) Permeable Material May Be Gravel Wrapped in Filter Fabric (Mirafi 140N or Equivalent). 3.) 4-lnch Diameter Perforated Pipe (SDR 35 or Equivalent) with Perforations Down. 4.) Pipe to Maintain a Minimum 1 Percent Fall. 5.) Concrete Cutoff Wall to be Provided at Transition to Solid Outlet Pipe. 6.) Solid Outlet Pipe to Drain to Approved Area. 7.) Cleanouts are Recommended at Each Property Line; SCHEMATIC TOE DRAIN DETAIL DETAIL 4 Geotechnical • Coastal • Geologic• Environmental ;I '• i! ! . ~ ,.-,, .,, :'I· :~ ' f \'ti-( .:: I I :·.1 1' :71 ,,.;;· ·I. I I .. :I I r .'t ---,r,··/"I' \. ·"''""-'~ •'' •'! • DETAILS N. T. S .. 2:1 SLOPE (TYPICAL).~ ! . ' RETAl~INGWALL ~ 12" MIN • I ' MIRAFI 140 FILTER FABRIC FINISHED GRA~E \ OR EQUAL 3/4' CRUSHED GRAVEL 4" DRAIN ..... .. 12 . . .. . ' SUBDRAIN ALONG RETAINING WALL DETAIL NOTTO SCALE I-. '. 1.) So_il Cap Compacted to 90 Percent • R~lative Compaction. 2.).Permeable Material May Be Gravel . · Wrapped in Filter Fabric (Mir~fi 140N , ' . or Equivalent). · 3.) 4-lnch Diameter Perforated Pipe ,. (SDR-35 of Equivalent) with .. Perforations Down. t 4.) Pipe to Maintain a Minimum 1 · Percent Fall. • 5.) C~ncrete Cutoff Wall to be Provided 'at Transition to ~olid Outlet Pipe. I' • 6.) Solid Outlet Pipe to ~rain t~ , Approved Area. · "7.) Cleanouts are Recommended at ' · Each Property Line: . · · · 8.) Compacted Effort Sho~ld Be Applied to Drain Rock.' · ' . ' I'. '. •i . \ SUBDRAIN ALONG RETAININ_G WALL-DETAIL • 'DETAIL 5 iii::/~ ~ ,, ... , . _. , Ge.~t~~h-~ica~·•.,,Coa~1~ •. ~e:~fcwic • En~~ironmental l~:t.~.....;· ~:;.;.~ ,.'.;;;..11 -~~-•. .,-... ,.-., -, .--.. --,--. -.-, __ ..;;. ,LC<·-.-, ---.-"'--·-~ ·: -. ' ___ ...... '-.--.,_..;,..,;...1..;..·,--.,.-,-;,;..;..·_.;.;.,._.;..;.,, -_, ~t~-.11. --......... ~ .... --. -.. -=-=~-.. --~."~~,.,--~-., .-. -.•• ~-·'_ili:-, •• ~-,, --.•• --. --.. --. ..... ' ' .-· ~~~·~::·~:i~'!. .. ~-~ ... ·.;,L_ ... ~Ci'.i ~ •-i.~~-··~~,,i~~-~-~~2: ~.;1~~,·i~·~,.:-·_~J:·~t:.:L~-n1r:~.:~:&.~'Y .... ,.-.. ,.,raec·JM:dt:M:¥:'IMPf, .~:~:!--..-~.:A:,~_, ... ; "i~~ >~f}J I I I I I I I I I I I- I I I I I I I I Subsurface and Surface Water Subsurface and surface water are not anticipated to affect site development, provided that the recommendations contained in this report are incorporated into final design and construction and that prudent surface and subsurface drainage practices are incorporated into the construction plans. Perched groundwater conditions along zones of contrasting permeabilities may not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities, and should be anticipated. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. Groundwater conditions may change with the introduction of irrigation, rainfall, or other factors. Site Improvements Recommendations for exterior concrete flatwork design and construction can be provided upon request. If in the future, any additional improvements (e.g., pools, spas, etc.) are planned for the site, recommendations concerning the geological or geotechnical aspects of design and construction of said improvements could be provided upon request. This office should be notified in -advance of any fill placement, grading of the site, or trench backfilling after rough grading has been completed. This includes any grading, utility trench, and retaining wall backfills. Tile Flooring Tile flooring can crack, reflecting cracks in the concrete slab below the tile, although small cracks in a conventional slab may not be significant. Therefore, the designer should consider additional steel reinforcement for concrete slabs-on-grade where tile will be placed. The tile installer should consider installation methods that reduce possible cracking of the tile such as slipsheets. Slipsheets or a vinyl crack isolation membrane (approved by the Tile Council of America/Ceramic Tile Institute) are recommended between tile and concrete slabs on grade. Additional Grading This office should be notified in advance of any fill placement, supplemental regrading of the site, or trench backfilling after rough grading has been completed. This includes completion of grading in the street and parking areas and utility trench and retaining wall backfills. Footing Trench Excavation All footing excavations should be observed by a representative of this firm subsequent to trenching and prior to concrete form and reinforcement placement. The purpose of the observations is to verify that the excavations are made into the recommended bearing material and to the minimum widths and depths recommended for construction. If loose Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 40 I I I I I I I I I I I I 1· I I I I I I or compressible materials are exposed within the footing excavation, a deeper footing or removal and recompaction ofthe subgrade materials would be recommended atthat time. Footing trench spoil and any excess soils generated from utility trench excavations should be compacted to a minimum relative compaction of 90 percent, if not removed frqm the site. Trenching Considering the nature of the onsite soils, it should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the trench walls at the angle of repose {typically 25 to 45 degrees) may be necessary and should be anticipated. All excavations should be observed by one of our representatives and minimally conform to CAL-OSHA and local safety codes. Utility Trench Backfill 1 . All interior utility trench backfill should be brought to at least 2 percent above optimum moisture content and then compacted to obtain a minimum relative compaction of 90 percent of the laboratory standard. As an alternative for shallow (12-inch to 18-inch) under-slab trenches, sand having a sand equivalent value of 30 or greater may be utilized and jetted or flooded into place. Observation, probing. and testing should be provided to verify the desired results. 2. 3. 4. Exterior trenches adjacent to, and within areas extending below a 1 :1 plane projected from the outside bottom· edge of the footing, and all trenches beneath hardscape features and in slopes, should be compacted to at least 90 percent of the laboratory standard. Sand backfill, unless excavated from the trench, should not be used in these backfill areas. Compaction testing and observations, along with probing, should be accomplished to verify the desir~d results. All trench excavations should conform to CAL-OSHA and local safety codes. Utilities crossing grade beams, perimeter beams, or footings should either pass below the footing or grade beam utilizing a hardened collar or foam spacer, or pass through the footing or grade beam in accordance with the recommendations of the structural engineer. Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 41 I I I I I I I 1· I I I I I I I I I I I SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING We recommend that observation and/or testing be performed by GSI at each of the following construction stages: • • • • • • • • • • During grading/recertification . During significant excavation . During placement of subdrains, toe drains, or other subdrainage devices, prior to placing fill and/or backfill. After excavation of building footings, retaining wall footings, and free standing walls footings, prior to the placement of reinforcing steel or concrete. Prior to pouring any slabs or flatwork, after presoaking/presaturation of building pads and other flatwork subgrade, before the placement of concrete, reinforcing steel, capillary break (i.e., sand, pea-gravel, etc.), or vapor barriers (i.e., visqueen, etc.). During retaining wall subdrain installation, prior to backfill placement. During placement of backfill for area drain, interior plumbing, utility line trenches, and retaining wall backfill. During slope construction/repair. When any unusual soil conditions are encountered during any construction operations, subsequent to the issuance of this report. When any developer or homeowner improvements, such as flatwork, spas, pools, walls, etc., are constructed. • A report of geotechnical observation and testing should be provided at the conclusion of each of the above stages, in order to provide concise and clear documentation of site work, and/or to comply with code requirements. OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer, structural engineer, post-tension designer, architect, landscape architect, wall designer, etc., should review the recommendations provided herein, incorporate those recommendations into all their respective plans, and by explicit reference, make this report part of their project plans. In order to mitigate potential Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page 42 I I I I I I I I I I I I I I I I I I I distress, the foundation and/or improvement's designer should confirm to GSI and the governing agency, in writing, that the proposed foundations and/or improvements can tolerate the amount of differential settlement and/or expansion characteristics and design criteria specified herein. PLAN REVIEW Final project plans should be reviewed by this office prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Based on our review, supplemental recommendations and/or further geotechnical studies may be warranted. LIMITATIONS The materials encountered on the project site and utilized for our analysis are believed representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors.· Inasmuch as our study is based upon our review and engineering analyses and laboratory data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty is expressed or implied. Standards of practice are subject to change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction; or work performed when GSI is not requested to be onsite, to evaluate if our recommendations have been properly implemented. Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place. In addition, this report may be subject to review by the controlling authorities. Thus, this report brings to completion our scope of services for this project. Karnak Planning and Design, Inc. Romeria Pointe, Carlsbad File:e:\wp9\4400\4460a.pge W.O. 4460-A-SC September 27, 2004 Page43 I I I I I I I I I I I I I I I I I I I APPENDIX A REFERENCES I I I I I I I I I I I I I I I I I I I APPENDIX A REFERENCES Blake, Thomas F., 2000a, EQFAULT, A computer program for the estimation of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version. __ , 2000b, EQSEARCH, A computer program for the estimation of peak horizontal acceleration from California historical earthquake catalogs; Updated to December 2002, Windows 95/98 version. __ , 2000c, FRISKSP, A computer program for the probabilistic estimation of peak acceleration and uniform hazard spectra using 3-D faults as earthquake sources; Windows 95/98 version. Bozorgnia, Y., Campbell K.W., and Niazi, M., 1999, Vertical ground motion: Characteristics, relationship with horizontal component, and building-code implications; Proceedings of the SMIP99 seminar on utilization of strong-motion data, Oakland, pp. 23-49, September 15. Campbell, K.W. and Bozorgnia, Y., 1997, Attenuation relations for soft rock conditions; in EQFAULT, A computer program for the estimation of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version, Blake, 2000a. East. County Soil Consultation and Engineering, Inc., 2001, Limited site investigation, Proposed 4-unit townhouse, Southwest corner of Gibraltar Street and Rorileria Street, City of Carlsbad, California, Project no. 01-1147H1, dated May 10. Hart, E.W. and Bryant, W.A., 1997, Fault-rupture hazard zones in California, Alquist-Priolo earthquake fault zoning act with index to earthquake fault zones maps; California Division of Mines &nd Geology . Special..· Publication 42, · with Supplements 1 and 2, 1999 .. International Conference of Building Officials, 1997, Uniform building code: Whittier, · California, vol. 1, 2, and 3. JNL Consulting Civil Engineers, Inc., 2003, Conceptual grading plan for nine lots, Condominium at Lots 392 and 393 of La Costa South unit no. 5, APN # 216-300-12, 13, 10-scale, No drawing no. No job no. dated June 11. Jennil"!gs; C.W., 1994, Fault activity map of California and adjacent areas: California Division of Mines and.Geology, Map sheet no. 6, Scale 1 :750,000. Joyner, W.B, and Boore, D.M., 1982a, Estimation.of response-spectral values as functions of magnitude, distance and site conditions, in eds., Johnson, J.A., Campbell, K.W., and _Blake, T.F.: AEG Short Course, Seismic Hazard Analysis, June 18,.1994. I I I 1. I I I I I I I I I I I I I I I __ , 1982b, Prediction .of earthquake response spectra, ·u.s. Geological SuNey Open-File Report 82-977, 16p. Kennedy, M.P. and Tan S.S., 1996, Geologic maps of the northwest part of San Diego County, California., Division of Mines and Geology, Plate 2, scale 1 :24,000. Krinitzsky, E.L.; Gould, J.P., and Edinger, P.H., 1993, Fundamentals of earthquake resistant construction: John H. Wiley & Sons, Inc., 299 p. Soil Pacific Inc., 2003, Addendum report and clarification letter, proposed nine unit condominium, Lots 392 and 393 of [La) Costa South, Unit no. 5, City of Carlsbad, California, Project no. A-2452-03, dated August 25. Sowers and Sowers, 1970, Unified soil classification system (After U. S. Waterways Experiment Station and ASTM 02487-667) in Introductory Soil Mechanics, New York. Taniguchi, E., and Sasaki, Y., 1986, Back analysis of landslide due to Naganoken Seibu Earthquake of September 14, 1984; Proceedings, XI ISSMFE Conference, Session 78, San Francisco, California. Rolla, MO: University of Missouri. Karnak Planning and Design, inc. File:e:\wp9\4400\4460a.pge Appendix A Page2 I I I I . I I I I· I I I I I I I·. I I I I APPENDIX B . BORING LOGS I I I I I I I 1· I I I I I I I I I I I GeoSoils, Inc. PROJECT: KARNAK Romeria Points, Carlsbad Sample g ~'o ~ Cl)] ~ a.. -5 J, 'O C: -.... ·-a, 3: UE ::, C. 'O.O ~ a, :'i C: ... 0 Cl) >, 0 Ill ::, .a iii ::, Cl) 0 CL SM 101.1 ush 1 "CL 113.1 1-18" CL 15 us 113.9 20 25 Romeria Points, Carlsbad 19.4 15.3 17.0 C: 0 ;:, e! .a m Cl) 81.0 87.9 99.7 BORING LOG W.O. 4460-A-SC BORING B-1 SHEET_1_ OF 1 DATE EXCAVATED 8-12-04 SAMPLE METHOD: NEED TO FIND OUT .'"'('°'.· ,;.,,.,· -~·. ·..;r..· . . ;,,,,,,-,..· -~·. ·..;,-.·. . '<' .. . :.,...:...· ·,.;,:,,·, Standard Penetration Test "Sl.. Groundwater Undisturbed, Ring Sample Description of Material ARTIFICIAL FILL: @ O' SANDY CLAY, gray brown, dry, soft; porous, non-uniform. @ 1' SANDY CLAY, olive gray to brown to dark brown, damp to moist, medium stiff; oversize rock {12") encountered@ 2', non-uniform. @ 5' SIL TY SAND, yellow brown to gray brown, moist, medium dense; non-uniform. @ 1 O' SANDY CLAY, yellow brown to gray brown, moist, stiff; non-uniform. TERTIARY SANTIAGO FORMATION: @ 11 Yz' SANDY CLA YSTONE, dark gray brown to brown, moist, medium stiff to stiff. @ 15' SANDY CLA YSTONE, medium brown, moist, very stiff to CLAYEY SAND, yellow brown to gray to dark gray brown to orange, moist, dense; abundant angular pebble-to cobble-size clasts. Practical Refusal Due to Oversize Rock @ 16Yz' No Groundwater/Caving Encountered Backfilled 8-12-2004 GeoSoils, Inc. PLATE B-1 I I BORING LOG GeoSoils, Inc. w.o. 4460-A-SC I PROJECT: KARNAK BORING B-2 SHEET_ OF~ Romeria Points, Carlsbad I DATE EXCAVATED 8~12-04 Sample SAMPLE METHOD: NEED TO FIND OUT I Ill Standard Penetration Test ~'£' ~ ~ "S/.-Groundwater -0 C: ~ Undisturbed, Ring Sample s. I!! 0 E Cl) :g :!:O C. ~ I .~i C: -.a = U) :::> C. _,., -o.o 3: UE U) :, Q) :i C: ... 0 Cl) >, ~ 0 iii Description of Material 0 CD :::> .a iij :>Cl) 0 :::E Cl) CL ARTIFICIAL FILL: I @ O' SANDY CLAY, brown, dry, soft; porous, occasional pebble- to cobble-size clasts (subrounded to subangular), non-uniform. @2' SANDY CLAY, brown, moist, medium stiff; occasional I subangular cobble-to boulder-size clasts, non-uniform. 5 @ 5' SANDY CLAY, brown to dark brown, moist to wet, medium I stiff; occasional to abundant subangular cobble-to boulder-size clasts, non-uniform. I 10 104.1 20.8 93.7 @ 10' SANDY CLAY, yellow brown to gray, moist, soft to I medium stiff; occasional subrounded cobble-size clasts, non-uniform. I 15 M/C 111.9 14.2 79.0 @ 15' SIL TY SAND, yellow brown, moist, medium dense to I SANDY-CLAY, gray to brown, rnoist, stiff; non-uniform. I 20 Push 6 CL 110.9 17.8 96.0 @ 20' SANDY CLAY, olive gray, moist, stiff, non-uniform. I /1 I CL TERTIARY DELMAR FORMATION {REPROCESSED}: 25 @24' SANDY CLAYSTONE, dark gray brown to brown, moist, I 111.4 18.3 100.0 medium stiff· or anic odor subhorizontal contact. @ 25' SANDY CLAYSTONE, orange to gray, moist, stiff. I SM .~.· @ 29' SIL TY SANDSTONE w/GRAVEL, brown, moist to wet, . c.r .. I Romeria Points, Carlsbad GeoSoils, .Inc. PLATE B-2 I I I I I I I I I I I I I I I I I I I GeoSoils, Inc. PROJECT: KARNAK Romeria Points, Carlsbad Sample -~'fi" IE. ~ en o ~ Cl. -~i c~ :5 .,. 3: u.a ::::, a. 3 "C .a 0 en [ ~ Cl> C .._ Q in ::::, .3 iii ::>(I) 0 CL - - SW SM 35 ~ 8 CL 101.9 - - - - 40 ~ 12 SM 116.2 - - - - 45- - - - - 50- - - - - 55- - - - - Romeria Points, Carlsbad BORING LOG W.O. 4460-A-SC BORING B-2 SHEET~ OF~ DA TE EXCAVATED 8-12-04 SAMPLE METHOD: NEED TO FIND OUT ~ Standard Penetration Test -C. "SJ_ Groundwater ~ C ~ Undisturbed, Ring Sample !!! 0 ;, .3 e! UJ ::, 0 iii Description of Material :E en \ dense. I @ 30' SANDY CLAYSTONE w/GRAVEL, brown, moist to wet, dense; abundant rounded cobble-size clasts. . .. .. @ 33' Grades to SANDSTONE w/GRAVEL, brown, damp, . . . . . . dense· abundant pebble-to cobble-size clasts. . ""'("' .. ' r .:.r .. @ 34' SIL TY SANDSTONE w/CLAY, gray to orange, moist, ... 18.1 76.9 dense· weak subhorizontal beddina caliche. ! @ 35' CLAYEY SANDSTONE, gray, moist, very dense; occasional subangular cobble-size clasts, weak subhorizontal bedding. 13.6 85.1 .'-('°.· @ 40' SIL TY SANDSTONE, gray brown, damp, very dense. . :.r .. . . . ':-J"":' • . . . Total Depth= 41%' No Groundwater/Caving Encountered Backfilled 8-12-2004 GeoSoils, Inc. PLATE . B-3 I· I I I I I I I I I I I I I I I I I. I APPENDIX C . . . . EQFAULT, EQSEARCH, AND FRISKSP I I I MAXIMUM EARTHQUAKES I KARNAK I I I 1 I X X X I .-.. X en ..__. X I C: .1 ~ 0 ·-.... <U "" , I Q) -Q) CJ I CJ <C I .01 I I I .001· .,1 1 10 100 I Distance (mi) I W .0. 4460-A-SC Plate C-1 I Ge@Soils, lne .. I I I I I I I I.. m G) I > --z - I ,n ... C G) > w I -0 I.. G) .c I E :::J z G) I > .:= m -:::J E I E :::J 0 I I I I I I 100 10 1 .1 .01 .001 EARTHQUAKE RECURRENCE CURVE KARNAK .. ~ . . -.._. ........... 1 ........ ...... ~ 4 --•• ...... 0 •• I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I. 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 Magnitude (M) W .0. 4460-A-SC Plate C-2 I I I I I I I I I I I I I I I I I I I 1000 900 800 700 600 500 400 . 300 200 100 0 LEGEND X M=4 Q M=S 0 M=6 EARTHQUAKE EPICENTER MAP KARNAK -100-+-<-1....J'-'-~-'---'---'-+...L...J-L-J'-+-.L.....L-..___._+-L ............ ~_._L.L..L.+-..1......L....._.,4-l:lC..l....;L..a-~-'----L...J...-+-'-'-'-'--I -400 -300 -200 -100 0 100 200 300 400 500 600 . W .0. 4460-A-SC Plate C-3 I I I I I I I I I I I I I I I I I I I ..-,... ·o ~ ..__ >a ..... ·--·-.c m .c 0 I.a a.. (I) CJ C m "C (I) (I) CJ >< w PROBABILITY OF EXCEEDANCE BOZO ET AL.(1999)HOR SR UNC 1 100 90 80 70 60 50 40 30 20 10 0 ---- ---,---------- ------------ ' \ • l I • I 25yrs I • I 75 yrs -\~~ --- -\\ l --- -' ~~ --'hi -1 I I I • I I l I l I I • I SO yrs I _T I 100 yrs I l I l 1 I 1 I 1· 0.00 0.25 0.50 0. 75 1.00 1.25 1.50 Acceleration {g) w .0. 4460-A-SC Plate C-4 ------------------- ~ ~ ~ ~ 0 1211, a,,11 ~ .. llllllO ~ "' .. \,. ~-p .,::i. .,::i. 0) 0 I )> I "' 0 "ti iii' .... CD n. I c,, ....... Cl) ll.. >-........ "CS 0 ·-ll.. Q) a. . C .ll.. :l +" Q) a: 100000 10000 1000 100 RETURN PERIOD vs. ACCELERATION 802. ET AL.(1999)HOR SR UNC 1 --./ _.,,,,,. / / ., --/ ./ / ./ V -., ~ / ./ /f' / ~ -,r i, / ; I I -I I r II I I 1 · I I I I I I I I I I· I I I I I I I I I I - -- - I 0.00 0.25 0.50 0.75 1.00 1.25 1.50 Acceleration (g) I I I I I I APPENDIX D I LABORATORY DATA. I·" I I I I I I I I I I I· I I I I I I I I I I I I I I I I I I I 3,0001 I I I i I I 2,500 i I I 2,000 I I ' .... Ill C. J :c I-(!) z ~-w 1,500 a:: ~ I-II) ~ a:: ~ l I J: II) -~ I 1,000 ~ ~ l ~ 500 ~ 0 -0 500 . 1,000 1,500 · 2,000 2,500 3,000 NORMAL PRESSURE, psf I Sample Depth/El. Primary/Residual Shear Sample Type t MC% C <I> • B-1 0.0 Primary Shear Re molded 108.0 12.5 440 22 "" g II B-1 0.0 Residual Shear Re molded 108.0 12.5 428 22 t:! CD ... 0 ii 1/) ::, -, Note: Sample lnnundated prior to testing n. l!J 0 "' "' DIRECT SHEAR TEST "" a: GeoSoils, Inc. <( UJ 57 41 Palmer Way Project: KARNAK ; G~~I!i~~-Carlsbad, CA 92008 Telephone:. (760) 438-3155 Number: 4460-A-SC a: i5 Fax: (760) 931-0915 Date: August 2004 Plate: D-1 1/) ::, I I I I I I I I I I I I I I I I I I I ' 3,0001 I I I I i \ I I I - 2,500 . -/~ / ~ 2,000 I ~· i I ';;; // \ a. I f-CJ z w 1,500 Cl'. v· f-en a: ,/;? ~ ::c en 1,000 ~ ~ / 500 ~ --·-- . 