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HomeMy WebLinkAboutCDP 04-18; Oliver Residence; Preliminary Geotechnical Evaluation; 2004-07-09PRELIMINARY GEOTECHNICAL EVALUATION 6467 SURFSIDE LANE CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA FOR MR. GUY OLIVER 6465 FRANCISCAN ROAD CARLSBAD, CALIFORNIA 92009 W.O. 4401 -A-SC JULY 9, 2004 Geotechnical • Geologic • Environmental 5741 Palmer Way • Carlsbad, California 92008 • (760)438-3155 • FAX (760) 931-0915 July 9, 2004 W.O. 4401-A-SC Mr. Guy Oliver 6465 Franciscan Road Carlsbad, California 92009 Subject: Preliminary Geotechnical Evaluation, 6467 Surfside Lane, Carlsbad, San Diego County, California Dear Mr. Oliver: 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 the available data (see Appendix A), field exploration, laboratory testing, geologic and engineering analysis, the proposed development of the property appears to be feasible from a geotechnical viewpoint, provided the recommendations presented in the text of this report are properly incorporated into the design and construction of the project. The most significant elements of this study are summarized below: A review of the grading plans, provided by Robert Bowlus Architecture, Inc., indicates that proposed construction is to consist of preparing the site for the construction of a two-story, single-family residence with associated residential improvements. An excavation of approximately 3 feet below the existing ground surface will be necessary to achieve the design grade for the residence. The residence will be supported by continuous footings with a wood-frame and/or masonry block construction and a slab-on-grade. All deleterious debris and vegetation should be removed from the site and properly disposed, should settlement sensitive improvements be proposed within their influence. Removals of compressible, undocumented artificial fill and weathered Quaternary terrace deposits will be necessary prior to fill placement. Depths of removals are outlined in the "Conclusions and Recommendations" section of this report. In general, removals of unsuitable soils will be on the order of ±2 to ±2V2 feet across the site. However, localized deeper removals cannot be precluded. It is anticipated that the removal of unsuitable bearing soils will be accomplished during the excavation for the proposed residence. Overexcavation of the building pad may be required in order to mitigate the potential for differential settlement due to pervasive paleoliquefaction features that were observed during an investigation of a nearby site (Franklin and Kuhn, 2000). Overexcavation, below finish grade, to provide for a 3-foot thick compacted fill blanket, or 18 inches of compacted fill beneath ali footings (whichever is greater) is recommended at this time, if paleoliquefaction features are encountered during site grading. • The expansion potential of tested onsite soils is very low (Expansion Index [E.I.] Oto 20). Post-tension foundations are specifically recommended to mitigate the potential for differential settlement by the presence of regionally pervasive paleoliquefaction features. If paleoliquefaction features are not encountered, conventional slabs on grade fountdations may be considered. Unsupported excavations should be constructed in accordance with criteria established in Article 6 of the State of California, Construction Safety Orders (CAL/OSHA) for Type "B" soils. Temporary slopes should be further evaluated during site grading. • Site soils, tested, present a negligible sulfate exposure to concrete and are 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/terrace deposit contacts), and should be anticipated. Our evaluation indicates that the site has a very low potential for liquefaction. Therefore, no recommendations for mitigation are deemed necessary. • The seismic acceleration values and design parameters provided herein should be considered during the design of the proposed development. • Our evaluation indicates there are no known active faults crossing the site. Adverse geologic features that would preclude project feasibility were not encountered. Mr. Guy Oliver W.O. 4401-A-SC File:e:\wp9\4400\4401a.pge Page Two GeoSoils, Inc. The recommendations presented in this report should be incorporated into the design and construction considerations of the project. The opportunity to be of sen/ice 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 ofthe undersigned. Respectfully submitted, GeoSoils, Inc. Ryan Boehmer Staff Geologist Paul L. McClay Engineering Geologist RB/PLM/DWS/jk Distribution: (4) Addressee )avid W. Ske Civil Engineer, RCE 4 Mr. Guy Oliver Fiie:e:\wp9\4400\4401 a.pge W.O. 4401-A-SC Page Three GeoSoils, Inc. TABLE OF CONTENTS SCOPE OF SERVICES 1 SITE CONDITIONS/PROPOSED DEVELOPMENT 1 SITE EXPLORATION 3 REGIONAL GEOLOGY 3 Lineament Analysis 3 Paleoliquefaction Features 5 SITE GEOLOGIC UNITS 5 Undocumented Artificial Fill (Not Mapped) 5 Quaternary Terrace Deposits (Map Symbol - Qt) 5 FAULTING AND REGIONAL SEISMICITY 6 Regional Faults 6 Seismicity 6 Seismic Shaking Parameters 8 Seismic Hazards 9 GROUNDWATER 9 LIQUEFACTION POTENTIAL 10 SETTLEMENT 11 SLOPE STABILITY 11 LABORATORY TESTING 11 General 11 Classification 11 Laboratory Standard 11 Expansion Potential 12 Direct Shear Test 12 Corrosion/Sulfate Testing 12 CONCLUSIONS AND RECOMMENDATIONS 13 General 13 EARTHWORK CONSTRUCTION RECOMMENDATIONS 15 General 15 Site Preparation 15 Removals (Unsuitable Surficial Materials) 15 Overexcavation 16 GeoSoils, Inc. Fill Placement 16 Temporary Cut Slopes 16 RECOMMENDATIONS - FOUNDATIONS 17 Preliminary Foundation Design 17 Bearing Value 17 Lateral Pressure 17 Preliminary Foundation Settlement Evaluation 18 Footing Setbacks 18 Construction .18 CONVENTIONAL FOUNDATIONS 19 Expansion Classification - Very Low to Low (E.I. 0 to 50) 19 POST-TENSIONED SLAB SYSTEMS 20 Post-Tensioning Institute Method 20 CORROSION 22 UTILITIES 22 WALL DESIGN PARAMETERS 22 Conventional Retaining Walls 22 Restrained Walls 23 Cantilevered Walls 23 Retaining Wall Backfill and Drainage 23 Wall/Retaining Wall Footing Transitions 27 TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS 28 Slope Creep 28 Top of Slope Walls/Fences 28 DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS 29 DEVELOPMENT CRITERIA 31 Slope Deformation 31 Slope Maintenance and Planting 32 Drainage 32 Toe of Slope Drains/Toe Drains 33 Erosion Control 34 Landscape Maintenance 34 Gutters and Downspouts 34 Subsurface and Surface Water 37 Site Improvements 37 Tile Flooring 37 Mr. Guy Oliver Table of Contents File:e:\wp9\4400\4401 a.pge Page 11 GeoSoils, Inc. Additional Grading 37 Footing Trench Excavation 38 Trenching 38 Utility Trench Backfill 38 SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING 39 OTHER DESIGN PROFESSIONALS/CONSULTANTS 40 PLAN REVIEW 40 LIMITATIONS 40 FIGURES: Figure 1 - Site Location Map 2 Figure 2 - Boring Location Map 4 Figure 3 -California Fault Map 7 Detail 1 - Typical Retaining Wall Backfill and Drainage Detail 24 Detail 2 - Retaining Wall Backfill and Subdrain Detail Geotextile Drain 25 Detail 3 - Retaining Wall and Subdrain Detail Clean Sand Backfill 26 Detail 4 - Schematic Toe Drain Detail 35 Detail 5 - Subdrain Along Retaining Wall Detail 36 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 - General Earthwork and Grading Guidelines Rear of Text Mr. Guy Oliver Flle:e:\wp9\4400\4401 a.pge Table of Contents Page iii GeoSoils, Inc. PRELIMINARY GEOTECHNICAL EVALUATION 6467 SURFSIDE LANE 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, a review of aerial photographs, subsurface exploration with three exploratory hand auger borings (see Appendix B), sampling, and mapping. 3. General areal seismicity evaluation (see Appendix C). 4. Appropriate laboratory testing of representative soil samples (see Appendix D). 5. Engineering and geologic analysis of data collected. 6. Preparation of this report. SITE CONDITIONS/PROPOSED DEVELOPMENT The subject site is a rectangular, generally flat-lying to very gently sloping, vacant property located on the west side of Surfside Lane in the City of Carlsbad, San Diego County, California (see Figure 1, Site Location Map). Site drainage appears to be directed to the east via sheet flow runoff. The site is located approximately ±67 feet above Mean Sea Level (MSL). The site is generally devoid of vegetation. Based on the plans, provided by Robert Bowlus Architecture, Inc., proposed development is to consist of the construction of a two-story single-family residence with a partial subterranean first floor. Proposed site grading consists of cut excavation to approximately 3 feet below existing grades for the proposed pad level subgrade. Flooring systems are anticipated to consist of raised wood floors within the entry area and conventional concrete slabs on grade throughout the remainder of the structure's footprint. Foundation systems are currently proposed to use conventional design and construction, however, the findings of this study indicate that a post-tension design may be warranted. Building loads are assumed to be typical for this type of relatively light construction (slab-on-grade, wood frame, and/or masonry block). It is anticipated that sewage disposal will be tied into the municipal system. The need for import soils is unknown at this time. GeoSoils, Inc. J-D TopoQuads Copyright« 1999 DtUrme YannouUi, ME 04096 .Source Data: USGS Base Map: Encinitas Quadrangle, California—San Diego Co., 7.5 Minute Series (Topographic), 1968 (photorevised 1975), by USGS, 1'=2000' 2000 Scale 4000 Feet N W.O. 4401-A-SC SITE LOCATION MAP Figure 1 SITE EXPLORATION Surface observations and subsurface explorations were performed on June 22, 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 exploration. Near surface soil and geologic conditions were explored with three hand auger borings within the site. The approximate locations of each boring are shown on Figure 2 (Boring Location Map). 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 Ranges. 