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Home My WebLink AboutTR 33486 UPDATED GEOTECHNICAL EVALUATION FOR PROS RES DEV 5-25-17 UPDATED GEOTECHNICAL EVALUATION FOR PROPOSED RESIDENTIAL DEVELOPMENT TRACT No. 33486 MCKENNA COURT PROJECT CITY OF LAKE ELSINORE, RIVERSIDE COUNTY, CALIFORNIA PREPARED FOR D•R•HORTON Los ANGELES HOLDING COMPANY, INC. 2280 WARDLOW CIRCLE, SUITE 100 CORONA, CALIFORNIA 92880 PREPARED BY GEOTEK, INC. 710 E. PARKRIDGE AVENUE, SUITE I OS CORONA, CALIFORNIA 92879 PROJECT NO. 1604-CR FEBRUARY 3, 2017 REVISED MAY 25, 201 7) GEOTEK,cx, GeoTek,Inc. 710 E.Parkridge Avenue,Suite 105,Corona,California 92879-1097 (951) 710-1 160 Office (951) 710-1 167 Fax www.geotekusa,com February 3, 2017 (Revised May 25, 2017) Project No. 1604-CR D•R•Horton Los Angeles Holding Company, Inc. 2280 Wardlow Circle, Suite 100 Corona, California 92880 Attention: Mr. Steve Rowland Subject: Updated Geotechnical Evaluation Proposed Residential Development Tract No. 33486, McKenna Court Project City of Lake Elsinore, Riverside County, California Dear Mr. Rowland: We are pleased to provide the results of our updated geotechnical evaluation for the subject property located in the city of Lake Elsinore, Riverside County, California. This report presents a discussion of our evaluation and provides preliminary geotechnical recommendations for earthwork, foundation design, and construction. In our opinion, site development appears feasible from a geotechnical viewpoint provided that the recommendations presented in this report are incorporated into the design and construction phases of the project. The opportunity to be of service is sincerely appreciated. If you have any questions, please do not hesitate to call our office. Respectfully submitted, aE Sro GeoTek, Inc. w e ^q`fi ��PED 0 ?� C 84'OQ �L m �- ¢ W N 1892 O �N Exp 331/lf� i!/ ` j 10 9e erli4ied Noelle C. Toney spa �I'' ` �° Edward H. LaMont 9TF gr+nq G�oQ? PE 84700, Exp. 03/31/18 TFof ua�`Fi CEG 1892, Exp. 07/3 I/18 Project Engineer Principal Geologist Distribution: (1) Addressee via email (one PDF file) G:\Projects\1601 to 1650\1604CR DR Horton Tract 33486 McKenna Court Lake ElsinorelGeo Update\1604CR Revised Updated Geotechnical Evaluation Tract No.34866.doc GEOTECHNICAL I ENVIRONMENTAL I MATERIALS D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486, Lake Elsinore, California Page i TABLE OF CONTENTS I. PURPOSE AND SCOPE OF SERVICES............................................................................................. 1 2. SITE DESCRIPTION AND PROPOSED DEVELOPMENT...............................................................2 2.1 SITE DESCRIPTION..................................................................................................................................................................2 2.2 PROPOSED DEVELOPMENT....................................................................................................................................................2 3. FIELD EXPLORATION AND LABORATORY TESTING................................................................3 3.1 PREVIOUS GEOTECHNICAL WORK........................................................................................................................................3 3.2 CURRENT FIELD EXPLORATION............................................................................................................................................4 3.3 LABORATORY TESTING..........................................................................................................................................................5 4. GEOLOGIC AND SOILS CONDITIONS...........................................................................................5 4.1 REGIONAL SETTING................................................................................................................................................................5 4.2 GENERAL SOIL/GEOLOGIC CONDITIONS............................................................................................................................6 4.2.1 Engineered Fill..................................................................................................................................................................................6 4.2.2 Undocumented Fill..........................................................................................................................................................................6 4.2.3 Younger Alluvium............................................................................................................................................................................6 4.2.4 Older Alluvium..................................................................................................................................................................................6 4.3 SURFACE AND GROUNDWATER..........................................................................................................................................6 4.3.1 Surface Water.................................................................................................................................................................................6 4.3.2 Groundwater.....................................................................................................................................................................................7 4.4 FAULTING AND SEISMICITY....................................................................................................................................................7 4.4.1 Seismic Design Parameters..........................................................................................................................................................7 4.5 LIQUEFACTION........................................................................................................................................................................8 4.6 SEISMICALLY INDUCED SETTLEMENT.....................................................................................................................................8 4.7 OTHER SEISMIC HAZARDS.......................................................................................................................................................9 S CONCLUSIONS AND RECOMMENDATIONS................................................................................9 5.1 GENERAL..................................................................................................................................................................................9 5.2 EARTHWORK CONSIDERATIONS..........................................................................................................................................9 5.2.1 Building Areas and Retaining Wall Footings.......................................................................................................................10 S.2.2 Pavement and Hardscope Areas............................................................................................................................................I 0 5.2.3 Preparation of Areas to Receive Engineered Fill................................................................................................................10 5.2.4 Engineered Fills............................................................................................................................................................................. 10 5.2.5 Excavation Characteristics........................................................................................................................................................ 11 5.2.6 Shrinkage, Subsidence and Bulking........................................................................................................................................ 11 5.3 DESIGN RECOMMENDATIONS.............................................................................................................................................11 5.3.1 Foundation Design Criteria.......................................................................................................................................................11 5.3.2 Miscellaneous Foundation Recommendations....................................................................................................................14 5.3.3 Foundation Setbacks................................................................................................................................................................... 14 5.3.4 Retaining and Garden Wall Design and Construction.....................................................................................................15 5.3.5 Soil Corrosivity...............................................................................................................................................................................17 5.3.6 Soil Sulfate Content.....................................................................................................................................................................18 5.3.7 Import Soils.................................................................................................................................................................................... 18 5.3.8 Concrete Flatwork........................................................................................................................................................................18 5.4 POST CONSTRUCTION CONSIDERATIONS.......................................................................................................................19 'G�' GEOTEK D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486, Lake Elsinore, California Page ii TABLE OF CONTENTS 5.4.1 Landscape Maintenance and Planting..................................................................................................................................19 5.4.2 Drainage.........................................................................................................................................................................................20 5.5 PLAN REVIEW AND CONSTRUCTION OBSERVATIONS....................................................................................................20 6 INTENT...............................................................................................................................................21 7 LIMITATIONS....................................................................................................................................21 8 SELECTED REFERENCES.................................................................................................................22 ENCLOSURES Figure I —Site Location Map Figure 2—Geologic Map Figure 3—Exploration Location Map Appendix A — Logs of Exploratory Borings (Leighton, 2004) and Logs of Exploratory Trenches (GeoTek, 2017) Appendix B—Laboratory Testing Results Appendix C—Summary of Field Density Tests for Existing Sewer Trench Backfill Appendix D—Settlement Analysis Appendix E—General Grading Guidelines GEOTEK D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No 33486 Lake Elsinore California Page I 1. PURPOSE AND SCOPE OF SERVICES The purpose of this study was to evaluate the existing geotechnical conditions for the currently proposed development. Services provided for this study included the following: ■ Research and review of readily available geologic data and general information pertinent to the site, including geotechnical reports provided for the subject tract prepared by Leighton and Associates, Inc. (Leighton, 2004, 2007a, 2007b); Rough Grading Plans for Tract 33486 prepared by REN Civil (dated October 31, 2006); Precise Grading Plans for Tract 33486 prepared by REN Civil (I 5C submission dated August 2006); Perimeter Wall Plans for Tract 33486 prepared by REN Civil (approval date of April 23, 2007); Sewer & Water Improvement Plans for Tract 33486 prepared by REN Civil (approval date of February 22, 2007); and Off and On-Site Storm Drain Improvement Plans for Tract 33486 prepared by REN Civil (2"1 submission dated September 2006), ■ Site reconnaissance's, ■ Excavation of 12 exploratory trenches on-site, ■ Collection of soil samples of the on-site materials, ■ Laboratory testing of selected soil samples collected from the site, ■ Evaluation of liquefaction potential, ■ Review and evaluation of site seismicity, and; ■ Compilation of this updated geotechnical report which presents our preliminary recommendations for site development. The intent of this report is to aid in the evaluation of the site for future proposed development from a geotechnical perspective. The professional opinions and geotechnical information contained in this report may need to be updated based upon our review of the final site development plans. These plans should be provided to GeoTek, Inc. (GeoTek) for review when available. G E O T E K D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486, Lake Elsinore, California Page 2 2. SITE DESCRIPTION AND PROPOSED DEVELOPMENT 2.1 SITE DESCRIPTION The subject project is located adjacent to the north side of Machado Street and Herborn Street in the city of Lake Elsinore, Riverside County, California. The property is bounded to the southeast by Machado Street, a single occupied residence (Lot 43) and an existing church with single-family residential developments beyond; and bounded to the north, northeast, west, and southwest by single-family residential developments. A single occupied residence with an open field and horse corrals is located towards the northwest side of the property (Lot 81). Lots 44 and 45 were left low during the referenced rough grading (Leighton 2007b) to serve as temporary storm water detention basins. The subject site is comprised of approximately 25 acres of vacant rough graded land with visible indications of underground utilities. Existing northern perimeter/retaining walls have been constructed; however, no visual signs of drainage outlets were observed with one exception in the vicinity of Lots 40 and 41. Topographically, the property slopes gently down to the southeast with an overall vertical relief of approximately 37 feet. Site drainage is directed to the southeast. 