0 0 500 1,000 · · 1,500 2,000 . 2,500 3,000 NORMAL PRESSURE, psf · Sample Depth/El. Primary/Residual Shear Sample Type y~ MC% C 4> • 8-2 35.0 Primary Shear Re molded 105.7 18.1 301 36 ... g Iii 8-2 • 35.0 Residual Shear Re molded 105.7 18.1 177 37 C? a, I-0 (!) ~ ai ! . :5 "' :::i -, Note: Sample lnnundated prior to testing a. (!) ci "' ... DIRECT SHEAR TEST ... a: GeoSoils, Inc. < w 5741 Palmer Way Project: KARNAK ~ ·:;:··,:~ .. ,:·}2 .':· ..f),~ ,_ G~Soils, ·~c. Carlsbad, CA 92008 ~ · ... ~ .. -~;f \~r:'.!i::': {j~ Telephone: (760) 438-3155 Number: 4460-A-SC a: 0 Fax: (760) 931-0915 Date: August 2004 Plate: 0-2 "' :::i I I I I I I I I I I I I I I I I I I I 60 CL CH ML MH I 0~~~~~~1~....._~~~~~~~~-----o~~~....._~~~~~----:'-~~~~~~....._~~~ 0 W ~ ~ 00 "' ::, -, 0.. Cl 0 ID .., .., e 8-1 m 8-2 Sample 100 LIQUID LIMIT Depth/El. LL PL Pl Fines Classification 0.0 43 20 23 5.0 41 20 21 1/l·t-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ... ~ GeoSoils, Inc. ~ ;7.-;_ ,tN~.,~:· 5741 PalmerWay ~ GeoSo~:Inc. Carlsbad, CA 92008 a:: ~ ··+ ·; .• -.:-·· v·.M··-:..: -~. ~:s w q,<c;.,;,· ,,4:::t1--~,-;;;, Telephone: (760) 438-3155 ATTERBERG LIMITS' RESULTS Project: KARNAK Number: 4460-A-SC S Fax: (760) 931-0915 "' Date: August 2004 ::, ______________________________________ ..,.. ____________________________________ --' Plate: 0~3 I I I I I I I I I I I I I I I I I I I 0.0 0.5 1.0 1.5 2.0 2.5 3.0 '.!-z ~ 3.5 I-U) 4.0 4.5 5.0 5.5 6.0 6.5 7.0 100 Sample ... • B-1 ~ "' al ~ C Cl a, :5 Ul ::, -, Q. C!) ci "' .., .., z ~ t:;. ... -:-~~~ r.~ ~t~ _, GeoSoi~".Inc:. 0 t,.<",:.; ···.,~, •• ··~--:.ii ·~ ~ ~-~~ \~..-,.v~ 0 u Ul ::) ... ~ -....... 11 I i \ \ I'---. I ' '-I I', I \ NI. ~~ I i : i i I \ \ I --.'--\ " ' ' \ ~ ~ ~ \ I'--- ............ \ i---... r--... r-,. 1,000 10,000 . 105 STRESS, psf Depth/El. Visual Classification t MC MC H20 Initial Initial Final 5.0 Sandy Clay 101.1 19.4 23.4 1000 GeoSoils, Inc. CONSOLIDATION TEST 5741 Palmer Way Project: KARNAK Carlsbad, CA 92008 Telephone: (760) 438-3155 Number: 4460-A-SC Fax: (760) 931-0915 Date: August 2004 Plate: D-4. I I I I I I I I I I I I I I I I I I I -0.0 - -----I I I I : I .. ......._ I'-~, l I I i ; I I ! I ! I 0.5 I', i I ! I I "'~- \ \ I \ I I 1.0 ·~ I 1.5 \ 2.0 I\ 2.5 3.0 1\ ::!! \ 0 z ~ 3.5 ... • I-" !/) ,. \ 4.0 "\. ~ \ 4.5 '\ \ ""' 5.0 ''\ \ 5.5 \ \ 6.0 ['\ I\ 6.5 ;\ I \ ~ '\ 7.0 100 1,000 10,00-0 105 STRESS, psf Sample Depth/El. Visual Classification 'Yci MC MC H20 Initial Initial Final ~ • 8-2 10.0 . Sandy Clay 104.1 20.8 20.8 1440 N ii5 ~ C c:, iri :5 "' ::, .., a. c:, c:i ~ .., CON SO LIDA TION TEST z GeoSoils, Inc. ~ :;; .~·~~'~ • ._..,"'J,·,1\ ~1,. 57 41 Palmer Way Project: KARNAK 5 ~~~,~c:. Carlsbad, CA 92008 ~ ~~ ~~ ~\ Telephone: (760) 438-3155 Number: 4460-A-SC 8 Fax: (760) 931-0915 Date: August 2004 Plate: D-5 "' ::, I I I I I I I I I I I I I I I I I I I -0.0 ---N .._ I ,.._ t---i .... h ~ I 0.5 ~~ i I I I 1.0 I'-.. I ~ ~ I I~ I\ 1.5 I\ \ 2.0 [\ ~ I\ i\ \ 2.5 '\ \ \ 3.0 ~ \ \ 0 . z ~ 3.5 I\ \ \ I-en 4.0 I\ ~ 4.5 I"\ " l's. 5.0 'N 5.5 6.0 6.5 7.0 100 1,000 10,000 STRESS, psf Sample Depth/El. Visual Classlficatlon 'Yci MC MC Initial Initial Final i e B-2 24.0 Clay 106.3 19.0 20.6 5l .... 0 (!) ai :5 "' :, .., 0.. (!) ci co ; CONSOLIDATION TEST z GeoSoils, Inc. < a: :;; -ifJ:;,:-.;. ,.~.,~ ~ 5741 Palmer Way Project: KARNAK 5 ~~~~ Carlsbad, CA 92008 ~ ~'i'!J!§ ~,r(!;.;. Telephone: (760) 438-3155 Number: 4460-A-SC 0 o Fax: (760) 931-0915 Date: August 2004 Plate: "' :, I I I I ! I ' I ' l i ! ! I ' I : I I ; I I I I ' I 1 as H20 4000 D-6 ! I I I I I I I .I I I I I I I I I I I I M. J. Schiff & Associates, Inc. Cnnsulting Corrosion Engineers -Since /959 431 W. Ba..,;eli1te Rnad Claremont, CA 91711 .Phnne: (909) 616-0967 Fax: (909) 626-3316 E-mail lab(ji)_Jnjschiff.com website: mjsc1,iff.com Table 1 -Laboratory Tests on Soil Samples S11mple ID Karnak Your #4460-A~C. M.TS&A #04-l l 70LA.B U-Aug-04 B-1 @0-2' •• .,,..,..,,.,,,,..,,_•••-••-•:--°"-••-••--•, ••• •• Noo,, , .. •, •• • o' .""' ......... •.. . . ,• !-:· ......... ,·:, .. ·:·-··8···. Resistivity .is-received. saturated pH Electrical Conductivity Chemical Analyses Cations calcium ci• magnesium Mg2• sodium Na1+ Anions carbonate C032- Units ohm-cm ohm-cm mS/cm mg/kg mg/kg mg/kg mg/l<g bicarbonate HC03 '· mg/kg chloride c1 1• mg/kg sulfate so,2• mg/kg OtherTe!lts ammonium NH/ mg/kg nitrate No'· ~ mg/kg sulfide s2· qual Redox mV 45,000 410 7.6 0.70 36 36 643 ND 311 525 617 no na na no Electrical conductivity in millisicmcns/cm and chemic.al analr-,is were made on a l :5 soil-to-water extract. mg/kg= milligrams per lcilograr.n (pamo. per million) of dry soil. · Redox = oxidation-reduction potential in millivolts ND = not detected na = not analyzed W.O. 4460-A-SC Page I of I Plate D-7 I I I I I I. 1· I I I I I I I I I I 1. I APPENDIX E ECSCEI (2001) .BORING "AND TEST PIT LOGS I I I I I I I I I I I I I I I I I I I -- LEGACY DEVELOPMENT. LLC PROJECT NO Ol-l 147Hl I s BORING NO.I N 0 I p s -L EQUIPMENT: GAS-POWERED AUGER L 0 A I C C D L L SAMPLING METIIOD: E E A p s s C= CHUNK SAMPLE D T A s B= BULK SAMPLE, R H M I y p F U= UNDISTURBED DRIVE I L I D N E C E A N F T T s E y I I E p 0 SOIL DESCRIPTION T T E N y 0 SC TAN. DAMP TO MOIST, SOFT TO MEDIUM STIFF SANDY Cl.A Y (Qsf) . . I DARK BROWN, MOIST, LOOSE TO MEDIUM DENSE, Cl.A VEY SAND . 2 . SC TAN, MOIST, SOFT TO MEDIUM STIFF SANDY CL.A Y 3 . . 4 . ' . 6 .. . 7 . g . 9 . 10 -CL SAN11AGO FORMATION (Tsa) . DARK GRA YlSH BROWN, MOIST, MEDIUM STIFF Cl.A Y II B . -12 BROWN. MOIST. MEDIUM STIFF SANDY Cl.A Y . 13 . 14 . ' IS . 16 SC-TAN MOIST. DENSE, SA."JDSTONE . SM 17 BOTIOM OF EXPLORATORY HOLE . 18 PLATE NO. 2 I I DA TE LOGGED: APRIL 12, 200 I LOGGED BY: M. DUNCAN 9 W .0. 4460-A-SC R E M L 0 A I T s I T V u E R ,. E C 0 C M 0 p N A T C E T N I T 0 N % "" Plate E-1 I I I I I I I I I I I I I I I I I I I LEGACY DEVELOPMENT, LLC PROJECT NO.01-1147Hl I s BORING NO. 2 N 0 l p s L EQUIPMENT: GAS-POWERED AUGER L 0 A I C C D L L SAMPLING METIIOD: E E A p s s C= CHUNK SAMPLE D T A s B= BULK SAMPLE, R H M l . y p F U= UNDISTURBED DRIVE I L l D N E C E A N F T T s E y . I I E p 0 SOIL DESCRIPTION T T E N y 0 -TAN, MOIST, SOFT TO MEDIUM STIFF SANDY CL.A Y (Qaf) . B I . 2 --. 3 -BROWN, MOIST, SOFT TO MEDIUM STIFF SANDY CLAY 4 . SC TAN, MOIST TO WET, LOOSE TO MEDIUM DENSE, SILTY, Cl.A YEY SAND s -6 . 7 CL GRAYISH BROWN. MOIST. SOFT TO MEDIUM STIFF SANDY CLAY . 8 . 9 . 10 CL SANTIAGO FORMATION (Tsa) . 11 DARK BROWN, MOIST, MEDIUM STIFF SANDY CLAY . 12 GRAYISH BROWN.MOIST, MEDIUM STIFF, SANDY CLAY . 13 . 14 . IS B SC-TAN MOIST, DENSE. SANDSTONE . SM 16 -BOTTOM OF EXPLORATORY HOLE . 17 . 18 PLATE NO. J I DA TE LOGGED: APRIL 12, 200 I LOGGED BY: M. DUNCAN 10 W .0. 446.0-A-SC R E M L 0 A I T s I T V u E R E C 0 C M 0 p N A T C E T N I T 0 N % ~. i I Plate E-2 I I I I I I I I I I I I I I I I I LEGACY DEVELOPMENT. LLC PROJECT NO. Ol-1147Hl I s TRENCH NO. 1 N 0 1 p s L EQUIPMENT: CASE 580 E BACKHOE L 0 A I C C D l L SAMPLING METHOD: E E A p s s U= UNDISTURBED DRIVE D T A s C= CHUNK SAMPLE R H M I y p F B= BULK SAMPLE I L I D N E C E A N F T T s E y ( I E p 0 T T E N SOIL DESCRIPTION y 0 SC TAN, DAMP TO MOIST, SOFT TO MEDIUM STIFF SANDY CL6. y WITH ORA va (Qaf) . I DARK BROWN, MOIST LOOSE TO MEDIUM DENSE, CL.A YEY SAND . 2 C lOS.8 . SC TAN, MOIST, SOFT TO MED!l."M S11fF SANDY CLAY J C 103.4 . BROWN, MOIST. SOFT TO MEDIUM STIFF, SANDY CLAY 4 -GRAYISH BROWN, MOIST, LOOSE. SIL TY. Cl.A VEY SAND s - 6 C IOS.0 -7 -g -9 BLUEISH BROWN, MOIST, LOOSE TO MEDIUM DENSE. Cl.A VEY SAND . 10 CL SANTIAGO FORMATION lT~ -DARK ORA YlSH BROWN, MOIST, MEDIUM STIFF ClA Y: BOTI'OM OF EXPLORATORY TRENCH II - 12 - 13 - 14 -lS I I . PLATE NO. 4 I I DATE LOGGED: MAY 2, 2001 LOGGEDBY:M.DUNCAN 11 W.O. 4460-A.:.SC K E M L 0 A I T-s I T V u E R E C 0 C M 0 p N A T C E T N I T 0 N % "· ' 18.7 20.2 : 18.0 Plate E-3 I I I I I I I I I I I I I I I I I I I LEGACY DEVELOPMENT. LLC PROJECT NO. OJ-1147Hl I s TRENCHN0.2 N 0 I p s L EQUIPMENT: CASE 580 E BACKHOE L 0 A I C C D L L SAMPLING METHOD: E E A p s s U= UNDISTURBED DRIVE D T A s C= CHUNK SAMPLE R H M I y p F B= BUI.I<. SAMPLE I L I D N E C E A N F T T s E y l I E p 0 T T E N SOIL DESCRIPTION y 0 SC TAN, DAMP TO MOIST, SOFT TO MEDIUM S11FF SANDY Cl.A Y (Qaf) - I - 2 ~ 3 -BROWN. MOIST, SOFT TO MEDIUM STIFF SANDY CLAY 4 -TAN, MOIST TO w1c.-r, LOOSE TO MEDIUM DENSE. sn. TY, Cl.A VEY SAND s C 110.3 -TAN BROWN, WET, SOFT TO MEDIUM STIFF SANDY CLAY: LA YER OF OVERSIZED ROCK 6 - 7 LIGHT TAN, MOIST, LOOSE TO MEDIUM DENSE, SIL TY SAND . 8 . -9 - 10 a. SANTIGO FORMATION (Tsa) -DARK GRAYISH BROWN, MOIST, MEDIUM STIFF Cl.A Y: BOTTOM OF EXPLORATORY TRENCH II -12 - IJ .; 14 . IS • .. i PLATE NO. 5 I I DATE LOGGED: MAY 2, 2001 LOGGED BY: M. DUNCAN 12 W .0. 4460-A-SC R E M L 0 A I T s I T V u E R E C 0 C M 0 p N A T C E T N I T 0 N % % 17.2 I Plate E-4 I I· I I I I I I I I I I I I I I I I I APPENDIX F ECSCEI (2001) LABORATORY DATA I I I I I I I I I I I I I I I I I I I """'-'J" • ..., LEGACY DEVELOPMENT. LLC PROJECT NO. OJ-1147Hl LABORATORY TEST RESULTS PAGE L-1 An expansion test in conformance with UBC 18-2 was performed on representative samples of on- site soils to detennine volumetric change characteristics with change in moisture content. The recorded expansion of the sample is presented as follows: INITIAL MOISTURE CONTENT% SATURATED MOISTURE CONTENT% TRENCH NO. 2@ 1.0' TO 3.5' 12.4 25.7 TRENCH NO. 2@ 10.0' 15.8 31.9 W .0. 4460-A-SC INITIAL DRY DENSITY LB.ICU. FT. 101.7 90.7 13 EXPANSION INDEX 56 102 Plate F-1 I I I I I I I I I I I I I I I I I I I ' Wd9t> : 9 . 0 "t • J3CI 3W!l CI3I\ I 3:l:3tl 0 1 G-r--... Q... r---. 2 ~ ........ ~ ..... i',..~ 3 \:lo-. r---. __ ~ WATER ADDED -,----.. ~ --....... ..... --/ ; 4 ~ -... --~ ---. -C: -Cl) ~ ~ u --. ~ 5 G) C. -z 0 6 .:: ~ 7 C ::i 0 en 8 z 0 0 9 .10 11 12 13 14 15 0.1 0.5 1.0 5.0 10.0 LOAD (kip I sq. ft.) H3@ 10'-15' t,.,. .. ,,.) LEGACY DEVELOPMENT PROJECT H,:: • SOUTHERN CALIFORNIA "SC /~-~) SOIL & TESTING, INC. BY: DBA/KMS DATE: 04/27/01 \,,,._,>("'-~---JOB NUMBER:Ol-l 147Hl PAGE L-2 W .0. 