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Home My WebLink AboutMS 08-03; NOLAN DEVELOPMENT; PRELIMINARY GEOTECHNICAL EVALUATION; 2008-02-25PRELIMINARY GEOTECHNICAL EVALUATION FOR PROPOSED RESIDENTIAL DEVELOPMENT 7331 LAS BRISAS COURT CA A MAR 04201k LAND uVEwPMENT N G FRANK AND JOANN NOLAN TRUST 7331 LA BRISAS COURT LA COSTA AREA, CARLSBAD, CALIFORNIA 92009 PREPARED BY GEOTEK, INC. 1384 POINSETTIA AVENUE, SUITE A VISTA, CALIFORNIA 92081 PROJECT No.: 3281SD3 FEBRUARY 25, 2008 GEOTECHNICAL I ENVIRONMENTAL I MATERIALS GeoTek, Inc. 1384 Poinsettia Avenue, Suite A,Visa, CA 92081-8505 760-599-0509 Office 760-599-0593 Fax www.geotekusa.com February 25, 2.008 Project No.: 3281 SD3 Frank and Joann Nolan Trust 7331 Las Brisas Court Carlsbad, California 92009 Subject: Preliminary Geotechnical Evaluation Proposed Residential Development 7331 Las Brisas Court Carlsbad, California Dear Mr. and Mrs. Frank and Joann Nolan: As requested and authorized, GeoTek, Inc. (GeoTek) has performed a preliminary geotechnical evaluation for the proposed parcel map split and additional residential development located at 7331 Las Brisas Court in the area of La Costa in the City of Carlsbad, California. This report presents the results of our evaluation, a discussion of our findings, and provides geotecimical recommendations for foundation design and construction. In our opinion, the proposed development of the site appears to be feasible from a geotechnical viewpoint, provided that the recommendations included herein are incorporated into the design and construction phases of the project. The opportunity to be of service is sincerely appreciated. If you should have any questions, please do not hesitate to call our office. Respectfully submitted, GeoTek, Inc. ; h~g al~e~ GE 285, Exp. 3/31/08 Senior Engineer IR OtESS,o, PAL No. 0Qfl28 ) -,' 7IIY -v I (( - l(t No.1t42 - * Exp./ * ca e 11>1 ol I 142fExp. 4/30/08 'k OrWY OF Cp-t!..d Prin (5) Addressee (I) PDF via email to Yvette Herman of bHa at yhermann1bhaincsd,com (I) PDF via email to Eric Farmer of bRa at efarmer@bhaincsd.com JD/TM/lg G:\ProjcctsWrojecis 3000 to 3999Wrojecis 3250 to 3299U281SD3 Nolan Res_LnBrisas\328I .GcoRpt-JAOlom.cIoc GEOTECHNICAL I ENVIRONMENTAL I MATERIALS FRANK AND JOANN NOLAN TRUST Project No.: 3281 SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page i TABLE OF CONTENTS 1.0 PURPOSE AND SCOPE OF SERVICES .........................................................................................................I 2.0 SITE DESCRIPTION AND PROPOSED DEVELOPMENT ......................................................................... I 2.1 SITE DESCRIPTION .........................................................................................................................................I 2.2 PROPOSED DEVELOPMENT.............................................................................................................................2 3.0 FIELD EXPLORATION AND LABORATORY TESTING...........................................................................2 3.1 FIELD EXPLORATION .....................................................................................................................................2 3.2 LABORATORY TESTING ..................................................................................................................................3 4.0 GEOLOGIC AND SOILS CONDITIONS........................................................................................................3 4.1 GENERAL .......................................................................................................................................................3 4.1.1 Topsoil.................................................................................................................................................3 4.1.2 Residual Soil.......................................................................................................................................3 4.2 SURFACE AND GROUND WATER ....................................................................................................................4 4.3 FAULTING AND SEISMICITY ...........................................................................................................................4 4.4 FLOOD PLAIN REVIEW, TSUNAMIS, AND SEICHES..........................................................................................5 4.5 OTHER GEOTECHNICAL CONSIDERATIONS ....................................................................................................5 5.0 CONCLUSIONS AND RECOMMENDATIONS.............................................................................................5 5.1 GENERAL ....................................................................................................................................................... S 5.2 EARTHWORK CONSIDERATIONS.....................................................................................................................6 5.2.1 Site Clearing.......................................................................................................................................6 5.2.2 Remedial Grading...............................................................................................................................6 5.2.3 Remedial Grading - Paving/Hardscape Area.....................................................................................7 5.2.4 Fill and Backfill Soils (Import) ...........................................................................................................7 5.2.5 Excavation Characteristics.................................................................................................................7 5.2.6 Soil Balancing.....................................................................................................................................8 5.3 DESIGN RECOMMENDATIONS ........................................................................................................................8 5.3.1 Seismic Design Parameters.................................................................................................................9 5.3.2 Foundation Set Backs ........................................................................................................................10 5.3.3 Slab-on-Grade ................................................................................................................................... 10 5.3.4 Subgrade Moisture............................................................................................................................11 5.3.5 Soil Corrosivity ................................................................................................................................. 11 5.4 CONCRETE CONSTRUCTION .........................................................................................................................11 5.4.1 General..............................................................................................................................................11 5.4.2 Cement Type......................................................................................................................................12 5.4.3 Concrete Flatwork.............................................................................................................................12 5.5 SLOPE STABILITY ........................................................................................................................................12 5.6 RETAINING WALLS.......................................................................................................................................13 5.6.1 General..............................................................................................................................................13 5.7 POST CONSTRUCTION CONSIDERATIONS .....................................................................................................14 5.7.1 Landscape Maintenance and Planting..............................................................................................14 5.7.2 Drainage...........................................................................................................................................14 5.8 PLAN REVIEW AND CONSTRUCTION OBSERVATIONS...................................................................................15 6.0 INTENT / LIMITATIONS ...............................................................................................................................16 7.0 SELECTED REFERENCES............................................................................................................................17 GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I FRANK AND JOANN NOLAN TRUST Project No.: 3281SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page ii TABLE OF CONTENTS ENCLOSURES Figure 1 - Site Vicinity Map Figure 2 - Site Plan— Preliminary Grading Plan - Exploratory Trench Location Plan- Site Geologic Map Appendix A - Logs of Exploratory Trench Appendix B - Results of Laboratory Testing Appendix C - General Grading Guidelines for Earthwork Construction GEOTECHNICAL I ENVIRONMENTAL I MATERIALS FRANK AND JOANN NOLAN TRUST Project No.: 3281 SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 1 1.0 PURPOSE AND SCOPE OF SERVICES The purpose of this study was to evaluate the surface and subsurface soil and geologic conditions at the site and based on our analysis of data obtained, provide recommendations for the development of the property as presently proposed. Tasks/services performed during the course of our geotechnical evaluation include the following: Research and review of available geologic data and general information pertinent to the site. Site exploration consisting of the excavation, logging, and sampling of five exploratory trenches. Laboratory testing on representative samples collected during the field evaluation. Review and evaluation of site seismicity. Geotechnical evaluation of field and laboratory data. Compilation of this geotechnical report which presents our findings, conclusions, and recommendations for site development. 2.0 SITE DESCRIPTION AND PROPOSED DEVELOPMENT 2.1 SITE DESCRIPTION I The subject property is located at 7331 Las Bnsas Court, Carlsbad, California, see Figure 1, Vicinity Map. Legally described as lot 389, Carlsbad Tract No. 72-20, Unit 3, Map No.7950, APN 223-211-18. The property is bound by lot 388 to the north, lot 390 to the east, SDG&E I easement to the south and Piragua Street to the west. A single family residence occupies the eastern, 0.483 acres, portion of the 1.06 acre pie I shaped lot, at an existing pad at elevation of approximately 435 feet msl. A 30 to 50 foot descending slope defines the western terminus of the developed portion of the property. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS FRANK AND JOANN NOLAN TRUST Project No.: 3281 SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 2 2.2 PROPOSED DEVELOPMENT As proposed, site development includes splitting the lot into 2 parcels. Parcel 1 consists of the existing developed area as discussed above and parcel 2 consisting of the western approximately 0.580 acres of the lot, the subject of this study, see Figure 2, Site Plan. Review of preliminary grading plans prepared by bfla, Inc., indicates parcel 2 will be graded to construct a 2 level building pad. The upper pad is be at elevation 407 and the lower pad at 403 feet msl requiring cuts and fill placement of up to 8 feet. A 5 foot high masonry retaining wall is planned along the northern/eastern perimeter of the upper pad. A 3 to 6 foot high 2h:lv cut slope to the top of this retaining wall is proposed. The lower pad terminates into a 3 to 11 foot high daylight 2h: I fill slope along the northern and western sides. A 2 foot maximum height masonry retaining wall is proposed along the southern alignment of the proposed concrete driveway from Piragua Street. An existing sewer line, running southeast to northwest through the proposed building site, will be abandoned and relocated. I The locations of the proposed structure(s) or improvements within the limits of the upper pad are unknown at this time. It is anticipated that the proposed single family residence will be a 2-story wood frame structure founded on a shallow foundation system with conventional slab I on grade floors. The garage may be attached or a stand alone structure. At the present time, no structures or improvement are proposed for the lower pad. 1 3.0 FIELD EXPLORATION AND LABORATORY TESTING 3.1 FIELD EXPLORATION I Our field exploration, performed on January 29, 2008, consisted of excavating five (5) exploratory trenches at the approximate locations as shown on Figure 2, Site Plan. I Exploratory trenches were