2.2 PROPOSED DEVELOPMENT Based on the referenced geotechnical reports (Leighton, 2004, 2007a, 2007b) and site development plans, proposed site improvements include 81 single-family residential structures. It is assumed that the proposed structures will be of wood-framed construction, incorporate concrete slab-on-grade floors and will be supported by conventional shallow isolated and continuous foundations. Lot reprocessing for the existing building pads and fills of up to three feet (Lots 44 and 45) are proposed to bring the site to design grades. Based on review of the referenced Perimeter Wall Plan, prepared by REN Civil (approval date of April 23, 2007), retaining and garden walls with a maximum height of six feet and nine feet, respectively, are proposed for the site. If the site development differs from the noted information made in this report, the recommendations should be subject to further review and evaluation by GeoTek. Final site development plans should be reviewed by GeoTek when they become available. GEOTEK D-R-Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No 33486 Lake Elsinore California Page 3 3. FIELD EXPLORATION AND LABORATORY TESTING 3.1 PREVIOUS GEOTECHNICAL WORK Based on the referenced Geotechnical Investigation previously completed by Leighton and Associates, Inc. (Leighton, 2004), a field exploration consisting of excavating, sampling and logging seven exploratory borings to depths of approximately 18 to 50.5 feet below the existing ground surface with a hollow-stem auger drill rig was completed on October 14, 2004. Laboratory testing was subsequently completed on representative bulk and undisturbed samples collected from the field exploration. Undocumented artificial fill was encountered in one boring and was observed to be up to five feet thick. Holocene-aged alluvium consisting of yellow-brown to gray silty very fine to fine sand with local lenses of silt and channel deposits consisting of medium to coarse sand with interbedded lenses and laminations of gray loose to medium dense very fine to fine sand was reported in all areas of the subject site. Pleistocene- aged older alluvium consisting of light gray-brown to red-brown dense medium to coarse gravel with granitic rock clasts was also reported to underlie the site. Logs of exploratory borings from Leighton's field exploration are included in Appendix A. Groundwater was not encountered in the field exploration and was reported to be over 200 feet below existing ground surface. No evidence of on-site landslides nor active or potentially active faulting was observed or encountered during the field exploration. Due to the presence of dense underlying soils and the absence of shallow groundwater, Leighton concluded that the project site has a very low potential for liquefaction. Results of Leighton's dry settlement analysis indicates a potential total seismic settlement of less than '/z-inch. Based on the reported laboratory testing, the on-site materials have a very low expansion potential, a negligible sulfate exposure and a potential for corrosion of buried steel improvements. Earthwork recommendations indicated a minimum building pad removal depth on the order of five feet below existing grade or three feet below the bottom of anticipated footings, whichever was deeper. Lateral extents of removals were recommended to include the area within a perimeter of at least ten feet beyond the outermost foundation elements or a 1:1 (horizontal:vertical) projection from the edge of fill soils supporting settlement-sensitive structures. The on-site soils were determined to be suitable for reuse as compacted fill and placed at or above the optimum moisture content and compacted to 90 percent of the maximum dry density as determined by ASTM D1557. Leighton recommended an estimated 15 percent shrinkage and a subsidence value of 0.25 to be applied for planning purposes. Additionally, Leighton recommended the use of post-tensioned or conventional foundations but did not provide recommendations for the foundation systems. Recommendations were provided for retaining walls, preliminary pavement design and cast-in-place concrete pipes. GEOTEK D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486, Lake Elsinore, California Page 4 Based on the referenced "As-Graded Report of Rough-Grading for Home Sites 40 through 42 (Model Lots)" (Leighton, 2007a), the model home sites were included in the mass grading of Tract No. 33486 from December 2006 through January 2007. Rough grading for the model home sites included removals of topsoil and near surface alluvium. The removals and overexcavations were reported to be on the order of a minimum of five feet or until medium dense to dense, damp to moist, alluvium was encountered, whichever was greater, in general accordance with the referenced geotechnical investigation (Leighton, 2004). Engineered fill consisting of on-site soils were reported to be moisture conditioned to near optimum moisture content and compacted to a minimum relative compaction of 90 percent (ASTM D 1557). Approximate maximum fill thicknesses on the reported pads were on the order of nine feet. Laboratory testing was performed on the site soils following the rough grading operations. Leighton described the near surface soils as having "very low" expansion potential (EI=6) and soluble sulfate contents less than 0.1 in percentage by weight, which is considered to be "not applicable" (i.e. negligible). Additionally, Leighton provided updated seismic, post- tensioned and conventional foundation design parameters, and construction recommendations. Based on the referenced "As-Graded Report of Rough-Grading for Home Sites I through 39, 46 through 80, 82 and 83" (Leighton, 2007b), rough grading of Tract No. 33486 was completed from December 2006 through January 2007 to create 81 single-family residential lots. The model home sites (Lots 40 through 42) were previously reported on (Leighton, 2007a). Rough grading for the subject lots were reported to be completed in the same manner as the model home sites previously described. Additional fill soil was imported to the site to create the design grades. Approximate maximum fill thicknesses on the reported pads were on the order of five to ten feet. Laboratory testing was performed on the site soils following the rough grading operations. Leighton described the near surface soils as having "very low" expansion potential (EI=0 to 10) and soluble sulfate contents less than 0.1 in percentage by weight, which is considered to be "not applicable" (i.e. negligible). Home Sites 44 and 45 were left low and configured as temporary storm water detention basins. Leighton recommended additional fill placement for Lots 44 and 45 to be placed in accordance with the recommendations of the preliminary geotechnical investigation (Leighton, 2004). Additionally, Leighton provided updated seismic, post-tensioned and conventional foundation design parameters, and construction recommendations. 3.2 CURRENT FIELD EXPLORATION Our most recent geotechnical field exploration was conducted on December 19, 2016. An engineer from GeoTek logged twelve exploratory trenches excavated by a rubber tire backhoe. The trenches were situated at various locations across the site (see Exploration Location Map, Figure 3). The trenches were excavated to a maximum depth of 7.5 feet below GEOTEK'G, D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486 Lake Elsinore California Page 5 the existing ground surface. Logs of the exploratory trenches are included in Appendix A. Samples of on-site soils encountered in the excavations were returned to the laboratory for testing and evaluation. A field representative of GeoTek was also present on January 10, 2017 as potholes were excavated (by others) to determine the depths and level of compaction of the existing utility trench backfill within the street areas. Results of the compaction testing that reference locations according to the Sewer & Water Improvement Plans prepared by REN Civil (approval date of February 22, 2007) are included in Appendix C. 3.3 LABORATORY TESTING Laboratory testing was performed on selected bulk soil samples collected during our field exploration. The purpose of the laboratory testing was to confirm the field classification of the soil materials encountered and to evaluate the physical properties of the soils 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. GEOLOGIC AND SOILS CONDITIONS 4.1 REGIONAL SETTING The property is situated in the Peninsular Ranges geomorphic province. The Peninsular Ranges province is one of the largest geomorphic units in western North America. Basically, it extends from the point of contact with the Transverse Ranges geomorphic province, southerly to the tip of Baja California. This province varies in width from about 30 to 100 miles. It is bounded on the west by the Pacific Ocean, on the south by the Gulf of California and on the east by the Colorado Desert Province. The Peninsular Ranges are essentially a series of northwest-southeast oriented fault blocks. Several major fault zones are found in this province. The Elsinore Fault zone and the San Jacinto Fault zone trend northwest-southeast and are found in the near middle of the province. The San Andreas Fault zone borders the northeasterly margin of the province. More specific to the subject property, the site is located in an area underlain by engineered fill and alluvium (Leighton, 2004). The nearest zoned fault is the Glen Ivy North Fault located within a '/2-mile of the subject site. GEOTEK D-R-Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486, Lake Elsinore, California Page 6 4.2 GENERAL SOIL/GEOLOGIC CONDITIONS A brief description of the earth materials reported to be and encountered on the site is presented in the following sections. 4.2.1 Engineered Fill Engineered fill materials were reported on (Leighton, 2007a, 2007b) and were also encountered in seven of our most recent exploratory trenches (Trenches TP-I, TP-2, TP-5, TP-6, TP-7, TP-9 and TP-1 1) excavated on the site. In general, the engineered fill materials typically consist of loose to very dense silty sand fine to coarse sand with varying amounts of gravel and trace clay. These engineered fill materials are reported to be up to ten feet in thickness on the site (Leighton, 2007a, 2007b). 4.2.2 Undocumented Fill Undocumented fill materials were encountered in five of our most recent exploratory trenches (Trenches TP-3, TPA TP-8, TP-10 and TP-12) excavated on the site. In general, the undocumented fill materials typically consist of loose to medium dense silty sand fine to coarse sand with varying amounts of gravel and clay. These undocumented fill materials were encountered up to five feet in thickness within the street areas of the site. 4.2.3 Younger Alluvium Younger alluvium was encountered in previous explorations (Leighton, 2004) and in one of our most recent exploratory trenches (Trench TP-7) excavated on the site. In general, the younger alluvium typically consists of loose to medium dense, fine to coarse sand with varying amounts of silt. These soils were reported to be generally encountered to a maximum depth of approximately 10 to 15 feet below original ground. 