4460-A-SC Plate F-2 I I I I I I I I I I I I I I I I I I I APPENDIX G SLOPE STABIL.ITY ANALYSIS I I I I I I I I I I I I I I I I I I I Introduction APPENDIXG SLOPE STABILITY ANALYSIS INTRODUCTION OF GSTABL7 v.2 COMPUTER PROGRAM GSTABL7 v.2 is a fully integrated slope stability analysis program. It permits the engineer to develop the slope geometry interactively and perform slope analysis from within a single program. The slope analysis portion of GSTABL7 v.2 uses a modified version of the popular STABL program, originally developed at Purdue University. GSTABL7 v.2 performs a two dimensional limit equilibrium analysis to compute the factor of safety for a layered slope using the simplified Bishop or Janbu methods. This program can be used. to search for the most critical surface or the factor of safety may be determined for specific surfaces. GSTABL7, Version 2, is programmed to handle: . 1 . Heterogenous soil systems 2. Anisotropic soil strength properties 3. Reinforced slopes 4. Nonlinear Mohr-Coulomb strength envelope 5. Pore water pressures for effective stress analysis using: a. Phreatic and piezometric surfaces b. Pore pressure grid · c. R factor d. Constant pore water pressure 6. Pseudo-static earthquake loading · 7. Surcharge boundary loads 8. Automatic generation and analysis of an unlimited number of circular, noncircular and block-shaped failure surfaces 9. Analysis of right-facing slopes 10. Both SI and Imperial units General Information If the reviewer wishes to obtain more information concerning slope stability analysis, the following publications may be consulted initially: 1. The Stability of Slopes, by E.N. Bromhead, Surrey University Press, Chapman and Hall, N.Y., 411 pages, ISBN 412 01061 5, 1992. 2. Rock Slope Engineering, by E. Hoek and J.W. Bray, Inst. of Mining and Metallurgy, London, England, Third Edition, 358 pages, ISNB O 900488 573, 1981. 3. Landslides: Analysis and Control, by R.L. Schuster and R.J. Krizek (editors), Special Report 176, Transportation Research Board, National Academy of Sciences, 234 pages, ISBN O 309 02804 3, 1978. I I I I I I I I I I I I I I I I I I I GSTABL7 v.2 Features The present version of GSTABL7 v.2 contains the following features: 1. Allows user to calculate factors of safety for static stability and dynami_c stability situations. 2. Allows user to analyze stability situations with different failure modes. 3. Allows user to edit input for slope geometry and calculate corresponding factor of safety. 4. Allows user to readily review on-screen the input slope geometry. 5. Allows user to automatically generate and analyze unlimited number of circular, non-.circular and block-shaped failure surfaces (i.e., bedding plane, slide. plane, etc.). Input Data Input data includes the following items: 1. Unit weight, residual cohesion, residual friction angle, peak cohesion, and peak friction angle of fill material, bedding plane, and bedrock, respectively. Residual cohesion and friction angle is used for static stability analysis, where as peak cohesion and friction angle is for dynamic stability analysis. 2. Slope geometry and surcharge boundary loads. 3. Apparent dip of bedding plane can be specified in angular range (i.e., from Oto . 90 degrees. 4. Pseudo-static earthquake loading (an earthquake loading of 0.11 i was used in the analysis)_. Seismic Discussion Seismic stability analyses were approximated using a pseudo-static approach. The major difficulty in the pseudo-static approach arises from the appropriate selection of the seismic coefficient used in the analysis. The use of a static inertia force equal to this acceleration during an earthquake (rigid-body response) would be extremely conservative for several reasons including: (1) only low height, stiff/dense embankments or embankments in confined areas may respond essentially as rigid structures; (2) an earthquake's inertia force is enacted on a mass for a short time period. Therefore, replacing a transient force by a pseudo-static force representing the maximum acceleration is considered unrealistic; · (3) assuming that total pseudo-static loading is applied evenly throughout the embankment Karnak Planning and Design, Inc. File:e:\wp9\4400\4460a.pge Appendix G Page2 I I I I I I I I I I I I I I I I I I I for an extended period of time is an incorrect assumption, as the length of the failure surface analyzed is usually much greater than the wave length of seismic waves generated by earthquakes; and (4) the seismic waves would place portions of the mass in compression and some in tension, resulting in only a limited portion of the failure surface analyzed moving in a downslope direction, at any one instant of time. The coefficients usually suggested by regulating agencies, counties and municipalities are in the range of 0.05g to 0.25g. For example, past regulatory guidelines within the city and county of Los Angeles indicated that the slope stability pseudostatic coefficient = 0.15 i.· The method developed by Krinitzsky, Gould, and Edinger (1993) which was in turn based· on Taniguchi and Sasaki, 1986, (T&S, 1986), was referenced. This method is base_d on empirical data and the performance of existing earth embankments during seismic loading. Our review of "Guidelines for Evaluating and Mitigating Seismic Hazards in California (Davis, 1997) indicates the State of California recommends using pseudo-static coefficient of 0.15 for design earthquakes of M 8.25 or greater and using 0.1 for earthquake parameter M 6.5. Therefore, for conservatism a seismic coefficient of 0.12 i was used in our analysis. Output Information Output information includes: 1. All input data. 2. Factors of safety for the ten most critical surfaces for static and pseudo-static stability situation. 3. High quality plots can be generated. The plots include the slope geometry, the critical surfaces and the factor of safety. 4. Note, that in the analysis, a minimum of 100 trial surfaces were analyzed for each section for either static or pseudo-static analyses. Results of Slope Stability Calculation Table E-1 shows parameters used in slope stability calculations. Summaries of the slope stability analysis are presented in Table E-2. Detailed output information is presented in Figures E-1 through E-5. The locations of the geologic cross sections are presented on Plate 1. The geologic cross sections, used for analysis, are presented on Plate 2. Karnak Planning and Design, Inc. File:e:\wp9\4400\4460a.pge Appendix G Page3 I I. .. 11· I I ,,. . :··i . I· 1· # •• I ~ I. I I I 1· 1·.· I I I ... I 1· ·l . j ·,'. ' . ,/ . • ,I ,, ·I TABLE G-1 .· .. SOI.L PARAMETER~ USED . · -i . ', - ' . . '. ~:.. . .. , , ' ·. ····· PEAK VALUES. .. ,, > .; " ....... ·" -;_;:so,c ~ATERIALs :::.·, 'Artificial Fill , 200* 0 , ' 20*·, ··Tertiary.Santiago Formatjon . 177 ,1 *Based on the relative compaction and non-uniform nature ofthe ,·, 'existing undocumented fill material'being generally below .the current industry· standard •of 90 .percent relative compaction,· •· .-. ·slope/ gradients .that are steeper 'than 2:1 (h:v), reasonably ' conservative values were utilized for our slope stability analysis. TABLE G:..2 .. ,,. SUMMARY OF SLOPE ANALYSIS· < ' Gross A-A'· ±20-Foot High Fill-Over-· Cut Slope· 1.5:1 1.7 · ,1.4 Gros~ B 7 B' ±25-Foot High.Fiil-O~er- Surficial .· .. ' Cut Slope Above an ~-: -foot High Retaining Wall Fill Sia 'es ., .. ' ... '·' . :) . ' . . ·,' ...... , 1.5:1 1.5:1 . . . , 1:5 · 1.2 ·' 1.2 N/A- . • . ' ' '1 I' . . \ \.• -· ,, . •'".] " . 'I !1. ', ,. . ~: .... • I '':~ ... .. .. ' .. . . ' ' " Bishop, mod~ed .. I. I Bishop, modified ' ,· ·"· ... . . . . .• J;. . •. 1 •;. ,, .. . ' ~. f.. t ':t' .~ - • .If , . . ' ' . KARNAK 4460 SECTION A-A' .. STATIC 1 OO rr====:::,;:===i=======--:-.i=c=:\=-pr_og:._r=am=fil=es~\g=7:::i:2s=w=\44=60=a=a~.p=l2 ~ ~u~. By: GEOSOILS 9/15/2004 04:37PM·~------ # FS I Soil : Soil Total Salt;,rated Cohesion Fric;tion Pore Pressure Piez. I LoJd Val~e-· I a 1.697; Oescj Type Unit Wt. Unit Wt. Intercept Angle Pressure Consiant Surface I Li . . JOO ps~ b 1.7371; : No. (pcf) (pcf) (psi) (d~g) Param. (psO No. I'---~ c 1.774 1 Tsa: 1 120.0 145.0 177.0 31$.0 0.00 O.Q o d 1.8091: Afu: 2 115.0 140.0 200.0 2Q.O 0.00 0.0 O e 1.815 , .. · · r 1.8281 I = ·~··1::~~l·········+-························1······ 1.840 : 80 ... ·--· .--······--···---··· 1.852 : .a ; 60 ;-·····················..-:········ . . ············-·: ··-·····--··············:········-.... .2. .......... ~ ........•.......... I i I ' I ! I . . 20 ~···········:···········l········· ........................ ; .......... . 8 1 .. ·····---:------·········----------: -· .. . . : . . . ···········i··············-········--:---···· ................. :,. ..•.............. o I ____ L-._ __ .1__ 0 20 40 60 80 100 120 GSTABL7 v.2 FSmin=1.697 Safety Factors Are Calculated By The Modified Bishop Method 140 7 2 2 l ! . ·-i 0 CJ) I < I 0 160 "' ~ ~ C? ~ - - - - - - - - - - - - - - - ---- - KARNAK 4460 SECTION A-A' -SEISMIC 100 c:\program files\g72sw\4460aas.pl2 Run By: GEOSOILS 9/15/2004 04:37PM ··············:--·······-········· .a 7 2 LI: 2 60 . . ........ ·-----· ... ~-...... -· ····· ....... ---·--:·---·-·. ---. . . . -·························4•····· ! i . ' ~ ~ ..;.-~~8~~~ .. -~~~~ 1 I: 40~,~~~~--!:,-1~~-----....i~::::;,..!!!."!!i~' I I ' ' . . . ··················--······ ····························· . . ~ ~ : : ; : . . : . : : . ~ '20 ....................... ; . ··············----~---------------·········· ; ......... ---... . .. , ········-----·····-----·;---·······-······ . . 0'--------L-----_J_ 0 20 40 60 80 100 GSTABL7 v.2 F5mln=1.378 . . ·····i························1· .... 120 140 Safety Factors Are Calculated By The Modified Bishop Method 160 0 en I Cl: I 0 CD 'It v 0 == ------------------- 120 # FS a 1.499 b 1.502 C 1.506 d 1.507 e 1.508 f 1.511 g 1.513 KARNAK 4460 SECTION B·B' -STATIC c:\program files\g72sw\4460bb1.pl2 Run By: GEOSOILS 9/15/2004 03:54PM Soil Soil To\al Saturated Cohesion Friction Pore Pressure Piez. Load Value Desc. Type Unit:Wt. Unit Wt. Intercept Angle\ Pressure Conslant Surface LI JOO psr No. (p~ (pcf} (psi) (deg): Param. (psi) No. l'-...;.---.....:..c..:..=;__......J Tsa 1 120.0 125.0 177.0 36.0: 0:00 o o o Afu 2 11$.0 . 120.0 200.0 20.0: 0.00 o:o 0 i h 1.514\ ; 1 I 1.516 90 ~.l .. 1:~17.) ..................... . .. ···························i···-----------·····-······ .. . ..... ~ --.. -.. ---... --............... -........... ; .. . a : 2 GO i /""" :,,,./ ......................... .,.......