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 rocks of the southern California batholith. In the San Diego County region, deposition occurred dunng 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 ofthe 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. Lineament Analysis In order to identify possible unmapped faults, a photo-lineament analysis was performed. As indicated previously, stereoscopic "false-color" infrared, aerial photographs (United States Department of Agriculture, 1980) at a scale of approximately 1"= ±3,333', were utilized in our lineament analysis. Lineaments were classified according to their development as strong, moderate, or weak. A strong lineament is a well defined feature that can be continuously traced several hundred feet to a few thousand feet. A moderate lineament is less well defined, somewhat discontinuous, and can be traced for only a few hundred feet. A weak lineament is discontinuous, poorly defined, and can be traced for a few hundred feet or less. During the analysis, a northwest - southeast trending lineament was observed just to the north of the site. This lineament represents a tonal variation within the terrace deposits and is considered weak to moderate in nature. The lineament is generally parallel to subparallel to the regional trend ofthe offshore Newport-lnglewood/Rose Canyon Fault Zone (NIRC). Mr. Guy Oliver W.O. 4401-A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401a.pge Page 3 GeoSoils, Inc. > • •o CO fi> CO rs o O II CO N) \ o -o (A o - X « 3 o c r* o 9 Ql O — O) <D 2 •o = 3 <D (D ^ <D o fi) o — 9 m O m fl) o (D a. o •D O 2. (0 3 m o w - S o ' « "O c o o a. 3 O SURFSIDE LANE Paleoliquefaction Features A recent geologic investigation conducted by Franklin and Kuhn (2000), located approximately mile southeast of the site, indicated "several epochs of liquefied sediments (sand dikes, lateral spreads, and asand laccolith)." These liquefied sediments range from late Holocene (no more than 2,000 to 3,000 years old), to perhaps Pleistocene in age, and reflect at least two, and perhaps multiple paleoliquefaction events, based on soil and stratigraphic relationships. Other pervasive paleoliquefaction features ("mima mounds") were also observed during air photo analysis conducted in preparation of this report. However, features potentially associated with paleoliquefaction were not observed onsite. SITE GEOLOGIC UNITS The site geologic units encountered dunng our subsurface investigation and site reconnaissance included undocumented artificial fill underlain by Quaternary terrace deposits (Kennedy and Tan, 1996). The earth materials are generally described below from the youngest to the oldest. The distribution of these materials is shown on Figure 2 (Boring Location Map). Undocumented Artificial Fill (Not Mapped) A thin veneer of artificial fill was observed to mantle the site in all of our exploratory borings and consists of light red brown to brown, dry, loose, silty sands that are on the order of ±1 footto ±iy2feetthick. These materials are considered potentially compressible in their existing state and will require removal and recompaction if settlement-sensitive improvements are proposed within their influence. Quaternarv Terrace Deposits (Map Svmbol - Qt) Quaternary terrace deposits were observed to directly underlie the undocumented fill soils, and consist of medium dense to dense, silty sands. These deposits are generally dark red brown to red brown and dry to damp. The upper ±1 foot of these sediments are generally weathered and are considered unsuitable for structural support in their present condition, and should be removed and recompacted. Bedding structure was not readily observed, but regionally is typically flat lying to sub-horizontal. These sediments are typically massive to weakly bedded. Although not observed during our site exploration, paleoliquefaction features (as discussed above) could be encountered within these terrace deposits during future site earthwork. Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401 a.pge Page 5 GeoSoils, Inc. FAULTING 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; the San Jacinto fault; the Elsinore fault; 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 3 (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): ABBREVIATED FAULT NAME APPROXIMATE DISTANCE MILES (KM) Rose Canyon 4.1 (6.6) Newport - Inglewood (Offshore) 7.2 (11.6) Coronado Bank 19.6 (31.6) EIsinore-Temecula 25.7 (41.4) Eisinore-Julian 25.7 (41.4) Elsinore-Glen Ivy 36.9 (59.4) Palos Verdes 37.7 (60.7) Earthquake Valley 43.1 (69.4) San Jacinto - Anza 48.5 (78.1) Newport - Inglewood (L.A. Basin) 49.0 (78.8) San Jacinto - San Jacinto Valley 49.5 (79.6) Seismicitv 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. Mr. Guy Oliver 6467 Surfside Lane, Carlsbad Fiie:e:\wp9\4400\4401 a.pge W.O. 4401-A-SC July 9, 2004 Page 6 GeoSoils, Inc. CALIFORNIA FAULT MAP OLIVER 1100 1000 900 -- 800 -- 700 -- 600 -- 500 400 -- 300 -- 200 100 0 -- -100 I I I I I I I I I I I I I I I I I jl I I I -400 -300 -200 -100 0 100 200 300 400 500 600 W.O. 4401-A-SC Figure 3 GeoSoils, Inc. 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 EQFAULT program, peak horizontal ground accelerations from an upper bound event at the site may be on the order of 0.62g to 0.73g. The computer printouts of portions ofthe EQFAULT program are included within Appendix C. Historical site seismicity was evaluated with the acceleration-attenuation relations of Campbell and Bozorgnia (1997) 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 0.39g. A historic earthquake epicenter map and a seismic recurrence curve are also estimated/generated from the historical data. Computer printouts ofthe EQSEARCH program are presented in Appendix C. . A probabilistic seismic hazards analyses was performed using FRISKSP (Blake, 2000c), which models earthquake sources as 3-D 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 0.35g was calculated. This value was chosen as it corresponds to a 10 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: 1997 UBC CHAPTER 16 TABLE NO. SEISMIC PARAMETERS Seismic Zone (per Figure 16-2*) 4 Seismic Zone Factor (per Table 16-1*) 0.40 Soil Profile Type (per Table 16-J*) SD Seismic Coefficient C^ (per Table 16-Q*) O.44N3 Mr. Guy Oliver 6467 Surfside Lane, Carlsbad File:e:\wp9\4400\4401 a.pge GeoSoils, Inc. W.O. 4401-A-SC July 9, 2004 Page 8 1997 UBC CHAPTER 16 TABLE NO. SEISMIC PARAMETERS Seismic Coefficient C„ (per Table 16-R*) 0.64N^ Near Source Factor N^ (per Table 16-S*) 1.0 Near Source Factor N^ (per Table 16-T*) 1.15 Distance to Seismic Source 4.1 mi (6.6 km) Seismic Source Type (per Table 16-U*) B Upper Bound Earthquake (Rose Canyon fault) M„ 6.9 * Figure and Tabie references from Chapter 16 of the UBC (ICBO, 1997) Seismic Hazards The following list includes other seismic related hazards that have been considered during our evaluation ofthe site. The hazards listed are considered negligible and/or completely mitigated as a result of site location, soil characteristics, and typical site development procedures: • Dynamic Settlement Surface Fault Rupture 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 thatthe 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 regional groundwatertable is anticipated to be near MSL (approximately 67 feet below the site). Mr. Guy Oliver 6467 Surfside Lane, Carlsbad File:e:\wp9\4400\4401 a.pge GeoSoils, Inc. W.O. 4401-A-SC July 9, 2004 Page 9 Perched groundwater conditions along fill/terrace 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 post-development perched groundwater conditions develop, this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions 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 watertable; but after liquefaction has developed, 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 cohesionless 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. Significant 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. In the site area, we found there is a potential for seismic activity. However, the regional groundwater table is located approximately 67 feet below the site and the terrace deposits, encountered onsite, were composed of massively bedded, silty sands that become dense with depth. 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, it is our opinion that the liquefaction potential does not constitute a significant risk to site development. It should be noted thatthe presence of "paleoliquefaction features" in the vicinity does not indicate that the area is currently susceptible to liquefaction. "Paleo" liquefaction, by definition, describes events which occurred in the geologic past, and under conditions that Mr. Guy Oliver W.O. 4401-A-SC 6467 Surfside Lane, Carisbad July 9, 2004 File:e:\wp9\4400\4401 a.pge Page 10 GeoSoils, Inc. were much different than what is observed at present. Based on the criteria presented above, future seismic events should not result in damage from liquefaction onsite. The importance of "paleoliquefaction" as it pertains to this study, is related to differential soil conditions underlying the site and the impact of these conditions on the total and differential settlement that the project could be subject to. SETTLEMENT The presence of paleoliquefaction features creates a non uniform condition within the underlying native soils that has the potential to provide for relatively large differential settlement. This potential differential settlement could be on the order of 1 inch to 1 Va inches in a 40 foot span, an angular distortion of 1/320. A differential settlement on the order of 1 inch in a 40 foot span (1/480), is considered to be the tolerance limit for typical concrete slabs-on-grade and conventional foundation systems. As such, the presence of paleoliquefaction features would preclude the use of conventional foundations, and a post- tension design would then be more appropriate and recommended. SLOPE STABILITY Based on site conditions and planned improvements, significant cut and/or fill slopes are not anticipated. LABORATORY TESTING General Laboratory tests were performed on representative samples of the onsite earth materials in order to evaluate their physical characteristics. The test procedures used and results obtained are presented below. Classification Soils were classified visually according to the Unified Soils Classification System (Sowers and Sowers, 1970). The soil classifications are shown on the Boring Logs in Appendix B. Laboratorv Standard The maximum dry density and optimum moisture content was determined forthe major soil type encountered in the borings. The laboratory standard used was ASTM D-1557. The moisture-density relationship obtained for this soil is shown below: Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401a.pge Page 11 GeoSoils, Inc. SOIL TYPE TEST PIT MAXIMUM DRY DENSITY (pcf) OPTIMUM MOISTURE CONTENT (%) Dark Brown, Silty SAND B-1 to B-3 (Composite) 133.0 8.0 Expansion Potential Expansion testing was performed on a representative samples of site soil in accordance with UBC Standard 18-2. The results of expansion testing are presented in the following table. LOCATION EXPANSION INDEX EXPANSION POTENTIAL B-1 to B-3 (Composite) <5 Very Low Direct Shear Test Shear testing was performed on a representative, "remolded" sample of site soil in general accordance with ASTM Test Method D-3080 in a Direct Shear Machine ofthe strain control type. The shear test results are presented as follows and are provided in Appendix D: SAMPLE LOCATION PRIMARY RESIDUAL SAMPLE LOCATION COHESION (PSF) FRICTION ANGLE (DEGREES) COHESION (PSF) FRICTION ANGLE (DEGREES) B-1 to B-3 (Composite) 112 30 94 30 Corrosion/Sulfate Testinq 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 slightly acidic (pH=6.4) with respect to acidity and have a saturated resistivity of 1,900 ohm-cm. Thus, the site soils are corrosive to ferrous metals when saturated. Corrosive soils are considered to range between 1,000 and 2,000 ohms-cm. Testing indicates that the site soils have a sulfate content of 0.0110 percentage by weight. This corresponds to a negligible sulfate exposure to concrete (UBC range for negligible sulfate exposure is 0.00 to 0.10 percentage by weight soluble [SOJ in soil). Alternative testing methods and additional comments should be obtained from a qualified corrosion Mr. Guy Oliver 6467 Surfside Lane, Carlsbad File:e:\wp9\4400\4401 a.pge W.O. 4401-A-SC July 9, 2004 Page 12 GeoSoils, Inc. engineer with regard to foundations, piping, etc. Laboratory test results are presented in Appendix D. 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. This report presents minimum design criteria for the design of slabs, foundations, and other elements possibly applicable to the project. These criteria should not be considered as substitutes for actual designs by the structural engineer. The structural engineer should analyze actual soil-structure interaction and consider, as needed, bearing, expansive soil influence, and strength, stiffness, and deflections in the various slab, foundation, and other elements in order to develop appropriate, design-specific details. As conditions dictate, it is possible that other influences will also have to be considered. The structural engineer should consider all applicable codes and authoritative sources, where needed. If analyses by the structural engineer result in less critical details than are provided herein as minimums, the minimums presented herein should be adopted. It is considered likely that some, more restrictive details will be required." Ifthe structural engineer has any questions or requires further assistance, please do not hesitate to call or othen/vise transmit his requests. The primary geotechnical concerns with respect to the proposed development are: Depth to competent material. Overexcavation ofthe building pad. Potential for perched groundwater after development Expansion potential of site soils. Regional seismic activity. The recommendations presented herein consider these as well as other aspects ofthe 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. Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401 a.pge Page 13 GeoSoils, Inc. 1. Soil engineering, observation, and testing sen/ices 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. 3. All compressible artificial fill on the order of ± 1 foot to ± 1 Vz feet thick and the upper ± 1 foot ofthe weathered terrace deposits are considered unsuitable forthe support of settlement-sensitive improvements 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. 4. If paleoliquefaction features are encountered during site earthwork, overexcavation of the building pad, to a depth of at least 3 feet below slab subgrade, or 18 inches below the bottom ofthe footing (whichever is deeper), will be necessary in order to mitigate the potential differential settlements. If observations made during site grading indicate that paleoliquefaction features are not present, then the pad area may be cut to plan grade and the foundation excavations for the structure completed into the underlying native soil. . 5. In general and based upon the available data to date, groundwater is not expected to be a major factor in development ofthe site. However, perched groundwater conditions along fill/terrace 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. 6. Unsupported excavations should be constructed in accordance with criteria established in Article 6 of the State of California, Construction Safety Orders (CAL/OSHA) for Type "B" soils. 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. 7. General Earthwork and Grading Guidelines are provided at the end of this report as Appendix E. Specific recommendations are provided below. 8. Our laboratory test results and experience on nearby sites, related to expansion potential, indicate that soils with very low expansion indices underlie the site. This should be considered during project design and construction. Mr. Guy Oliver ~~~ W.O. 4401-A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401a.pge Page 14 GeoSoils, Inc. 9. Post-tension foundations are specifically recommended to support the residence in order to mitigate the potential for differential settlement caused by regionally pervasive paleoliquefaction features. Preliminary post-tension foundation design and construction recommendations are provided herein for a very low expansion potential classification. Final post-tension foundation design and construction recommendations will be provided at the conclusion of site grading. 10. The seismicity-acceleration values provided herein should be considered during the design and construction of the proposed development. EARTHWORK CONSTRUCTION RECOMMENDATIONS General All grading should conform to the guidelines presented in Appendix Chapter A33 of the UBC, the requirements ofthe City, and the Grading Guidelines presented in Appendix E, 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 deleterious materials should be removed from the site prior to the start of construction. Removals (Unsuitable Surficial Materials) Due to the relatively loose condition of the undocumented artificial fill, and weathered, near-surface terrace deposits, these materials should be removed and recompacted in areas proposed for settlement sensitive improvements or areas to receive compacted fill. At this time, removal depths on the order of ±2 to ±2V2 feet (including weathered terrace deposits) below existing grade should be anticipated throughout the site; however, locally deeper removals cannot be precluded and should be anticipated. Removals should be completed below a 1:1 projection down and away from the edge of any settlement-sensitive improvement 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 Mr. Guy Oliver W.O. 4401-A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401a.pge Page 15 GeoSoils, Inc. 90 percent relative compaction. A review of the grading plans, provided by the Client, indicate that the design grade for the residence is approximately 3 feet below the existing ground surface. Therefore, the removal of unsuitable bearing soils will be completed by default during the excavation for the residence. Overexcavation During site grading, the proposed building pad area will be observed by this office to determine if paleoliquefaction features are present. If present, the building pad should be overexcavated to at least 3 feet below pad grade, or 18 inches below the bottom of the footings (whichever is greater) and brought back to grade with compacted fill. 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 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 low expansive (Expansion Index [E.I.] less than 50). The use of subdrains atthe bottom ofthe fill cap may be necessary, and subsequently recommended based on compatibility with onsite soils. Temporary Cut Slopes Unsupported excavations should be constructed in accordance with criteria established in Article 6 ofthe State of California, Construction Safety Orders (CAL/OSHA) for Type "B" soils. On a preliminary basis, temporary slopes for removals may be inclined at gradient of 1:1 (h:v) to a maximum height of 20 feet. 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. Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401 a.pge Page 16 GeoSoils, Inc. RECOMMENDATIONS - FOUNDATIONS Preliminarv Foundation Desian 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 forthe 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 additionai consultation regarding soil parameters, as related to foundation design. Our review, field work, and recent laboratory testing indicates that onsite soils have a very low expansion potential (E.I. Oto 20). Preliminary recommendations for foundation design and construction are presented below. Final foundation recommendations will be provided atthe conclusion of grading, based on laboratory testing of fill materials exposed at finish grade and the presence/or absence of paleoliquefaction features. Bearing Value 1. The foundation systems should be designed and constructed in accordance with guidelines presented in the latest edition ofthe UBC. 2. An allowable bearing value of 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 inches 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 bythe 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. Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401a.pge Page 17 GeoSoils, Inc. 3. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. Preliminarv Foundation Settlement Evaluation Foundation systems for all settlement-sensitive improvements should be designed to accommodate a differential settlement of at least 3/4 inch in a 40 foot span (1/640) for foundations bearing in uniform native soil, or IVa inches in a 40-foot span (1/320) for foundations supported on a 3 foot thick compacted fill layer, underiain with non uniform native soils (i.e., paleoliquefaction features). Footina Setbacks Footings should maintain a minimum horizontal setback of H/3 (H = slope height) from the base of the footing to any descending slope face and no less than 7 feet, nor need be greater than 40 feet. If the location of proposed footings conflicts with GSI's setback recommendations, proper setbacks may be maintained by simply deepening the footings. Footings adjacent to 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" section of this . report. Construction The following foundation construction recommendations are presented as a minimum criteriafrom a soils engineering standpoint. The onsite soil expansion potential is generally very low (E.I. 0 to 20). For site conditions indicating a suitable, uniform native soil (i.e., terrace deposits), a conventional foundation design may be used. However, due to the potential for regionally pen/asive paleoliquefaction features (Franklin and Kuhn, 2000), a post-tension foundation system is specifically recommended for the support of the residence, should non-uniform soil conditions (i.e., paleoliquefaction features) be identified, to mitigate the potential for differential settlement. Preliminary recommendations for conventional and post-tensioned foundation systems 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. Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401 a.pge Page 18 GeoSoils, Inc. CONVENTIONAL FOUNDATIONS Expansion Classification - Verv Low to Low (E.I. 0 to 50) 1. Conventional continuous footings should be founded at a minimum depth of 12 inches below the lowest adjacent ground surface for one-story floor loads and 18 inches below the lowest adjacent ground surface for two-story floor loads. Interior footings may be founded at a depth of 12 inches below the lowest adjacent ground surface. Footings for one-story floor loads should have a minimum width of 12 inches, and footings for two-story floor loads should have a minimum width of 15 inches. All footings should have one No. 4 reinforcing bar placed at the top and one No. 4 reinforcing bar placed at the bottom of the footing. Isolated interior or exterior footings should be founded at a minimum depth of 24 inches below the lowest adjacent ground surface. 2. A grade beam, reinforced as above, and at least 12 inches square, should be provided across the garage entrances. The base of the reinforced grade beam should be at the same elevation as the adjoining footings. 3. Concrete slabs in residential and garage areas should be a minimum of 4 inches thick, and underiain with a vapor barrier consisting of a minimum of 10-mil, pdlyvinyl-chloride membrane with all laps sealed, per the UBC. This membrane should be covered with a minimum of 2 inches of sand to aid in uniform curing of the concrete. 4. Concrete slabs, including garage slabs, should be reinforced with No. 3 reinforcement bars placed on 18-inch centers, in two horizontally perpendicular directions (i.e., long axis and short axis). All slab reinforcement should be supported to ensure proper mid-slab height positioning during placement of the concrete. "Hooking" of reinforcement is not an acceptable method of positioning. 5. Garage slabs should be poured separately from the residence footings and be quartered with expansion joints or saw cuts. A positive separation from the footings should be maintained with expansion joint material to permit relative movement. 6. The residential and garage slabs should have a minimum thickness of 4 inches, and the slab subgrade should be free of loose and uncompacted material prior to placing concrete. 7. Presaturation is recommended for these soil conditions, the moisture content ofthe subgrade soils should be equal to or greater than optimum moisture to a depth of 12 inches below the adjacent ground grade in the slab areas, and verified by this office within 72 hours ofthe vapor barrier placement. Mr. Guy Oliver ~~~~~ W.O. 4401-A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401a.pge Page 19 GeoSoils, Inc. 8. Soils generated from footing excavations to be used onsite should be compacted to a minimum relative compaction 90 percent of the laboratory standard, whether it is to be placed inside the foundation perimeter or in the yard/right-of-way areas. This material must not alter positive drainage patterns that direct drainage away from the structural areas and toward the street. 9. Foundations near the top of slope should be deepened to conform to the latest edition ofthe UBC (ICBO, 1997) and provide a minimum 7-foot horizontal distance from the slope face. Rigid block wall designs located along the top of slope should be reviewed by a soils engineer. 10. As an alternative, an engineered post-tension foundation system may be used. Recommendations for post-tensioned slab design are provided in following sections. POST-TENSIONED SLAB SYSTEMS Post-tension foundations are specifically recommended to mitigate the potential for differential settlement that may be caused by regionally pervasive paleoliquefaction features. 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. Upon request, GSI can provide additional data/consultation regarding soil parameters as related to post-tensioned slab design. Perimeter cut off walls should be a minimum of 12 inches deep for very low expansive soils. The cut off walls may be integrated into the slab design or independent ofthe slab. The concrete slab should be a minimum of 5 inches thick. Slab underlayment should consist of 4 inches of washed sand with a vapor barrier consisting of 10-mil polyvinyl chloride, or equivalent, will all laps sealed per the UBC, placed mid-depth within the sand, per the UBC. Specific soil presaturation is not required for very low expansive soils. However, the moisture content ofthe slab subgrade soils should be equal to, or slightly above, the soil's optimum moisture content to a depth of 12 inches below the lowest adjacent grade. Post-Tensionina 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 Mr. Guy Oliver W.O. 4401-A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401a.pge Page 20 GeoSoils, Inc. evaluated using the 1997 UBC, 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. 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 0.7 inches/month The coefficients are considered minimums and may not be adequate to represent worst case conditions 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 ofthe 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. As an alternative, the spanability method may be considered for these soil conditions, as long as the minimum differential settlements provided herein are incorporated into the overall foundation design. EXPANSION INDEX OF SOIL SUBGRADE VERY LOW EXPANSION POTENTIAL (E.l. = 0-50) e„ center lift 5.0 feet e„ edge lift 2.5 feet y^, center lift 1.0 inch y„, edge lift 0.3 inch Deepened footings/edges around the slab perimeter must be used to minimize non-uniform surface moisture migration (from an outside source) beneath the slab. An edge depth of 12 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 Mr. Guy Oliver 6467 Surfside Lane, Carlsbad File:e:\wp9\4400\4401 a.pge GeoSoils, Inc. W.O. 4401-A-SC July 9, 2004 Page 21 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 system, the values in the above tables would need to be reviewed and/or modified to reflect more highly variable moisture fluctuations along the edges ofthe foundations. 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 enclosed 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 by slabs that are incorporated into the building foundation or constructed on a rigid slab with flexible couplings for plumbing and electrical lines. A/C waste wateriines should be drained to a suitable outlet. WALL DESIGN PARAMETERS Conventional Retainina Walls The design parameters provided below assume that either non expansive soils (Class 2 permeable filter material or Class 3 aggregate base) or native materials (up to and including an Expansion Index [E.I.] of 65) are used to backfill any retaining walls. 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. Recommendations for specialty walls (i.e., crib, earthstone, geogrid, etc.) can be provided upon request, and would be based on site specific conditions. Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401a.pge Page 22 GeoSoils, Inc. 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 ofthe wall (2H) laterally from the corner. Cantilevered Walls The recommendations presented below are for cantilevered retaining walls up to 10 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 ofthe wall is not restrained from minor deflections. An equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. 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. SURFACE SLOPE OF RETAINED MATERIAL (HORIZONTAL:VERTICAL) EQUIVALENT FLUID WEIGHT P.C.F. (SELECT BACKFI LLl EQUIVALENT FLUID WEIGHT P.C.F. (NATIVE BACKFILL) Level* 2 tol 35 50 45 60 * 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. Retainina Wall Backfill and Drainaae 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 back drainage 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 Va-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 Retaining Wall Backfill and Mr. Guy Oliver 6467 Surfside Lane, Carlsbad File:e:\wp9\4400\4401 a.pge W.O. 4401-A-SC July 9, 2004 Page 23 GeoSoils, Inc. DETAILS N.T.S. Provide Surface Drainage ©Waterproofing Membrane (optional) ® Weep Hole Finished Surface 1 or Flatter (D WATERPROOFING MEMBRANE (optionai): Liquid boot or approved equivalent. ® ROCK: 3/4 to 1-1/2" (inches) rock. (D FILTER FABRIC: Mirafi MON or approved equivalent; place fabric flap behind core. ® 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 surface. (No weep holes for basement walls.) TYPICAL RETAINING WALL BACKFILL AND DRAINAGE DETAIL DETAIL 1 Geotechnical • Geologic • Environmental DETAILS N.T.S. Provide Surface Drainage ©Waterproofing Membrane (optional) Weep Hole Finished Surface 1 or Flatter ® 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. (D 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 DETAILS Provide Surface Drainage @ Clean Sand Backfill ® WATERPROOFING MEMBRANE (optional): Liquid boot or approved equivalent. ® CLEAN SAND BACKFILL: 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 surface. (No weep holes for basement walls.) RETAINING WALL AND SUBDRAIN DETAIL CLEAN SAND BACKFILL DETAIL 3 Geotechnical • Geologic • Environmental 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 E.I. potential of greater than 65 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 structures. The use of a waterstop should be considered for all concrete and masonry joints. Wall/Retaining Wall Footina 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: 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 ofthe 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 besealed with a flexible, non-shrink grout. c) Embed the footings entirely into native formational 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. Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401a.pge Page 27 GeoSoils, Inc. TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS Slope Creep Soils at the site may be expansive and therefore, may become desiccated when allowed to drv. 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 seasonal 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 ofthe 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 10 feet, some settlement and tilting ofthe walls/fence with the corresponding distresses, should be expected. To mitigate the tilting of top of slope walls/fences, we recommend that the walls/fences be constructed on deepened foundations without any consideration for creep forces, where the expansion index ofthe materials comprising the outer 15 feet ofthe slope is less than 50, or a combination of grade beam and caisson foundations, for expansion indices greater than 50 comprising the slope, with creep forces taken into account. 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 ofthe project structural engineer, and include the utilization of the following geotechnical parameters: Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401 a.pge Page 28 GeoSoils, Inc. Creep Zone: 5-footvertical zone belowthe 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 ofthe creep prone zone above the point of fixity, to passive resistance, should be disregarded. Allowable Axial Capacitv: ' Shaft capacity : 350 psf applied below the point of fixity over the surface area of the shaft. Tip capacity: 4,500 psf. DRIVEWAY. FLATWORK. AND OTHER IMPROVEMENTS The soil materials on site may 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 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. 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. If very low expansive soils are present, only optimum moisture content, or greater, is required and specific presoaking is not Mr. Guy Oliver W.O. 4401-A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\44(ila.pge Page 29 GeoSoils, Inc. warranted. The moisture content ofthe subgrade should be verified within 72 hours prior to pouring concrete. 2. Concrete slabs should be cast over a non-yielding surface, consisting of a 4-inch layer of crushed rock, gravel, or clean sand, that should be compacted and level priorto pouring concrete. If very low expansive soils are present, the rock or gravel or sand may be deleted. The layer or subgrade should be wet-down completely prior to pouring concrete, to minimize loss of concrete moisture to the surrounding earth materials. 3. 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. 4. 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. If subgrade soils within the top 7 feet from finish grade are very low expansive soils (i.e., El <20), then 6x6-W1.4xW1.4 welded-wire mesh may be substituted for the rebar, provided the reinforcement is placed on chairs, at slab mid-height. The exterior slabs should be scored or saw cut, to % inches deep, often enough so that no section is greater than 10 feet by 10 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. 5. 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. 7. Planters and walls should not be tied to the house. Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401 a.pge Page 30 GeoSoils, Inc. 8. Overhang structures should be supported on the slabs, or structurally designed with continuous footings tied in at least two directions. If very low expansion soils are present, footings need only be tied in one direction. 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. 11. 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. Air conditioning (A/C) 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. A/C 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 designed 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 ofthe 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 of improvements located Mr. Guy Oliver W.O. 4401-A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File;e:\wp9\4400\4401a.pge Page 31 GeoSoils, Inc. 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 ofthe 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. Expansion joints in walls should be placed no greater than 20 feet on-center, in accordance with the structural engineer's recommendations. 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 Plantina 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. Drainaae Adequate lot surface drainage is a very important factor in reducing the likelihood of adverse performance of foundations, 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. Mr. Guy Oliver W.O. 4401-A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e;\wp9\4400\4401a.pge Page 32 GeoSoils, Inc. 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 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 a 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 10 feet tend to have more problems due to storm runoff and irrigation than slopes of a lesser height. Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401 a.pge Page 33 GeoSoils, Inc. • Do the slopes "toe out" into a residential lot or a lot where perched or ponded water may adversely impact its proposed use? 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 10 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. Ifthe 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 othen/vise infiltrate the soils adjacent to the structures. If utilized, the downspouts should be drained into PVC collector pipes Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401a.pge Page 34 GeoSoils, Inc. DETAILS N.T.S. SCHEMATIC TOE DRAIN DETAIL Drain May Be Constructed Into, or at, the Toe of Slope Drain Pipe 12" Minimum 24" Minimum NOTES: 1. ) Soil Cap Compacted to 90 Percent Relative Compaction. 2. ) Permeable li/laterial May Be Gravel Wrapped in Filter Fabric (Mirafi 140N or Equivalent). 3. ) 4-Inch 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 Outiet Pipe. 6. ) Solid Outlet Pipe to Drain to Approved Area. 7. ) Cleanouts are Recomended at Each Property Line. SCHEMATIC TOE DRAIN DETAIL DETAIL 4 Geotechnical • Coastal • Geologic • Environmental TOP OF WALL RETAINING WALL FINISHED GRADE WALL FOOTING DETAILS N.T.S. 2:1 SLOPE (TYPICAL) BACKFILL WITH COMPATED NATIVE SOILS MIRAFI 140 FILTER FABRIC OR EQUAL 3/4" CRUSHED GRAVEL 4" DRAIN 1" TO 2' 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-Inch Diameter Perforated Pipe (SDR-35 of 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. 8. ) Compacted Effort Should Be Applied to Drain Rock. SUBDRAIN ALONG RETAINING WALL DETAIL NOT TO SCALE SUBDRAIN ALONG RETAINING WALL DETAIL DETAIL 5 Geotechnical • Coastal • Geologic • Environmental 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). 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 forthe 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 Floorina Tile flooring can crack, reflecting cracks in the concrete slab belowthe 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 wiil 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 Gradina 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. Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401 a.pge Page 37 GeoSoils, Inc. Footina Trench Excavation All footing excavations should be obsen/ed by a representative of this firm subsequent to trenching and prior to concrete form and reinforcement placement. The purpose of the obsen/ations 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 or compressible materials are exposed within the footing excavation, a deeper footing or removal and recompaction ofthe subgrade materials would be recommended at that 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 from the site. Trenchina 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 obsen/ed by one of our representatives and minimally conform to CAL-OSHA and local safety codes. Utilitv 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. 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 obsen/ations, along with probing, should be accomplished to verify the desired results. 3. All trench excavations should conform to CAL-OSHA and local safety codes. 4. 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 ofthe structural engineer. Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401a.pge Page 38 GeoSoils, Inc. 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 (i.e., higher than 4 feet). • 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 obsen/ation 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. • GSI should review project sales documents to homeowners/homeowners associations for geotechnical aspects, including irrigation practices, the conditions outlined above, etc., priorto any sales. At that stage, GSI will provide homeowners maintenance guidelines which should be incorporated into such documents. Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401a.pge Page 39 GeoSoils, Inc. 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. This report presents minimum design criteria for the design of slabs, foundations and other elements possibly applicable to the project. These criteria should not be considered as substitutes for actual designs by the structural engineer/designer. The structural engineer/designer should analyze actual soil-structure interaction and consider, as needed, bearing, expansive soil influence, and strength, stiffness and deflections in the various slab, foundation, and other elements in order to develop appropriate, design-specific details. As conditions dictate, it is possible that other influences will also have to be considered. The structural engineer/designer should consider all applicable codes and authoritative sources where needed. If analyses by the structural engineer/designer result in less critical details than are provided herein as minimums, the minimums presented herein should be adopted. It is considered likely that some, more restrictive details will be required. Ifthe structural engineer/designer has any questions or requires further assistance, they should not hesitate to call or othen/vise transmit their requests to GSI. In order to mitigate potential 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 ofthe 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. Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 Flle:e:\wp9\4400\4401a.pge Page 40 GeoSoils, Inc. 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 sen/ices for this portion of the project. Mr. Guy Oliver W.O. 4401 -A-SC 6467 Surfside Lane, Carlsbad July 9, 2004 File:e:\wp9\4400\4401a.pge Page 41 GeoSoils, Inc. APPENDIXA REFERENCES APPENDIXA 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, 2003, 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, September 15, Oakland, pp. 23-49. Campbell, K.W. and Bozorgnia, Y., 1997, Attenuation relations for soft rock conditions; jn EQFAULT, A computer program for the estimation of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version, Blake, 2000a. Franklin, J.P. and Kuhn, G.G., 2000, Paleoseismic features exposed by trenching the lowest coastal terrace at Carlsbad, California; in Neotechnics and Coastal Instability, Orange and Northern San Diego Counties, California; Joint Field Conference, Volume 1; AAPG, Pacific Section; SPE, Western Section, dated June 19 through 22. 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 and 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. Jennings, 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. Kennedy, M.P. and Tan S.S., 1996, Geologic maps ofthe northwest part of San Diego County, California., Division of Mines and Geology, Plate 2, scale 1:24,000. Robert Bowlus Architecture, Inc., 2004, Area grading (Oliver Residence, Carisbad, California), sheet Gl, 20-scale, dated April 30. GeoSoils, Inc. Sowers and Sowers, 1970, Unified soil classification system (After U. S. Watenways Experiment Station and ASTM 02487-667) in Introductory Soil Mechanics, New York. United States Department of Agriculture, 1980, Aerial photographs, project no. 615020, flight date August 21, flight line 680, photos nos. 134 and 135, scale 1"=3333'±. Mr. Guy Oliver Appendix A File:e:\wp9\4400\4401a.pge Page 2 GeoSoils, Inc. APPENDiX B BORING LOGS GeoSoils, Inc. PROJECT: GUY OLIVER 6467 Surfside Lane BORING LOG W.O. 4401-A-SC BORING B-1 Sample I- 3 " E to >. D OT : ex. a 9> w DATE EXCAVATED SAMPLE METHOD: HAND AUGER SHggr 1 OF 1 6-22-04 Standard Penetration Test Undisturbed, Ring Sample 2 Groundwater Description of Material SM SM 6467 Surfside Lane ARTIFICIAL FILL (UNDOCUMENTED^: @ 0' SILTY SAND, light red brown, dry, medium dense; occasional angular pebble size clasts. QUATERNARY TERRACE DEPOSITS: @ VA' SILTY SAND, red brown, dry to damp, medium dense to dense; upper 1 foot is weathered. Total Depth = I'A' No Groundwater/Caving Encountered Backfilled 6-22-2004 GeoSoils, Inc. PLATE B-1 GeoSoils, Inc. PROJECT: GUY OLIVER 6467 Surfside Lane BORING LOG W.O. 4401-A-SC BORING B-2 Q. 0) Q Sample 1^ 3 o m " E 3 Q o OT D/\r££X'C/lU.4r£D SAMPLE METHOD: HAND AUGER SHEET_±_ OF 1 6-22-04 Standard Penetration Test Undisturbed, Ring Sample 2 Groundwater Description of Material SM ARTIFICIAL FILL fUNDOCUMENTED): @ 0' SILTY SAND, light red brown, dry, medium dense. SM QUATERNARY TERRACE DEPOSITS: @ VA' SILTY SAND, dark red brown to red brown, dry to damp, medium dense to dense; upper 1 foot is weathered. 5- Total Depth = 3' No Groundwater/Caving Encountered Backfilled 6-22-2004 6467 Surfside Lane GeoSoils, Inc. PLATE B-2 GeoSoils, Inc. PROJECT: GUY OLIVER 6467 Surfside Lane BORING LOG W.O. 4401-A-SC BORING B-3 o. (D Q Sample 51 OT g, 3 W CO W DATE EXCAVATED SAMPLE METHOD: HAND AUGER SHEET 1 OF 1 6-22-04 Standard Penetration Test Undisturbed, Ring Sample 2 ¥- Groundwater Description of Material SM ARTIFICIAL FILL (UNDOCUMENTED): @ 0' SILTY SAND, brown to light red brown, dry, medium dense. SM QUATERNARY TERRACE DEPOSITS: @ r SILTY SAND, dark red brown to red brown, dry to damp, medium dense to dense; upper 1 foot is weathered. 5- Total Depth = I'A' No Groundwater/Caving Encountered Backfllled 6-22-2004 6467 Surfside Lane GeoSoils, Inc. PLATE B-3 APPENDIX C EQFAULT, EQSEARCH, AND FRISKSP 2 c o mmmm (0 s o o o < MAXIMUM EARTHQUAKES OLIVER .1 1 10 Distance (mi) 100 W.O. 4401-A-SC GeoSoils, Inc. Plate C-1 RS (0 +-> c 0) > IJJ 0) E 3 z > « 3 E E 3 o EARTHQUAKE RECURRENCE CURVE OLIVER 100 10 .1 .01 .001 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.O. 4401-A-SC Plate C-2 GeoSoils, Inc. EARTHQUAKE EPICENTER MAP OLIVER 1100 1000 -- 900 800 -- 700 -- 600 -- 500 400 -- 300 200 -- 100 -- -100 I I • ' I I I I ' ' ' -400 -300 -200 -100 100 200 300 400 500 600 W.O. 4401-A-SC Plate C-3 GeoSoils, Inc. PROBABILITY OF EXCEEDANCE CAMP. & BOZ. (1997 Rev.) SR 1 100 25 yrs 75 yrs 50 yrs 100 yrs 0.00 0.25 0.50 0.75 1.00 1.25 1.50 Acceleration (g) W.O. 4401-A-SC Plate C-4 GeoSoils, Inc. p o I > CO o RETURN PERIOD vs. ACCELERATION CAMP. & BOZ. (1997 Rev.) SR 1 1OOOOO ? o 3 O c cS cr 10000 1000 100 2 a> o I Ol 0.00 0.25 0.50 0.75 1.00 Acceleration (g) 1.25 1.50 APPENDIX D LABORATORY DATA 3.000 2,500 2,000 f (3 z UJ I- tc X (0 1.500 1.000 500 1,000 1.500 NORMAL PRESSURE, psf 2.000 2,500 3,000 Sample Depth/El. Primary/Residual Shear Sample Type Yd MC% C • B-1 thm B-3 0.0 Primary Shear Remolded 119.7 8.0 112 30 • B-1 thru B-3 0.0 Residual Shear Remolded 119.7 8.0 94 30 Note: Sample Innundated prior to testing GeoSoils, Inc. . *j. 5741 Palmer Way C^eoSo^'^ Carlsbad, CA 92008 '-^T,^ \ ' Telephone: (760)438-3155 4^ax: (760)931-0915 DIRECT SHEAR TEST Project: OLIVER Number: 4401-A-SC Date: June 2004 Plate D-1 M. J. Schiff 4fc Assodates, Inc. Consulting Corrosion Engineers - Since 1959 431 W. Baseline Road Claremont, CA 91711 Sample ID Phone: (909) 626-0967 Fax: (909) 626S316 E-mail lah@mjschijf.com website: mjschijf.com Table 1 - Laboratory Tests on Soil Samples Oliver Your U401.A-SC, MJSAA §04-0890LAB 25-.Jun-04 .B-1 thm B-3 Re.fistivity 09-reccivcd .saturated pH Electrical Conductivity Chemical AJialysei; Units ohrn-cni). ohm-cm inS/cm 97,000 1,900 6.4 0.16 Cations calcium Ca^* mg/kg 36 magnesium mg/kg 7 sodium Na'* mg/kg 93 A.T)ions carbonate CO/-mg/kg ND bicarbonate HCO, "mg/kg 64 chloride Cl'- ' mfi/kg no sulfate SO,'-mg/kg no er Tests ammonium NH;* mg/kg na nitrate mg/kg na sulfide qual na Redox mV na Electrical conductivity in millisiemens/cm and chemical analysis were made on a 1:5 soil-to-watcr extract mg/kg = milligrams per kilogram (parts per million) of dry soil. Redox =5 oxidation-reduction potential in miIlivolt.i ND = not detected na - not analyzed W.O. 4401-A-SC Page 1 of 1 Plate D-2 APPENDIX E GENERAL EARTHWORK AND GRADING GUIDELINES 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 ofthe 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 supersede these guidelines or the recommendations contained in the geotechnical report. The contractor is responsible forthe satisfactory completion of all earthwork in accordance with provisions of the project plans and specifications. The project soil engineer and engineering geologist (geotechnical consultant) or their representatives should provide observation and testing services, and geotechnical consultation during the duration ofthe project. EARTHWORK OBSERVATIONS AND TESTING Geotechnical Consultant Priorto 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 obsen/ed 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. Laboratorv 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 GeoSoils, Inc. would vary depending on the soil conditions and the size ofthe 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 safisfaction of the soil engineer, and to place, spread, moisture condifion, mix and compact the fill in accordance with the recommendafions ofthe soil engineer. The contractor should also remove all major non- earth material considered unsafisfactory by the soil engineer. It is the sole responsibility ofthe 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 compacfion equipment should be provided by the contractor with due considerafion for the fill material, rate of placement, and climafic condifions. If, in the opinion of the geotechnical consultant, unsafisfactory condifions such as quesfionable weather, excessive oversized rock, or deleterious material, insufficient support equipment, etc., are resulfing in a quality of work that is not acceptable, the consultant will inform the contractor, and the contractor is expected to rectify the condifions, and if necessary, stop work until condifions are safisfactory. During construcfion, 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 unfil such fime as permanent drainage and erosion control measures have been installed. SITE PREPARATION All major vegetafion, 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. Exisfing fill, soil, alluvium, colluvium, or rock materials determined by the soil engineer or engineering geologist as being unsuitable in-place should be removed prior to fill placement. Depending upon the soil condifions, 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, sepfic tanks, wells, pipelines, or other structures not located priorto 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 Mr. Guy Oliver Appendix E File:e:\wp9\4400\4401a.pge Page 2 GeoSoils, Inc. processing cannot adequately improve the condition should be overexcavated down to firm ground and approved by the soil engineer before compacfion and filling operafions continue. Overexcavated and processed soils which have been properly mixed and moisture condifioned should be re-compacted to the minimum relative compacfion as specified in these guidelines. Exisfing 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 opfimum moisture content or greater and mixed, the materials should be compacted as specified herein. If the scarified zone is 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. Exisfing ground which is not safisfactory to support compacted fill should be overexcavated as required in the geotechnical report or by the on-site soils engineer and/or engineering geologist. Scarificafion, disc harrowing, or other acceptable form of mixing should confinue unfil the soils are broken down and free of large lumps or clods, unfil the working surface is reasonably uniform and free from ruts, hollow, hummocks, or other uneven features which would inhibit compacfion as described previously. Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to verficai), 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 withthe key founded on firm material, as designated bythe Geotechnical Consultant. As a general rule, unless specifically recommended othenwise by the Soil Engineer, the minimum width of fill keys should be approximately equal to Vz 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 ofthe 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 priorto placement of fill. Fills may then be properly placed and compacted unfil design grades (elevafions) are attained. Mr. Guy Oliver Appendix E File:e:\wp9\4400\4401 a.pge Page 3 GeoSoils, Inc. 