4.2.4 Older Alluvium Older alluvium was encountered in previous explorations (Leighton, 2004) excavated on the site. In general, the older alluvium typically consists of dense medium to coarse gravel. These soils were reported to be generally encountered at depths of approximately 10 feet to 15 feet below original ground. 4.3 SURFACE AND GROUNDWATER 4.3.1 Surface Water Surface water was not observed on the site during our recent subsurface exploration or site reconnaissance. If encountered during earthwork operations, surface water on this site is the ,C-3r-- GEOTEK D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486 Lake Elsinore, California Page 7 result of precipitation or surface run-off from surrounding areas. Overall surface drainage is generally to the southeast. 4.3.2 Groundwater Regional groundwater was not encountered in previous exploratory excavations by others or in our trenches. Based on a review of groundwater levels (http://www.water.ca.gov/waterdatalibrary/) in the vicinity of the site, the depth to regional groundwater is greater than 200 feet. 4.4 FAULTING AND SEISMICITY The geologic structure of the entire southern California area is dominated mainly by northwest-trending faults associated with the San Andreas system. The site is in a seismically active region. No active or potentially active fault is presently known to exist at this site nor is the site situated within an "Alquist-Priolo" Earthquake Fault Zone. The nearest zoned fault is the Glen Ivy North Fault, located approximately '/2-mile to the northeast. 4.4.1 Seismic Design Parameters The site is located at approximately 33.6873 Latitude and -1 17.3789 Longitude. Site spectral accelerations (Ss and Si), for 0.2 and 1.0 second periods for a Class "D" site, were determined from the USGS Website, Earthquake Hazards Program, U.S. Seismic Design Maps for Risk- Targeted Maximum Considered Earthquake (MCER) Ground Motion Response Accelerations for the Conterminous 48 States by Latitude/Longitude. The results are presented in the following table: GEOTEK D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486, Lake Elsinore, California Page 8 SITE SEISMIC PARAMETERS Mapped 0.2 sec Period Spectral Acceleration, S5 2.405g Mapped 1.0 sec Period Spectral Acceleration, Si 0.971g Site Coefficient for Site Class "D", Fa 1.0 Site Coefficient for Site Class "D", Fv 1.5 Maximum Considered Earthquake Spectral Response 2.405g Acceleration for 0.2 Second, Sms Maximum Considered Earthquake Spectral Response 1.456g Acceleration for 1.0 Second, SM i 5% Damped Design Spectral Response Acceleration 1.603g Parameter at 0.2 Second, SDs 5% Damped Design Spectral Response Acceleration 0.971g Parameter at I second, SDI Peak Ground Acceleration Adjusted for Site Class Effects, 0.964g PGAM Final selection of the appropriate seismic design coefficients should be made by the project structural engineer based upon the local practices and ordinances, expected building response and desired level of conservatism. 4.5 LIQUEFACTION The site is located within an area designated by the County of Riverside as having "moderate" liquefaction potential. Liquefaction is not considered a hazard at the site due to the anticipated depth to groundwater (>200 feet) and the presence of dense underlying soils (Leighton, 2004). 4.6 SEISMICALLY INDUCED SETTLEMENT Seismic-induced settlement can occur both above and below the groundwater table. Settlement below the groundwater table during a strong seismic event occurs in response to liquefaction. It is anticipated that major earthquake groundshaking will occur during the lifetime of the proposed development from the seismically active Glen Ivy North fault which is situated approximately '/z-mile from the site. The estimated earthquake magnitude of 7.0 and a peak horizontal ground acceleration of 0.96g were obtained from the United States Geological Survey (USGS) 2008 deaggregations website. Free ground water was not encountered in the previous (Leighton, 2004) nor our test excavations. Based on ground water data, it is anticipated that ground water is at a depth greater than 200 feet below existing grade. For a liquefaction analysis, ground water would not G E Q T E K D-R-Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486, Lake Elsinore, California Page 9 be a factor. Since actual liquefaction will not occur, an analysis for seismically induced settlement was performed. This analysis was conducted on Boring B-2 (Leighton, 2004). Based on our analysis we estimate a maximum total seismic-induced settlement of 2.5 inches. The total settlement will occur over a large area and should not adversely affect local buried utilities. Within a 40-foot span, we would estimate the differential dynamic settlement would be about one-half the total. Based on a span of 40 feet and seismic-induced settlement of 2.5 inches, a maximum angular distortion of about 1/379 is calculated, which is within tolerable limits. The analysis incorporates that the upper compressible materials have been removed and replaced with engineered fill. The results of the analysis are included in Appendix D. 4.7 OTHER SEISMIC HAZARDS Evidence of ancient landslides or slope instabilities at this site was not observed during our investigation. Thus, the potential for landslides is considered negligible for design purposes. The potential for secondary seismic hazards such as a seiche or tsunami is considered negligible due to site elevation and distance to an open body of water. 5 CONCLUSIONS AND RECOMMENDATIONS 5.1 GENERAL The anticipated site development appears feasible from a geotechnical viewpoint provided that the following recommendations, and those provided by this firm at a later date are properly incorporated into the design of the project. Final site development and grading plans should be reviewed by GeoTek when they become available. 5.2 EARTHWORK CONSIDERATIONS Earthwork and grading should be performed in accordance with the applicable grading ordinances of the City of Lake Elsinore, the 2016 California Building Code (CBC), and recommendations contained in this report. The Grading Guidelines included in Appendix E outline general procedures and do not anticipate all site-specific situations. In the event of conflict, the recommendations presented in the text of this report should supersede those contained in Appendix E. GEOTEK D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486, Lake Elsinore, California Page 10 5.2.1 Building Areas and Retaining Wall Footings The surface of the existing lots can generally be reprocessed while removing any existing vegetation, debris and other deleterious material. The pads should be moisture conditioned to at least the optimum moisture content and compacted to a minimum relative compaction of 90 percent as determined by ASTM Test Method D 1557. Soils within three feet of pad grade should be confirmed to meet the minimum relative compaction and moisture content recommendations provided in this report. Lots 44 and 45 may require the placement of up to approximately three feet of fill to achieve design grades. On these lots, the upper 12 inches of the existing materials should be cleared of vegetation, debris and other deleterious material, scarified, moisture-conditioned and recompacted to project standards prior to placement of additional engineered fill. Where not removed as part of the recommended lot re-grading operations, the backfill associated with the exploratory test pits should be removed and replaced with engineered fill materials. 5.2.2 Pavement and Hardscape Areas The soils below asphaltic concrete pavement and Portland cement concrete hardscape areas should be prepared as described above for building areas. Existing utility trench backfill areas should be removed until competent material is encountered. Competent soil is defined as relatively non-porous material exhibiting a relative compaction of at least 90 percent as determined by ASTM Test Method D 1557. 5.2.3 Preparation of Areas to Receive Engineered Fill A representative of this firm should observe areas prepared to receive fill. Upon approval, the exposed soils in areas to receive engineered fill should be scarified to a minimum depth of eight inches, moistened to at least the optimum moisture content and compacted to a minimum relative compaction of 90 percent as determined by ASTM Test Method D 1557. 5.2.4 Engineered Fills The on-site soils are generally considered suitable for reuse as engineered fill provided they are free from vegetation, debris and other deleterious material. The undercut areas should be brought to the final subgrade elevations with fill materials that are placed in eight-inch or less loose lifts, moisture conditioned to at least the optimum moisture content and compacted to a minimum relative compaction of 90 percent as determined by ASTM Test Method D 1557. The upper 12 inches of the pavement subgrade should be compacted to 95 percent as determined by ASTM Test Method D 1557. GEOTEK'GX' D-R-Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486, Lake Elsinore, California Page 11 5.2.5 Excavation Characteristics Excavation in the on-site soils is expected to be feasible utilizing heavy-duty grading equipment in good operating condition. All temporary excavations for grading purposes and installation of underground utilities should be constructed in accordance with local and Cal-OSHA guidelines. Temporary excavations within the on-site materials should be stable at 1:1 (horizontal:vertical) inclinations for cuts less than five feet in height. 5.2.6 Shrinkage, Subsidence and Bulking Several factors will impact earthwork balancing on the site, including shrinkage, subsidence, trench spoil from utilities and footing excavations, as well as the accuracy of topography. Shrinkage is primarily dependent upon the degree of compactive effort achieved during construction. For planning purposes, a shrinkage factor of 10 to 15 percent may be considered for the materials requiring removal and/or recompaction. Site balance areas should be available in order to adjust project grades, depending on actual field conditions at the conclusion of earthwork construction. Subsidence on the order of 0.25 foot may be anticipated for areas to receive fill. 5.3 DESIGN RECOMMENDATIONS 5.3.1 Foundation Design Criteria It is assumed that the single-family residential structures will be supported by conventional shallow isolated and continuous footings. Foundation design criteria, in general conformance with the 2016 CBC, are presented below. These are typical design criteria and are not intended to supersede the design by the structural engineer. Our investigation indicates that the on-site soils have a "very low" expansion potential. A summary of our preliminary foundation design recommendations is presented in the following table: G E O T E K D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486, Lake Elsinore, California Page 12 Fd JN0AT1 N ©ESiG.N t3ign,Pax�ameter 6a�ci `Pdtalt. Foundation Depth or Minimum Perimeter Beam Depth One-and two-story— 12 (inches below the lowest adjacent grade) Minimum Foundation Width (Inches)* One-and two-story- 12 Minimum Slab Thickness (inches) 4—Actual Sand Blanket and Moisture Retardant Membrane below 2 inches of sand**overlying moisture On-Grade Building Slabs vapor retardant membrane overlying 2 inches of sand Minimum Slab Reinforcing 6"x 6"—W 1.4/W 1.4 welded wire fabric placed in middle of slab Minimum Reinforcement for Continuous Footings,Grade Two No.4 reinforcing bars, Beams and Retaining Wall Footings one placed near the top and one near the bottom of the footing Minimum of 100%of the optimum Presaturation of Subgrade Soil moisture content to a depth of at (Percent of Optimum/Depth in Inches) least 12 inches prior to placing concrete *Code minimums per Table 1809.7 of the 2016 CBC **Sand should have a sand equivalent of at least 30 It should be noted that the above recommendations are based on soil support characteristics only. The structural engineer should design the slab and beam reinforcement based on actual loading conditions. An allowable bearing capacity of 2000 pounds per square foot (psf) may be used for design of building and retaining wall footings with a minimum embedment of 18 inches into engineered fill. This value may be increased by 300 psf for each additional 12 inches of embedment depth and by 200 psf for each additional 12 inches in width to a maximum of 3000 psf. The allowable bearing capacity may be increased by one-third when considering short-term wind and seismic loads. Structural foundations may be designed to withstand a total settlement of one inch and maximum differential settlement of one-half of the total settlement over a horizontal distance of 40 feet. The passive earth pressure may be computed as an equivalent fluid having a density of 200 psf per foot of depth, to a maximum earth pressure of 2000 psf for footings founded on engineered fill. A coefficient