-;· --·······-····. JO,/,.,. : _,.,.,.,.-1 : ... . ---......:....--~.,/ i -----·-······-.----------········ 9 1 30 ...... ···········.·········-··················· 0 ,_. ____ _ _...._ _______ ......... 1 0 30 60 90 120 GSTABL7 v.2 FSmin=1.499 Safety Factors Are Calculated By The Modified Bishop Method 11 150 C? I C, G> .... ~ 0. 0 "' I ct I 0 co ~ ~ 0 3': ------------------- 120 # FS a 1.171 b 1.172 C 1.173 1 d 1.175 e 1.175 1 f 1.176 I g 1.177 KARNAK 4460 SECTION B-B1 -SEISMIC c:\program files\g72sw\4460bb1s.pl2 _Run By: GEOSOILS 9/15/2004 03:56PM Soil Soil Tolal Saturated Cohesion Friction Pore Pressure Piez. : load Value Desc. Type Unit:WL Unit WL Intercept Angle: Pressure Constant Surface No. (p6cf) (pcf) (psf) (deg): Param. (psi) No. Tsa 1 12 .. 0 125.0 177.0 36.0: 0.00 O.O o Afu 2 111?.0 120.0 200.0 20.0 j 0.00 0.0 O : LI 300 psf :Peak(A) 0.290(g) :kh Coe(. __ Q: 120(9)< 90 ~1 .. tliU ..................... ) .. . I . ; ! ~I 2 : ,,,... :.,,./ // ·60 ·.·------··--··-·············· .-1' ·······---······-·····--········ .... 10.,./: 30 0'-------- 0 30 . . .. ········-------~------·-······------·------------····· .. : ... 60 90 GSTABL7 v.2 FSmln=1.171 ... _- ,,,..,,,.. .... ,. .......... 1 ,,,..- Safety Factors Are Calculated By The Modified.Bishop Method 120 150 V I c., Cl) .. a, a: 0 en I < I 0 <O v V 0 3 ------------------- CD . Q.. It) V [' 0 I [' V (.D Q.. (\J (T) .. V 0 V 0 CXl 0 Q.. OJ en SURFICIAL SLOPE STABILITY FOR UNDOCUMENTED FILL SLOPES SLOPE ANGLE i {degrees) = VERTICAL DEPTH OF SATURATION z (ft)= SATURATED SOIL UNIT WEIGHT ysat (pct)= UNIT WEIGHT OF WATER yw {pcf) = EFFECTIVE COHESION C' (psf) = EFFECTIVE FRICTION ANGLE 4> (degrees)= .INPUT PARAMETERS 33 4 125 62.4 200 20 OUTPUT CALCULATIONS SLOPE ANGLE IN RADIANS 0.575959 EFFECTIVE FRICTION ANGLE IN RADIANS 0.349066 FACTOR OF SAFETY = 1.16 0 en I < I 0 '° 111:1' 111:1' tj ~ ------------------- I I I I I I I I. I I I I I I I I I I I APPENDIX H GENERAL EARTHWORK AND GRADING GUIDELINES I I I I I I I I I I I I I I I I I I I GENERAL EARTHWORK AND GRADING GUIDELINES General These guidelines present general procedures and requirements for earthwork and grading as shown on the approved grading plans, including preparation of areas to filled, placement of fill, installation of subdrains and excavations. The recommendations contained in the geotechnical report are part of the earthwork and grading guidelines and would supercede the provisions contained hereafter in the case of conflict. Evaluations performed by the consultant during the course of grading may result in new recommendations which could supercede these guidelines or .the recommendations contained in the geotechnical report. · The contractor is responsible for the satisfactory completion of all earthwork in accordance with provisions of the project plans and specifications. The project soil ~ngineer and engineering geologist (geotechnicai consultant) .or their representatives should. provide observation and testing services, and geotectinical consultation during the duration of the project. EARTHWORK OBSERVATIONS AND TESTING Geotechnical Consultant Prior to the commencement of grading, a qualified geotechnical consultant (soil engineer and engineering geologist) should be employed for the purpose of observing earthwork procedures and testing the fills for conformance with the recommendations of the geotechnical report, the approved grading plans, and applicable grading codes and ordinances. The geotechnical consultant should provide testing and observation so that determination may be made that the work is being accomplished as specified. It is the responsibility of the contractor to assist the consultants and keep them apprised of anticipated work schedules and _changes, so that they may schedule their personnel accordingly. All clean-outs, prepared ground to receive fill, key excavations, and subdrains should be observed and documented by the project engineering geologist and/or soil engineer prior to placing and fill. It is the contractors's responsibility to notify the engineering geologist and soil engineer when such areas are ready for observation. Laboratory and Field Tests Maximum dry density tests to determine the degree of compaction should be performed in accordance with American Standard Testing Materials test method ASTM designation D-1557-78. Random field compaction tests should be performed in accordance with test method ASTM designation D-1556-82, D-2937 or D-2922 and D-3017, at intervals of approximately 2 feet of fill height or ·every 100 cubic yards of fill placed. These criteria I I I I I I I I I I I I I I I I I I I would vary depending on the soil conditions and the size of the project. The location and frequency of testing would be at the discretion of the geotechnical consultant. Contractor's Responsibility All clearing, site preparation, and earthwork performed on the project should be conducted by the contractor, with observation by geotechnical consultants and staged approval by the governing agencies, as applicable. It is the contractor's responsibility to prepare the ground surface to receive the fill, to the satisfaction of the soil engineer, and to place, spread, moisture condition, mix and compact the fill in accordance with the recommendations of the soil engineer. The _contractor should also remove all major non- earth material considered Unsatisfactory by the soil engineer. It is the sole responsibility of the contractor to provide adequate equipment and methods to accomplish the earthwork in accordance with applicable grading guidelines, codes or agency ordinances, and approved grading plans. Sufficient watering apparatus and compaction equipment should be provided by the contractor with due consideration for the fill material, rate of placement, and climatic conditions. If, in the opinion of the geotechnical consultant, unsatisfactory conditions such as questionable weather, excessive oversized rock, or deleterious material, insufficient support equipment, etc., are . resulting in a quality of work that is not acceptable, the consultant will inform the contractor, and the contractor is expected to rectify the conditions, and if necessary, stop work until conditions are satisfactory. During construction, the contractor shall properly grade all surfaces to maintain good drainage and prevent ponding of water. The contractor shall take remedial measures to control surface water and to prevent erosion of graded areas until such time as permanent drainage and erosion control measures have been installed. SITE PREPARATION . All major vegetation, including brush, trees, thick grasses, organic debris, and other deleterious material should be removed and disposed of off-site. These removals-must be concluded prior to placing fill. Existing fill, soil, alluvium, colluvium, or rock materials determined by the soil engineer or engineering geologist as bei°ng unsuitable in-place should be removed prior to fill placement. Depending upon the soil conditions, these materials may be reused as compacted fills. Any materials incorporated as part of the compacted fills should be approved by the soil engineer. Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic tanks, wells, pipelines, or other structures not located prior to grading are to be removed or treated in a manner recommended by the soil engineer. Soft, dry, spongy, highly fractured, or otherwise unsuitable ground extending to such a depth that surface Karnak Planning and Design, Inc. File:e:\wp9\4400\4460a.pge Appendix H Page2 I I I I I I I I I I I I I I I 1. I I I processing cannot adequately improve the condition should be overexcavated down to firm ground and approved by the soil engineer before compaction and filling operations continue. Overexcavated and processed soils which have been properly mixed and moisture conditioned should be re-compacted to the minimum relative compaction as specified in these guidelines. Existing ground which is determined to be satisfactory for support of the fills should be scarified to a minimum depth of 6 inches or as directed by the soil engineer. After the scarified ground is brought to optimum moisture content or greater and mixed, the materials should be compacted as specified herein. If the scarified zone i's grater that 6 inches in depth, it may be necessary to remove the excess and place the material in lifts restricted to about 6 inches in compacted thickness. Existing ground which is not satisfactory to support compacted fill should be overexcavated as required in the geotechnical report or by the on-site soils engineer and/or engineering geologist. Scarification, disc harrowing, or other acceptable form of mixing should continue until the soils are broken down and free of large lumps or clods, until the working surface is reasonably uniform and free from ruts, hollow, hummocks, or other uneven features which would inhibit compaction as described previously. Where fills are to be placed on ground with slopes steeper than 5: 1 (horizontal to vertical), the ground should be stepped or benched. The lowest bench, which will act as a key, should be a minimum of 15 feet wide and should be at least 2 feet deep into firm material, and approved by the soil engineer and/or engineering geologist. In fill over cut slope conditions, the recommended minimum width of the lowest bench or key is also 15 feet with the key founded on firm material, as designated by the Geotechnical Consultant. As a general rule, unless specifically recommended otherwise by the Soil Engineer, the minimum width of fill keys should be approximately equal to % the height of the slope. Standard benching is generally 4 feet (minimum) vertically, exposing firm, acceptable material. Benching may be used to remove unsuitable materials, although it is understood that the vertical height of the bench may exceed 4 feet. -Pre..:stripping may be considered for unsuitable materials in excess of .4 feet in thickness. · · All areas to. receive fill, including processed areas, removal areas, and the toe of fill benches should be observed and approved by the soil engineer and/or engineering geologist prior to placement of fill. Fills may then be properly placed and compacted until design grades (elevations) are attained. Karnak Planning and Design, Inc. File:e:\wp9\4400\4460a.pge Appendix H