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 gradafion, undesirable expansion potential, or substandard strength characterisfics may be designated by the consultant as unsuitable and may require blending with other soils to serve as a safisfactory fill material. Fill materials derived from benching operafions should be dispersed throughout the fill area and blended with other bedrock derived material. Benching operafions 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 greaterthan 12 inches should not be buried or placed in fills unless the locafion of materials and disposal methods are specifically approved by the soil engineer. Oversized material should betaken off-site or placed in accordance with recommendafions ofthe soil engineer in areas designated as suitable for rock disposal. Oversized material should not be placed within 10 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 foundafion excavations, future ufilifies, or underground construcfion 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 ufilized 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 6 inches in thickness. The soil engineer may approve thick lifts if tesfing indicates the grading procedures are such that adequate compacfion 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 opfimum should be watered and mixed, and wet fill layers should be aerated by scarification or should be blended with drier material. Moisture condifion, blending, and mixing of the fill layer should confinue unfil the fill materials have a uniform moisture content at or above opfimum moisture. Mr. Guy Oliver Appendix E File:e:\wp9\4400\4401 a.pge Page 4 GeoSoils, Inc. After each layer has been evenly spread, moisture condifioned and mixed, it should be uniformly compacted to a minimum of 90 percent of maximum density as determined by ASTM test designafion, D-1557-78, or as otherwise recommended by the soil engineer. Compacfion equipment should be adequately sized and should be specifically designed for soil compaction or of proven reliability to efficiently achieve the specified degree of compacfion. Where tests indicate that the density of any layer of fill, or portion thereof, is below the required relafive 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 addifional 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 accomplished by over-building a minimum of 3 feet horizontally, and subsequently trimming back to the design slope configurafion. 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 compacfion in the fill slope zone. Final slope shaping should be performed by trimming and removing loose materials with appropriate equipment. Afinal determination of fill slope compacfion should be based on observation and/or tesfing of the finished slope face. Where compacted fill slopes are designed steeper than 2:1 (horizontal to vertical), specific material types, a "higher niinimum 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 compacfion in the outer 10 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 confinuously 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 ofthe slope. 2. 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. 3. 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. 4. After complefion of the slope, the slope face should be shaped with a small tractor and then re-rolled with a sheepsfoot to achieve compacfion to near the slope face. Subsequent to testing to verify compacfion, the slopes should be grid-rolled to Mr. Guy Oliver Appendix E Flle:e:\wp9\4400\4401a.pge Page 5 GeoSoils, Inc. achieve compacfion to the slope face. Final tesfing should be used to confirm compacfion after grid rolling. Where tesfing indicates less than adequate compacfion, the contractor will be responsible to rip, water, mix and re-compact the slope material as necessary to achieve compacfion. Addifional testing should be performed to verify compaction. 6. Erosion control and drainage devices should be designed by the project civil engineer in compliance with ordinances ofthe controlling governmental agencies, and/or in accordance with the recommendafion ofthe 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 locafions 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 condifions. The locafion of constructed subdrains should be recorded by the project civil engineer EXCAVATIONS Excavafions and cut slopes should be examined during grading by the engineering geologist. If directed by the engineering geologist, further excavafions or overexcavafion 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 othenwise approved, the cut portion ofthe slope should be observed bythe engineering geologist prior to placement of materials for construcfion 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 potenfial adverse geologic condifions are encountered, the engineering geologist and soil engineer should investigate, evaluate and make recommendafions to treat these problems. The need for cut slope buttressing or stabilizing should be based on in-grading evaluafion by the engineering geologist, whether anficipated or not. Unless othen/vise 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. Mr. Guy Oliver Appendix E File:e:\wp9\4400\4401a.pge Page 6 GeoSoils, Inc. Erosion control and drainage devices should be designed by the project civil engineer and should be constructed in compliance with the ordinances ofthe controlling governmental agencies, and/or in accordance with the recommendafions of the soil engineer or engineering geologist. COMPLETION Observafion, tesfing and consultation bythe geotechnical consultant should be conducted during the grading operafions in order to state an opinion that all cut and filled areas are graded in accordance with the approved project specificafions. After complefion of grading and after the soil engineer and engineering geologist have finished their observafions ofthe work, final reports should be submitted subject to review by the controlling governmental agencies. No further excavation or filling should be undertaken without prior nofificafion 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 specificafions and/or as recommended by a landscape architect. Such protecfion and/or planning should be undertaken as soon as pracfical after complefion 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 construcfion sites. On ground personnel are at highest risk of injury and possible fatality on grading and construcfion projects. GSI recognizes that construcfion activifies 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 fimes. To achieve our goal of avoiding accidents, cooperafion between the client, the contractor and GSI personnel must be maintained. In an effort to minimize risks associated with geotechnical testing and observafion, the following precaufions 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 meefings. Safety Vests: Safety vests are provided for and are to be worn by GSI personnel at all fimes when they are working in the field. Mr. Guy Oliver Appendix E Flle:e:\wp9\4400\4401a.pge Page 7 GeoSoils, Inc. 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 rotafing or flashing amber beacon, or strobe lights, on the vehicle during all fleld tesfing. While operafing a vehicle in the grading area, the emergency flasher on the vehicle shall be activated. In the event that the contractor's representafive 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 selecfing test pit locations. A primary concern should be the technicians's safety. Efforts will be made to coordinate locafions with the grading contractors authorized representative, and to select locafions following or behind the established traffic pattern, preferably outside of current traffic. The contractors authorized representafive (dump man, operator, supervisor, grade checker, etc.) should direct excavafion 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 tesfing 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 vibrafion which typically decreased test results. When taking slope tests the technician should park the vehicle directly above or below the test locafion. If this is not possible, a prominent flag should be placed at the top of the slope. The contractor's representafive should effectively keep all equipment at a safe operafion 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 ofthe 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. Mr. Guy Oliver Appendix E Flle:e:\wp9\4400\4401a.pge Page 8 GeoSoils, Inc. In the event that the technicians safety is jeopardized or compromised as a result of the contractors failure to comply with any ofthe above, the technician is required, by company policy, to immediately withdraw and notify his/her supervisor. The grading contractors representafive will eventually be contacted in an effort to effect a solution. However, in the interim, no further tesfing will be performed until the situafion is rectified. Any fill place 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. Effecfive 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 compacfion tesfing is needed. Our personnel are directed 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 condifions 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 compacfion testing, our company policy requires that the soil technician withdraw and notify his/her supervisor. The contractors representafive will eventually be contacted in an efl'ort to effect a solution. All backfill not tested due to safety concerns or other reasons could be subject to reprocessing and/or removal. If GSI personnel become aware of anyone working beneath an unsafe trench wall or verficai excavafion, we have a legal obligafion to put the contractor and owner/developer on nofice to immediately correct the situafion. If corrective steps are not taken, GSI then has an obligation to nofify CAL-OSHA and/or the proper authorities. Mr. Guy Oliver Appendix E Flle:e:\wp9\4400\4401a.pge Page 9 GeoSoils, Inc. CANYON SUBDRAIN DETAIL TYPE A PROPOSED COMPACTED FILL •NATURAL GROUND y "^N^ ^^COLLUVIUM AND ALLUVIUM (REMOVE)^^^^ ^{/^ul --^ TYPICAL BENCHING ^^^^^ ^ BEDROCK SEE ALTERNATIVES TYPE^B PROPOSED COMPACTED RLL NATURAL GROUND COLLUVIUM AND ALLUVIUM IREMOVE) J lr BEDROCK TYPICAL BENCHING SEE ALTERNATIVES NOTE: ALTERNATIVES. LOCATICN AND EXTENT OF SUBDRAINS SHOULD BE DETERMINED BY THE SOILS ENGINEER AND/QR ENGINEERING GEOLOGIST DURING GRADING. PLATE EG~1 CANYON SUBDRAIN ALTERNATE DETAILS ALTERNATE 1: PERFORATED PIPE ANO FILTER MATERIAL A-1 MINIMUM 12* MINIMUM FILTER MATERIAL MINIMUM VOLUME OF /LINEAR FT. 6" if ABS OR PVC PIPE OR SUBSTITUTE WITH MINIMUM 8 (1/4" jfl PERFS. LINEAR FT. IN BOTTOM HALF OF PIPE. ASTM D2751. SDR 35 OR ASTM D1527. SCHD, ASTM 03034. SDR 35 OR ASTM 01785, SCHD. 40 FOR CONTINUOUS RUN IN EXCESS OF 500 FT. USE B"jar PIPE 6-MINIMUM B-1 FILTER MATERIAL. SIEVE SIZE PERCENT PA??