of friction between soil and concrete of 0.30 may be used with 'G�'. GEOTEK D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No 33486 Lake Elsinore California Page 13 dead load forces. The upper one foot of soil below the adjacent grade should not be used in calculating passive pressure. When combining passive and frictional resistance, the passive pressure component should be reduced by one-third. A moisture and vapor retarding system should be placed below slabs-on-grade where moisture migration through the slab is undesirable. Guidelines for these are provided in the 2013 California Green Building Standards Code (CALGreen) Section 4.505.2 and the 2016 CBC Section 1907.1 and ACI 360R-10. The vapor retarder design and construction should also meet the requirements of ASTM E 1643. A portion of the vapor retarder design should be the implementation of a moisture vapor retardant membrane. It should be realized that the effectiveness of the vapor retarding membrane can be adversely impacted as a result of construction related punctures (e.g. stake penetrations, tears, punctures from walking on the aggregate layer, etc.). These occurrences should be limited as much as possible during construction. Thicker membranes are generally more resistant to accidental puncture than thinner ones. Products specifically designed for use as moisture/vapor retarders may also be more puncture resistant. Although the CBC specifies a six mil vapor retarder membrane, it is GeoTek's opinion that a minimum 10 mil thick membrane with joints properly overlapped and sealed should be considered, unless otherwise specified by the slab design professional. The membrane should consist of Stego wrap or the equivalent. Moisture and vapor retarding systems are intended to provide a certain level of resistance to vapor and moisture transmission through the concrete, but do not eliminate it. The acceptable level of moisture transmission through the slab is to a large extent based on the type of flooring used and environmental conditions. Ultimately, the vapor retarding system should be comprised of suitable elements to limit migration of water and reduce transmission of water vapor through the slab to acceptable levels. The selected elements should have suitable properties (i.e., thickness, composition, strength, and permeability) to achieve the desired performance level. Consideration should be given to consulting with an individual possessing specific expertise in this area for additional evaluation. Moisture retarders can reduce, but not eliminate, moisture vapor rise from the underlying soils up through the slab. Moisture retarders should be designed and constructed in accordance with applicable American Concrete Institute, Portland Cement Association, Post-Tensioning Concrete Institute, ASTM and California Building Code requirements and guidelines. GeoTek recommends that a qualified person, such as the flooring contractor, structural engineer, and/or architect be consulted to evaluate the general and specific moisture vapor transmission paths and any impact on the proposed construction. GEOTEK D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No 33486 Lake Elsinore California Page 14 In addition, the recommendations in this report and our services in general are not intended to address mold prevention, since we along with geotechnical consultants in general, do not practice in areas of mold prevention. If specific recommendations are desired, a professional mold prevention consultant should be contacted. 5.3.2 Miscellaneous Foundation Recommendations ■ To reduce moisture penetration beneath the slab on grade areas, utility trenches should be backfilled with engineered fill, lean concrete or concrete slurry where they intercept the perimeter footing or thickened slab edge. ■ Soils from the footing excavations should not be placed in the slab-on-grade areas unless properly compacted and tested. The excavations should be free of loose/sloughed materials and be neatly trimmed at the time of concrete placement. ■ Under-slab utility trenches should be compacted to project specifications. Compaction should be achieved with a mechanical compaction device. If soils to be used as backfill have dried out, they should be thoroughly moisture conditioned prior to placement in trenches. ■ Unsuitable soil removals along the property lines will likely be restricted due to adjacent improvements. Special considerations will be required for foundation elements in these areas. Such considerations may include deepening of foundations, reduced bearing capacity, or other measures. This issue should be further evaluated once site plans become available for review. 5.3.3 Foundation Setbacks Minimum setbacks for all foundations should comply with the 2016 CBC or City of Lake Elsinore requirements, whichever is more stringent_ Improvements not conforming to these setbacks are subject to the increased likelihood of excessive lateral movements and/or differential settlements. If large enough, these movements can compromise the integrity of the improvements. The following recommendations are presented: ■ The top outside edge of all building, retaining wall and screen wall footings should be set back a minimum of H/3 (where H is the slope height) from the face of any descending slope. The setback should be at least five feet and need not exceed 40 feet. ■ The bottom of all footings for new structures near retaining walls should be deepened so as to extend below a I:I projection upward from the bottom inside edge of the wall footing. GEOTEK D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486 Lake Elsinore, California Page 15 5.3.4 Retaining and Garden Wall Design and Construction 5.3.4.1 General Design Criteria Recommendations presented in this report apply to typical masonry or concrete vertical retaining walls to a maximum height of up to six feet. Additional review and recommendations should be requested for higher walls. These are typical design criteria and are not intended to supersede the design by the structural engineer. Retaining wall foundations should be embedded a minimum of 18 inches into engineered fill. Retaining wall foundations should be designed in accordance with Section 5.3.1 of this report. Structural needs may govern and should be evaluated by the project structural engineer. All earth retention structure plans, as applicable, should be reviewed by this office prior to finalization. The seismic design parameters as discussed in this report remain applicable to all proposed earth retention structures at this site, and should be properly incorporated into the design and construction of the structures. Earthwork considerations, site clearing and remedial earthwork for all earth retention structures should meet the requirements of this report, unless specifically provided otherwise, or more stringent requirements or recommendations are made by the designer. The backfill material placement for all earth retention structures should meet the requirement of Section 5.3.4.3 in this report. In general, cantilever earth retention structures, which are designed to yield at least 0.001 H, where H is equal to the height of the wall to the base of the footing, may be designed using the active condition. Rigid earth retention structures (including but not limited to rigid walls, and walls braced at top, such as typical basement walls) should be designed using the at-rest condition. In addition to the design lateral forces due to retained earth, surcharges due to improvements, such as an adjacent building or traffic loading, should be considered in the design of the earth retention structures. Loads applied within a I:1 (horizontal:vertical) projection from the surcharge on the stem and footing of the earth retention structure should be considered in the design. Final selection of the appropriate design parameters should be made by the designer of the earth retention structures. GEOTEK D-R-Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No 33486 Lake Elsinore California Page 16 5.3.4.2 Cantilevered Walls The recommendations presented below are for cantilevered retaining walls up to six feet high. Active earth pressure may be used for retaining wall design, provided the top of the wall is not restrained from minor deflections. An equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. Appropriate fluid unit weights are given below for specific slope gradients of the retained material. These do not include other superimposed loading conditions such as traffic, structures, seismic events, or adverse geologic conditions. ACTIVE EARTH PRESSURES Surface Slope of Retained Equivalent FW Pressure Materials (per) (h v) Level 35 2:1 50 * The design pressures assume the backfill material has an expansion index less than or equal to 20. Backfill zone includes area between the back of the wall and footing to a plane (1:1 h:v) up from the bottom of the wall foundation to the ground surface. 5.3.4.3 Retaining Wall Backfill and Drainage Retaining walls should be provided with an adequate pipe and gravel back drain system to help prevent buildup of hydrostatic pressures. Backdrains should consist of a four-inch diameter perforated collector pipe (Schedule 40, SDR 35, or approved equivalent) embedded in a minimum of one cubic foot per linear foot of 3/4- to I-inch clean crushed rock or an approved equivalent, wrapped in filter fabric (Mirafi 140N or an approved equivalent). The drain system should be connected to a suitable outlet. Waterproofing of site walls should be performed where moisture migration through the wall is undesirable. Retaining wall backfill should be placed in lifts no greater than eight inches in thickness and compacted to a minimum of 90% relative compaction in accordance with ASTM Test Method D 1557. The wall backfill should also include a minimum one foot wide section of 3/4- to 1-inch clean crushed rock (or an approved equivalent). The rock should be placed immediately adjacent to the back of the wall and extend up from a back drain to within approximately 12 inches of the finish grade. The upper 12 inches should consist of compacted on-site soil. 'G,. GEOTEK D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486, Lake Elsinore, California Page 17 As an alternative to the drain rock and fabric, Miradrain 2000, or approved equivalent, may be used behind the retaining wall. The Miradrain 2000 should extend from the base of the wall to within 2 feet of the ground surface. A perforated pipe should be placed at the base of the wall in direct contact with the Miradrain 2000. The Miradrain fabric at the base of the Miradrain 2000 panel should be wrapped around the perforated pipe to prevent soil intrusion into the pipe. The presence of other materials might necessitate revision to the parameters provided and modification of the wall designs. Proper surface drainage needs to be provided and maintained. 5.3.4.4 Restrained Retaining Walls Retaining walls that will be restrained prior to placing and compacting backfill material or that have reentrant or male corners, should be designed for an at-rest equivalent fluid pressure of 65 pcf, plus any applicable surcharge loading. For areas of male or reentrant corners, the restrained wall design should extend a minimum distance of twice the height of the wall laterally from the corner, or a distance otherwise determined by the project structural engineer. 5.3.4.5 Other Design Considerations ■ Retaining and garden wall foundation elements should be designed in accordance with building code setback requirements. A minimum horizontal setback distance of five (5) feet as measured from the bottom outside edge of the footing to a sloped face is recommended. ■ Wall design should consider the additional surcharge loads from superjacent slopes and/or footings, where appropriate. ■ No backfill should be placed against concrete until minimum design strengths are evident by compression tests of cylinders. ■ The retaining wall footing excavations, backcuts, and backfill materials should be approved by the project geotechnical engineer or their authorized representative. • Positive separations should be provided in garden walls at horizontal distances not exceeding 20 feet. 5.3.5 Soil Corrosivity Corrosivity testing on 14 samples obtained from the project site are currently pending. Laboratory test results and recommendations for protection of buried ferrous metal will be provided in a separate report. 'Gc' GEOTEK D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486 Lake Elsinore, California Page 18 5.3.6 Soil Sulfate Content Based on the chemical test results included in Appendix B, the sulfate test results on samples obtained from the project site indicate soluble sulfate contents of less than 0.1% by weight should be expected for the site. Soluble sulfate contents of this level would be in the range of "not applicable" (i.e. negligible) per Table 4.2.1 of ACI 318. Based on the test results and Table 4.3.1 of ACI 318, no special concrete mix design would be necessary to resist sulfate attack. 