Page3 I I I I I I I I I I I I I I I I I I I COMPACTED FILLS Any earth materials imported or excavated on the property may be utilized in the fill provided that each material has been determined to be suitable by the soil engineer. These materials should be free of roots, tree branches, other organic matter or other deleterious materials. All unsuitable materials should be removed from the fill as directed by the soil engineer. Soils of poor gradation, undesirable expansion potential, or substandard strength characteristics may be designated by the consultant as unsuitable and may require blending with other soils to serve as a satisfactory fill material. Fill materials derived from benching operations should be dispersed throughout the fill area and blended with other bedrock derived material. Benching operations should not result in the benched material being placed only within a single equipment width away from the fill/bedrock contact. Oversized materials defined as rock or other irreducible materials with a maximum dimension greater than 12 inches should not be buried or placed in fills unless the location of materials and disposal methods are specifically approved by the soil engineer. Oversized material should be taken off-site or placed in accordance with recommendations of the soil engineer in areas designated as suitable for rock disposal. Oversized material should not be placed within 1 O feet vertically of finish grade (elevation) or within 20 feet horizontally of slope faces. To facilitate future trenching, rock should not be placed within the range of foundation excavations, future utilities, ~r underground construction unless specifically approved by the soil engineer and/or the developers representative. If import· material is required for grading, representative samples of the materials to be utilized as compacted fill should be analyzed in the laboratory by the soil engineer to determine its physical properties. If any material other than that previously tested is encountered during grading, an appropriate analysis of this material should be conducted by the soil engineer as soon as possible. Approved fill material should be placed in areas prepared to receive fill in near horizontal layers that when compacted should not exceed ·s inches in thickness. The soil engineer . . may approve thick lifts if testing indicates the grading procedures are such that adequate compaction is being achieved with lifts of greater thickness. Each layer should be spread evenly and blended to attain uniformity of material and moisture suitable for compaction. Fill layers at a moisture content less than optimum should be watered and mixed, and wet fill layers should be aerated by scarification or should be blended with drier material. Moisture condition, blending, and mixing of the fill layer should continue until the fill materials have a uniform moisture content at or above optimum moisture. Karnak Planning and Design, Inc. File:e:\wp9\4400\4460a.pge Appendix H Page4 I I I I I I I I I I I I I I I I I I I After each layer has been evenly spread, moisture conditioned and mixed, it should be uniformly compacted to a minimum of 90 percent of maximum density as determined by ASTM test designation, D-1557-78, or as otherwise recommended by the soil engineer. Compaction equipment should be adequately sized and should be specifically designed for soil compaction or of proven reliability to efficiently achieve the specified degree of compaction. Where tests indicate that the density of any layer of fill, or portion thereof, is below the required relative compaction, or improper moisture is in evidence, the particular layer or portion shall be re-worked until the required density and/or moisture content has been attained. No additional fill shall be placed in an area until the last placed lift of fill has been tested and found to meet the density and moisture requirements, and is approved by the soil engineer.- Compaction of slopes should be accompl_ished by over-building a minimum of 3 feet horizontally, and subsequently trimming back to the design slope configuration. Testing shall be performed as the fill is elevated to evaluate compaction as the fill core is being developed. Special efforts may be necessary to attain the specified compaction in the fill slope zone. Final slope shaping should be performed by trimming and removing loose materials with appropriate equipment. A final determination offill slope compaction should be based on observation and/or testing of the finished slope face. Where compacted fill slopes are designed steeper than 2:1 (horizontal to vertical), specific material types, a higher minimum relative compaction, and special grading procedures, may be recommended. If an alternative to over-building and cutting back the compacted fill slopes is selected, then special effort should be made to achieve the required compaction in the outer 1 O feet of each lift of fill by undertaking the following: 1. An extra piece of equipment consisting of a heavy short shanked sheepsfoot should be used to roll (horizontal) parallel to the slopes continuously as fill is placed. The sheepsfoot roller should also be used to roll perpendicular to the slopes, and extend out over the slope to provide adequate compaction to the face of the slope. 2. 3. 4. Loose fill should not be spilled out over the face of the slope as each lift is compacted. Any loose fill spilled over a previously completed slope face should be .. trimmed off or be subject to re-rolling. Field compaction tests will be made in the outer (horizontal) 2 to 8 feet of the slope at appropriate vertical intervals, subsequent to compaction operations. After completion of the slope, the slope face should be shaped with a small tractor and then re-rolled with a sheepsfoot to achieve compaction to near the slope face. S.ubsequent to testing to verify compaction, the slopes should be grid-rolled to Karnak Planning and Design, Inc. File:e:\wp9\4400\4460a.pge Appendix H Pages I I I I I I I I I I I I I I I I I I I 5. 6. achieve compaction to the slope face. Final testing should be used to confirm compaction after grid rolling. Where testing indicates less than adequate compaction, the contractor will be · responsible to rip, water, mix and re-compact the slope material' as necessary to achieve compaction. Additional testing should be performed to verify compaction. Erosion control and drainage devices should be designed by the project· civil engineer in compliance with ordinances of the controlling governmental agencies, and/or in ac"cordance with the recommendation of the soil engineer or engineering geologist. SUBDRAIN INSTALLATION Subdrains should be installed in approved ground in accordance with the approximate alignment and details indicated by the geotechnical consultant. Subdrain locations or materials should not be changed or modified without approval of the geotechnical consultant. The soil engineer and/or engineering geologist may recommend and direct changes in subdrain line, grade and drain material in the field, pending exposed conditions. The location of constructed subdrains should be recorded by the project civil . engineer. EXCAVATIONS Excavations and cut slopes should be. examined during grading by the engineering geologist. If directed by the engineering geologist, further excavations or overexcavation and re-filling of cut areas should be performed and/or remedial grading of cut slopes should be performed. When fill over cut slopes are to be graded, unless otherwise approved, the cut portion of the slope should be observed by the engineering geologist prior to placement of materials for construction of the fill portion of the· slope. The engineering geologist should observe all cut slopes and should be notified by the contractor when cut slopes are started. If, during the course of grading, unforeseen adverse or potential adverse geologic conditions are encountered, the engineering geologist and soil engineer should investigate, evaluate and make recommendations to treat these problems. The need for cut slope buttressing or stabilizing should be based on in-grading evaluation by the engineering geologist, whether anticipated or not. Unless otherwise specified in soil and geological reports, no cut slopes should be excavated higher or steeper than that allowed by the ordinances of controlling governmental agencies. Additionally, short-term stability of temporary cut slopes is the. contractors responsibility. · Karnak Planning and Design, Inc. File:e:\wp9\4400\4460a,pge Appendix H Page 6 I I I I I I I I I I I I I I I I I I I Erosion control and drainage devices should be designed by the project civil engineer and should be constructed in compliance with the ordinances of the controlling governmental agencies, and/or in accordance with the recommendations of the soil engineer or engineering geologist. COMPLETION Observation, testing and consultation by the geotechnical consultant should be conducted during the grading operations in order to state an opinion that all cut and filled areas are graded in accordance with the approved project specifications. After completion of grading and after the soil engineer and engineering geologist have finished their observations of the work, final reports should be submitted subject to review by the controlling governmental agencies. No further excavation or filling should be undertaken without prior notification of the soil engineer and/or engineering.geologist. All finished cut and fill slopes should be protected from erosion and/or be planted in accordance with the project specifications and/or as recommended by a landscape architect. Such protection and/or planning should be undertaken as soon as practical after completion of grading. JOB SAFETY General At GeoSoils, Inc. (GSI) getting the job done safely is of primary concern. The following is the company's safety considerations for use . by all employees on multi-employer construction sites. On ground personnel are at highest risk of injury and possible fatality on grading and construction projec,s ... GSI recognizes that construction activities will vary on each site and that site safety is· the ·prime responsibility of the contractor; however, everyone must be safety conscious and responsible at all times. To achieve. our goal of