excavated utilizing a rubber tired Case Super L backhoe equipped with a 24" wide bucket. Trench excavations were extended to depths ranging from 4 to 6 feet below existing grades where practical refusal on bedrock was experienced. Locations of I exploratory trenches were based on elements of proposed site development and equipment accessibility considerations. A geologist from our firm visually examined, collected representative samples of soils encountered and logged the excavations. Logs of exploratory I trenches and additional information regarding field sampling and testing procedures are included in Appendix A. I GEOTECHNICAL I ENVIRONMENTAL I MATERIALS FRANK AND JOANN NOLAN TRUST Project No.: 3281 SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 3 3.2 LABORATORY TESTING Laboratory testing was performed on selected representative samples of the prevailing soils encountered during our field exploration. The purpose of laboratory testing was to confirm field classification of the soil materials and to evaluate physical properties of the soils encountered for use in the engineering design and analysis. Results of the laboratory testing program along with a brief description and relevant information regarding testing procedures are included in Appendix B. 4.0 GEOLOGIC AND SOILS CONDITIONS 4.1 GENERAL A brief description of the earth materials encountered is presented in the following sections. More detailed descriptions of these materials are provided on the exploratory excavation logs included in Appendix A. Based on our review of published geologic maps and confirmed by our field exploration, the site is mantled by topsoil and residual soils which are in turn underlain to the depth explored by weathered Jurassic Undifferentiated Santiago Peak Volcanics. Scattered piles of soil and debris were encountered along the western property line and near the center of the lot, and may be spoils associated with grading of the dirt access road through the property to SDG&E's easement south of the property. 4.1.1 Topsoil A thin layer, up to 1.5 feet, of topsoil was encountered in our exploratory excavations. Topsoil was found to consist of reddish brown, moist to wet, loose clayey fine sands to sandy clays. These soils possess moderate to high expansion characteristics and will require migration during site grading. 4.1.2 Residual Soil I A layer of residual soil was encountered in exploratory trenches 1-4 underlying the topsoil layer and extending to a maximum depth of 3.5 feet below existing site grade at exploratory trench 3. These materials were generally found to consist of red-brown, I moist to saturated silty clay and clayey sand with scattered roots and angular rock. Expansion Index (El) testing was performed on a representative sample of the residual soils, indicating a very high expansion potential (El> 130) with a plastic limit of 40 I (test results are included in Appendix B). As with site topsoil, residual soils will require mitigation during site grading. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS FRANK AND JOANN NOLAN TRUST Project No.: 3281 SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 4 4.1.3 Santiago Peak Volcanics Jurassic-aged metavolcanic bedrock underlies the site. The Santiago Peak Volcanics are classified as completely to slightly weathered, with some fracturing and jointing in a northwest and northeast trends within the depth excavated (maximum of 6 feet). Fractures were found to be weathered to varying degrees. Metavolcanic rocks breaks down to red-brown to yellow-brown silty highly expansive clay extending to 5 feet below existing site grades. Partially exposed boulders with encountered in trench sidewalls and bottoms and should be anticipated throughout site grading operations. 4.2 SURFACE AND GROUND WATER No surface water flow or ponding was observed at the site at time of the field exploration. The site drainage should be reviewed and designed by the project civil engineer. Positive site drainage will be imperative in site development with expansive site soils. Groundwater was not encountered in any of our exploratory excavations. Seepage of runoff ' water was noted within the sidewalls of the trenches due to an exceptional wet weather during our evaluation. No natural groundwater condition is known to be present which would impact site development. However, changes in groundwater or localized seepage conditions I can occur due to variations in rainfall, irrigation practices, and other factors not evident at the time of this evaluation. 4.3 FAULTING AND SEISMICITY The site is situated within Seismic Zone 4 (as designated by California Building Code). No active or potentially active fault is known to exist at this site, or were there indications of active faulting observed during our subsurface exploration at the site. The computer program EQFAULT (Blake, 2000a) was used to approximate the distance to I known late Quaternary faults. The Rose Canyon Fault, located approximately 7.3 miles west of the site, is considered to represent the highest risk to generate ground shaking. I Seismically resistant structural design in accordance with local building ordinances should be followed during the design of all structures. The California Building Code (CBC) has been I developed to reduce the potential for structural damage. However, some level of damage as the result of ground shaking generated by nearby earthquakes is considered likely in this general area. I GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I I FRANK AND JOANN NOLAN TRUST Project No.: 3281 SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 5 1 4.4 FLOOD PLAIN REVIEW, TSUNAMIS, AND SEICHES I We have reviewed flood plain maps prepared by the Federal Emergency Management Agency (FEMA) and provided by the SanGIS regional geographic database at http://www.sangis.org. The Flood Zone data became effective June 19, 1997, and applies to cities in San Diego I County as well as unincorporated areas. According to SanGis FEMA Map Panel 1053F of 2375, the proposed development will be located within 'Other', which is area determined i outside 500-year flood zone. Given the distance between the subject site and the coast, and the site's elevation of I approximately 390 to 415 feet msl, damage due to tsunamis is considered negligible. There does not appear to be any open or confined bodies of water up-gradient from the site. Therefore, the possibility of earthquake-induced flooding due to seiches is considered I negligible. 1 4.5 OTHER GEOTECHNICAL CONSIDERATIONS 1 . Liquefaction potential is considered to be low due to the relatively dense nature of the bedrock. Dynamic settlement is not expected to be a concern due to the relatively dense nature I of the underlying bedrock and prevailing soils conditions. 5.0 CONCLUSIONS AND RECOMMENDATIONS I 5.1 GENERAL Proposed development of the site appears feasible from a geotechnical engineering viewpoint I provided that the recommendations presented herein are incorporated into project design and construction. Existing near surface soils and the upper weathered zone of the Santiago Peak I Volcanics were found to possess high to very high expansion potential and will require mitigation during grading operation as discussed below. Although, no structures or improvement are presently proposed for the lower building pad, we are assuming future 1 construction may occur. As such, the term "building pad" as used in the following sections shall be inclusive of both the proposed upper and lower pads. 1 I GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I FRANK AND JOANN NOLAN TRUST Project No.: 3281 SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 6 5.2 EARTHWORK CONSIDERATIONS Earthwork and grading should be performed in accordance with the appropriate grading ordinances of the City of Carlsbad and recommendations presented hereinafter. The Grading Guidelines included in Appendix C outline general procedures and do not anticipate all site- specific situations and have been included to supplement recommendation of this report. In the event of conflict, recommendations presented in the text of this report shall supersede those contained in Appendix C. 5.2.1 Site Clearing In all areas of planned grading and/or improvements, the site should be cleared of vegetation, roots and debris, and properly/legally disposed of offsite. Any cavities/holes resulting from site clearing attributed to removal of trees or demolition of the existing structures and/or improvements should be filled with properly compacted earth materials. 5.2.2 Remedial Grading Existing topsoil, residual soils and near surface highly weathered Santiago Peak Volcanics possess high to very high expansion potential detrimental to support of proposed structures and improvement. Where not removed by proposed grading, these materials should be completely removed and replaced with select materials. Based on results of our subsurface exploration, we estimate the approximate depth of removal to range from 4 to 5 feet below existing site grades. These expansive materials should be disposed of off-site or may be re-used as fill soil within site areas outside the limits of proposed building pads, fill slopes, and/or improvements. As an alternative, if blended with less expansive materials to reduce the El to <91, materials may then be placed as fill soils to a maximum elevation of five (5) feet below finished pad grades. Following removal of the nears surface expansive soils and/or soils and rock to depths required to allow for construction of a minimum 5 foot thick select material cap, which ever is deeper, the bottom of the resulting excavation(s) should be observed by a representative of GeoTek to check that the highly expansive materials have been adequately removed. It should be understood that localized deeper removals may be needed based on observations of our field representative. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I FRANK AND JOANN NOLAN TRUST Project No.: 328 1SD3 I Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 7 I Excavation bottoms should be scarified a minimum depth of 8 inches, moisture I conditioned to optimum moisture or slightly above and recompacted to a minimum of 90 percent relative compaction as determined in accordance with laboratory test method ASTM D1557 (latest edition) to prior to the placement of fill. Overexcavated I areas should then be filled with suitable import (EI<50) materials in accordance with Appendix C until design finish grades are reached. Remedial earthwork should extend I laterally from the outside edge of the proposed fill areas to a minimum distance of five (5) feet. 5.2.3 Remedial Grading - PavingfHardscape Area Remedial grading as discussed above shall be performed to provide a minimum three I (3) foot thick uniformly compacted select fill mat for support of paving and hardscape. Remedial grading should extend a minimum of three feet beyond the outside edge of - paving and hardscape. 5.2.4 Fill and Backfill Soils (Import) I All fill soils within the upper five feet of finished building pads, the upper three feet below pavements and hardscape areas and retaining wall backfill shall be granular with a maximum EI<50 and approved by GeoTek, Inc. prior to delivery to the site. I All fill soils and backfill materials shall be placed in horizontal lifts not exceeding 12 inches in loose thickness, moisture conditioned to optimum moisture or slightly above I and compacted to a minimum of 90 percent relative compaction as determined in accordance with laboratory test method ASTM Dl 557 (latest edition). 5.2.5 Excavation Characteristics Practical refusal of exploratory trenching equipment was experienced at depths I ranging from 4 to 6 feet below existing grades in metavolcanic bedrock and/or boulders. As such, it is our opinion, near surface soils and highly weather bedrock should be rippable with conventional earthmoving equipment in good operating I condition. Deeper excavations within the underlying metavolcanic rock may encounter harder, less weathered zones requiring heavy-duty grading equipment and are likely to generate large size boulders/rocks. All temporary excavations for grading purposes and installation of underground I utilities should be constructed in accordance with OSHA guidelines. Temporary GEOTECHNICAL I ENVIRONMENTAL I MATERIALS FRANK AND JOANN NOLAN TRUST Project No.: 3281SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 8 excavations within the bedrock material should be stable at 1:1 inclinations for cuts less than 10 feet in height. 