5.3.7 Import Soils Import soils should have expansion characteristics similar to the on-site soils. GeoTek also recommends that the proposed import soils be tested for expansion and corrosivity potential. GeoTek should be notified a minimum of 72 hours prior to importing so that appropriate sampling and laboratory testing can be performed. 5.3.8 Concrete Flatwork 5.3.8.1 Exterior Concrete Slabs, Sidewalks and Driveways Exterior concrete slabs, sidewalks and driveways should be designed using a four-inch minimum thickness. No specific reinforcement is required from a geotechnical perspective. However, some shrinkage and cracking of the concrete should be anticipated as a result of typical mix designs and curing practices commonly utilized in industrial construction. Sidewalks and driveways may be under the jurisdiction of the governing agency. If so, jurisdictional design and construction criteria would apply, if more restrictive than the recommendations presented in this report. Subgrade soils (typically "very low" expansion potential) should be pre-moistened prior to placing concrete. The subgrade soils below exterior slabs, sidewalks, and driveways should be pre-saturated to a minimum of 100% of optimum moisture content to a depth of at least 12 inches. All concrete installation, including preparation and compaction of subgrade, should be done in accordance with the City of Lake Elsinore specifications, and under the observation and testing of GeoTek and a City inspector, if necessary. 5.3.8.2 Concrete Performance Concrete cracks should be expected. These cracks can vary from sizes that are essentially unnoticeable to more than 0.125-inch in width. Most cracks in concrete, while unsightly, do 'G, GEOTEK D-R-Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486, Lake Elsinore, California Page 19 not significantly impact long-term performance. While it is possible to take measures (proper concrete mix, placement, curing, control joints, etc.) to reduce the extent and size of cracks that occur, some cracking will occur despite the best efforts to minimize it. Concrete can also undergo chemical processes that are dependent upon a wide range of variables, which are difficult, at best, to control. Concrete, while seemingly a stable material, is subject to internal expansion and contraction due to external changes over time. One of the simplest means to control cracking is to provide weakened control joints for cracking to occur along. These do not prevent cracks from developing; they simply provide a relief point for the stresses that develop. These joints are a widely accepted means to control cracks but are not always effective. Control joints are more effective the more closely spaced they are. GeoTek suggests that control joints be placed in two orthogonal directions and located a distance apart approximately equal to 24 to 36 times the slab thickness. Exterior concrete flatwork (patios, walkways, driveways, etc.) is often some of the most visible aspects of site development. They are typically given the least level of quality control, being considered "non-structural" components. We suggest that the same standards of care be applied to these features as to the structures themselves. SA POST CONSTRUCTION CONSIDERATIONS SAA Landscape Maintenance and Planting Water has been shown to weaken the inherent strength of soil, and slope stability is significantly reduced by overly wet conditions. Positive surface drainage away from graded slopes should be maintained and only the amount of irrigation necessary to sustain plant life should be provided for planted slopes. Controlling surface drainage and runoff, and maintaining a suitable vegetation cover can minimize erosion. Plants selected for landscaping should be lightweight, deep-rooted types that require little water and are capable of surviving the prevailing climate. Overwatering should be avoided. Care should be taken when adding soil amendments to avoid excessive watering. An abatement program to control ground-burrowing rodents should be implemented and maintained. This is critical as burrowing rodents can decreased the long- term performance of slopes. 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. GEOTEK D-R-Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486, Lake Elsinore, California Page 20 5.4.2 Drainage The need to maintain proper surface drainage and subsurface systems cannot be overly emphasized. Positive site drainage should be maintained at all times. Drainage should not flow uncontrolled down any descending slope. Water should be directed away from foundations and not allowed to pond or seep into the ground adjacent to the footings. Soil areas within 10 feet of the proposed structure should slope at a minimum of 5-percent away from the building, if possible unless the area is paved. Paved areas are to be sloped at 2-percent away from the structure. Side-yard swales should maintain a minimum I-percent slope. Roof leaders and downspouts should discharge onto paved surfaces sloping away from the structure or into a closed pipe system which outfalls to the street gutter pan or directly to the storm drain system. Pad drainage should be directed toward approved areas and not be blocked by other improvements. The project civil engineer should design all site drainage. It is the owner's responsibility to maintain and clean drainage devices on or contiguous to their lot. In order to be effective, maintenance should be conducted on a regular and routine schedule and necessary corrections made prior to each rainy season. 5.5 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 observe and document proper implementation of the geotechnical recommendations. The owner/developer should verify that GeoTek representatives perform at least the following duties: ■ Observe site clearing and grubbing operations for proper removal of unsuitable materials. ■ Observe and 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 trench backfill. Also, perform field density testing of the fill materials. ■ Observe and probe foundation excavations to confirm suitability of bearing materials. If requested, a construction observation and compaction report can be provided by GeoTek, which can comply with the requirements of the governmental agencies having jurisdiction over 'G, GEOTEK D•R•Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No 33486 Lake Elsinore California Page 21 the project. We recommend that these agencies be notified prior to commencement of construction so that necessary grading permits can be obtained. 6 INTENT 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 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 boundaries of the subject property. This update 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 our 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, our fee estimate (Proposal No. P-1201 1 16r) dated December 7, 2016 and geotechnical engineering standards normally used on similar projects in this locality at the present. 7 LIMITATIONS Our findings are based on site conditions observed and the stated sources. Thus, our comments are professional opinions that are limited to the extent of the available data. GeoTek has prepared this report in a manner consistent with that level of care and skill ordinarily exercised by members of the engineering and science professions currently practicing under similar conditions in the jurisdiction in which the services are provided, subject to the time limits and physical constraints applicable to this report. Since our recommendations are based on the site conditions observed and encountered, and laboratory testing, our conclusions 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 of any kind is expressed or implied. Standards of care/practice are subject to change with time. GEOTEK-G, D-R-Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 (revised May 25, 2017) Tract No. 33486, Lake Elsinore, California Page 22 8 SELECTED REFERENCES American Concrete Institute (ACI), 2006, Publication 302.2R-06, Guide for Concrete Slabs That Receive Moisture Sensitive Flooring Materials. 2010, Publications 360R-10, Guide to Design of Slabs-On-Ground. American Society of Civil Engineers (ASCE), 2013, "Minimum Design Loads for Buildings and Other Structures," ASCE/SEI 7-10, Third Printing, Errata Incorporated through March 15. California Code of Regulations, Title 24, 2016, "California Building Code," 3 volumes. GeoTek, Inc., In-house proprietary information. Leighton and Associates, Inc. (Leighton), 2004, "Preliminary Geotechnical Investigation, 25-Acre Site Adjacent to the North Side of Machado Street and Herborn Street, City of Lake Elsinore, Riverside County, California," Project No. 1 1 1401-002, dated November 9. , 2007a, "As-Graded Report of Rough-Grading, Home Sites 40 through 42 (Model Lots), Tract 33486, City of Lake Elsinore, California," Project No. 1 1 1401-005, dated January 31. 2007b, "As-Graded Report of Rough-Grading, Home Sites I through 39, 46 through 80, 82 and 83," Project No. 1 1 1401-005, dated March 16. Morton, D.M., and Miller, F.K., 2006, "Geologic Map of the San Bernardino and Santa Ana 30'x60' Quadrangles, California," U.S. Geological Survey Map OF-2006-1217, scale 1:100,000. Seismic Design Values for Buildings (http://geohazards.usgs.gov/designmaps/us/applicatio. hp). Southern California Earthquake Center (SCEC), 1999, Martin, G. R., and Lew, M., ed., "Recommended Procedures for Implementation of DMG Special Publication 117, Guidelines for Analyzing and Mitigating Liquefaction Hazards in California,", dated March 1999. State of California, California Geological Survey (CGS, formerly referred to as the California Division of Mines and Geology), 2008, "Guidelines for Evaluating and Mitigating Seismic Hazards in California," Special Publication 117A. ,G, GEOTEK ,rT y t a e Approximate Site Location X3. .u. 74 ;ate„ �r x , l � y z , _ K XF +u t sW' DR Horton Los Angeles Holding Company,Inc. Tract No.33486 McKenna Court Project Figure 1 City of Lake Elsinore Riverside County,California Site Location Map GeoTek Project No. 1604-CR G E O T E K w r k � a � t r. i j d r tl i i , Approximate Site Location ; 4 r a 1 ,�YYa u rrA "� f't.saPo re �.. Etta l y y , AA ♦ " ~ ` CA kZ 4 4 L i oT— Jyv .w i Ch- 3, , DR Horton Los Angeles Holding Company,Inc. Tract No. McKenna Court Project Figure 2 City of Lakea Elsinore i Riverside County,California Z Geologic Map GeoTek Project No. 1604-CR G E O T E K t.A Nu, 611 i 34 .33 X 31 3t ■ `y 23 — -- 7 -- _ 15 16 1 �- 00 25 36■ 37 O g 44 TP-6 TP-5 18 19 20 2 22 23 T11 — -- _ TP-1 y 6 9 14 17 26 38 40 41 142 1 35 5 10 Tit 27 39 13 ■ �61 4 � 11 28 34 p, 3 �� 78 77 76 75 74 73 72 71 70 T 33 `Lpj \ 12 ® 79 � 6a 80 ■ 29 32 44 LOT 43 94, q, 2 62 K 64 65 66 •67 68 69 30 31 50' 44 ?� 1 61 TP-9 / 45 / 60 WOODCREST DRIVE —— —— � LOT 81 2 • F os 59 • NEW SONG CALVARY CHAPEL 2 30, P' 33 2 5> 6 57 56 55 54 53 52 51 50 49 848 47 TP-111 r piti4 i 3 12 0 9 3 i A 4:rl MAP NO, 3f,12 • LEGEND ;u U ,00 -700 sca TP-12 Approximate Location of AP4iil SCaL.E _ Exploratory Trench Basemap from"Rough Grading Plans,"prepared by RENCivil Engineering,dated October 31,2006. DR Horton Los Angeles Holding Company,Inc. Tract No. McKenna Court Project Figure 3 City of Lakea Elsinore Riverside County.California Exploration Location Map GeoTek Project No. 1604-CR G E O T E K APPENDIX A LOGS OF EXPLORATORY BORINGS (Leighton, 2004) LOGS OF EXPLORATORY TRENCHES (GeoTek, Inc., 2017) Tract No. 34866, McKenna Court Project City of Lake Elsinore, Riverside County, California Project No. 1604-CR GEOTEK D-R-Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 Tract No. 34866, Lake Elsinore, California Page A-I A - FIELD TESTING AND SAMPLING PROCEDURES Bulk Samples (Large) These samples are normally large bags of earth materials over 20 pounds in weight collected from the field by means of hand digging or exploratory cuttings. Bulk Samples (Small) These are plastic bag samples which are normally airtight and contain less than 5 pounds in weight of earth materials collected from the field by means of hand digging or exploratory cuttings. These samples are primarily used for determining natural moisture content and classification indices. B— BORING AND TRENCH LOG LEGEND The following abbreviations and symbols often appear in the classification and description of soil and rock on the logs of trenches: SOILS USCS Unified Soil Classification System f-c Fine to coarse f-m Fine to medium GEOLOGIC B: Attitudes Bedding: strike/dip J: Attitudes Joint: strike/dip C: Contact line ........... Dashed line denotes USCS material change Solid Line denotes unit/formational change Thick solid line denotes end of trench (Additional denotations and symbols are provided on the log of trenches) 'C� GEOTEK GEOTECHNICAL BORING LOG B-1 Date 10-14-04 Sheet 1 of 2 Project Carman Leigh Black Property Project No. 111401-002 _ Drilling Co. Cal Pac Type of Rig B-61 Hole Diameter 8"___` Drive Weight _ 140 lbs Drop 30" Elevation Top of Hole+!