avoiding accidents, cooperation between the client, the contractor and GSI personnel must be maintained. In an effort to minimize risks associated with geotechnical testing and observation, the following precautions are to be implemented for the safety of field personnel on grading and construction projects: Safety Meetings: GSI field personnel are directed to attend contractors regularly scheduled and documented safety meetings. Safety Vests: Safety vests are provided for and are to be worn by GSI personnel at all times when they are working in the field. Karnak Planning and Design, Inc. File:e:\wp9\4400\4460a.pge Appendix H Page 7 I I I I I I I I I I I I I I I I I I I Safety Flags: Two safety flags are provided to GSI field technicians; one is to be affixed to the vehicle when on site, the other is to be placed atop the spoil pile on all test pits. Flashing Lights: All vehicles stationary in the grading area shall use rotating or flashing amber beacon, or strobe lights, on the vehicle during all field testing. While operating a vehicle in the grading area, the emergency flasher on the vehicle shall be activated. In the event that· the contractor's representative observes any of our personnel not following the above, we request that it be brought to the attention of our office. Test Pits Location. Orientation and Clearance The technician is responsible for selecting test pit locations. A primary concern should be the technicians's safety. Efforts will be made to coordinate locations· with the grading contractors authorized representative, and to select locations following or behind the established traffic pattern, preferably outside of current traffic. The contractors authorized representative (dump man, operator, supervisor, grade checker, etc.) should direct excavation of the pit and safety during the test period. Of paramount concern should be the soil technicians safety and obtaining enough tests to represent the fill. Test pits should be excavated so that the spoil pile is placed away form oncoming traffic, whenever possible. The technician's vehicle is to be placed next to the test pit, opposite the spoil pile. This necessitates the fill be maintained in a driveable condition. Alternatively, the contractor may wish to park a piece of equipment in front of the test holes, particularly in small fill areas or those with limited access. A zone of non-encroachment should be established for all test pits. No grading equipment should enter this zone during the testing procedure. The zone should extend approximately 50 feet outward from _the center of the test pit. ·This zone is established for safety and to avoid excessive ground vibration which typically decreased test results. When taking slope tests the technician should park the vehicle directly above or below the test location. If this is not possible, a prominent flag should be placed at the top of the slope. The contractor's representative should effectively keep all equipment at a safe operation distance (e.g., 50 feet) away from the slope during this testing. The technician is directed to withdraw from the active portion of the fill as soon as possible following testing. The technician's vehicle should be parked at the perimeter of the fill in a highly visible location, well away from the equipment traffic pattern. The contractor should inform our personnel of all changes to haul roads, cut and fill areas or other factors that may affect site access and site safety. Karnak Planning and Design, Inc. File:e:\wp9\4400\4460a.pge Appendix H Page a I I I I I I I I I I I I I I I I I I I In the event that the technicians safety is jeopardized or compromised as a result of the contractors failure to comply with any of the above, the technician is required, by company policy, to immediately withdraw and notify his/her supervisor. The grading contractors representative will eventually be contacted in an effort to effect a solution. However, in the interim, no further testing will be performed until the situation is rectified. Any fill plaqe can be considered unacceptable and subject to reprocessing, recompaction or removal. In the event that the soil technician does not comply with the above or other established safety guidelines, we request that the contractor brings this to his/her attention and notify this office. Effective communication and coordination between the contractors representative and the soils technician is strongly encouraged in order to implement the · above safety plan. Trench and Vertical Excavation It is the contractor's responsibility to provide safe access into trenches where compacti9n testing is needed. Our personnel are direct.ed not to enter any excavation or vertical cut which: 1) is 5 feet or deeper unless shored or laid back; 2) displays any evidence of instability, has any loose rock or other debris which could fall into the ·trench; or 3) displays any other evidence of any unsafe conditions regardless of depth. All trench excavations or vertical cuts in excess of 5 feet deep, which any person enters, should be shored or laid back. Trench access should be provided in accordance with CAL-OSHA and/or state and local standards. Our personnel are directed not to enter any trench by being lowered or "riding down" on the equipment. If the contractor fails to provide safe access to trenches for compaction testing, our company policy requires that the soil technician withdraw and notify his/her supervisor. The contractors represe.ntative will event~ally be contacted in an effort to effect a solution. All backfill not tested due to safety concerns or other· reasons could be subject to reprocessing and/or re·moval. If GSI personnel become aware of anyone working beneath an unsafe trench wall or . vertical excavation, we have a legal obligation to put the contractor and owner/developer. on notice to immediately correct the situation. If corrective steps are not taken, GSI then has an obligation to notify CAL-OSHA and/or the proper authorities.· Karnak Planning and Design, Inc. File:e:\wp9\4400\4460a.pge Appendix H Page 9 I I I I I I I 1· I I I I I I I I I I I CANYON SUBDRAIN DETAIL TYPE A '\ '\ PROPOSED COMPACTED FILL '\ ' SEE ALTERNATIVES TYPE B ----------------------..... ~--------------. ' ' ' PROPOSED COMPACTED FILL . ' .. -"\:.· ', -~NATU_RAL GROUND -==~ '* 11,\\\ ', lit ·NOTE: ALTERNATIV~S. LOCATION ANO EXTENT OF SUBDRAINS SHOULD BE DETERMINED BY THE SOILS ENGINEER ANO/OR ENGINEERING GEOLOGIST·D URING GRADING. PLATE EG-1 I I I I I I I I I I I I I I I I I I I CANYON SUBDRAIN ALTERNATE DETAILS ALTERNATE 1: PERFORATED PIPE AND FILTER MATERIAL 1i9 MINIMUM • MINIMUM A-1 · FILTER MATERIAL. . SIEVE SIZE PERCENT PASSING 1 INtH ,10~ ·J/1. INCH 90-::100 3/8 INCH l.0-100 NO. 4 25-40. NO. 8 18-33 .NO. 30 :S-15 ·No. 5 0 .0-7 .. NO. 200 0-3 ALTERNATE 2: PERFORATED-PIPE, GRAVEL AND.FlLTER FABRIC ~Nl~UJ,{ OVERLAP 5• MINIMUM OVER~)I A-2 PERFORAlEO PIPE: SEE ALTERNATE 1 GRAVEL: CLEAN 3/ 4 IND-I ROa< OR APPROVED SUBSTITUTE FILTER FABRIC: MIRAFI 140 OR APPROVED SUBSTITUTE PLATE EG-2 I I I I I I I I I I I I I I I I I I I DETAIL FOR FILL SLOPE TOEING OUT ON FLAT ALLUVIA TED CANYON TOE OF SLOPE AS SHOWN ON GRADING PLAN ORIGINAL GROUND SURFACE TO BE . RESTORED WITH COMPACTED FILL -2"::~Gl:L.:OUN~U~~ 8ACKCU~ VARIES. FOR DEEP REMOVALS. /.....f." r . SACKCUT ~~SHOULD BE MADE NO <_,$-~ STEEPER·THA~:1 OR AS NECESSARY {~ ANTICIPATED ALLUVIAL REMOVAL FOR SAFETY ......._.~,CONSIDERATIONS-:,/ l ~ , DEPTH PER SOIL ENGINEER. ~1\·m{\/ -. . ~\\ }~~ PfHWIOEA ;-; MmlMUM PRO-;;CTION~;; T~ ;;- SLOPE AS SH OWN ON GRADING PLAN TO THE RECOMMENDED REMOVAL DEPTH. SLOPE HEIGHT. SITE CONDITIONS AND/OR LOCAL CONDITIONS COULD DICTATE FLATTER PROJECTIONS. . REMOVAL ADJACENT TO EXISTING FILL ADJOINING CANYON FILL ------------------ PROPOSED ADDITIONAL COMPACTED F.ILL COMPACTED RLL LIMITS UN~\ , TEMPORARY COMPACTED FlLL ~ --- . )., FOR DRAINAGE ONLY ------ ?' ~ Oaf · u'(0, Oaf / Oal (TO BE REMOVED) (EXISTING ,COMPArED FlLLI --"'2:, ~" . ~~~~'ll~zyl/~ ~1f"Y~~' .. 1 LEGEND - '71);,.Y~' .., \ TO BE REMOVED BEFORE Oaf ARTIFICIAL FILL PLACING ADDITIONAL COMPACTED Fill· Oal ALLUVIUM PLATE EG-3 ------------------- -0 r )> ~ rn rn G> I +- . TYPICAL STABILIZATION I BUTTRESS. _FILL DETAIL 15" TYPICAL OUTLETS TO BE SPACED AT 100' MAXIMUM INTERVALS, .AND SHALL EXTEND 1i9 BEYOND THE FACE OF SLOPE AT TIME OF .ROUGH GRADING COMPLETION. f' 15' MINIMUM •f BLANKET FILL IF RECOMMENDED BY THE SOIL ENGINEER V, \ 3'MINIMUM KEY DEPTH ---------------- - - - "1J r )> -f rn rn G) I U1 PIPE \. TYPICAL STABILIZATION I BUTTRESS SU BO RAIN DETAIL r MINtMUM FJLTER MATERIAL: MINIMUM OF FIVE Fl' /LINEAR Fl OF PIPF OR FOUR F'P/LINEAR Fl OF PIPE WHEN PLACED IN SQUARE CUT TRENCH. AI.ItRNATIVE IN LIEU Of FILTER MATERIAL: GRAVEL MAY B ENCA~ED IN APPROVED FILTER FABRIC. FILTER FABRIC SI-JALL BE MIRAFI 140 OR EQUIVALENT. FILTER FABRIC SijALL BE LAPPED A MINIMUM OF 1 i9 ON ALL JOINTS. MINIMUM 4 • DIAMETER PIPE: ABS-ASTM D-2 751, SOR 35 OR ASTM D-1527 SCHEDULE 40 PVC-ASTM D-3034, SOR _35 OR ASTM D-1785 SCHEDULE 40 WI.TH A CRUSHING STRE~OTH OF' 1,000 POUNDS MINIMUM, AND A MINIMUM OF 8 UNIFORMLY SPACED PERFORATIONS PER FOOT OF PIPE INSTALLED WITH PERFORATIONS OF BOTTOM OF PIPE. PROVIDE CAf' AT UPSTREAM END OF PIPE_. SLOPE AT 2% TO OUTLET PIPE, OUTLET PIPE TO BE CONNECTED TO SUBDRAIN PIPE WITH TEE OR ELBOW, OOTE:: 1. TRENCH FOR OUTLET PIPES TO BE BACKFILLED WITH ON-SITE SOIL. 2. BACKDRAINS AND LATERAL DRAINS SHALL BE LOCATED AT ELEVATION OF EVERY BENCH DRAIN. FIRST DRAIN LOCATED AT ELEVATION JUST ABOVE LOWER LOT GRADE. ADDITIONAL DRAINS MAY BE REQUIRED AT THE DISCRETION OF THE SOILS ENGINEER AND/OR ENGINEERING ~EOLOGIST. FILTER MATERIAL SHALL BE OF THE FOLLOWING SPECIFICATION OR AN APPROVED EQUIVALENT: SIEVE SIZE PERCENT PASSING 1 INCH 100 3/ 4 INCH 90-100 3/8 INCH 40-100 NO. 4 25-40 NO. 8 18-33 NO. 30 5-15 NO. 50 0-7 N0.200 0-3 GRAVEL SHALL BE OF THE FOLLOWING SPECIFICATION OR AN APPROVED EpUIVALENT: SIEVE SIZE PERCENT PASSING 1 1 / 2 IN CH.. 100 NO. 4 50 N0.200 B SAND EQUIVALENT: MINIMUM OF 5 I --------------- FILL OVER NATURAL DETAIL SIDEHILL FILL TOE OF SLOPE AS SHOWN ON GRADING PLAN PROVIDE A 1:1 MINIMUM PR.OJECTION FROM DESIGN TOE OF SLOPE TO TOE OF KEV AS SHOWN ON AS BUILT NATURAL SLOPE TO BE RESTORED WITH -,"'r------..J ~: MINIM~M BENCH WIDTH MAY VARY - - - - COMPACTED FILL 4' MINIMUM ..