5.2.6 Soil Balancing 1 Several factors will impact earthwork balancing on the site, including shrinkage, bulking, subsidence, trench spoils from utilities and footing excavations, amount of oversized material, and final pavement section thickness as well as the accuracy of I topography. I Shrinkage, bulking and subsidence are primarily dependent upon the relationship of in-situ density verses compactive effort achieved during construction. For preliminary planning purposes, a shrinkage factor of 10 to 15 percent may be applied for the soil I materials and a bulking factor of 5 to 10 percent may be assumed for bedrock materials. I The above estimates are intended as an aid for project engineers in determining earthwork quantities. It is recommended that site development be planned to include an area that could be raised or lowered to accommodate final site balancing. 5.3 DESIGN RECOMMENDATIONS Design recommendations for conventional shallow foundation system presented herein assume remedial and site grading has been performed in accordance with the recommendations of this report. Design recommendations assume bearing materials will consist of select engineered fill soils (import) with a maximum expansion potential (EI50). — The proposed residential structure may be supported on conventional continuous and isolated I spread footings bearing on properly compacted engineered fill. Foundations supporting the proposed two story structures should be constructed with an embedment of at least 18 inches below adjacent finish grade. Continuous strip footings should have a minimum width of 15 I inches and isolated spread (column) footings should have minimum dimensions of 24" x 24". Continuous footings supporting single-story structures should have minimum width and embedment of 12 inches and 15 inches, respectively. Footings with the above minimum dimensions may be designed for an allowable soil bearing I value of 3,000 psf. when considering dead plus live loads. This value may be increased by one-third for loads of short duration, such as wind and seismic forces. I GEOTECHNICAL I ENVIRONMENTAL I MATERIALS FRANK AND JOANN NOLAN TRUST Project No.: 3281 SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 9 Minimum reinforcement should consist of two No. 4 rebars, one top and one bottom for strip footing and four No. 4 rebars 12 inch on center in two directions for spread footings, based on geotechnical considerations. Actual foundation reinforcement should be determined by the project Structural Engineer based on calculated loading conditions The passive soil resistance against foundations poured neat in engineered fills and or properly compacted backfill may be computed as an equivalent fluid pressure having a density of 250 psf per foot of depth, to a maximum earth pressure of 3,500 psf. A coefficient of friction of 0.35 between soil and concrete of may be used with dead load forces against sliding. When combining passive pressure and frictional sliding resistance, the passive pressure component should be reduced by one-third. In order to help reduce the potential for misalignment of proposed garage door openings, we recommend that foundations be continuous across garage door opening. Based on the above design recommendations and site preparation as discussed in section 5.2, the total settlement is expected to be less than 1 inch based on the proposed loading conditions. It is anticipated that the majority of the settlement will occur during construction. Differential settlement is expected to be less than one-half of the total settlement. 5.3.1 Seismic Design Parameters The site is located at approximately 33.0888 Latitude and 117.2353 Longitude. Site spectral accelerations (Ss and Si), for 0.2 and 1.0 second periods and 2 percent probability of exceedance in 50 years (MCE) for a Class "B" site, was determined from the USGS Website, Earthquake Hazards Program, Interpolated Probabilistic Ground Motion for the Conterminous 48 States by Latitude/Longitude, 2002 Data. The results are presented in the following table: I I I I GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I FRANK AND JOANN NOLAN TRUST Project No.: 328 1SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 10 I SITE SEISMIC PARAMETERS Mapped 0.2 sec Period Spectral Acceleration, Ss 1.113g Mapped 1.0 sec Period Spectral Acceleration, Si 0.419g Site Coefficient for Site Class "B", Fa 1.0 Site Coefficient for Site Class "B", Fv 1.0 Maximum Considered Earthquake Spectral Response Acceleration Parameter at 0.2 Second, 1.113g SMS Maximum Considered Earthquake Spectral Response Acceleration Parameter at 1 second, 0.419g SMI Design Spectral Response Acceleration 0.742g . g Parameter for 0.2 Second, SOS Design Spectral Response Acceleration 0.279g . g Parameter for 1.0 Second, SD1 1 5.3.2 Foundation Set Backs Where applicable, the following setbacks should apply to all foundations. Any I improvements not conforming to these setbacks may be subject to excessive lateral movements and/or differential settlements: The bottom of all footings for structures near retaining walls and/or lower level subterranean structures should be deepened so as to extend below a 1:1 projection upward from the bottom inside edge of the wall stem. I • The bottom of any adjacent existing foundations for structures should be deepened so as to extend below a 1:1 projection upward from the bottom of ' the nearest excavation. 5.3.3 Slab-on-Grade I Interior building slabs should be designed by the project structural engineer for the anticipated loading and should conform to the requirements of the 2007 CBC and with I recommendations contained in current AC! Guide for Concrete Floor and Slab Construction (ACT 302.1R-04). We recommend building slabs be a minimum of 5 - inches in thickness and be reinforced based on a geotechnical standpoint with at No. 4 bars spaced 18 inches on center, each way. Slab reinforcing should be designed by the project Structural Engineer based on calculated loading conditions. I GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I FRANK AND JOANN NOLAN TRUST Project No.: 3281SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 11 To decrease the likelihood of problems related to damp slabs, suitable moisture protection measures should be used where moisture sensitive floor coverings or other I factors warrant. I A commonly used moisture protection in southern California consists of placing ±2 inches of clean sand (SE> 30) on properly prepared subgrade soils covered by at least 10 mil plastic sheeting, with 2 inches of clean sand placed over the plastic to aid in I curing of the concrete floor slab. If this method is used, then it should be noted that moisture migration levels through a concrete floor slab are still possible and may be excessive for some applications, particularly for sheet vinyl, wood flooring, vinyl tiles, I or carpeting with impermeable backing that use water soluble adhesives. 5.3.4 Subgrade Moisture The subgrade should be properly moisture conditioned prior to placing concrete. The moisture content of subgrade soils should be at least optimum moisture to a minimum depth of 12 inches below finish pad grade for the anticipated as graded select fill soils. Our representative should check moisture content prior to placing the vapor retarding barrier and reinforcing steel. If the subgrade is not reasonably sealed within 24 hours by placing the vapor barrier or concrete or the concrete is not poured within 96 hours of testing, the moisture tests should be considered invalid unless evaluated otherwise by this office. The foundation contractor should be responsible to request additional verification/testing 5.3.5 Soil Corrosivity ' The soil pH and resistivity of imported fill should be checked as part of the evaluation of the materials prior to delivery relative to corrosive conditions to buried metallic elements. Based on test results, a corrosion engineer may need to be consulted to 1 provide recommendations for proper protection of buried metal pipes at this site. 5.4 CONCRETE CONSTRUCTION I 5.4.1 General Concrete construction should follow the 2007 CBC and ACI guidelines regarding design, placement and curing of the concrete. If desired, we could provide quality I control testing of the concrete during construction. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I I FRANK AND JOANN NOLAN TRUST Project No.: 3281 SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 12 1 5.4.2 Cement Type Soluble sulfate and chloride content of imported fill should be checked as part of the I evaluation of the materials prior to delivery. It is recommended that fill soils possess a water soluble sulfate content of less than 0.10 percent by weight, which is considered I negligible as per Table 19-A-4 of the 2007 CBC. The structural engineer should evaluate the laboratory test results in conjunction with the 2001 CBC to specify a suitable cement type. 1 5.4.3 Concrete Flatwork Exterior concrete flatwork (patios, walkways, driveways, etc.) is often some of the I most visible aspects of site development. They are typically given the least level of quality control, being considered "non-structural" components. Cracking of these I features is fairly common due to various factors. While cracking is not usually detrimental, it is unsightly. We suggest that the same standards of care be applied to these features as to the structure itself. One of the simplest means to control cracking is to provide weakened joints for I cracking to occur along. These do not prevent cracks from developing; they simply provide a relief point for stresses that develop. These joints are widely accepted means to control cracks but are not always effective. However, control joints are more I effective, the more closely spaced they are. Control joints should be provided in accordance with ACI Guidelines. 1 5.5 SLOPE STABILITY I Proposed 2:1 fill slopes constructed with select engineered fill soils in accordance with the grading requirements presented in this report will have calculated factors of safety in excess I of 1.5 for maximum slope heights up to 15 feet. It is our opinion that shallow fill slope stability will possess a factor of safety of at least 1.50 for slopes constructed of select materials in accordance with grading recommendation I presented herein. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS FRANK AND JOANN NOLAN TRUST Project No.: 3281 SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 13 5.6 RETAINING WALLS 5.6.1 General Recommendations presented herein may apply to typical masonry or concrete vertical retaining walls to a maximum height of 10 feet. Additional review and recommendations should be requested for higher walls. Assuming site preparation has been performed in accordance with recommendations I presented herein, foundations supporting retaining walls embedded a minimum of 12 inches into engineered fill materials may be designed using an allowable bearing capacity of 3,500 psf. An increase of one-third may be applied when considering short-term live loads (e.g. I seismic and wind loads). The passive earth pressure may be computed as an equivalent fluid having a density of 250 psf per foot of depth, to a maximum earth pressure of 3,500 psf. A I coefficient of friction between soil and concrete of 0.35 may be used with dead load forces. When combining passive pressure and frictional resistance, the passive pressure component I : should be reduced by one-third. An equivalent fluid pressure approach may be used to compute the horizontal active pressure I against the wall. The appropriate fluid unit weights are given in Table 6.5.1 below for specific slope gradients of retained materials. ACTIVE EARTH PRESSURES Surface Slope of Retained Materials (H:V) Equivalent Fluid Pressure (PCF) Level 35 2:1 55 The above equivalent fluid weights do not include other superimposed loading conditions such as expansive soil, vehicular traffic, structures, seismic conditions or adverse geologic conditions. Retaining walls should be provided with an adequate pipe and gravel back drain system to prevent build up of hydrostatic pressures. Back drains should consist of a 4-inch diameter perforated collector pipe (Schedule 40) embedded in a minimum of one cubic foot per lineal foot of 3/8 to one inch clean crushed rock or equivalent, which should be wrapped in filter fabric (Mirafi 140N or approved equivalent). The drain system should be connected to a GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I I 1 I I I I FRANK AND JOANN NOLAN TRUST Project No.: 3281SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 14 suitable outlet. A minimum of two outlets should be provided for each drain section I (maximum section length of 200 feet). Walls from 2 to 4 feet in height may be drained using localized gravel packs (e.g. I approximately 1.5 cubic feet of gravel in a woven plastic bag) behind weep holes at 10 feet maximum horizontal spacing. Weep holes should be provided or the head joints omitted in the first course of block extended above the ground surface. However, nuisance water may still collect in front of wall. 5.7 POST CONSTRUCTION CONSIDERATIONS I 5.7.1 Landscape Maintenance and Planting Overwatering should be avoided. The soils should be maintained in a solid to semi- solid state as defined by the materials Atterberg Limits. Care should be taken when I adding soil amendments to avoid excessive watering. Leaching as a method of soil preparation prior to planting is not recommended. I It is common for planting to be placed adjacent to structures in planter or lawn areas. This will result in the introduction of water into the ground adjacent to the foundation. ' This type of landscaping should be avoided. If used, then extreme care should be exercised with regard to the irrigation and drainage in these areas. Waterproofing of the foundation and/or subdrains may be warranted and advisable. We could discuss I these issues, if desired, when plans are made available. 