- 133T Location 33 41'11 N1117 22'39 W C z° o ' 0 61� DESCRIPTION a > am W o p a dr- ' ro c m� t d `p C _as W C7 Z a Nn� My on Logged By PC c C ( Sampled By PC A ARY ALLUVIUM al - Bulk 2 @ SA EL MD 1330 ! R t 27 SM @ 2.5':Light brown,damp,medium dace,silty,fine to medium HCO 94.2 5.1 SAND;rootlets dense,porous S 94.8 I( 6.6 R3 29 ! i Ca,5':light brown,darttp,medium dense,silty,fine to coarse SAND; NCO,DS i porous,gravels conmmn i ! �I 1325 R4 28 ( @ 75:Light brown,damp.medimn dense,silty,fine to medium HCO 110.2' 5.0 SAND;few gravels 10 R5 43 @ 10':Brown ,medium me dense,si , dium ro coarse SAS -200 114.5 2.4 gravels abun stdmgular to angular gravels " I 1320 15 R6 79 Sh1 OLDER ALLUVIUM QUATERNARY DEPOS I 105.3 2.0 rows.darnp,dense,silty,moditun to coarse ;gravels I abundant,sut-gular to angular gavels 1J15 I 20 :: 57 76 @ 20':Brown,damp,dense medium to coarse SAND;gravels -200 common h 1310 25 •.� S8 50/4" 0.9 aQ 25':Brown-grey, very dense,silty,ttuodium to coarse SANS rock fragments from block 1305� a i SAh6kE TYPES. TYPE OFTESTS: HD ��SE CS comet ioN SURE G GRAB SAMPLE SU SULFATE MC MOISTURE CONTENT R RING SAMPLE C CORE SAMPLE D3 DIRECT SHEAR SA SIEVE ANALYSIS SE SAND EQUIVALENT a BULK SAMPLE mD MAXIMUM DENSITY AL ATrERBERG LIMITS -w no WASH T TUBE SAMPLE CH CONSOLIDATION EI EXPANSION INDEX RDS Ranwlded t1S CR CORROSION RV R-VALUE LEIGHTON GEOTECHNICAL BORING LOG B-1 Date �10-14-04 Sheet 2 of 2 Project _ Corman Leigh Black Property Project No. 111401-002 Drilling Co. Cal Pac Type of Rig B-61 Hole Diameter 8" _ Drive Weight 1401hs Drop 30^ Elevation Top of Hole+1- 1333' Location 33 41' 11N(11 T ZZ 39W 4 z m= ; �" DESCRIPTION ro rm ra M m ';"°o cr. 00 yc 9'u as J o CL I oLL G a o c 00i o W t3 C9 = fn m� C 2V rn� Logged By PC _ fl Sampled By PC 30 0': Y,da[P.q aY delve,st1y,-MUMto rnarsa SAND; l 1300-1 I 3s Total Depth 36_5- E No faamdwater Eammamred { BwkfUed with spoils 1014/04 1295 41U— tz90 - 45 1285 SO 1 l �I i I29Qi 1 f 1275+ i SAMPLE TYPES: TYPE OF TES NCO MrUROCOU APSE CS C0RR09QY SUM • S SAMPLE G GRAS yLE SU SULFATE ND MYDR011£Tt R Mc MotSTLIRE CONTENr itRWG SAMPLE C CORE SAMPLE DS DQtECT SHEAR SA SIEVE ANALYSIS SE SANDEOMALENT B BULK SAMPLE MID MAXIMUM DENStTr AL ATTERWRG UUM _00 200 WASH T TUBE SAMPLE CH CONSOLIDATION p EXPANSION INDEX RDS PjmxA1d DS CR CORROSfON RV R-VALUE LEIGHTON GEGTECHNICAL BORING LOG B-2 Date 10-i4-04 _ Sheet 'l of 2 Project Cormar Leigh Black Pr�q _ Proiect NO. 111401402 — -- Drilling Co. Cal Pac Type of Rig B-61 - Hole Diameter 8" Drive Weight 140 Ibs Drop 30" Elevation Top of Hole+1- 1339' Location 33 41'I W117 22'41 W _o` t„ z° j ao m �'� ay DESCRIPTION m o I a E,, m m ! dCo w w ~ U. oti �� Z a , l7 a e c Vu o w ' °�a. i 0 �v y? Logged By PC m a Sampled By Y PC 0 TTMkRYAUUV1M(0Ia0 R I 9 97.2 ! 6.0 rootlets dmrp,laosc,silty,fine to r xKt m SAND;few -200 1335 5 R2 70 I @ T:No Recovery .'Bulk SA 1330 � 10 ---- -- -- -- -- -- ---------- --- ----- - - - - R3 35 S.WSP @ 10: Li�trtd brown duip,meb�dayse,sity, fine SrNrD: 112.3 2.1 abundant subangfelar gfa 1325 l5 R5 63 , SM OLDER ALL1NAJlv1 ATERNARY DEPOS 116-7 3.9 5' wn,yJast dem stuy.fiw to n>edf m SAND; few gavels>1.in diameter,mic�ass 13 20 S6 37 @ 20':Dark fed-brown,mast dc'zs,-,shy,fine to rrdum SAND; -200 very frficmema 1315 25 --- - -- - - -- -- -- ----------- -------- - ------- � R7 50/S" 105.8 2.1 SM/SP @ 2S:Dark red-blown.moist very derma si ty,finetoatdun SXND;vay micaceous,gavels<3'In chanter 1 • i I 1310 SAMPLE TYPES: TYPE OF TESTS: tICO CORR�ON S1fitd S SPT G GRAB SAMPLE SU SULFATE ATE HD Hypp0NEFER MC MOISTURE CONIFJIT R RING SAMPLE C CORE SAMPLE DS DIRECT SHEAR SA SIEVE ANALYSIS SE SAND EQUIVALENT B BULK SAMPLE MO MAt0MUM DENSITY AL ATTERBERG LOWS QW 200 WASH T TUBE SAMPLE CN CONSOLIDATION EI EXPANSM 14" RIDS Rsnoldsd DS CR CORROSION RV R•VAUX LEIGHTON GEOTECHNICAL BORING LOG B-2 Date — 10-14-04 Sheet 2 of 2 Project Corman Leigh Black Property Project No. 111401-002 drilling Co. _ Cal Pac Type of Rig "I Hole Diameter 8" Drive Weight 140 Ibs _ Drop 30" Elevation Top of Hole+1- 1339' Location 33 41'13N/117 22'41W `o r �, z �o .� y DESCRIPTION mi I 4° E O G. o` Gc. cc o u� C9 i Z ni0. o 20 0=1 Logged By PC a t Sampled By PC — 30 S8 80/11' SP @� dam,silty,very d ,icy,rM b ooze SAM -200 -is Amdant t3os . 35 ———— R9 I SOWS" 111.9 4.4 SM ®35'c I}atk lavwo,d acsp,vcy drnu,�Ity, one b caazse SAND; —— :1 13001 i 40 = S 10 50/6" 4W:Red-brown @ var deasc,any,15me to coarse sArin;very micaceous,wdl sosc� t29s � i 45 ' ———— R L I SQl6" 102.0 8.1 SM/SP 45':Caa —— @ ——Y- o,d�>�!uy��, },fine to coarse SAND; —— -200 gravels co m m,very mcac oDu i I I 1290 50 Gay-lx*wn,&wV,vvydmm_silt}',face in case SAPID;very 120 SS Total D4 6 50.S No Goimdwata F�oomttced BacldMed with Spoils 10141-4 I SAMPLE TYPES: TYPE OF TESFATE SULFATE sU 14CO WMROCOLUIPSE Cs CORROSION=E s SPT G GRAB SAMPLE Ip hYDROMETER MC MOISTURE CONTENT R RING SAMPLE C CORE SAMPLE DS DIRECT SHEAR SA SIEVE ANALYSIS SE SAND EQUIVALENT B BUJ (SAMPLE MD '"A"DENSITY AL 11TTetwnGuAirs -m 2oc WASH T TUBE SAMPLE CH CONSOLIDATION Q EXPAUSION NM R DS Remolded DS CR CORROSION RV R•VA A E LEIGHTON GEOTECHNICAL BORING LOG B-3 Date 10-14-04 Sheet 1 of 2 Project Carman Leigh Black Propert _ Project No. 111401-002 Drilling Co. - Cal Pac Type of Rig S-61 Hole Diameter 8" -- Drive Weight 140lbs Drop 30" Elevation Top of Hole+/- 1345' Location 33 41' 14N1117 22 46W o„ DESCRIPTION m • ..m is { • • ;;o �� a I F- mX1L t3 aJ Z m C a o c f a W C7 ran , a o Mtoi m°� Logged By PC m Sampled By PC 13451 0 Bulk 2 Q � SA,RV as R 1 11 Nfl. Q 2.5':Light brown,d2up,stiff,sandy,Irn SILT,toales camrwn li HCO 99.6 4.0 i 1340 S R3 29 SM/SP A T AIL HCO 108.4 3.1 5:light brown urn rise,silty:f m to medium SAND; sibtotnded to to gavels,abundaa8 1 m dim=ter -- -- --+ __ --------------------- --- - - — —— Rd 26 SM (Qa 7.5':Light broanr da:rp,nndum dense,siky,foe to modium— HCO 110.0 2.8 SAND;tame tvutlet tm�+Y+■s some grd�els 1335 10 S5 40 1 SM Ot.DER AILMM!M 'ATERNARY DEPO 10':Lt t Uno+va, ty.tyae I tt.&UM �rr• SANi},tturaceaus 1330 15 R6 59 Q IS:Lightbroom,damp,dense,silty.IfimetornediunSAlND; 117.1 2.2 micaerats s+lt stmgms,few gavels I i I 1325 20 ---- -- -- -- -- SM-- ------ - ------ — R7 50l6" 1SP a�2d Lightgray-trowa,datrtQ,very d®se,arty fix to madium —— jI SAND;rmcaeemm tew kW gavels 1-2'to dimmer I I 1320 25 RS "O/S i !5 @ 25.No Recovery In SAMPLE TYPES: TYPE OF TESTS: HOD HYOROCOLLAP5E CS CORROSION SUrrE S SPT G GRAB SAMPLE SU DIRECT SULFATE HO HYDROMETER MC MORSTURE CO►(TENr R RING SAMPLE C COR9 SAMPLE SHEAR SA SEyE ANALYSIS SE SANO EQINALENT B BULK SAMPLE MO MAXIMUM DENSITY AL ATTERBERG UMITS -2"200 WASH T TUBE SAMPLE CN CONSOL1t AnoN El EXPANSION INDEX ROS Ranolded DS CR CORROSION RV R-VALLE LEIGHTON GEOTECHNICAL BORING LOG B-3 Date 10-14-04 — Sheet 2 of 2 Protect Corman Leigh Black Pro Project No, 111401-002 — Drilling Co. Cal Pac Type of Rig IB-61 _ Hole Diameter 81 Drive Weight 140 Ib$ prop 3p• Elevation Top of Hole+/- 1345' Location 33 41'14IV11 17 22'46W I I { •'' DESCRIPTION m �m '' ' m m a ;°o m 3" �� o .,c I- 0 w o I C7 ( z ma G I v Tn° Logged By - PC a Sampled By PC H 1315 30- S9 65/12- SWSP! Q30':Light grarylnown,dasV, , SAND; > vV2a s i I I P 1310 35 Total Depth 3l' No .Zd,r Eaeamtaed Bactfilled with Spoils VV14W 1305 40 J i i 13 45 12" 50 E 12" SS 1 � I 1 I I I SAMPLE rrPEs: TYPE of TESTS: kCO t+roeocci Lw� CS CORROBIOH sure 9 9PT G GRAB SAMPLE SU SULFATE HD HYDROMETER MG YOIS7URL CCNTENT It RING SAMPLE C CORE SAMPLE DS DIRECT SHEAR SA glEVEA4A-ySM SE &0MEDWALENT B BULK SAMPLE T TUBE SAMPLECN CONSOLIDATION El EXPANSION MEX RDS Rardded DS CR WMOSION W RVAU N LEIGHTON GEOTECHNICAL BORING LOG B4 Date 10-14-04 _ Sheet 1 of 1 Project Corman Leigh Black Property Project NO. 111401-002 Drilling Co. Cal Pac _ Type of Rig B-61 Hole Dlarneter 8" Drive Weight 140 Ibs Drop 30" Elevation Top of Hole+!- 1348' - Location 33 41-17N1117 22'46W a o , I Z m DESCRIPTION mLL G� AJ z tl C Q 621 O C —in o Lu ma c gv Logged By PC c Sampled By PC 0 UATFRNARY 1345 R I 34 SM Qa 2S'-Light brown,damp,mcdimn dense,silty,fine to modiwn 200 98.7 3.8 SAND;few rootlets,anexems,few pores 51'. . ---- — -- -- — — — — — — R2 33 SP/ <va;S1 Light bmwo,damp,median dc�silty,fine to medium SAND; 107.9 3.2 rootkts eon mnn,imieaceous,few gravels 1 l 1340 Q 7.5' Red-birmn,d ry madeum dense,silty,fine to coarse S&%M; -200 106.7 2.1 few graves 1-2"indhameer,mimmals 10 R4 44 137.4 2.5 OL.D1R ALLUMM QUAIEUNARY DEPOS Bulk S a(7 a?@+wedium a ty, me to camse SAND; gravels Ibmndaat,niaw=us SA 10-IS' e 13351 SM ®IS:Red-btowa damp,very dense,silty.fine to rrrediran SANE—— imeacmm rock fragments 1330 20 a R7 5(W 98.0 2.6 Q 20':Redbrowrl,dam very dome,silty,fime to awn SAND,, -200 mcacww,rock fragments ents 1325 I Total Deptlt 2r No Caasdww=Eacmmtwad f BackfiBed with Spoils IM4(04 1320 — i SAMPLSTYPES: fP OP TESTS: HODS SPIT GRAB SAMPLE SU SULFATE HD HYDROMETER MC NOMIRE CONRETfr R RING SAMPLE C CORE SAMPLE DS DIRECT SHEAR SA s1EYEANALYSIS SE SAND ECAWALENT B BILKXI SAMPLE MD MAXIMUM DENSITY AL ATTamm umus -wo no wAsk T TUBE SAMPLE CN CONSOLMA'noN p EXPANSION INDEX RDS Remolded OS CR CORROSION RV R-VALUE LEIGHTON GEOTECHNICAL BORING LOG B-5 Date 10-14-04 Sheet 1 of 1 Project _ Corman Leigh Black Property Project No. _111401-002 Drilling Co. Cal Pac _ _ Type of Rig B-61 Hole Diameter 6"_ _ Drive Weight 140 bs Drop 30" Elevation Top of Hole+/_ 1343' Location o z — M DESCRIPTION V EL mu. a z E a0m ! C a w� o w t7 a C .v alp Logged Sy PC Sampled By PC F- -R'A%ARY ALLUNUN(M 1340 R1 13 SM @ 23:Ligt brown,daarEt.loose, silty,5w to tttedrmt UND,rootlds abmrd=t rrncacaors,porvw S � R2 22 @ S:L*i kvwu,dar>g,madiram dense,sihy,f ore to modiurn SAND; 97.9 4.3 rootlets abuadbt,avewmmr.,porous ---- -- -- i�53 4.6 -- -------- ------- ------------ 1335, R3 25 SNUSP @ 7.5:Rad-brawn,dntp,nvAundmsc silty,fine to maiium SA1 -, DS few gravels,rmcamoas i i 10 R4 67/12" SP { OLDER ALLL -N rA ARYI?E -200 5 uartt nch�M,vwy east,Coa>se y G3iA M b Bulk l0 5'@ Q SA - I 1330-4 •i l5 -- -- --- - --- ------ R6 57 SM @ IS:Red-hnwo,moia,silty,6aetocoase SAND-,verymi ccous,- •• 114.3 4.5 fcw Oravds 1325 I i f - -- - ----------- S7 Sas" SM/S ®20:cry brmzrr,camp,medum to cosuse sAND;micaccvres, —— •�• - • •- abundant gavels 1320 i 2S— Total 14.Gtolmdwata Depth 22' Ewoualaed BackfMa3 with Sports 1314M4 13154 ' in f SAMPLE TYPES: TYPE OF TESTS: HCO HYDROCOL-WSE CS CofmMoN SLATE S SPT G GRAB SAMPLE SULFATE NO NYDROINETER YC RACNSTURECONTENT R RING SAMPLE C CORE SAMPLE DS DIRECT SHEAR SA SIEVE ANALYSIS SE SAND EQUWAL LINT B BULK SAMPLE MO MAXIMUM OB AL AM5MERG LOTS ZOe ZW WASH T TUBE SAMPLE CN CONSOLIDATION 8 EXPANSIONINDO( RDS Rerr d 03 CR CORROSION RV R-YALUE LEIGHTON GEOTECHNICAL BORING LOG B-6 Date 10-14-04 Sheet I of 1 Project Corman Leh Black Proper rt� _ Project No. 111401402 _ Drilling Co. Cal Pac Typo of Rig 841 Hole Diameter 8" Drive Weight 140 lbs Drop 30" Elevation Top of Hole+1- 1,355, Location m 0 z i tAo OU) M DESCRIPTION >U. cLL ! m� z° a p Q. 3 c Vy `o 1u I to ma o 20 an , Logged By PC a I Sampled By PC 1� _- QUATIERNAR YALL `VIUM I ' •- 111 24 SM Q 25`Lightbwowq dazes,madi®dens4 si ty,fire lo modium I -200, k 106.E 3.7 SAND;slightly nzi=ccus HCO 1350 5 R2 35 @ S:Rod-brown,damp.