------~ NOTE: 1, WHERE THE NATURAL, SLOPE APPROACHES OR EXCEEDS THE -u r )> --f m m G) I O'l 1 'MINIMUM KEY WIDT 2'X 3' MINIMUM KEY DEPTH 2' MINIMUM IN BEDROCK OR APPROVED MATERIAL. I DESIGN SLOPE RATIO. SPECIAL RECOMMENDATIONS WOULD BE PROVIDED BY THE SOILS ENGINEER. 2, THE NEED FOR AND OISPOSIJION OF DRAINS WOULD BE DETERMINED BY THE SOILS ENGINEER BASED UPON EXPOSED ,CONDITIONS. ------------------- FILL OVER CUT DETAIL CUT/FILL CONTACT MAINTAIN MINIMUM .15 1 FILL SECTION FROM · 1. AS SHOWN ON GRADING PLAN BACKCUT TO FACE OF FINISH SLOPE ---------- H 2. AS SHOWN ON AS· BUILT ORIGINAL TOPOGRAPHY \ r,~ I~\ BEDROCK OR APPROVED MATE~IAL -u r )> -I m rn G) I '-l LOWEST BENCH WIDTH 151 MINIMUM OR H/2 COMPACTED FILL NOTE: THE CUT PORTION OF THE SLOPE SHOULD BE EXCAVATED AND EVALUATED BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST PRIOR TO CONSTRUCTfN.G THE FILL PORTION. ----·-------- - --- - - -u r )> -j m rn G) I 00 STABILIZATION FILL FOR UNSTABLE MATERIAL EXPOSED IN PORTION OF CUT SLOPE REMOVE: UNSTABLE MATEijlAL NATURAL SLOPE MATERIAL ~ UNWEATHERED BEDROCK OR APPROVED MATERIAL NOTE: 1. SUBORAINS ARE NOT REQUIRED UNLESS SPECIFIED BY SOILS ENOINEER AND/OR ENGINEERING GEOLOGIST, 2. ·wr SHALL Bl; EQUIPMENT WIDTH 115") FOR SLOPE HEIGHTS LESS.THAN 25 FEET. FOR SLOPES GREATER· THAN 25 FEET ·w• SH.ALL BE DETERMINED BY THE PROJECT SOILS ENG~NEER AND /OR ENGINEERING GEOLOGIST. AT NO TIME SHALL •w• BE LESS THAN H/2. - - - -u s: -i n, rn. G) I lD --------- - -- SKIN FILL OF NA TUR AL GROUND 15' MINIMUM TO BE MAINTAINED FROM PROPOSED FINISH SLOPE FACE TO BACKCUT -- J" Ml~IMUM KEY DEPTH / NIMUM KEY WIDTH -- - - ORIGINAL SLOPE NOTE: 1. THE NEED AND DISPOSITION OF DRAINS WILL BE DETERMINED! BY THE SOILS ENGINEER AND/OR ENGINEERING ·GEOLOGIST BASED ON FIELD CONDITIONSi 2. PAD OVEREXCAVATION ANO RECOMPACTION SHOULD BE PERFORMED IF DEtE;RMINEO TO BE NECESSARY BY THE SOILS ENGINEER AND/OR ENGINEERING OEOLOOJST. - ------------ -0 r :r> -f rn m G) I _... 0 ------- DAYLIGHT CUT LOT DETAIL RECONSTRUCT COMPACTED FILL SLOPE AT 2:1 OR FLATTER (MAY INCREASE OR DECREASE·PAO AREA). OVEREXCAVATE AND RECOMPACT --- REPLACEMENT FILL AVOID AND/OR CLEAN UP SPILLAGE OF MATERIALS ON THE NATURAL SLOPE TYPICAL BENCHINO NOTE: 1. SUBDRAIN ANO KEY WIDTH REQUIREMENTS WILL BE DETERMINED BASED ON EXPOSED SUBSURFACE CONDITIONS AND THICKN_~ss OF OVERBURDEN. 2. PAD OVER EXCAVATION AND RECOMPACTION SHOULD BE PERFORMED IF DETERMINED NECESSARY BY THij_ SOILS ENGINEER ANO/OR THE ENGINEERING GEOLOGIST •. I I I I I I I I I I I I I I I I I I I TRANSITION LOT DETAIL CUT LOT (MATERIAL TYPE TRANSITION) --------------------- PAD GRADE COMPACTED FILL TYPICAL BENCH ING CUT-FILL LOT (DAYLIGHT TRANSITION) MUM PAD GRADE NOTE: * DEEPER OVEREXCAVATION MAY BE RECOMMENDED BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST IN STEEP CUT-FILL TRANSITION AREAS. PLATE EG.:._11" I I I I I I I I I I I I l- 1· I I I I I SETTLEMENT PLATE AND RISER DETAIL 2·x 2' X 1n.· STEEL PLATE STANDARD 3/1.· PIPE NIPPLE WELDED TO TOP OF PLATE. ~~---+--3/ 4 • X s· GALVANIZED PIPE, STANDARD PIPE TH READS TOP AND BOTTOM. EXTENSIONS THREADED ON BOTH ENDS AND ADDED IN 5• INCREMENTS. 3 INCH SCHEDULE 40 PVC PIPE SLEEVE. ADD IN 5° IHCREMENTS WITH GLU~ JOINTS. FINAL GRADE ! ][ . l MAINTAIN S'CLEARANCE OF HEAVY EQUIPMENT. s· / .I' -1-.\,,--L.i\,-MECHANICALLY. HANO COMPACT IN 2° VERTICAL -r\-·~ -r'\r LIFTS OR ALTERNATIVE SUITABLE TO AND t.,..---~ •---_..,• ACCEPTED BY THE SOILS ENGINEER. 1 s· ~ s· I I I I / / / I I I MECHANICALLY HAND COMPACT THE INITIAL 5• VERTICA~ WITHIN A 5' RADIUS OF PLATE BASE. ' . ' ' ' ' :•:: • •• :. ·: .:•. •• •• •. ·• •• • • •• BOTTOM OF CLEANOUT . . . . . . . . . . . . . ...... . PROVIDE A MINIMUM 1' BEDDING OF COMPACTED SAND NOTE: 1. LOCATIONS OF SETTLEMENT PLATES SHOULD BE CLEARLY MARKED AND READILY VISIBLE (RED FLAGGED) TO EQUIPMENT-OPERATORS. 2. CONTRACTOR SHOULD MAINTAIN CLEARANCE OF A 5' RADIUS OF PLATE BASE ANO WITHIN 5' (VERTICAU FOR HEAVY EQUIPMENT. ALL WITHIN CLEARANCE AREA SHOULD BE HAND'COMPACTED TO PROJECT SPECIFlCATIONS OR COMPACTED BY ALTERNATIVE APPROVED BY THE SOILS ENGINEER. 3. AFTER S"(VERTICAL) OF FILL IS IN PLACE, CONTRACTOR SHOULD MAINTAIN A 5.:..RAOIUS EQUIPMENT CLEARANCE FROM RISER. . . I.. PLACE AND MECHANICALLY HAND COMPACT INITIAL 2' OF FILL PRIOR TO ESTABLISHING· THE INITIAL READING. 5. IN THE EVENT OF DAMAGE TO THE SETTLEMENT PLATE OR EXTENSION RESULTING FROM EQUIPMENT OPERATING WITHIN THE SPECIFIED CLEARANCE AREA, CONTRACTOR SHOULD IMMEDIATELY NOTIFY THE SOILS ENGINEER AND SHOULD BE RESPONSIBLE FOR RESTORING THE SETTLEMENT PLATES TO WORKING ORDER. 6. AN ALTERNATE DESIGN AND METHOD OF INSTALLATION MAY BE PROVIDED AT THE DISCRETION OF THE· SOILS ENGINEER. PLATE EG-14 I I I I I I I I I- I' I I I I I I I I I TYPICAL SURFACE SETTLEMENT MONUMENT FtHISH GRADE --~~~~----~---------,------~--------- .._~ 3/a· DIAMETER X s· LENGTH -CARRIAGE BOLT OR EOUIVA.LENT • DIAMETER X 3 1/2"LENGTH HOLE ..__4-CONCRETE BACKFILL PLATE EG-15 I I I I I I I I I I I I I I I I I I I TEST PIT SAFETY DIAGRAM so FEET SPOIL PRE SIDE VIEW ( NOT TO SCALE ) TOP VIEW 100 FEET I- HI u. 0 an SO FEET :==:~~~~~=~~=~{:~::~=~tt~~~~--~ ==r = :~~::~t?~{:~:r.-::···:~~~~ =---l___.!_..!..___J , APPROXIMATE CENiER / ... lH u. FLAG CF TEST PlT 0 ll'l l NOT TO SCALE ) i:>1 A Tl= J:"G-16 I I I I I I I I· I I I I I I I I I I I OVERSIZE ROCK DISPOSAL VIEW NORMAL TO SLOPE FACE PROPOSED FINISH GRADE 1 O' MINIMUM (El c,:, Cf:J 00 co ~ 15• MINIMUM (A) (Bl 00 ~ co o· (GI 00 CICl ~ co oO cclA ViEW PARALLEL TO SLOPE FACE PROPOSED FINISH GRADE 10'MINIMUM (El ~ 3• MINIMUM ~ £ 1s· MINIMUM c.o.:: =~~ ~ 15" MINIMUM '/ BEDROCK OR APPROVED MATERIAL NOTE: (Al ONE EQUIPMENT WIDTH OR A MINIMUM OF 15 FEET. (B) HEIGHT AND WIDTH MAY VARY DEPENDING ON ROCK SIZE AND TYPE OF EQUIPMENT, LENGTH OF WINDROW SHALL BE NO GREATER THAN 100"MAXIMUM. IC) IF APPROVED BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST, WINDROWS MAY B·E PLACED DIRECTLY ON COMPETENT MATERIAL OR BEDROCK PROVIDED ADEOUA TE SPACE IS AVAILABLE FOR COMPACTION. ~ ID) ORIENTATION OF WINDROWS MAY VARY BUT SHOULD BE AS RECOMMENDED BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST. STAGGERING OF WINDROWS IS NOT NECESSARY UNLESS RECOMMENDED; IE) CLEAR AREA FOR UTILITY TRENCHES, FOUNDATIONS AND SWIMMING POOLS. (Fl ALL FILL OVER AND AROUND ROCK WINDROW SHALL BE COMPACTED TO 90% RELATIVE COMPACTION OR AS RECOMMENDED. IG) AFTER FILL BETWEEN WINDROWS IS PLACED AND COMPACTED WITH THE LIFT OF FILL COVERING WINDROW, WINDROW SHOULD BE PROOF ROLLED WITH A D-9 DOZER OR EQUIVALENT. VIEWS ARE DIAGRAMMATIC ONLY. ROD< SHOULD NOT TOUQ-i AND VOIDS SHOULD BE COMPLETELY FILLED IN. p LA TE RD-1 I I I I I I I I I I I I I- I I I I I I ROCK DISPOSAL PITS · VIEWS ARE DIAGRAMMATIC ONLY. ROD< SHOULD NOT TOUQ; ANO VOIDS SHOULD BE COMPLETELY FILLED IN. RLL LIFTS COMPACTED OVER ROCK AFTER EMBEDMENT ~---------I I GRANULAR MATERIAL I .-----------, 1 ; coMPACTe·o Fl LL I I I I SIZE OF EXCAVATION TO BE COMMENSURATE WITH ROCK SIZE ROCK DISPOSAL LAYERS I I I I I I GRANULAR SOIL TO FILL VOIDS.~ . FCOMPACTED RLL OENSIAEDBYFLOODING A--------...... . LAYER ONE ROCK HIGH o~o.a::U.cg: PROPOSED FINISH GRADE Io· MINIMUM OR BELOW LOWEST UTILIT ---------------~ 20· ... .... ... ..._ .. ...... ______ ------------- PROFILE ALONG LA YER 0:::o:JO:X:::,0::o:iGICl~CJCQ::jC0::::0000',~-' . ... ... COCPoocc:ac~X)(::::c:,0::::ioc:cx:~~:;c~~~ ...... ~"MINIMUM ''~ FILL SLOPE ICLEAR ZONE 20· MINIMUM PLATE RD-2 I I I I I I I I I I I I I I I I I I 1. ·, ... ,. _cj, '•. --- I ! r ~~1 ~~~10·_ ' afu. ~ .. (Taa) 0 F <( a.. Artificial fill -undocumented · Tertiary SentlaQJ>-formation (circled where buried) Approximate location of geologic contact queried where uncertain J\pproximate locatlon of eXf1loratory boring (ECSCEI, 2001), with total depth In fe~t Approximate lo"3tion of exploratory )est pit (ECSCEI, 2001), with total depth In feel Geologic cross section --· -...... ---------=-~--...... I• .. ' ______ .... ---· • 1 I_ L CJ[. 1\J .U """""""'a,. -PROPERTY Ul~E ,_ XXXX == --l'Rlll'DSED GRADll·Jfi CONTOUR --(XXX) --· (XISTIN(i liR/\fllNCi CIJNTOUR . --...... -.; . ~· TC TOP OF Cl.l~!B FL tLIJ\J UNF: CLl:::\/1,f:rJM TF TOP OF FOIJMJJA TIDl'J f' [NISH Cil~AO[l<G f-lMISH[Jl SlJf,!FAC[ T',/ TllP OF ,/ALL \JV R/IJ T~ ff 1.,/A ~ ~-p VA~-\Ii: RIGHT DI-VAY HIP OF P.[-~A:1~11,tG OF F[JQTJNG EXISTING / ./ !JI' l I \ \ '\ -OD. -co. --co. CITY OF CARLSBAD CONCEPTUAL GRADING PLAN FOR NINE LOTS C.ONDOMINIUM AT LOTS 3'12 AND 3'13 OF LA C:OSTA 50!/TH UNIT NO. 5 APKt121(;,-300·12, 1:l I I I I ! .. I I I .. ::· I I I I I I I I I I I I ·:-... ;·: ·1·: :?· :.::· .1 .... :;.:· ·:.,-.. . :-. ,· E· L. .E V . A· T I 0 N .. :r. . :i·: .. (IN FEET). B 95 75 65· 45 ... , .. :··.;:+?' ·-~: j"· :. ,·d, . .. -! ,._; ... .. --:-i. ]L ·:-'.:-.-::--··i· .· '''..{: ·:x.: .. H.!: .. ·. ::-i·:·· >r; )}!-if.:_·. .. -.. , ...... . 1.•.:.: !•: ~-- . --· ·-··'· .. ·Tsa ' ·e-1 ; ___ . (GS~ 2004!°; . ~-=-~--. ... ::;.1·1-1-·- !. ·. ~;~l~~~:;~s~J.~~tv <:' .. . ,,·.:-e-1 (ECSCEI, 2001),° ··~ '.:.~P~o~~~!!d _s2•1,·-~-·Locaiion of pro osed bulld1n ; '· - ·afu Tsa ·Tsa T1>:1r ·N39°W A'.. B-2 ·(GSl,.-2004)· Projected 38'~E . af~, [-------:. ,a.-~------~ afu; T0:41'/,~· ·-··· -; .. 95 .85 75 ·45· I . ·, .. E L .E ·V A T 1. ·o N (IN FEET) ·····-·~~1i:,1~::1,ul:1 ·····P~·~ ~'·-•••'lj,;;~~£~~~ ~~~·M~ .•. • • i~Ci . . . . ,-~ 1 ..... N _O: ; {~{,'',.: ···:·:···· · : f=~:~nf r~}t?:: . !_.:;-... i": i . ;.:.:. . J'.0: · .. !·· ··-·:-·: afu -? I I ··-J : ____ !!:!I~ .. ~--- .. , I I I ?.-.-. -· . --. ?-,- ? ./ TD:18'·· ?/. 'Tsa· .• .. i·t-.. ·_·-: __ ·1:_tesslve to Weak · ::::; : -;\::. S~horlzontal B~ddl~~:~.1·: /n.'d;· · ·· -::W·' .',;,' !·:·:.:i::· !_ ....... · :.· . T0:411/1•. .... :. \(_:·=·:·: .. :J. ··-'..;:\;··i·(·;.::· ,.j:. . ' r., .. ------jj\i N890W · ,. ·.! . ,, ·., ~:~:sed >;--FJ,:!_~~~1 I ·I· . ,: . .... ·::: ----!~.:':3.:~-----' t___ . c:r:----- ?---'-.,...---?.------- Tsa afu. ?.: . ?.----· __ i:_ __ _ :;, •. !.: ... -:· :~l .: ........ i ;~~! .. _:::-.LEGEND l • · afu. . · ·· ·il,imc1.i 1111 (undocumented)._,.· ~sa: ..... '.>~~rtlary Santleg~_Form~tl~n· :· .... : ... ·: .. :.:· ···:-':Approximate location of geolo~1c·:. -?~" ~ontact; ~uerled where uncarta ~ · 75 :55 45 E L E V A T I 0 N (IN FEET)" ·.,;· ~~rrJ. ~~n· RIVERSIDE CO. ORANGE CO. SAN DIEGO co. GEOLOGIC CROSS SECTION$ A-A'. -B-B'. Plate 2 W.O 4460-A-SC DATE 9/04 SCALE 1":10'