5.7.2 Drainage I The need to maintain proper surface drainage and subsurface systems cannot be overly emphasized. Positive site drainage should be maintained at all times. Water I should be directed away from foundations and not allowed to pond or seep into the ground. Pad drainage should be directed toward approved area(s). I I I GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I FRANK AND JOANN NOLAN TRUST Project No.: 328 1SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 15 5.8 PLAN REVIEW AND CONSTRUCTION OBSERVATIONS We recommend that site grading, specifications, and foundation plans be reviewed by this office prior to construction to check for conformance with the recommendations of this report. We also recommend that GeoTek representatives be present during site grading and foundation construction to check for proper implementation of the geotechnical recommendations. These representatives should perform at least the following duties: Observe site clearing and grubbing operations for proper removal of unsuitable materials. Observe and/or test bottom of removals prior to fill placement. Evaluate the suitability of on-site and import materials for fill placement, and collect soil samples for laboratory testing where necessary. Observe the fill for uniformity during placement including utility trenches. Provide field density tests to assess relative compaction. Observe and probe foundation materials to check suitability of bearing materials and proper footing dimensions. Observe wall backfill operations. Following observation of site construction we could provide a report summarizing observation and testing results intended to comply with requirements of the governmental agencies having jurisdiction. We recommend that these agencies be notified prior to commencement of construction so that necessary grading permits can be obtained. I I 1 I I GEOTECHNICAL I ENVIRONMENTAL I MATERIALS FRANK AND JOANN NOLAN TRUST Project No.: 3281SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 16 6.0 INTENT I LIMITATIONS It is the intent of this report to aid in the design and construction of the proposed development. Implementation of the advice presented in this report is intended to reduce risk associated with construction of the projects. The professional opinions and geotechnical advice contained in this report are not intended to imply total performance of the project or guarantee that unusual or variable conditions will not be discovered during or after construction. The scope of our evaluation is limited to the area explored, which is shown on Figure 2 - Site Plan. This evaluation does not and should in no way be construed to encompass any areas beyond the specific area of the proposed construction as indicated to us by the client. Further, no evaluation of any existing site improvements is included. The scope is based on our understanding of the project and the client's needs, and geoteclmical engineering standards normally used on similar projects in this region. The materials observed on the project site appear to be representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during site construction. Site conditions may vary due to seasonal changes or other factors. GeoTek, Inc. assumes no responsibility or liability for work, testing or recommendations performed or provided by others. Since our recommendations are based the site conditions observed and encountered, and laboratory testing, our conclusion and recommendations are professional opinions that are limited to the extent of the available data. Observations during construction are important to allow for any change in recommendations found to be warranted. 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. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS FRANK AND JOANN NOLAN TRUST Project No.: 328 1SD3 Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page 17 7.0 SELECTED REFERENCES ASTM, 2000, "Soil and Rock: American Society for Testing and Materials," vol. 4.08 for ASTM test methods D-420 to D- 4914, 153 standards, 1,026 pages; and vol. 4.09 for ASTM test method D-4943 to highest number. Blake, T., 2000a, "EQFAULT, version 3.00," a Computer Program for Deterministic Estimation of Maximum Earthquake Event and Peak Ground Acceleration. Blake, T., 2000, "FRISKSP, version 4.00," a Computer Program for Probabilistic Estimation of Peak Acceleration and Uniform Hazard Spectra Using 3-D Faults as Earthquake Sources. Bowles, J., 1982, "Foundation Analysis and Design," McGraw-Hill, Third Edition. California Code of Regulations, Title 24, 2001 "California Building Code," 3 volumes. California Division of Mines and Geology (CDMG), 1997, "Guidelines for Evaluating and Mitigating Seismic Hazards in California," Special Publication 117. California Division of Mines and Geology (CDMG), 1998, Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada: International Conference of Building Officials. California Division of Mines and Geology (CDMG), 1996, Open-File Report 96-02, Geologic Map of the Northwestern Part of Sand Diego County, Oceanside, San Luis Rey, and San Marcos 7.5 Quadrangles GeoTek, Inc., In-house proprietary information. Ishihara, K., 1985, "Stability of Natural Deposits During Earthquakes," Proceedings of the Eleventh International Conference on Soil Mechanics and Foundation Engineering, San Francisco, CA, Volume 1. Seed, H.B., and Idriss, I.M., 1982, "Ground Motions and Soil Liquefaction During Earthquakes," Earthquake Engineering Research Institute. US Army Corps of Engineers, No. 9, "Settlement Analysis," Technical Guidelines, ASCE Press, 1994 USGS Website, Earthquake Hazards Program, Interpolated Probabilistic Ground Motion for the Conterminous 48 States by Latitude/Longitude, 2002 Data. Youd, T. Leslie and Idriss, Izzmat M., 1997, Proceeding of the NCEER Workshop on Evaluation of Liquefaction Resistance of Soils, National Center for Earthquake Engineering Research, Technical Report NCEER-97-0022. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS APPENDIX A LOGS OF EXPLORATORY TRENCHES (Trenches T-1 to T-5) Proposed Residential Development Carlsbad, California Project No.: 3281SD3 GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I I FRANK AND JOANN NOLAN TRUST APPENDIX A Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page A-I LEGEND TO FIELD TESTING AND SAMPLING I A - FIELD TESTING AND SAMPLING PROCEDURES Standard Penetration Test (SPT) The SPT is performed in accordance with ASTM Test Method D 1586. The SPT sampler is typically I driven into the ground 12 or 18 inches with a 140-pound hammer free falling from a height of 30 inches. Blow counts are recorded for every 6 inches of penetration as indicated on the log of boring. The split-barrel sampler has an external diameter of 2 inches and an unlined internal diameter of 1-3/8 I inches. The samples of earth materials collected in the sampler are typically classified in the field, bagged, sealed and transported to the laboratory for further testing. I Modified Split-Barrel Sampler (Ring) The Ring sampler is driven into the ground in accordance with ASTM Test Method D 3550. The sampler, with an external diameter of 3.0 inches, is lined with 1-inch long, thin brass rings with inside I diameters of approximately 2.4 inches. The sampler is typically driven into the ground 12 or 18 inches with a 140-pound hammer free falling from a height of 30 inches. Blow counts are recorded for every 6 inches of penetration as indicated on the log of boring. The samples are removed from the I sample barrel in the brass rings, sealed, and transported to the laboratory for testing. Large Bulk Samples I These samples are normally over 20 pounds in weight, of earth materials collected from the field by means of hand digging or exploratory cuttings. I Small Bulk Samples These samples are normally less than 5 pounds in weight of earth materials collected from the field by means of the split spoon sampler, hand digging or exploratory cuttings and placed in moisture l resistant containers. These samples are primarily used for determining natural moisture content and classification indices. B - BORING LOG LEGEND The following abbreviations and symbols often appear in the classification and description of soil and rock on the logs of borings: SOILS USCS Unified Soil Classification System f-c Fine to coarse f-rn Fine to medium GEOLOGIC Attitudes Bedding: strike/dip J: Attitudes Joint: strike/dip Contact line Dashed line denotes USCS material change Solid Line denotes unit / formational change Thick solid line denotes end of boring (Additional denotations and symbols are provided on the logs of borings) GEOTECHNICAL I ENVIRONMENTAL I MATERIALS L (J ç Approximate Site Location I 'PIL;.!J' - - . __ .*. •• .. -'. rj• ' iL 7 L t4 i—I g'PA mg Source: Google Earth. 00 loll -117 1262770 .l.y 109 fr , j ..: -. •,. ;A,. -.!., lip - '. Ptp •j _hr. .. 'rr1.'• -:-x.,.-• -. . -../. - I - • .1 • trria.: 2E& .... • ____ FRANK AND JOANN NOLAN TRUST Proposed Residential Development 7331 La Brisas Court La Costa Area, Carlsbad, California PN: 328 ISD3 11Februari 2008 LJ Figure 1 Site Vicinity Map 1384 Poinsettia Avenue, Suite A Vista, California 92081-8505 I .. M.?'fU./9. ov EX/S7 Al kc 11. InA 089 1 \\t\ \'Th i/ < I I j ( (\ 9W AWABAN \I\ iEX/S\ ;RAC I .? H \ \ \ I SEI$fR 0. l / ,' ExIsT8,EJw , rr 2 W. \\ \ -7 U \/ I T V 4Y eAu is I I I I RE7'ANC WALL EX 41 - PIR %TAIMNG WI /ff WA LL J 111V AIN ER \\ I _- I ACCESS I I \ / 'ST.12 J PR0P?14ED MN 'N I -" ,-EWER 1AEME1VT ER I/I (/.E. 4O43) '..• \ " . AIWO.5O'; — - — I I RO~K PUPEJS4 T < ( C., ,, OPEN & EX1517NC \ EASEMEN1 LOT 401 ",- : •j ---' 30 15 0 30 60 90 II1e2end I 114 15 Approximate location of exploratory trenches SCALE: 1 30' " = II Afli Undocumented Fill Af Documented Fill KJsp Note: Base Plan by bHa Inc. Parcel Map, print dated 1/10/2008. I FRANK AND JOANN NOLAN TRUST Figure 2— Site Plan Proposed Residential Development 7331 La Brisas Court Geotechnical La Costa Area, Carlsbad, California Map 1384 Poinsettia Avenue, Suite A PN. 3281SD3 February 2008 Vista, California 92081 I GeoTek, Inc. LOG OF EXPLORATORY TRENCH PROJECT NO.: 3281-SD3 LOGGED BY: LG PROJECT NAME: LasBrisas/NolanResidence EQUIPMENT: 580CaseSuperL CLIENT: NolanTrust DATE: 1/2912008 LOCATION: See Site Plan ELEVATION: - ± 414 feet - SAMPLES - Laboratory Testing TRENCH NO.: T-1 120 5 EE U) CL - o Cs Cs MATERIAL DESCRIPTION AND COMMENTS _____ SC Topsoil '- Red-brown, moist to wet, loose, clayey line to medium SAND with rock Ti-i X Residual Soil CH Red-brown, moist to wet, soft silty CLAY with sand & rock fragments: T11-2 cobble & boulder size - angular - - El, AL, SA Santiago Peak Volcanics CH Highly weathered; breaks into yellow, wet, soft, silty CLAY; with rock fragments )< T1-3 Highly to moderately weathered; Some fracturing; Blocky; angular - cobble & boulder size; water seepage along fractures; fractures Tl-4 trending northwest; fractures filled with Clay Moderately weathered; less fractured rock at bottom of trench - - -TRENCH TERMINATED AT 6 FEET- No groundwater encountered Trench backfilled with excavation spoils Practical refusal on metamorphic rock 10 15 LU ]Sample Type: --_Small Plastic Bag --- Chunk Sample '--- Large Bulk Sample ---Water Table Laboratory Testing: AL = Atterberg Limits El = Expansion Index MD = Maximum Density SA = Sieve Analysis SR = Sulfate/Resistivity Test SH = Shear Testing RV = R-Value Test CO Consolidation I I GeoTek, Inc. LOG OF EXPLORATORY TRENCH PROJECT NO.: 3281-SD3 LOGGED BY: LG PROJECT NAME: LasBrisas/NolanResidence EQUIPMENT: 580CaseSuperL CLIENT: NolanTrust DATE:1/29/2008 LOCATION: See Site Plan ELEVATION: ± 408 feet - SAMPLES - Laboratory Testing 0 - - C1 E TRENCH NO.: T-2 EE ° 0 Cs U) Cs 0 MATERIAL DESCRIPTION AND COMMENTS Topsoil T2-1 SC Red-brown, moist to wet, loose, clayey fine to medium SAND with rock; roothairs - T2-2 Residual Soil CH Red-brown, wet, soft silty CLAY; root