>mdum dense,silty,fix to curie SAND; HCO 106.1 39 few toodels,slightly imcaceous,pcmas R3 65i 12- 114.9 6.5 @ TY:Red-hmwm,daub,°a}'derm,silty,fine to medium SANS; 200, few gravels,vncaceaas HCO I i I 1345� 10 R5 54 @ 10• Redbeown,mast dense,silty,fine to rrwdum SAM}cLkium HCO Bulk 4 I t2.4 5.5 I carbonate sumgas,tmcaceoas,few gavels 5-10 @ j I I 1340 IS 56 77/12" ®15':Red bewn dates dense silllr,fine oomodiamSA -200 na� -grsy ,very dense hi lly veatherod f i 1335 20 � I i Total Depth 1 V No Gracmdwaier Enoatmkrnd 134-ViiIlcd with Spoils 1QIV04 1330 Z5 i i SAMPLE TYPES: TYPE OF TESTS: HCO HYOROCO-LAPSE CS coRRcwoNSIATE S SPT G GRAB SAMPLE SU SULFATE HD HYDROMETER MC UgSrURE CONTENT R RING SAMPLE C CORE SAMPLE DS DIRECT SHEAR SA SEYB ANALYSIS SE SAND SX� T B BULK SAMPLE MO MAXIMUMDENSITY AL D AL ArratsERG uwrs -me 23e t#wH T TUBE SAMPLE CN CONSOUDATION El EXPA S"INO©C RDS RMWA:kd OS CR CORROSION RV RVALUE LEIGHTON GEOTECHNICAL BORING LOG B-7 Date 10-14-04 Sheet 1 of 1 Project _ Carman Leigh Black Property _ Project No. 111401-002 Drgling Co. Cal Pac ^, _— Type of Rig B-61 _ Hole Diameter 8" Drive Weight 140 Ibs _ Drop 30" Elevation Top of Hole+1- 1353' Location I z41w •� a- DESCRIPTION a go N. 4-1Z a °�CLO G rL o c C�t�j ° LU y mIL o �� r»� Logged By PC Sampled By PC �- �- 0 „ - QUATERNARY ALLUVIUM(Oal) — Bulk 2 @ � j MD.CS, 5' { SA.El 1350 Rl 12 03.6 6.3 ML @ 2-Y:Light brown damp,stiff,lean SILT;Lew rootlets � HCO 5 R3 24 @ 5':Red-brown,darnp,medium dense,silty,fine In medium SAND; HCO 107.41 5.4 few rootlets,slightly micaceous ---- -- -- -- — -- ------ - -- - ----- 1345 j R4 40 -- -- SM/SP @ 7.5':Drift gray-brown.moist,medium dense,silty,medium to 108.6 3.9 coarse SAND;very micaceous,abundant gravels 10 ---- -- -- -- -- -- ------- --- ------------------ R5 48 STv1 @ l0':Real-brown ro gray-brown,moist,medium dense,silty,fine to 112.1 8.3 medium SAND;micaceous,mottled L740 i i IS R6 81/12" SM/SP LD S 114.0 I.8 ly: ems,very Mto SAND;very micaceous,wcuhered gta nitics&agn ats 1335 SII S7 65 @ 20':Cray,moist,dense,silty,fine to coarse SAND;comprised of weathered granities fizgm=ts 1330 25 j Total Depth 24' 1325,E No Carnmdwater EncOMACrad Backfilled with Spoils 10/14/04 i SAMPLE TYPES. TYPE OF TESTS: NCO NYDROCOLLAPSE CS CORROSION SURE S SPT G GRAS SAMPLE SU SULFATE NO 14YOROIMETER MC MOISTURE CONTENT R RtkG SAMPLE C CORE SAMPLE DS DIRECT SHEAR SA SIEVE ANALYSIS SE SAID EQUIVALENT B BULK SAMPLE MD MAXIMUM DENSITY AL ATrome fi UMiTs -we Zoo WASH T TUBE SAMPLE CN CONSOLIDATION El EXPANSION INDEX ROS Rearotded 09 CR CORROSION RV R•VALUE LEIGHTON GeoTek, Inc. LOG OF EXPLORATORY TRENCH CLIENT: DR Horton LOGGED BY: NCT PROJECT NAME: Tract No.33486 McKenna Court EQUIPMENT Backhoe PROJECT NO.: 1604-CR DATE: 12/19/2016 LOCATION: See Exploravor Location Map SAMPLES Laboratory Testing 0 r E r TRENCH NO.: TP-I m = z o v UU B lJ a s O E N MATERIAL DESCRIPTION AND COMMENTS Engineered Fill: SM Dark brown silty f-m SAND with trace gravel,wet,loose to medium El,MD,SR dense SB-I Becomes slightly moist and dense at 1.5' LB-I 5 TRENCH TERMINATED AT S FEET No groundwater encountered. Trench backfilled with soil cuttings. 10 15 ZSample pe: ■ --Ring ®__Large Bulk Q ---Water Table w w Lab teStl ng: AL=Atterberg Limits El=Expansion Index SA=Sieve Analysis RV= R-Value Test J SR=Sulfate/Resieruviry Test SH=Shear Test HC= Consolidation MD=Maximum Density GeoTek, Inc. LOG OF EXPLORATORY TRENCH CLIENT: DR Horton LOGGED BY: NCT PROJECT NAME: Tract No 33486 McKenna Court EQUIPMENT Backhoe PROJECT NO.: 1604-CR DATE: 12/19/2016 LOCATION: See Exploration Location Map SAMPLES Laboratory Testing _ o o E r TRENCH NO.:TP-2 U d? w t a o V O ° E U U O ° MATERIAL DESCRIPTION AND COMMENTS ° Engineered Fill: SM Dark brown silty f-m SAND with trace gravel and coarse sand,wet,loose to medium dense Becomes slightly moist and dense at 1.75' TRENCH TERMINATED AT 3.S FEET 5 No groundwater encountered. Trench backfilled with soil cuttings. 10 15 ZSample type: ---Ring ®---Large Bulk ---Water Table w w Lab testing: AL=Atterberg Limits El=Expansion Index SA=Sieve Analysis RV= R-Value Test SR=Sulfate/Resisitivity Test SH=Shear Test HC= Consolidation MD=Maximum Density GeoTek, Inc. LOG OF EXPLORATORY TRENCH CLIENT: DR Horton LOGGED BY: NCT PROJECT NAME: Tract No.33486 McKenna Court EQUIPMENT Backhoe PROJECT NO.: 1604-CR DATE: 12/19/2016 LOCATION: See Exploration Location Map SAMPLES Laboratory Testing 0 r a r TRENCH NO.: TP-3 a m z ° c w E U U r O ° MATERIAL DESCRIPTION AND COMMENTS ° 8 Uncodumented Fill: SM Dark brown silty f-m SAND with trace gravel and coarse sand,wet,loose 12 to medium dense 25/0.5" Becomes slightly moist and dense at 1.5' 25/0.5" TRENCH TERMINATED AT 2.5 FEET No groundwater encountered. Trench backfilled with soil cuttings. 5 10 15 ZSample Me: ---Ring ®___Large Bulk -!Z --Water Table w W Lab testing: AL=Atterberg Limits El=Expansion Index SA=Sieve Analysis RV= R-Value Test J SR=Sulfate/Resisitiviry Test SH=Shear Test HC= Consolidation MD=Maximum Density GeoTek, Inc. LOG OF EXPLORATORY TRENCH CLIENT: DR Horton LOGGED BY: NCT PROJECT NAME: Tract No.33486 McKenna Court EQUIPMENT Backhoe PROJECT NO.: 1604-CR DATE: 12/19/2016 LOCATION: See Exploration Location Map SAMPLES Laboratory Testing 0 a o r TRENCH NO.:TP-4 v z 0 D O ° E U U ° MATERIAL DESCRIPTION AND COMMENTS ° 8 Undocumented Fill: SM Light to dark brown silty f-c SAND with trace gravel and coarse sand, moist,loose to medium dense Becomes moist and dense at 0.5' 12 Becomes medium dense at 2' 8 5 Crushed 3/4"aggregate for sanitary sewer backfill at 5.5' TRENCH TERMINATED AT S.S FEET No groundwater encountered. Trench backfilled with soil cuttings. 10 15 ZSample tX Q pe: ---Ring ®---Large Bulk ---Water Table w WLab testing: AL=Atterberg Limits El=Expansion Index SA=Sieve Analysis RV= R-Value Test J SR=Sulfate/Resisitivity Test SH=Shear Test HC= Consolidation MD=Maximum Density GeoTek, Inc. LOG OF EXPLORATORY TRENCH CLIENT: DR Horton LOGGED BY: NCT PROJECT NAME: Tract No,33486 McKenna Court EQUIPMENT Backhoe PROJECT NO.: 1604-CR DATE: 1 211 9/20 1 6 LOCATION: See Exploration Location Map SAMPLES Laboratory Testing 0 a r TRENCH NO.: TP-5 - o a tL o m U U g s E o U a P O MATERIAL DESCRIPTION AND COMMENTS 3 ° Engineered Fill: SB-I SM Dark brown silty f-m SAND with trace gravel and clay,moist,loose to medium dense Becomes slightly moist and dense at I' 25/0.25" 25/0.75" TRENCH TERMINATED AT 4 FEET 5 No groundwater encountered. Trench backfilled with soil cuttings. 10 15 ZSample type: ---Ring ®---Large Bulk Q ---Water Table w WLab testing: AL=Atterberg Limits El—Expansion Index SA=Sieve Analysis RV= R-Value Test J SR=Sulfate/Resisitivity Test SH=Shear Test HC= Consolidation MD=Maximum Density GeoTek, Inc. LOG OF EXPLORATORY TRENCH CLIENT: DR Horton LOGGED BY: NCT PROJECT NAME: Tract No.33486 McKenna Court EQUIPMENT Backhoe PROJECT NO.: 1604-CR DATE: 12/19/2016 LOCATION: See Exploration Location Map SAMPLES Laboratory Testing 0 a 3 E r TRENCH NO.:TP-6 o m 0 Z ° n o U O n L E " j v 0 ° MATERIAL DESCRIPTION AND COMMENTS ° Engineered Fill: S13-1 SM Dark brown silty f-m SAND with trace gravel and clay,moist,loose to 7 medium dense Becomes slightly moist and dense at 2' 25/1.0" Trace small cobbles at 4' 5 25/1.5" Dark brown silty f SAND,moist,dense 25/1-0" TRENCH TERMINATED AT 7 FEET No groundwater encountered. Trench backfilled with soil cuttings. 10 15 ZSamole CVDe: ---Ring ®---Large Bulk �_ --Water Table W WLab testing: AL=Atterberg Limits El=Expansion Index SA=Sieve Analysis RV= R-Value Test -J SR=Sulface/Resisitivity Test SH=Shear Test HC= Consolidation MD=Maximum Density GeciTek, Inc. LOG OF EXPLORATORY TRENCH CLIENT: DR Horton LOGGED BY: NCT PROJECT NAME: Tract No.33486 McKenna Court EQUIPMENT Backhoe PROJECT NO.: 1604-CR DATE: 1 211 9/2 0 1 6 LOCATION: See Exploration Location Map SAMPLES Laboratory Testing 0 r 3 E T TRENCH NO.:TP-7 2 C = N O c m ° a o d U U a r E U U Q j MATERIAL DESCRIPTION AND COMMENTS 3 Engineered Fill: SM Dark brown silty f-m SAND with trace clay,moist,loose to medium El,MD,SR 23 dense SB-1 LB-1 Light brown silty f-c SAND,slightly moist,dense at 2' 25/0.5" 5 29 Light brown silty f-c SAND with gravel,slightly moist,dense Alluvium: SM/SC Dark brown silty f-c SAND to bluish gray silty CLAY with f-m sand, slightly moist,dense TRENCH TERMINATED AT 7.S FEET 10 No groundwater encountered. Trench backfilled with soil cuttings. IS ZSample type: ---Ring ®---Large Bulk -!Z- ---Water Table w WLab testing: AL=Atterberg Limits El=Expansion Index SA=Sieve Analysis RV= R-Value Test J SR=Sulfate/Resisitivity Test SH=Shear Test HC= Consolidation MD=Maximum Density GeoTek, Inc. LOG OF EXPLORATORY TRENCH CLIENT: DR Horton LOGGED BY: NCT PROJECT NAME: Tract No.33486 McKenna Court EQUIPMENT Backhoe PROJECT NO.: 1604-CR DATE: 12/19/2016 LOCATION: See Exploration Location Map SAMPLES Laboratory Testing 0 r O E TRENCH NO.:TP-8 Z o c v 1, 'o E U U ° MATERIAL DESCRIPTION AND COMMENTS ° Undocumented Fill: SM Dark brown silty f-m SAND with some gravel and clay,wet,loose to 22 medium dense 25/0.75" Becomes moist and medium dense at 2' 28 Becomes slightly moist and dense at 3' 16 5 Crushed 3/4"aggregate for sanitary sewer backfill at 5.0' TRENCH TERMINATED AT 5 FEET No groundwater encountered. Trench backfilled with soil cuttings. 10 15 ZSage type: ---Ring ®-_-Large Bulk !Z_ --Water Table W W Lab testing: AL=Atterberg Limits El=Expansion Index SA=Sieve Analysis RV= R-Value Test J SR=Sulfate/Resisitivity Test SH=Shear Test HC= Consolidation MD=Maximum Density GeoTek, Inc. LOG OF EXPLORATORY TRENCH CLIENT: DR Horton LOGGED BY: NCT PROJECT NAME: Tract No.33486 McKenna Court EQUIPMENT Backhoe PROJECT NO.: 1604-CR DATE: 12/19/2016 LOCATION: See Exploration Location Map SAMPLES Laboratory Testing a « a N TRENCH NO.:TP-9 m « o E V U — j v 0 ° A MATERIAL DESCRIPTION AND COMMENTS ° Engineered Fill: SM Dark brown silty f-c SAND with gravel,small cobbles and trace clay,wet, El,MD,SR medium dense SB-I 25/0.75' LB-I Becomes slightly moist and dense at 2' 25/0.75" TRENCH TERMINATED AT 4 FEET 5 No groundwater encountered. Trench backfilled with soil cuttings. 10 15 ZSample it ---Ring ®---Large Bulk �_ ---Water Table w w Lab testing: AL=Atterberg Limits El=Expansion Index SA=Sieve Analysis RV= R-Value Test SR=Sulfate/Resisitivity Test SH=Shear Test HC= Consolidation MD=Maximum Density GeoTek, Inc. LOG OF EXPLORATORY TRENCH CLIENT: DR Horton LOGGED BY: NCT PROJECT NAME: Tract No.33486 McKenna Court EQUIPMENT Backhoe PROJECT NO.: 1604-CR DATE: 12/19/2016 LOCATION: See Exploration Location Map SAMPLES Laboratory Testing 0 a E TRENCH NO.:TP-10 r o E N m o c v 0 v a e u u MATERIAL DESCRIPTION AND COMMENTS 3 Undocumented Fill: SM Brown silty f-m SAND with trace gravel and coarse sand,moist,medium 24 dense 21 Becomes moist and dense at 4' 13 5 TRENCH TERMINATED AT 5 FEET No groundwater encountered. Trench backfilled with soil cuttings. 10 15 ZSample type: Ring ®___Large Bulk !Z-_ ---Water Table w WLab testing: AL=Atterberg Limits El=Expansion Index SA=Sieve Analysis RV= R-Value Test J SR=Sulfate/Resisitivicy Test SH=Shear Test HC= Consolidation MD=Maximum Density GeoTek, Inc. LOG OF EXPLORATORY TRENCH CLIENT: DR Horton LOGGED BY: NCT PROJECT NAME: Tract No.33486 McKenna Court EQUIPMENT Backhoe PROJECT NO.: 1604-CR DATE: 12/19/2016 LOCATION: See Exploration Location Map SAMPLES Laboratory Testing 0 t r 3 TRENCH NO.:TP-I I 2 o v 0 a a o Z V U a L MATERIAL DESCRIPTION AND COMMENTS 3 ° Engineered Fill: SM Dark brown silty f-c SAND with gravel and clay,moist,medium dense 25/1.0" Becomes slightly moist and dense at I' 25/0.75" Becomes siltier,moist and dense at 4' 25/0.75" 5 TRENCH TERMINATED AT S FEET No groundwater encountered. Trench backfilled with soil cuttings. 10 15 ZSample type: ---Ring ®---Large Bulk !Z__ ---Water Table w W Lab testing: AL=Atterberg Limits El=Expansion Index SA=Sieve Analysis RV= R-Value Test J SR=Sulfate/Resistivity Test SH=Shear Test HC= Consolidation MD=Maximum Density GeoTek, Inc. LOG OF EXPLORATORY TRENCH CLIENT: DR Horton LOGGED BY: NCT PROJECT NAME: Tract No.33466 McKenna Court EQUIPMENT Backhoe PROJECT NO.: 1604-CR DATE: 1 211 9/20 1 6 LOCATION: See Exploration Location Map SAMPLES Laboratory Testing a r o r TRENCH NO.:TP-12 ti v m ° E U U c U `v r a O O � MATERIAL DESCRIPTION AND COMMENTS ° Undocumented Fill: SB-I SM Dark brown silty f-c SAND with gravel,small cobbles and trace clay,wet, medium dense 25/0.5" Becomes slightly moist and dense at 2' TRENCH TERMINATED AT 4 FEET 5 No groundwater encountered. Trench backfilled with soil cuttings. 