|N(? 1INCH .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 NO. 200 0-3 ALTERNATE 2: PERFORATED PIPE, GRAVEL AND.FILTER FABRIC ^J^(^6*M?N1MUM OVERLAP 6" MINIMUM OVERLAP 6' MINIMUM COVER =4* MINIMUM BEDDING A-2 4* MINIMUM BEDDING GRAVEL MATERIAL 9 FP/LINEAR FT. g_2 PERFORATED PIPE: SEE ALTERNATE 1 GRAVEL CLEAN 3/4 INCH ROCK OR APPROVED SUBSTITUTE FILTER FABRIC: MIRAFI 140 OR APPROVED SUBSTITUTE PLATE EG-2 DETAIL FOR FILL SLOPE TOEING OUT ON FLAT ALLUVIATED CANYON TOE OF SLOPE AS SHOWN ON GRADING PLAN ORIGINAL GROUND SURFACE TO BE RESTORED WITH COMPACTED FILL BACKCUT\.VARIES. FOR DEEP REMOVALS, ^xg^^ BACKCUT ^IksHOULD BE MADE NO STEEPER THAi>sl:1 OR AS NECESSARY FOR SAFETY r«oLie-inrT>ATrir»iJC r CONSIDERATIONS, COMPACTED RLL ORIGINAL GROUND SURFACE r ANTICIPATED ALLUVIAL REMOVAL DEPTH PER SOIL ENGINEER. r PROVIDE A 1:1 MINIMUM PROJECTION FROM TOE OF SLOPE AS SHOV/N ON GRADING PLAN TO THE RECOHMENDEO REMOVAL DEPTH. SLOPE HEIGHT. SITE CONDITIONS AMD/OR LOCAL CONDITIONS COULD DICTATE FLATTER PROJECTIONS. REMOVAL ADJACENT TO EXISTING FILL ADJOINING CANYON RLL COMPACTED RLL LIMITS LINE Qaf (EXISTING COMPACTED FILL) Qai (TO BE REMOVED) BE REMOVED BEFORE PLACING ADDITIONAL COMPACTED RLL LEGEND Qaf ARTIFICIAL RLL Qai ALLUVIUM PLATE EG-3 TYPICAL STABILIZATION / BUTTRESS FILL DETAIL 15' TYPICAL 1-2' CLEAI "D ^TOE OUTLETS TO BE SPACED AT 100'MAXIMUM INTERVALS. AND SHALL EXTEND 12- BEYOND THE FACE OF SLOPE AT TIME OF.ROUGH GRADING COMPLETION. > m m o I BLANKET RLL IF RECOMMENDED BY THE SOIL ENGINEER TYPICAL BENCHING 4* DIAMETER NON-PERFORATED OUTLET PIPE AND BACKDRAIN CSEE ALTERNATIVES) BEDROCK ^ W=15' 3'MINIMUM KEY DEPTH MINIMUM OR H/2 TYPICAL STABIUZATION / BUTTRESS SUBDRAIN DETAIL 4- MINIMUM PIPE 2- MINIMUM 4' MINIMUM PIPE > m m CT I CJI 2" MINIMUM RLTER MATERIAL MINIMUM OF FIVE FI'/LINEAR Fl OF PIPE OR FOUR FIVLINEAR Fl OF PIPE WHEN PLACED IN SQUARE CUT TRENCH. ALTERNATIVE IN LIEU OF RLTER MATERIAL: GRAVEL MAY BE ENCASED IN APPROVED RLTER FABRIC. RLTER FABRIC SHALL BE MIRAR 140 OR EQUIVALENT. RLTER FABRIC SHIALL BE LAPPED A MINIMUM OF 12" ON ALL JOINTS. MINIMUM 4- DIAMETER PIPE: ABS-ASTM D-2751. SDR 35 OR ASTM D-1527 SCHEDULE 40 PVC-ASTM D-3034. SpR 35 OR ASTM D-1785 SCHEDULE 40 WITH A CRUSHING STRENGTH 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 CAP AT UPSTREAM END OF PIPE. SLOPE AT 2% TO OUTLET PIPE. OUTLET PIPE TO BE CONNECTED TO SUBDRAIN PIPE WITH TEE OR ELBOW. NOTE: 1. TRENCH FOR OUTLET PIPES TO BE BACKRLLED WITH ON-SITE SOIL 2. BACKDRAINS AND LATERAL DRAINS SHALL BE LOCATED AT ELEVATION OF EVERY BENCH DRAIN. , RRST DRAIN LOCATED AT ELEVATION JUST ABOVE LOWER LOT GRADE. ADDITIONAL DRAINS MAY BE REQUIRED AT THE DISCRETION OF THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST. RLTER MATERIAL SHALL BE OF THE FOLLOWING SPECIFICATION OR AN APPROVED EQUIVALENT: SIEVE SIZE PERCENT PASSING 1 INCH 3/4 INCH 3/8 INCH NO. 4 NO. 8 NO. 30 NO. 50 NO. 200 100 90-100 40-100 25-40 18-33 5-15 0-7 0-3 GRAVEL SHALL BE OF THE FOLLOWING SPECIFICATION OR AN APPROVED EQUIVALENT: SIEVE SIZE PERCENT PASSING 1 1/2 INCH. NO. 4 NO. 200 100 50 8 SAND EQUIVALENT: MINIMUM OF 51 FILL OVER NATURAL DETAIL SIDEHILL FILL PROPOSED GRADE TOE OF SLOPE AS SHOWN ON GRADING PLAN PROVIDE A 1:1 MINIMUM PROJECTION FROM DESIGN TOE OF SLOPE TO TOE OF KEY AS SHOWN ON AS BUILT NATURAL SLOPE TO BE RESTORED WITH COMPACTED FILL . BACKCUT VARIES ^V/A\V/A\V/;j^. MINIMUM "D r~ > m m o I cn BENCH WIDTH MAY VARY it-MINIMUM KEY WIDTH 2*X 3'MINIMUM KEY DEPTH 2" MINIMUM IN BEDROCK OR APPROVED MATERIAL. "^•.MINIMUM OTE: 1 WHERE THE NATURAL SLOPE APPROACHES OR EXCEEDS THE ' DESIGN SLOPE RATIO. SPECIAL RECOMMENDATIONS WOULD BE PROVIDED BY THE SOILS ENGINEER. 2. THE NEED FOR AND DISPOSITION OF DRAINS WOULD BE DETERMINED BY THE SOILS ENGINEER BASED UPON EXPOSED CONDITIONS. FILL OVER CUT DETAIL rilT/RH CONTACT 1. AS SHOWN ON GRADING PLAN 2. AS SHOWN ON AS BUILT MAINTAIN MINIMUM 15* RLL SECTION FROM BACKCUT TO FACE OF RNISH SLOPE r MINIMUM ^ ^^^^ BEDROCK OR APPROVED MATERIAL LOWEST BENCH WIDTH 15'MINIMUM OR H/2 |4'MINIMUM BENCH WIDTH MAY VARY > m m o I NOTE: THE CUT PORTION OF THE SLOPE SHOULD BE EXCAVATED ANO EVALUATED BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST PRIOR TO CONSTRUCTING THE RLL PORTION. STABILIZATION FILL FOR UNSTABLE MATERIAL EXPOSED IN PORTION OF CUT SLOPE > m m o I cr) ^ UNWEATHERED BEDROCK OR APPROVED MATERIAL ^ COMPACTED STABILE ATION RLL NOTE: 1. 2. fr, m 1 /iV MINIM"" TILTED BACK IF RECOMMENDED BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST. THE REMAINING CUT PORTION OF THE SLOPE MAY REQUIRE REMOVAL AND REPLACEMENT WITH COMPACTED RLL SUBDRAINS ARE NOT REQUIRED UNLESS SPECIFIED BY SOILS ENGINEER AND/OR ENGINEERINO GEOLOGIST, •WT SHALL BE EQUIPMENT WIDTH (IB"! FOR SLOPE HEIGHTS LESS THAN 25 FEET. FOR SLOPES GREATER- THAN 25 FEET -W- SHALL BE DETERMINED BY THE PROJECT SOILS ENGINEER AND /OR ENGINEERING GEOLOGIST. AT NO TIME SHALL "W BE LESS THAN H/2. SKIN FILL OF NATURAL GROUND ORIGINAL SLOPE r^nSED RNISH GRADE 15" MINIMUM TO BE MAINTAINED FROM PROPOSED RNISH SLOPE FACE TO BACKCUT PROPOSED FINISH SLOPE Its'MINIMUM BEDROCK OR APPROVED MATERIAL i|3-MINIMUM KEY DEPTH H m m o I UD NOTE: 1. THE NEED AND DISPOSITION OF DRAINS WILL BE DETERMINED! BY THE SOILS ENGINEER AND/OR ENGINEERINO OEOLOOIST BASED ON FIELD CONDITIONS. , PAD OVEREXCLATION AND RECOMPACTION SHOULD BE PERFORMED IF DETERMINED TO BE NECESSARY BY THE SOILS ENGINEER AND/OR ENGINEERING OEOLOOIST. DAYLIGHT CUT LOT DETAIL RECONSTRUCT COMPACTED RLL SLOPE AT 2:1 OR FLATTER (MAY INCREASE OR DECREASE PAD AREAJ. OVEREXCAVATE AND RECOMPACT REPLACEMENT RLL NATURAL GRADE AVOID AND/OR CLEAN UP SPILLAGE OF MATERIALS ON THE NATURAL SLOPE PwnpnsED FINISH GRADE ^y^,^^^/ MINIMUM BLANKET FILL ^ 0^ V"r^ JL\V^-^ BEDROCK OR APPROVED MATERIAL TYPICAL BENCHING V TVP 2%GRADIENTi r- > -I m m o o NOTE: 1. SUBDRAIN ANO KEY WIDTH REQUIREMENTS WILL BE DETERMINED BASED ON EXPOSED SUBSURFACE CONDITIONS AND THICKNESS OF OVERBURDEN. Mcncs^iHV nv 2. PAO OVER EXCAVATION AND RECOMPACTION SHOULD BE PERFORMED IF DETERMINED NECESSARY BY THE SOILS ENGINEER AND/OR THE ENGINEERING GEOLOGIST. TRANSITION LOT DETAIL CUT LOT (MATERIAL TYPE TRANSITION) NATURAL GRADE COMPACTED RLL (//^/A\^/<<S^/^^^^^ 3" MINIMUM- ^ UNWEATHERED BEDROCK OR APPROVED MATERIAL TYPICAL BENCHING CUT-RLL LOT IDAYUGHT TRANSITION) "^l^m^W^i/^^^^^^W^' MINIMUM- UNWEATHERED BEDROCK OR APPROVED MATERIAL TYPICAL BENCHING NOTE: * DEEPER OVEREXCAVATION MAY BE RECOMMENDED BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST IN STEEP CUT-RLL TRANSITION AREAS. PLATE EG-ir SETTLEMENT PLATE AND RISER DETAIL 2'X 2'X 1/4- STEEL PLATE STANDARD 3/4" PIPE NIPPLE WELDED TO TOP OF PLATE. 3/4" X 5* GALVANIZED PIPE. STANDARD PIPE THREADS TOP AND BOTTOM. EXTENSIONS THREADED ON BOTH ENDS AND ADDED IN 5' INCREMENTS. 3 INCH SCHEDULE 40 PVC PIPE SLEEVE. ADD IN 5'INCREMENTS WITH GLUE JOINTS. RNAL GRADE T MAINTAIN 5'CLEARANCE OF HEAVY EQUIPMENT. MECHANICALLY HAND COMPACT IN 2*VERT1CAL -rV LIFTS OR ALTERNATIVE SUITABLE TO AND ACCEPTED BY THE SOILS ENGINEER. MECHANICALLY HAND COMPACT THE INITIALS* VERTICAL WITHIN A 5'RADIUS OF PLATE BASE. \;.:-. •..:. /.:•.•.-.•>.•.•/:./ Bon 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 CONTF&CTOR SHOULD MAINTAIN CLEARANCE OF A 5'RADIUS OF PLATE BASE AND • S/lTHm 5'"^^^ EQUIPMENT FjLL WrTHIN CLE ARAN C^^ BE HAND COMPACTED TO PROJECT SPECIRCATIONS OR COMPACTED BY ALTERNATIVE APPROVED BY THE SOILS ENGINEER. .,*,^,X».M * E-oAninc 3. AFTER S'lVERTICAU OF RLL IS IN PLACE. CONTRACTOR SHOULD MAINTAIN A 5_RADIUS EQUIPMENT CLEARANCE FROM RISER. 4. PLACE AND MECHANICALLY HAND COMPACT INITIAL 2'OF RLL PRIOR TO ESTABLISHING THE INITIAL READING. 5. IN THE EVENT OF DAMAGE TO THE SETTLEMENT PLATE OR EXTENSION RESULTING FROM EQUIPMENT OPERATING WITHIN THE SPECIRED 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-U TYPICAL SURFACE SETTLEMENT MONUMENT RNISH GRADE •-6-DIAMETER X 3 1/2*LENeTH HOLE 3/8" DIAMETER X 6" LENGTH CARRIAGE BOLT OR EQUIVALENT CONCRETE BACKRLL PLATE EG-15 OVERSIZE ROCK DISPOSAL VIEW NORMAL TO SLOPE FACE OO 20'MINIMUM CO _J5'MINIMUM (AX^ oO ootFl MINIMUM (C) PROPOSED RNISH GRADE 10'MINIMUM (E) Eo CO 15'MINIMUM (Al o—^ oa oo CO (Gl BEDROCK OR APPROVED MATERIAL VIEW PARALLEL TO SLOPE FACE PROPOSED FINISH GRADE -^ MINIMUM (C) BEDROCK OR APPROVED MATERIAL NOTE: (A) ONE EQUIPMENT WIDTH OR A MINIMUM OF 15 FEET. (B) HEIGHT AND WIDTH MAY VARY DEPENDING ON ROCK SIZE AND TYPE EQUIPMENT LENGTH OF WINDROW SHALL BE NO GREATER THAN 100 MAXIMUM. IC) IF APPROVED BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST WINDROWS MAY BE PLACED DIRECTLY ON COMPETENT MATERIAL OR BEDROCK PROVIDED ADEQUATE SPACE IS AVAILABLE FOR COMPACTION ID) ORIENTATION OF WINDROWS MAY VARY BUT SHOULD BE Af 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. IR ALL RLL OVER AND AROUND ROCK WINDROW SHALL BE COMPACTED TO 90% IGI AFTE%''F^L°BETWE'E^^^ COMPACTED WITH THE LIFT OF FILL COVERING V^^^^^^ BE PROOF ROLLED WITH A D-9 DOZER OR EQUIVALENT. VIEWS ARE DIAGRAMMATIC ONLY. ROCK SHOULD NOT TOUCH . ^r- or-» 1 AND VOIDS SHOULD BE COMPLETELY RLLED IN. PLATE RD —1 ROCK DISPOSAL PITS VIEWS ARE DIAGRAMMATIC ONLY. ROCK SHOULD NOT TOUCH AND VOIDS SHOULD BE COMPLETELY RLLED IN. RLL LIFTS COMPACTED OVER ROCK AFTER EMBEDMENT r I I GRANULAR MATERIAL I COMPACTED RLL SIZE OF EXCAVATION TO BE COMMENSURATE WITH ROCK SIZE ROCK DISPOSAL LAYERS GRANULAR SOIL TO RLL VOIDS. DENSIRED BY FLOODING LAYER ONE ROCK HIGH \1 ,COMPACTED RLL PROPOSED RNISH GRADE 10* MINIMUM OR BELOW LOWEST UTIU PRORLE ALONG LAYER OCCOoccjCQ: OVERSIZE LAYER "S, FRlD>^LOPE FACE COMPACTED FILL 13'MINIMUM O0C>DCOOCXX:OCO3COTC=oc^^ J^CLEAR ZONE 20'MINIMUM LAYER ONE ROCK HIGH PLATE RD'-2 TEST PIT SAFETY DIAGRAM SIDE VIEW Si%:::TEST PHWi^ a" ••••••I { NOT TO SCALE 1 TOP VIEW IQO FEET 50 FEET J V&HCLE III FLAG APPROXIMATE CENTER OF TEST PIT ( NOT TO SCALE 1 PLATE EG-16