hairs; gravel - >< T2-3 Santiago Peak Volcanics CL-CH Highly weathered; breaks into yellow, moist, silty CLAY and clayey T2-4 GRAVEL Moderately to slightly weathered; breaks into cobble size angular rock;, some fracturing -TRENCH TERMINATED AT 5 FEET- No groundwater encountered Trench backfilled with excavation spoils' Practical refusal on metamorphic rock 10 15 [Sample Type: --- Small Plastic Bag Chunk Sample --- Large Bulk Sample ---Water Table 0 Laboratory Testing: AL = Atterberg Limits El = Expansion Index MD = Maximum Density SA = Sieve Analysis SR = Sulfate/Resistivity Test SH = Shear Testing RV = R-Value Test CO = Consolidation I U GeoTek, Inc. LOG OF EXPLORATORY TRENCH PROJECT NO.: PROJECT NAME CLIENT: LOCATION: 328 1-SD3 Las Brisas/Nolan Residence Nolan Trust See Site Plan LOGGED BY: LG EQUIPMENT: CaseSuperL DATE: 1/29/2008 ELEVATION: - ±406feet - SAMPLES - 0 LaboratoryTesting CL -- E TRENCH NO.: T-3 CL EE Cs Cs D Cn MATERIAL DESCRIPTION AND COMMENTS T3-1 Topsoil T3-2 SC Grey-brown, moist to wet, clayey fine to medium SAND with root hairs X &rock - T3-3 ResidualSoil SM-ML Red-brown, moist, stiff, sandy SILT to silty SAND with clay and gravel T3-4 CL Red-brown, moist, stiff, sandy CLAY with gravel and boulder size rocks SantiagoPeakVolcanics Moderatelyweathered;breaksintohighlyfracturedrock;angular - - 5- -TRENCH TERMINATED AT 4 FEET- No groundwater encountered Trench backfilled with excavation spoils' Practical refusal on metamorphic rock 10 15 SampIeType:EJ--- SmallPlasticBag _--- ChunkSample _'-- LargeBulkSample ---Water Table CD Laboratory _Testing: AL = Atterberg Limits El = Expansion Index MD = Maximum Density SA = Sieve Analysis SR = Sulfate/Resistivity Test SH = Shear Testing RV = R-Value Test CO = Consolidation PROJECT NO.: PROJECT NAME: CLIENT: LOCATION: 3281-SD3 Las Brisas/Nolan Residence Nolan Trust See Site Plan LOGGED BY: LG EQUIPMENT: 580CaseSuperL DATE: 1/29/2008 ELEVATION: - ±400feet I GeoTek, Inc. LOG OF EXPLORATORY TRENCH I I - SAMPLES - 0 LaboratoryTesting - .0 TRENCH NO.: T-4 .5 • C1 M - EE ') . 0 (V (I) MATERIALDESCRIPTION ANDCOMMENTS - Topsoil - T4-1 CH Brown,wet,soft,sandyCLAYwithangularrock - ResidualSoil CH Red-brown, wet, soft sandy CLAY with gravel - SantiagoPeakVolcanics Highly weathered; fractured; iron staining; breaks into yellow sandy = T4-2 clayey GRAVEL; trench belling due to boulder size rock Slightly weatheredrock;notfractured - - -TRENCH TERMINATED AT 5 FEET- No groundwater encountered Trench backfilled with excavation spoils' - Practical refusal on metamorphic rock 10 15 ISample _Type: E--- Small Plastic Bag _--- ChunkSample _'-- LargeBulkSample --Water TablLU 0 Laboratory Testing., AL = Atterberg Limits El = Expansion Index MD = Maximum Density SA Sieve Analysis LU SR = Sulfate/Resistivity Test SH = Shear Testing RV = R-Value Test CO = Consolidation GeoTek, Inc. LOG OF EXPLORATORY TRENCH LOGGED BY: LG EQUIPMENT: CaseSuperL DATE: 1/29/2008 ELEVATION: ±398feet - SAMPLES LaboratoryTesting - .0 TRENCH NO.: T-5 EE U) . ____________________________________ .t? 0 Cs Cs 0 MATERIAL DESCRIPTION AND COMMENTS Topsoil CH Yellow-brown, wet to saturated, soft sandy CLAY — T5-1 SantiagoPeakVolcanics - SC Completely weathered; breaks into yellow, dry to moist, fine to coarse A T5-2 SAND with rock boulders: 26"x12"x9" Highly weathered; less fractured -TRENCH TERMINATED AT 4 FEET- No groundwater encountered Trench backfilled with excavation spoils' Practical refusal on metamorphic rock 10 15 Uj Isamoie_Type: --- SmallPlasticBag _--- chunkSample _'--Large Bulk Sample .—Water Table Laboratory AL = Atlerberg Limits El = Expansion Index MD = Maximum Density SA = Sieve Analysis _Testing: Lu .1 SR = Sulfate/Resistivity Test SH = Shear Testing RV = R-Value Test CO = Consolidation I I I I I I I I I I I I I I I I I I I PROJECT NO.: 328 1-SD3 PROJECT NAME: Las Brisas/Nolan Residence CLIENT: Nolan Trust LOCATION: SeeSitePlan I I F IH [ I APPENDIX B RESULTS OF LABORATORY TESTING I Proposed Residential Development Carlsbad, California I Project No.: 32815D3 I I GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I FRANK AND JOANN NOLAN TRUST APPENDIX B Preliminary Geotechnical Evaluation February 25, 2008 Proposed Residential Development Page B- I SUMMARY OF LABORATORY TESTING I Classification Soils were classified visually according to the Unified Soil Classification System (ASTM Test Method D2487). Soil classifications are shown on the logs of exploratory borings in I Appendix A. Grain size distribution (particle size analysis) was performed on selected samples in general I accordance with ASTM D422. Results of the grain size analysis are included herein (see Plates SA-1 through SA-3). I Atterberg Limits Liquid limit, plastic limit and plasticity index were determined in general accordance with ASTM Test Method D4318. Results are shown on the logs of exploratory trenches in I Appendix A Sulfate Content I Analysis to determine the water-soluble sulfate content was in general accordance with California Test No. 417. Results of the testing are included herein. I pH and Resistivity To assess the potential for reactivity with buried metal pipe and below grade ferrous I materials, selected soil samples were tested for pH and resistivity in general accordance with the laboratory procedures outlined in Caltrans test method 643. The tests results are included herein. Chloride Water soluble chloride testing was performed on a representative near-surface sample. Chloride content was estimated in general accordance with the Caltrans Test Method 422. Results of the testing indicated water soluble chloride content of less than 0.01 percent by weight. I Expansion Index Expansion Index testing was performed on a representative near-surface samples. Testing was I performed in general accordance with ASTM Test Method D4829. The results indicate an Expansion Index El =166 for the soils tested. This is considered a very high potential for expansion in accordance with Table 18-I-B of the 2007 CBC. Moisture-Density Relations Laboratory testing was performed on representative samples collected during the subsurface I exploration. The laboratory maximum dry density and optimum moisture content for representative soil types were determined in general accordance with test method ASTM D1557. Test results are presented in Appendix A. I GEOTECHNICAL I ENVIRONMENTAL I MATERIALS MAXIMUM DENSITY CURVE Curve No.: A Project No.: 328 1-SD3 Date: 2/4/08 Project: Nolan Residense Location: Elev./Depth: Remarks: MATERIAL DESCRIPTION Description: Reddish brown silty clay Classifications - USCS: AASHTO: Nat Moist. = Sp.G. = Liquid Limit = Plasticity Index = %>3181n.= % <No.200 = TEST RESULTS Maximum dry density = 115 pcf Optimum moisture = 16.5 % 140 = = = = = = s. : Test specification: -- - ASTM D 1557-00 Method B Modified 130— —NL - - - - - - 120 -- - - 100% SATURATION CURVES -- - FOR SPEC. GRAy. EQUAL TO: - - - - 28 -- 27 110=::::::•- — 90 2.6 - C IOU - --- --- _ - -- - - - - - --- - 90————-- - - ., -- - - -----s - - - - -- - - - - - S - - -- 80 - - - - - - - - -- ------------- -- 70 0 5 10 15 20 25 30 35 40 Water content, % Plate GeoTek. Inc. READINGS______ DATE TIME READING 2/5/2008 11:20 0.170 215/2008 . 11:30 0.169 21512008 11:31 0.172 21512008 11:36 0.185 2/5/2008 1:10 0.270 2/612008 8:00 1 0.326 Initial 10 mm/Dry I mm/Wet 5 mm/Wet Random Final FINAL MOISTURE Weight or wet sample & tare weigni 01 dry sample & tare Tare % Moisture 163.1 142.2 18.5 16.9% EXPANSION INDEX TEST (ASTM D4829) Project Name: Nolan Residence Testedl Chocked By: NT Lab No 2810 Project Number: 3281-SD3 Date Tested: 2/5/2008 Sample Source: T1@2' Sample Description: brown silty day F G H J K Ring Id12 Ring Dia. 4' Ring 1" Loading weight: 5516. grams DENSITY DETERMINATION A Weight of compacted sample & ring 734.3 B Weight of ring 371.4 C Net weight of sample 362.9 D Wet Density, lb / ft3 (C*0.3016) 109.5 SATURATION DETERMINATION Moisture Content, % (EF) (E/167.232) (62.41) (G/J) L % Saturation 16.9 1582.3 0.56 0.44 27.5 57.6 I EXPANSION INDEX = 166 L SATURATION) LIQUID AND PLASTIC LIMITS TEST REPORT Dashed line indicates the approximate -- 1 upper limit boundary for natural soils - ON, , MLrOL ______ ______ MHrOH • I 6C 50 40 30 20 10 7 10 30 50 70 90 1 1 0 LIQUID LIMIT I I I I I I I I I I I I I I I I I I I 66 65 -- __ __ • 11111 iiçiiIIIIIIiiIII F- 63 - - Lu 62 o61 - ------------- w -60 N 59 - -- -- -- -- 58 -------------- N 57 ----------------- 565 lo 20 53 40 NUMBER OF BLOWS MATERIAL DESCRIPTION LL PL P1 %c#40 %<#200 USCS Reddish brown silty clay 60 20 40 Project No. 328 1-SD3 Client: Nolan Trust Project: Nolan Residense S Source: T1@2 Sample No.: TI®2 LIQUID AND PLASTIC LIMITS TEST REPORT GeoTek, Inc. Plate r -. Part! c le Size Distribution Report 100 90 80 70 IIIIIIflhIHhIIllIUhi!IH!!IIiIIIIOhIUIiiiiiii1i IIIIOIIHIIIllHIHIIIIDhIIIIiuIiiI!IIIUIIIIIIII___ IIIIIIIUIIIllhIIHIIlIOHIIIIHIIIIVKiIIIIIIIIIII__ IIIIIllIIIHUIIOhIIHhINIllhIIUIhiIIOIIi!UIIIlIIII-- UhIIIUhIHIIIHIIIIJIIlIllhIIIIUIIIIHIIIUiii{i!!i IIIIIIIIIHIIllOIHIIIIllhIII1IllhIllHhIIIIIIOIIIII IUII1UIIHUflhIIHIIUIIIIIIIIIIIHuIIIIIIIIIIII__ IIIIUIUIIIIDIOIIIIUIllhIIIIlIIII1IIIIIIIIIIIIII___ iIIUIIIIHH1HhIIHIIIIllh1IIHhIllHhIIIIIIIUhlII 1401' 100 10 'III '111.1 (K/kIN SILb - mm I % COBBLES % GRAVEL % SAND %SiLT I %CLAY 60 I W Z U- F— z 50 I 0 .40 I 30 20 I 1: SIEVE SIZE PERCENT FINER SPEC.' PERCENT PASS? (XNO) #4 98.0. #8. 95,2 #16 93.0 #30 92.0 #50 91.0 #100 88.4 #200 84.6 Soil Description Brown silty clay Atterbera Limits PL= 20 LL= 60 P1= 40 Coefficients D85= 0.0767 D60 0.0135 050= 0.0017 D30= D15= . CU= cc= Classification USCS= CH AASHTO= A-7-6(36) Remarks none I Sample No.: T2@3 Location: Source of Sample: Date: 02/05/08 Elev./Depth: Client: Nolan Trust i GeoTek, Inc. Project: No Residense Project No: 328 1-SD3 I Plate Particle Size Distribution Report 100 1111111 I I Iii 90 - 80 - 70 - W 60 - Z U- F- z 50 - Ui C-) LU 40- 30 - I0 0 GRAIN SIZE - mm % COBBLES % GRAVEL % SAND % SILT % CLAY 12.2 846 SIEVE SIZE PERCENT FINER SPEC.* PERCENT PASS? (X=NO) #4 96.8 #8 95.7 #16 95.1 #30 94.2 #50 92.7 #100 89.1 #200 84.6 Soil Description Reddish brown silty clay Atterbera Limits PL= 20 LL= 60 P1= 40 Coefficients D55= 0.0797 D60= D50= D30= D15= 1310= CU= cc= Classification USCS= CH AASHTO= A-7-6(36) Remarks none Sample No.: TI@2 Source of Sample: T1@2 Date: 02/06/2008 Location: Elev./Depth: Client: Nolan Trust GeoTek, Inc. Project: Nolan Residense Project No: 3281-SD3 Plate I. LABORATORY REPORT I Telephone (619) 425-1993 Fax 425-7917 Established 1928 CLARKSON LABORATORY AND SUPPLY INC. 350 Trousdale Dr. Chula Vista, Ca. 91910 www.clarksonlab.com ANALYTICAL AND CONSULTING CHEMISTS I Date: February 8, 2008 Purchase Order Number: 1189 Sales Order Number: 91684 Account Number: GEOT I -----* ------------------------------------------------- I GeoTek,Inc. 1384 Poinsetta Avenue, Suite A Vista, CA 92083 Attention: David Cliff I Laboratory Number: S03072 Customers Phone: 760-599-0509 Fax: 760-599-0593 Sample Designation: 1 * ------------------------------------------------- One soil sample received on 2/5/08, taken on from Job#3281-SD3 marked as Lab#2810. Analysis By California Test 643, Department of Transportation Division of Construction, Method for Estimating the Service Life of Steel Culverts. pH 7.0 Water Added (ml) Resistivity (ohm-cm) 10 6200 5 3200 5 1400 5 780 5 620 5 •500 5 500 5 560 5 .580 16 years to perforation for a 16 gauge metal culvert. 21 years to perforation for a 14 gauge metal culvert. 29 years to perforation for a 12 gauge metal culvert. 37 years to perforation for a 10 gauge metal culvert. 