10 15 ZSample type: ---Ring ®---Large Bulk ---Water Table w LO Lab testing: AL=Atterberg Limits El=Expansion Index SA=Sieve Analysis RV= R-Value Test w J SR=Sulfate/Resisitivity Test SH=Shear Test HC= Consolidation MD=Maximum Density APPENDIX B LABORATORY TESTING RESULTS Tract No. 34866, McKenna Court Project City of Lake Elsinore, Riverside County, California Project No. 1604-CR GEOTEK_c:r_, D-R-Horton Los Angeles Holding Company, Inc. Project No. 1604-CR Updated Geotechnical Evaluation February 3, 2017 Tract No. 34866, Lake Elsinore, California Page B-I SUMMARY OF LABORATORY TESTING Classification Soils were classified visually in general accordance to the Unified Soil Classification System (ASTM Test Method D2487). The soil classifications are shown on the boring logs in Appendix A. Expansion Index The expansion potential of the soils was determined by performing expansion index testing on three samples in general accordance with ASTM Test Method D4829. The results of the testing are provided below. Bong beE?th Soil fi Expansion lrtdex, Lion ; TP-1 0-2 Silty f-m SAND I Very Low with trace gravel TP-7 0-2 Silty f-m SAND 5 Very Low with trace clay Silty f-c SAND TP-9 0-2 with gravel 0 Very Low Moisture-Density Relationship Laboratory testing was performed on two samples obtained during the subsurface exploration. The laboratory maximum dry density and optimum moisture content was determined in general accordance with ASTM Test Method D 15ST The results of the testing are provided below. Maxirminx �`' &rin ( ) F.. E?esc i ri '^At Content' r F,. zr,,. f "„r.. % 4;,:. ., % v f��- r „r':�. r,. '�,�,' 1r Silty f-m SAND with TP-I 2-4 130.5 8.5 trace gravel Silty f-m SAND with TP-7 2-5 129.0 9.0 trace clay Silty f-c SAND with TP-9 0-3 127.0 9.5 gravel Sulfate Content, Resistivity and Chloride Content Testing to determine the water-soluble sulfate content was performed by others in general accordance with California Test No. 417. The results of the testing are provided below. r rj F F Sutate Boring No. Depth (k r.. )CZ41 J"( b,*e ght) TP-1 0-2 0.0150 TP-7 0-2 0.0180 TP-9 1 0-2 0.0060 GEOTEK APPENDIX C SUMMARY OF FIELD DENSITY TESTS FOR EXISTING SEWER TRENCH BACKFILL Tract No. 34866, McKenna Court Project City of Lake Elsinore, Riverside County, California Project No. 1604-CR GEOTEK DR Horton Los Angeles Holding Company,Inc. 21612017 Tract No.33486 McKenna Court Project Project No. 1604-CR City of Lake Elsinore,Riverside County,California Page I of I TABLE I SUMMARY OF FIELD DENSITY TESTS Depth Optimum Moisture Dry Maximum Relative Test Below Soil Moisture Test DATE Location Content Density Density Compaction No. Existing Type Content Type Grade ��) �Pc� �Pc� N ��) 01/10/17 1 Woodcrest Dr.Sewer Sta:21+25.00 -2 13.4 112.5 C 127.0 9.5 ND 89 01/10/171 2 1 Woodcrest Dr.Sewer Sta:21+25.00 -4 9.6 113.3 C 127.0 9.5 ND 89 01/10/17 3 Courtney Ct.Sewer Sta:I 1+00.00 -1 12.9 109.6 C 127.0 9.5 ND 86 01/10/17 4 Courtney Ct.Sewer Sta:I 1+00.00 -3 10.1 1 1 1.9 C 127.0 9.5 ND 88 01/10/17 5 Woodcrest Dr.Sewer Sta:17+75.00 -2 15.3 107.2 C 127.0 9.5 ND 84 01/10/17 6 Woodcrest Dr.Sewer Sta:17+75.00 -4 16.5 100.6 C 127.0 9.5 ND 79 01/10/17 7 Woodcrest Dr.Sewer Sta:16+75.00 -2 13.9 103.1 C 127.0 9.5 ND 81 01/10/17 8 Woodcrest Dr.Sewer Sta:16+75.00 -4 12.7 105.9 C 127.0 9.5 ND 83 01/10/17 9 Woodcrest Dr.Sewer Sta:15+00.00 -1 14.6 109.7 C 127.0 9.5 ND 86 01/10/17 10 Woodcrest Dr.Sewer Sta:15+00.00 -3 13.9 111.6 C 127.0 9.5 ND 88 01/10/17 11 Woodcrest Dr.Sewer Sta:13+25.00 -2 13.7 113.8 C 127.0 9.5 ND 90 01/10/17 12 Woodcrest Dr.Sewer Sta:13+25.00 -4 9.9 114.4 C 127.0 9.5 ND 90 01/10/17 13 Woodcrest Dr.Sewer Sta:10+60.00 -1 13.2 1 13.0 C 127.0 9.5 ND 89 01/10/17 14 Woodcrest Dr.Sewer Sta:10+60.00 -3 11.7 109.5 C 127.0 9.5 ND 86 01/10/17 15 Clement St.Sewer Sta:12+50.00 -2 14.2 107.8 C 127.0 9.5 ND 85 01/10/17 16 Clement St.Sewer Sta:12+50.00 -4 13.7 112.1 C 127.0 9.5 ND 88 01/10/17 17 Megan Ct.Sewer Sta:17+50.00 -I I S.4 110.6 C 127.0 9.5 ND 87 01/10/17 18 Megan Ct.Sewer Sta:17+50.00 -3 13.6 107.1 C 127.0 9.5 ND 84 01/10/17 19 K m Ct.Sewer Sta:10+75.00 -2 13.1 115.8 C 127.0 9.5 ND 91 01/10/17 20 K m Ct.Sewer Sta:10+75.00 -4 13.0 113.2 C 127.0 9.5 ND 89 01/10/17 21 Megan Ct.Sewer Sta:14+25.00 -2 13.4 113.3 C 127.0 9.5 ND 89 01/10/17 22 Megan Ct.Sewer Sta:14+25.00 -4 12.9 112.5 C 127.0 9.5 ND 89 01/10/17 23 Mandy Ct.Sewer Sta:11+60.00 -1 14.8 114.7 C 127.0 9.5 ND 90 01/10/17 24 Mandy Ct.Sewer Sta:11+60.00 -3 14.1 1 1 1.3 C 127.0 9.5 ND 88 01/10/17 25 Megan Ct.Sewer Sta:12+25.00 -2 13.9 112.0 C 127.0 9.5 ND 88 01/10/17 26 Megan Ct.Sewer Sta:12+25.00 -4 13.4 113.0 C 127.0 9.5 ND 89 Lepen ND - ND=Nuclear Densometer Test All elevations are approximate G E 0 T E K APPENDIX D SETTLEMENT ANALYSIS Tract No. 34866, McKenna Court Project City of Lake Elsinore, Riverside County, California Project No. 1604-CR GEOTEK LIQUEFACTION ANALYSIS Tract No. 33486 McKenna Court Hole No.=B-2 Water Depth=200 ft Magnitude=6.8 Acceleration=0.964g Shear Stress Ratio Factor of Safety Settlement Soil Description rRa 0 1 0 1 5 0(in.) 10 engineered fill 10 I I silty sand to sandy sift - silty sand I 20 XT silty sand to sandy silt - s I 30 sand silty sand 40 silty sand to sandy silt i 50 fs1=t.30 S=2.53 in. CRR CSR fs9--- Saturated — Shaded Zone has Liquefaction Potential Unsaturat. — m a Q D 60 LD 0 it m V a — 70 r m it GeoTek Lake Elsinore, Riverside County D-1 APPENDIX E GENERAL EARTHWORK AND GRADING GUIDELINES Tract No. 34866, McKenna Court Project City of Lake Elsinore, Riverside County, California Project No. 1604-CR GEOTEK-G, GENERAL GRADING GUIDELINES APPENDIX E D•R•Horton Los Angeles Holding Company, Inc. Page E-I Tract No. 33486 Lake Elsinore Riverside County California GENERAL GRADING GUIDELINES 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 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 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 California Building Code, CBC (2016) and the guidelines presented below. 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 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 I. 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 density tests that day. If our representative does not provide the contractor with these reports, our office should be notified. 2. Testing and observation procedures are, by their nature, specific to the work or area observed and 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 should not be considered as relieving the contractor's responsibility to properly compact the fill. 3. 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 our representative or office when such areas are ready for observation. 4. Density tests may be made on the surface material to receive fill, as considered warranted by this firm. GEOTEK GENERAL GRADING GUIDELINES APPENDIX E D•R•Horton Los Angeles Holding Company, Inc. Page E-2 Tract No. 33486, Lake Elsinore, Riverside County, California 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 tests should be made to evaluate the required compaction and moisture content is generally being obtained. 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 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 different source areas for materials. 7. Procedures for testing of fill slopes are as follows: a) Density tests should be taken periodically during grading on the flat surface of the fill, three to five feet horizontally from the face of the slope. b) 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 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 complete. Site Clearing I. 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 performed in advance of any grading in a specific area. 2. 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 should be aware of these efforts. Laborers may be required as root pickers. 3. Nonorganic debris or concrete may be placed in deeper fill areas provided the procedures used are observed and found acceptable by our representative. Treatment of Existing Ground I. Following site clearing, all surficial deposits of alluvium and colluvium as well as weathered or creep effected bedrock, should be removed unless otherwise specifically indicated in the text of this report. GEOTEK GENERAL GRADING GUIDELINES APPENDIX E D•R•Horton Los Angeles Holding Company, Inc. Page E-3 Tract No. 33486, Lake Elsinore, Riverside Count, California 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. 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. 4. Subsequent to removals, the natural ground should be processed to a depth of six inches, moistened to near optimum moisture conditions and compacted to fill standards. S. Exploratory back hoe or dozer trenches still remaining after site removal should be excavated and filled with compacted fill if they can be located. Fill Placement I. 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, 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 contractor should rework the fill until it is in accordance with the following: a) 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 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. b) 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. In most cases, the testing method is ASTM Test Designation D I SS7. 4. Rock fragments less than eight inches in diameter may be utilized in the fill, provided: a) They are not placed in concentrated pockets; b) 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. S. Rocks exceeding eight (8) inches in diameter should be taken off site, broken into smaller fragments, or placed in accordance with recommendations of this firm in areas designated suitable for rock disposal. On projects where significant large quantities of oversized materials are anticipated, alternate guidelines for placement may be included. If significant oversize materials are encountered during construction, these guidelines should be 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 'G, GEOTEK GENERAL GRADING GUIDELINES APPENDIX E D•R•Horton Los Angeles Holding Company, Inc. Page E-4 Tract No 33486 Lake Elsinore Riverside County California 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 I. 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 to the compacted core, or by direct compaction of the slope face with suitable equipment. 2. 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 results in trimming not exposing the compacted core and additional compaction after trimming may be necessary. 3. If fill slopes are built "at grade" using direct compaction methods, then the slope construction 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 built. 4. Corners and bends in slopes should have special attention during construction as these are the most difficult areas to obtain proper compaction. 5. Cut slopes should be cut to the finished surface. Excessive undercutting and smoothing of the face with fill may necessitate stabilization. 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 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. 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 to construction. We will offer comments based on our knowledge of site conditions and experience. I. 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 laboratory standard. Soil should be moisture conditioned prior to placing in the trench. ,G, GEOTEK GENERAL GRADING GUIDELINES APPENDIX E D•R•Horton Los Angeles Holding Company, Inc. Page E-5 Tract No. 33486, Lake Elsinore, Riverside County, California 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 typically limited to the following uses: a) shallow (12 + inches) under slab interior trenches and, b) as bedding in pipe zone. 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 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 I:I projection from the outside bottom edge of a footing, unless it is similar to the surrounding soil. S. 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 General Personnel safety is a primary concern on all job sites. The following summaries are safety considerations for use by all our employees on multi-employer construction sites. On ground personnel are at highest 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. 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 projects. 1. Safety Meetings: Our field personnel are directed to attend the contractor's regularly scheduled safety meetings. 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 when on site, the other is to be placed atop the spoil pile on all test pits. 'G, GEQTEK GENERAL GRADING GUIDELINES APPENDIX E D•R•Horton Los Angeles Holding Company, Inc. Page E-6 Tract No. 33486, Lake Elsinore, Riverside County, California In the event that the contractor's representative observes any of our personnel not following the above, we request that it be brought to the attention of our office. Test Pits Location, Orientation and Clearance The technician is responsible for selecting test pit locations. The primary concern is the technician's 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 locations following or behind the established traffic pattern, preferably 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. 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 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 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. TEST PIT SAFETY PLAN SIDE VIEW Test Pit Spoil pile 50 ft Zone of Traffic Direction Non-Encroachment Vehicle parked here Test Pit Spoil pile 100ftZoneof Non-Encroachment 50 ft Zone of Non-Encroachment PLAN VIEW GEOTEK GENERAL GRADING GUIDELINES APPENDIX E D•R•Horton Los Angeles Holding Company, Inc. Page E-7 Tract No. 33486, Lake Elsinore, Riverside CounV, California 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. Trench Safety It is the contractor's responsibility to provide safe access into trenches where compaction testing is 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; I. is 5 feet or deeper unless shored or laid back, 2. exit points or ladders are not provided, 3. displays any evidence of instability, has any loose rock or other debris which could fall into the trench, or 4. 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 G E O T E K GENERAL GRADING GUIDELINES APPENDIX E D•R•Horton Los Angeles Holding Company, Inc. Page E-8 Tract No. 33486 Lake Elsinore Riverside County California 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. GEOTEK