45 years to perforation for a 8 gauge metal culvert. Water Soluble Sulfate Calif. Test 417 Water Soluble Chloride Calif. Test 422 Laura Torres LT / rm 0.006% 0.019% APPENDIX C GENERAL GRADING GUIDELINES FOR EARTHWORK CONSTRUCTION I I I Proposed Residential Development I Carlsbad, California Project No.: 32815D3 I 1 GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I I FRANK AND JOANN NOLAN APPENDIX C Proposed Residential Development Project No. :3281SD3 7331 Las Brisas Court, Vista, California Page 1 I GENERAL GRADING GUIDELINES I Guidelines presented herein are intended to address general construction procedures for earthwork construction. Specific situations and conditions often arise which cannot reasonably be discussed in I general guidelines, when anticipated these are discussed in the text of the report. Often unanticipated conditions are encountered which may necessitate modification or changes to these guidelines. It is our hope that these will assist the contractor to more efficiently complete the project by providing a reasonable understanding of the procedures that would be expected during earthwork and the testing and I observation used to evaluate those procedures. General Grading should be performed to at least the minimum requirements of governing agencies, Chapters 18 and 33 of the Uniform Building Code and the guidelines presented below. I Preconstruction Meeting A preconstruction meeting should be held prior to site earthwork. Any questions the contractor has regarding our recommendations, general site conditions, apparent discrepancies between reported and I actual conditions and/or differences in procedures the contractor intends to use should be brought up at that meeting. The contractor (including the main onsite representative) should review our report and these guidelines in advance of the meeting. Any comments the contractor may have regarding these guidelines should be brought up at that meeting. Grading Observation and Testing 1 1. Observation of the fill placement should be provided by our representative during grading. Verbal communication during the course of each day will be used to inform the contractor of test results. The Contractor should receive a copy of the "Daily Field Report" indicating results of field I density tests that day. If our representative does not provide the contractor with these reports, our office should be notified. Testing and observation procedures are, by their nature, specific to the work or area observed and I location of the tests taken, variability may occur in other locations. The contractor is responsible for the uniformity of the grading operations, our observations and test results are intended to evaluate the contractor's overall level of efforts during grading. The contractor's personnel are the only individuals participating in all aspect of site work. Compaction testing and observation I should not be considered as relieving the contractor's responsibility to properly compact the fill. Cleanouts, processed ground to receive fill, key excavations, and subdrains should be observed by our representative prior to placing any fill. It will be the Contractor's responsibility to notify I our representative or office when such areas are ready for observation. Density tests may be made on the surface material to receive fill, as considered warranted by this firm. I 5. In general, density tests would be made at maximum intervals of two feet of fill height or every 1,000 cubic yards of fill placed. Criteria will vary depending on soil conditions and size of the fill. More frequent testing may be performed. In any case, an adequate number of field density I tests should be made to evaluate the required compaction and moisture content is generally being obtained. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS 1 I I FRANK AND JOANN NOLAN APPENDIX C I Proposed Residential Development Project No. :3281SD3 7331 Las Brisas Court, Vista, California Page 2 1 6. Laboratory testing to support field test procedures will be performed, as considered warranted, based on conditions encountered (e.g. change of material sources, types, etc.) Every effort will be I made to process samples in the laboratory as quickly as possible and in progress construction projects are our first priority. However, laboratory workloads may cause in delays and some soils may require a minimum of 48 to 72 hours to complete test procedures. Whenever possible, our representative(s) should be informed in advance of operational changes that might result in I different source areas for materials. 7. Procedures for testing of fill slopes are as follows: Density tests should be taken periodically during grading on the flat surface of the fill I three to five feet horizontally from the face of the slope. If a method other than over building and cutting back to the compacted core is to be employed, slope compaction testing during construction should include testing the outer I six inches to three feet in the slope face to determine if the required compaction is being achieved. 8. Finish grade testing of slopes and pad surfaces should be performed after construction is I complete. Site Clearing I 1. All vegetation, and other deleterious materials, should be removed from the site. If material is not immediately removed from the site it should be stockpiled in a designated area(s) well outside of all current work areas and delineated with flagging or other means. Site clearing should be I performed in advance of any grading in a specific area. Efforts should be made by the contractor to remove all organic or other deleterious material from the fill, as even the most diligent efforts may result in the incorporation of some materials. This is especially important when grading is occurring near the natural grade. All equipment operators I should be aware of these efforts. Laborers may be required as root pickers. Nonorganic debris or concrete may be placed in deeper fill areas provided the procedures used are observed and found acceptable by our representative. Typical procedures are similar to those I indicated on Plate G-4. Treatment of Existing Ground I 1. Following site clearing, all surficial deposits of alluvium and colluvium as well as weathered or creep effected bedrock, should be removed (see Plates G-1, G-2 and G-3) unless otherwise specifically indicated in the text of this report. I 2. In some cases, removal may be recommended to a specified depth (e.g. flat sites where partial alluvial removals may be sufficient) the contractor should not exceed these depths unless directed otherwise by our representative. 3. I Groundwater existing in alluvial areas may make excavation difficult. Deeper removals than indicated in the text of the report may be necessary due to saturation during winter months. Subsequent to removals, the natural ground should be processed to a depth of six inches, I moistened to near optimum moisture conditions and compacted to fill standards. Exploratory back hoe or dozer trenches still remaining after site removal should be excavated and filled with compacted fill if they can be located. I GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I I I FRANK AND JOANN NOLAN APPENDIX C Proposed Residential Development Project No. :3281SD3 7331 Las Brisas Court, Vista, California Page 3 I Subdrainage Subdrainage systems should be provided in canyon bottoms prior to placing fill, and behind I buttress and stabilization fills and in other areas indicated in the report. Subdrains should conform to schematic diagrams G-1 and G-5, and be acceptable to our representative. For canyon subdrains, runs less than 500 feet may use six-inch pipe. Typically, runs in excess of 1 500 feet should have the lower end as eight-inch minimum. Filter material should be clean, 1/2 to 1 -inch gravel wrapped in a suitable filter fabric. Class 2 permeable filter material per California Department of Transportation Standards tested by this I office to verify its suitability, may be used without filter fabric. A sample of the material should be provided to the Soils Engineer by the contractor at least two working days before it is delivered to the site. The filter should be clean with a wide range of sizes. I Approximate delineation of anticipated subdrain locations may be offered at 40-scale plan review stage. During grading, this office would evaluate the necessity of placing additional drains. All subdrainage systems should be observed by our representative during construction and prior I to covering with compacted fill. Subdrains should outlet into storm drains where possible. Outlets should be located and protected. The need for backflow preventers should be assessed during construction. I 7. Consideration should be given to having subdrains located by the project surveyors. Fill Placement I 1. Unless otherwise indicated, all site soil and bedrock may be reused for compacted fill; however, some special processing or handling may be required (see text of report). 2. Material used in the compacting process should be evenly spread, moisture conditioned, I processed, and compacted in thin lifts six (6) to eight (8) inches in compacted thickness to obtain a uniformly dense layer. The fill should be placed and compacted on a nearly horizontal plane, unless otherwise found acceptable by our representative. 3. If the moisture content or relative density varies from that recommended by this firm , the I Contractor should rework the fill until it is in accordance with the following: Moisture content of the fill should be at or above optimum moisture. Moisture should be evenly distributed without wet and dry pockets. Pre-watering of cut or removal areas I should be considered in addition to watering during fill placement, particularly in clay or dry surficial soils. The ability of the contractor to obtain the proper moisture content will control production rates. I Each six-inch layer should be compacted to at least 90 percent of the maximum dry density in compliance with the testing method specified by the controlling governmental agency. Inmost cases, the testing method is ASTM Test Designation D-1557. I 4. Rock fragments less than eight inches in diameter may be utilized in the fill, provided: They are not placed in concentrated pockets; I There is a sufficient percentage of fine-grained material to surround the rocks; C) The distribution of the rocks is observed by and acceptable to our representative. 5. Rocks exceeding eight (8) inches in diameter should be taken off site, broken into smaller I fragments, or placed in accordance with recommendations of this firm in areas designated suitable for rock disposal (See Plate G-4). On projects GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I where significant large quantities of I I FRANK AND JOANN NOLAN APPENDIX C Proposed Residential Development Project No. :3281SD3 7331 Las Brisas Court, Vista, California Page 4 oversized materials are anticipated, alternate guidelines for placement may be included. If significant oversize materials are encountered during construction, these guidelines should be I requested. 6. In clay soil dry or large chunks or blocks are common; if in excess of eight (8) inches minimum dimension then they are considered as oversized. Sheepsfoot compactors or other suitable I methods should be used to break up blocks. When dry they should be moisture conditioned to provide a uniform condition with the surrounding fill. Slope Construction 1 1. The Contractor should obtain a minimum relative compaction of 90 percent out to the finished slope face of fill slopes. This may be achieved by either overbuilding the slope and cutting back I to the compacted core, or by direct compaction of the slope face with suitable equipment. Slopes trimmed to the compacted core should be overbuilt by at least three (3) feet with compaction efforts out to the edge of the false slope. Failure to properly compact the outer edge l results in trimming not exposing the compacted core and additional compaction after trimming may be necessary. If fill slopes are built "at grade" using direct compaction methods then the slope construction I should be performed so that a constant gradient is maintained throughout construction. Soil should not be "spilled" over the slope face nor should slopes be "pushed out" to obtain grades. Compaction equipment should compact each lift along the immediate top of slope. Slopes should be back rolled or otherwise compacted at approximately every 4 feet vertically as the slope is I built. Corners and bends in slopes should have special attention during construction as these are the most difficult areas to obtain proper compaction. I 5. Cut slopes should be cut to the finished surface, excessive undercutting and smoothing of the face with fill may necessitate stabilization. I Keyways, Buttress and Stabilization Fills Keyways are needed to provide support for fill slope and various corrective procedures. 1. Side-hill fills should have an equipment-width key at their toe excavated through all surficial soil I and into competent material and tilted back into the hill (Plates G-2, G-3). As the fill is elevated, it should be benched through surficial soil and slopewash, and into competent bedrock or other material deemed suitable by our representatives (See Plates G- 1, G-2, and G-3). I 2. Fill over cut slopes should be constructed in the following manner: a) All surficial soils and weathered rock materials should be removed at the cut-fill interface. I b) A key at least one (1) equipment width wide (or as needed for compaction) and tipped at least one (1) foot into slope should be excavated into competent materials and observed by our representative. C) The cut portion of the slope should be excavated prior to fill placement to evaluate if I stabilization is necessary, the contractor should be responsible for any additional earthwork created by placing fill prior to cut excavation. (See Plate G-3 for schematic details.) I 3. Daylight cut lots above descending natural slopes may require removal and replacement of the outer portion of the lot. A schematic diagram for this condition is presented on Plate G-2. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I I ' - FRANK AND JOANN NOLAN APPENDIX C Proposed Residential Development Project No. :3281SD3 7331 Las Brisas Court, Vista, California Page 5 I A basal key is needed for fill slopes extending over natural slopes. A schematic diagram for this I .condition is presented on Plate G-2. All fill slopes should be provided with a key unless within the body of a larger overall fill mass. Please refer to Plate G-3, for specific guidelines. I Anticipated buttress and stabilization fills are discussed in the text of the report. The need to stabilize other proposed cut slopes will be evaluated during construction. Plate G-5 is shows a schematic of I buttress construction. All backcuts should be excavated at gradients of 1:1 or flatter. The backcut configuration should be determined based on the design, exposed conditions and need to maintain a minimum fill ' width and provide working room for the equipment. On longer slopes backcuts and keyways should be excavated in maximum 250 feet long segment. The specific configurations will be determined during construction. I All keys should be a minimum of two (2) feet deep at the toe and slope toward the heel at least one foot or two (2%) percent whichever is greater. Subdrains are to be placed for all stabilization slopes exceeding 10 feet in height. Lower slopes I are subject to review. Drains may be required. Guidelines for subdrains are presented on Plate G- 5. Benching of backcuts during fill placement is required. Lot Capping When practical, the upper three (3) feet of material placed below finish grade should be comprised of the least expansive material available. Preferably, highly and very highly expansive materials should not be used. We will attempt to offer advise based on visual evaluations of the materials during grading, but it must be realized that laboratory testing is needed to evaluate the expansive potential of soil. Minimally, this testing takes two (2) to four (4) days to complete. Transition lots (cut and fill) both per plan and those created by remedial grading (e.g. lots above stabilization fills, along daylight lines, above natural slope, etc.) should be capped with a three foot thick compacted fill blanket. I 3. Cut pads should be observed by our representative(s) to evaluate the need for overexcavation and replacement with fill. This may be necessary to reduce water infiltration into highly fractured bedrock or other permeable zones, and/or due to differing expansive potential of materials I beneath a structure. The overexcavation should be at least three feet. Deeper overexcavation may be recommended in some cases. ROCK PLACEMENT AND ROCK FILL GUIDELINES It is anticipated that large quantities of oversize material would be generated during grading. It's likely that such materials may require special handling for burial. Although alternatives may be developed in the field, the following methods of rock disposal are recommended on a preliminary basis. I I GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I I I FRANK AND JOANN NOLAN APPENDIX C Proposed Residential Development Project No. :3281SD3 7331 Las Brisas Court, Vista, California Page 6 Limited Larger Rock When materials encountered are principally soil with limited quantities of larger rock fragments or boulders, placement in windrows is recommended. The following procedures should be applied: 1. Oversize rock (greater than 8 inch) should be placed in windrows. Windrows are rows of single file rocks placed to avoid nesting or clusters of rock. Each adjacent rock should be approximately the same size (within —one foot in diameter). C) The maximum rock size allowed in windrows is four feet 2. A minimum vertical distance of three feet between lifts should be maintained. Also, the windrows should be offset from lift to lift. Rock windrows should not be closer than 15 feet to the face of fill slopes and sufficient space must be maintained for proper slope construction (see Plate G-4). 3. Rocks greater than eight inches in diameter should not be placed within seven feet of the finished subgrade for a roadway or pads and should be held below the depth of the lowest utility. This will allow easier trenching for utility lines. 4. Rocks greater than four feet in diameter should be broken down, if possible, or they may be placed in a dozer trench. Each trench should be excavated into the compacted fill a minimum of one foot deeper than the largest diameter of rock. The rock should be placed in the trench and granular fill materials (SE>30) should be flooded into the trench to fill voids around the rock. The over size rock trenches should be no closer together than 15 feet from any slope face. C) Trenches at higher elevation should be staggered and there should be a minimum of four feet of compacted fill between the top of the one trench and the bottom of the next higher trench. d) It would be necessary to verify 90 percent relative compaction in these pits. A 24 to 72 hour delay to allow for water dissipation should be anticipated prior to additional fill placement. Structural Rock Fills If the materials generated for placement in structural fills contains a significant percentage of material more than six (6) inch in one dimension, then placement using conventional soil fill methods with isolated windrows would not be feasible. In such cases the following could be considered. Mixes of large of rock or boulders may be placed as rock fill. They should be below the depth of all utilities both on pads and in roadways and below any proposed swimming pools or other excavations. If these fills are placed within seven (7) feet of finished grade they may effect foundation design. Rock fills are required to be placed in horizontal layers that should not exceed two feet in thickness, or the maximum rock size present, which ever is less. All rocks exceeding two feet should be broken down to a smaller size, windrowed (see above), or disposed of in non-structural fill areas. Localized larger rock up to 3 feet in largest dimension may be placed in rock fill as follows: individual rocks are placed in a given lift so as to be roughly 50% exposed above the typical surface of the fill, loaded rock trucks or alternate compactors are worked around the rock on all sides to the satisfaction of the soil engineer, GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I I FRANK AND JOANN NOLAN APPENDIX C Proposed Residential Development Project No. :328]SD3 7331 Las Brisas Court, Vista, California Page 7 C) the portion of the rock above grade is covered with a second lift. 3. Material placed in each lift should be well graded. No unfilled spaces (voids) should be permitted I in the rock fill. Compaction procedures: Compaction of rock fills is largely procedural. The following procedures have been found to generally I produce satisfactory compaction. 1. Provisions for routing of construction traffic over the fill should be implemented. Placement should be by rock trucks crossing the lift being placed and dumping at its I edge. The trucks should be routed so that each pass across the fill is via a different path and that ' all areas are uniformly traversed. C) The dumped piles should be knocked down and spread by a large dozer (D-8 or larger suggested). (Water should be applied before and during spreading.) 2. Rock fill should be generously watered (sluiced) I a) Water should be applied by water trucks to the: dump piles, front face of the lift being placed and, I ' surface of the fill prior to compaction. b) No material should be placed without adequate water. C) The number of water trucks and water supply should be sufficient to provide constant water. I d) Rock fill placement should be suspended when water trucks are unavailable: i) for more than 5 minutes straight, or, for more than 10 minutes/hour. I ii) 3. In addition to the truck pattern and at the discretion of the soil engineer, large, rubber tired compactors may be required. The need for this equipment will depend largely on the ability of the operators to provide I complete and uniform coverage by wheel rolling with the trucks. Other large compactors will also be considered by the soil engineer provided that I required compaction is achieved. 4. Placement and compaction of the rock fill is largely procedural. Observation by trenching should be made to check: the general segregation of rock size, I for any unfilled spaces between the large blocks, and C) the matrix compaction and moisture content. 5. Test fills may be required to evaluate relative compaction of finer grained zones or as deemed I appropriate by the soil engineer. a) A lift should be constructed by the methods proposed as proposed 6. Frequency of the test trenching is to be at the discretion of the soil engineer. I Control areas may be used to evaluate the contractors procedures. 7. A minimum horizontal distance of 15 feet should be maintained from the face of the rock fill and any finish slope face. At least the outer 15 feet should be built of conventional fill materials. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I I FRANK AND JOANN NOLAN APPENDIX C Proposed Residential Development Project No. .3281SD3 7331 Las Brisas Court, Vista, California Page 8 • Piping Potential and Filter Blankets: Where conventional fill is placed over rock fill, the potential for piping (migration) of the fine grained I material from the conventional fill into rock fills will need to be addressed. The potential for particle migration is related to the grain size comparisons of the materials present and in contact with each other. Provided that 15 percent of the finer soil is larger than the effective pore size of I the coarse soil, then particle migration is substantially mitigated. This can be accomplished with a well- graded matrix material for the rock fill and a zone of fill similar to the matrix above it. The specific gradation of the fill materials placed during grading must be known to evaluate the need for any type of filter that may be necessary to cap the rock fills. This, unfortunately, can only be accurately determined I during construction. In the event that poorly graded matrix is used in the rock fills, properly graded filter blankets 2 to 3 feet thick separating rock fills and conventional fill may be needed. As an alternative, use of two layers of filter fabric (Mirafi 700 x or equivalent) could be employed on top of the rock fill. In order to mitigate excess puncturing, the surface of the rock fill should be well broken down and smoothed prior to placing the filter fabric. The first layer of the fabric may then be placed and covered with relatively permeable fill material (with respect to overlying material) 1 to 2 feet thick. The relative permeable material should be compacted to fill standards. The second layer of fabric should be placed and conventional fill placement continued. - Subdraina2e Rock fill areas should be tied to a subdrainage system. If conventional fill is placed that separates the rock I . from the main canyon subdrain then a secondary system should be installed. A system consisting of an adequately graded base (3 to 4 percent to the lower side) with a collector system and outlets may suffice. I Additionally, at approximately every 25 foot vertical interval, a collector system with outlets should be placed at the interface of the rock fill and the conventional fill blanketing a fill slope I Monitoring Depending upon the depth of the rock fill and other factors, monitoring for settlement of the fill areas may be needed following completion of grading. Typically, if rock fill depths exceed 40 feet, monitoring would be recommend prior to construction of any settlement sensitive improvements. Delays of 3 to 6 I months or longer can be expected prior to the start of construction. UTILITY TRENCH CONSTRUCTION AND BACKFILL Utility trench excavation and backfill is the contractors responsibility. The geotechnical consultant typically provides periodic observation and testing of these operations. While, efforts are made to make I sufficient observations and tests to verify that the contractors' methods and procedures are adequate to achieve proper compaction, it is typically impractical to observe all backfill procedures. As such, it is critical that the contractor use consistent backfill procedures. I Compaction methods vary for trench compaction and experience indicates many methods can be successful. However, procedures that "worked" on previous projects may or may not prove effective on a given site. The contractor(s) should outline the procedures proposed, so that we may discuss them prior I to construction. We will offer comments based on our knowledge of site conditions and experience. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I I FRANK AND JOANN NOLAN APPENDIX C I Proposed Residential Development Project No. :3281SD3 7331 Las Brisas Court, Vista, California Page 9 I 1. Utility trench backfill in slopes, structural areas, in streets and beneath flat work or hardscape should be brought to at least optimum moisture and compacted to at least 90 percent of the I laboratory standard. Soil should be moisture conditioned prior to placing the trench. 2. Flooding and jetting are not typically recommended or acceptable for native soils. Flooding or jetting may be used with select sand having a Sand Equivalent (SE) of 30 or higher. This is I typically limited to the following uses: shallow (12 + inches) under slab interior trenches and, as bedding in pipe zone. I The water should be allowed to dissipate prior to pouring slabs or completing trench compaction. 3. Care should be taken not to place soils at high moisture content within the upper three feet of the trench backfill in street areas, as overly wet soils may impact subgrade preparation. Moisture may I be reduced to 2% below optimum moisture in areas to be paved within the upper three feet below sub grade. 4. Sand backfill should not be allowed in exterior trenches adjacent to and within an area extending below a 1:1 projection from the outside bottom edge of a footing, unless it is similar to the surrounding soil. 5. Trench compaction testing is generally at the discretion of the geotechnical consultant. Testing frequency will be based on trench depth and the contractors procedures. A probing rod would be used to assess the consistency of compaction between tested areas and untested areas. If zones are found that are considered less compact than other areas, this would be brought to the contractors attention. - JOB SAFETY I General Personnel safety is a primary concern on all job sites. The following summaries our safety considerations for use by all our employees on multi-employer construction sites. On ground personnel are at highest I risk of injury and possible fatality on grading construction projects. The company recognizes that construction activities will vary on each site and that job site safety is the contractor's responsibility. However, it is, imperative that all personnel be safety conscious to avoid accidents and potential injury. I In an effort to minimize risks associated with geotechnical testing and observation, the following precautions are to be implemented for the safety of our field personnel on grading and construction I projects. 1. Safety Meetings: Our field personnel are directed to attend the contractor's regularly scheduled safety meetings. I 2. Safety Vests: Safety vests are provided for and are to be worn by our personnel while on the job site. 3. Safety Flags: Safety flags are provided to our field technicians; one is to be affixed to the vehicle I when on site, the other is to be placed atop the spoil pile on all test pits. In the event that the contractor's representative observes any of our personnel not following the above, we request that it be brought to the attention of our office. I GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I I FRANK AND JOANN NOLAN APPENDIX C I Proposed Residential Development Project No. :3281SD3 7331 Las Brisas Court, Vista, California Page 10 I Test Pits Location, Orientation and Clearance The technician is responsible for selecting test pit locations. The primary concern is the technician's I safety. However, it is necessary to take sufficient tests at various locations to obtain a representative sampling of the fill. As such, efforts will be made to coordinate locations with the grading contractors authorized representatives (e.g. dump man, operator, supervisor, grade checker, etc.), and to select I locations following or behind the established traffic pattern, preferable outside of current traffic. The contractors authorized representative should direct excavation of the pit and safety during the test period. Again, safety is the paramount concern. I Test pits should be excavated so that the spoil pile is placed away from oncoming traffic. The technician's vehicle is to be placed next to the test pit, opposite the spoil pile. This necessitates that the fill be maintained in a drivable condition. Alternatively, the contractor may opt to park a piece of I equipment in front of test pits, particularly in small fill areas or those with limited access. A zone of non-encroachment should be established for all test pits (see diagram below) No grading I equipment should enter this zone during the test procedure. The zone should extend outward to the sides approximately 50 feet from the center of the test pit and 100 feet in the direction of traffic flow. This zone is established both for safety and to avoid excessive ground vibration, which typically decreases test results. ITEST PIT SAFETY PLAN Test Pit prile SIDE VIEW 50 ft Zone of Traffic Direction Non-Encroachment Vehicle - Test Pit Spoil parked here - - pile l00ft Zone of Non-Encroachment 50ft Zone of Non-Encroachment PLAN VIEW Slope Tests When taking slope tests, the technician should park their vehicle directly above or below the test location on the slope. The contractor's representative should effectively keep all equipment at a safe operation distance (e.g. 50 feet) away from the slope during testing. The technician is directed to withdraw from the active portion of the fill as soon as possible following testing. The technician's vehicle should be parked at the perimeter of the fill in a highly visible location. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I FRANK AND JOANN NOLAN APPENDIX C I Proposed Residential Development Project No. :3281SD3 7331 Las Brisas Court, Vista, California Page]] I Trench Safety: It is the contractor's responsibility to provide safe access into trenches where compaction testing is I needed. Trenches for all utilities should be excavated in accordance with CAL-OSHA and any other applicable safety standards. Safe conditions will be required to enable compaction testing of the trench backfill. All utility trench excavations in excess of 5 feet deep, which a person enters, are to be shored or laid back. Trench access should be provided in accordance with OSHA standards. Our personnel are directed not to enter any trench by being lowered or "riding down" on the equipment. Our personnel are directed not to enter any excavation which; is 5 feet or deeper unless shored or laid back, exit points or ladders are not provide, displays any evidence of instability, has any loose rock or other debris which could fall into the trench, or displays any other evidence of any unsafe conditions regardless of depth. If the contractor fails to provide safe access to trenches for compaction testing, our company policy requires that the soil technician withdraws and notifies their supervisor. The contractors representative will then be contacted in an effort to effect a solution. All backfill not tested due to safety concerns or other reasons is subject to reprocessing and/or removal. Procedures In the event that the technician's safety is jeopardized or compromised as a result of the contractor's failure to comply with any of the above, the technician is directed to inform both the developer's and contractor's representatives. If the condition is not rectified, the technician is required, by company policy, to immediately withdraw and notify their supervisor. The contractor's representative will then be contacted in an effort to effect a solution. No further testing will be performed until the situation is rectified. Any fill placed in the interim 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 bring this to technicians attention and notify our project manager or office. Effective communication and coordination between the contractors' representative and the field technician(s) is strongly encouraged in order to implement the above safety program and safety in general. The safety procedures outlined above should be discussed at the contractor's safety meetings. This will serve to inform and remind equipment operators of these safety procedures particularly the zone of non- encroachment. The safety procedures outlined above should be discussed at the contractor's safety meetings. This will serve to inform and remind equipment operators of these safety procedures particularly the zone of non- encroachment. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS I I I U I I I 4 FT TYPICAL - UU LIABLE MATERIAL 6 PERFORATED PIPE IN 9 CUBIC FEET PER LINEAL FOOT CLEAN GRAVEL WRAPPED IN FILTER FABRIC FRANK AND JOANN NOLAN Project No.: 3281SD3 Proposed Residential Development February 25, 2008 7331 Las Brisas, Carlsbad, California Page 1 of 5 ALTE RNATE SUITABLE 4 F MATERIAL TYPICAL CONSTRUCT BENCHES WHERE SLOPE EXCEEDS 5:1 BOTTOM OF CLEANOUT TO BE AT LEAST 1.5 TIMES THE WIDTH OF COMPACTION EQUIPMENT ' 6' PERFORATED PIPE IN 9 CUBIC FEET PER I LINEAL FOOT CLEAN GRAVEL WITH FILTER FABRIC TO COVER SURFACE OR COMPLETE - WRAP PER FOLD CONDITIONS ALTERNATE ''- ORIGINAL GROUND i - - - SUITABLE Z" MATERIAL *'8N CONSTRUCT BENCHES §xx'i:::::::::::::::::::: WHERE SLOPE EXCEEDS 5:1 BOTTOM OF CLEANOUT TO BE AT. LEAST 1.5 TIMES THE WIDTH OF COMPACTION EQUIPMENT STANDARD GRADING GUIDELINES '1. TYPICAL CANYON CLEANOUT GeoTek Insite, Inc. I PLATE G- 1 I FRANK AND JOANN NOLAN Project No.: 3281SD3 I Proposed Residential Development February 25, 2008 7331 Las Brisas, Carlsbad, California Page 2 of 5 TYPICAL FILL SLOPE OVER NATURAL DESCENDING SLOPE FINISH GRADE :::MIN. 36' COMPACTED ..,.:...v : FILL SLOPE FILL CAP cOIUM SLO PLAN PE PER PROJECT EDROCV L REMOVAL Al TO 1 BEDROCK zii . ... .. MINIMUM 15 FT CLEAR 11 11 OR 1.5 EQUIPMENT zz WIDTHS FOR DAYLIGHT CUT AREA OVER NATURAL DESCENDING SLOPE STRUCTURAL SETBACK WITHOUT CORRECTIVE WORK I DAYLIGHT CUTI PROJECT PEMOVALAT ITOl :::::'-[-FINISH GRADE - MIN. 36" COMPACTED FILL Zz-ZZBEDROCK 2 MIIN TOP SQIL I5FTCLEAR oR 1 5 EQUIPMENT WIDTHS FOR COMPACTIOI. BEDROCK TREATMENT ABOVE STANDARD GRADING GUIDELINES NATURAL SLOPES GeoTek Insite, Inc. PLATE C - 2 [1 I I I I I I LI I I R I I I I I I FRANK AND JOANNNOLAN Project No.: 3281SD3 Proposed Residential Development February 25, 2008 7331 Las Brisas, Carlsbad, California Page 3 of 5 TYPICAL FILL SLOPE OVER PROPOSED CUT SLOPE. SLOPE PER F PLAN ILL SWP>7 TOE OF FILL SLOPE AFTER REMOVAL OF UNSUITABLE MATERIALS.:. ................................ . . .........................•. :.. Ai 441" 1 NIMUM 15 FT OR 15 EQUIPMENT WIDTHS OR B~~R- 7 - - COLLUVJUM ,............ : COMPACTION SUITABLE DENSE 21 : . TYPICAL FILL SLOPE .. SLOPE MINIMUM MINIMUM HEIGHT KEY WIDTH KEY DEPTH 5 7 10 10 1.5 25 15 3 >25 SEE TEXT CONTRACTOR TO VERIFY WITH SOIL ENGINEER PRIOR TO CONSTRUCTION EDROCK OR SUITABLE DENSE COMMON FILL STANDARD GRADING GUIDELINES SLOPE KEYS Geolek Insite, Inc. PLATE G -3 - I I U Project No.: 3281 SD3 FRANK AND JOANN NOLAN I I Proposed Residential Development February 25, 2008 7331 Las Brisas, Carlsbad, California Page 4 of 5 CROSS SECTIONAL VIEW FINISH GRADE - SJOTE FILL SLOPE - 3 MIIN STAGGER ROWS MIIN N:•:. •- — '\':-::: :• :-: HORIZONTALLY MIN "— MIINIMUM 15 FT CLEAR OR 1.5 EQUIPMENT WIDTHS FOR COMPACTION PLAN VIEW k FILL SLOPE . MIINIMUM 15 FT CLEAR OR 1.5 EOUIPMENT WIDTHS FOR COMPACTION PLACE ROCKS END TO END. DO NOT PILE OR STACK. MIINIMUM 15 )T CLEAR OR 1.5 SOIL TO BE PLACED AROUND AND OVER ROCKS EQUIPMENT WIDTHS FOR COMPACTION AND FLOODED INTOOIDS.COMPACT AROUND I AND OVER'EACH WINDROW gwo qbg '5 NOTES: MININUM SOIL FILL OVER WINDROWS SHOULD BE 7 FEET AND SUFFICIENT FOR FUTURE EXCAVATIONS (e.g. SWIMMIING POOLS) TO AVOID ROCKS, MAXIMUM ROCK SIZE IN WINDROWS IS 4 FEET MINIMUM DIAMETER. - SOIL AROUND WINDROWS TO BE SANDY MATERIAL SUBJECT TO ACCEPTANCE BY SOIL ENGINEER ALL SPACING AND CLEARANCES MUST BE SUFFICIENT TO ALLOW FOR PROPER COMPACTION. - ROCK BURIAL STANDARD GRADING- GUIDELINES DETAILS GeoTek Insite, Inc. PLATE G-4 I I I I I I I I I I I I I H I FRANK ANDJOANNNOLAN Project No.: 3281SD3 Proposed Residential Development February 25, 2008 7331 Las Brisas, Carlsbad, California Page 5 of 5 GRADE TO DRAIN / FINISHED LOPE FACE MINIMUM 36 .......... N COMPACTED FILL BLANKET TERRACE DRAIN AS N. I REQUIRED 2 IFAER DRAINS N GRADE TO KEY TO FALL TO HEE MINIMUM 1 FT / KEY TO BE MINIMUM / 2 FT DEEP OR PER KEY TO BE MINIMUM 15 FT PLUS WIDTH REPORT OF TERRACE DRAINS OR 1.5 EQUIPMENT WIDTH USED FOR COMPACTION 2% MINIMUM FALL 4' DIAMETER PERFORATED DRAIN PIPE PVC SCH. 40 OR 4 DIAMETER SOLID OUTLET EQUIVALENT IN 6 CUBIC FT LATERALS TO SLOPE FACE OR DRAIN ROCK WRAPPED IN STORM DRAIN SYSTEM AT FILTER FABRIC MAXIMUM 100 FT INTERVALS NOTE: ADDITIONAL BACKORAINS MAY BE RECOMMENDED BUTTRESS AND STANDARD GRADING GUIDELINES STABILIZATION SLOPES GeoTek Insite, Inc. PLATE G-5 I I I I I I I I I I I I I 1 I I I I I