Appendix F Geology and Soils PRELIMINARY GEOTECHNICAL REPORT THE TRIANGLE SPECIFIC PLAN MURRIETA, CALIFORNIA Prepared For: GOLDEN TRIANGLE DEVELOPMENT, LLC One Better World Circle, Suite 300 Temecula, CA 92560 January 11, 2008 Project No. 601914-002 601914-002 January 11, 2008 TABLE OF CONTENTS Section Page 1.0 INTRODUCTION ............................................................................................................ 1 2.0 PROJECT DESCRIPTION ................................................................................................. 2 2.1 Site Description ..................................................................................................... 2 2.2 Proposed Development .......................................................................................... 2 3.0 INVESTIGATION AND LABORATORY TESTING.................................................................. 3 3.1 Research............................................................................................................... 3 3.2 Field Investigations................................................................................................ 3 3.2.1 Site Reconnaissance ....................................................................................... 3 3.2.2 Previous Field Investigation............................................................................. 3 3.3 Laboratory Testing ................................................................................................ 4 4.0 SUMMARY OF GEOTECHNICAL FINDINGS ........................................................................ 5 4.1 Site Constraints and Opportunities .......................................................................... 5 4.2 Regional Geology................................................................................................... 5 4.3 Site Geologic Units................................................................................................. 6 4.3.1 Undocumented Fill .......................................................................................... 6 4.3.2 Fill Placed under Leighton Observation and Testing............................................ 6 4.3.3 Fill Placed by Others........................................................................................ 7 4.3.4 Topsoil........................................................................................................... 7 4.3.5 Alluvium......................................................................................................... 7 4.3.6 Colluvium....................................................................................................... 7 4.3.7 Pauba Formation ............................................................................................ 8 4.4 Groundwater......................................................................................................... 8 4.5 Rippability............................................................................................................. 8 4.6 Faulting and Seismicity........................................................................................... 8 4.6.1 Seismic Design Parameters .............................................................................. 9 4.6.2 Ground Shaking............................................................................................ 10 4.6.3 Liquefaction ................................................................................................. 10 4.7 Hydroconsolidation and Subsidence....................................................................... 11 4.8 Evaluation of Photo Lineaments ........................................................................... 11 5.0 CONCLUSIONS AND RECOMMENDATIONS ..................................................................... 12 - i - 601914-002 January 11, 2008 5.1 General............................................................................................................... 12 5.2 Earthwork ........................................................................................................... 12 5.2.1 Site Preparation............................................................................................ 12 5.2.2 Removal and Recompaction........................................................................... 13 5.2.3 Structural Fills............................................................................................... 13 5.2.4 Utility Trenches............................................................................................. 14 5.2.5 Shrinkage and Bulking................................................................................... 14 5.3 Slope Stability ..................................................................................................... 15 5.4 Surface Drainage and Erosion ............................................................................... 16 5.5 Foundation Design............................................................................................... 16 5.6 Floor Slab Design................................................................................................. 17 5.7 Footing Setback................................................................................................... 18 5.8 Anticipated Settlement ......................................................................................... 18 5.9 Lateral Earth Pressures and Resistance.................................................................. 19 5.10 Geochemical Issues ............................................................................................. 20 5.10.1 Concrete .......................................................................................................... 20 5.10.2 Metallic Corrosion ............................................................................................. 20 5.11 Preliminary Pavement Section Design ....................................................................... 20 6.0 GEOTECHNICAL REVIEW .............................................................................................. 22 6.1 Plans and Specifications............................................................................................ 22 6.2 Construction Review................................................................................................. 22 7.0 Limitations .................................................................................................................. 23 Accompanying Figures, Plates and Appendices Figures Figure 1 - Site Location Map Rear of Text Figure 2 - Regional Fault Map Rear of Text Figure 3 - Retaining Wall Drainage Detail Rear of Text Plates Plate 1 – Geotechnical Map In Pocket Appendices Appendix A - References Appendix B - Logs of Borings/Trenches form Previous Site Investigations Appendix C - Laboratory Testing and Test Results, Previous Investigations Appendix D - General Earthwork and Grading Specifications Appendix E – AFSE, Important Information about Your Geotechnical Report - ii - 601914-002 January 11, 2008 1.0 INTRODUCTION This preliminary report is an updated report of the geotechnical conditions within the proposed Triangle Specific Plan site located south of Murrieta Hot Springs Road and between I-15 and I- 215 in the City of Murrieta, California. Our scope of services for this geotechnical update included the following: • Review of previously published geotechnical/geologic reports and maps prepared for this and adjacent sites, as well as other pertinent in-house and readily available documents regarding geotechnical/geological conditions at the subject site (Appendix A). • Site reconnaissance to observe and document the current surface conditions. • Provide seismic design parameters in accordance with the 2007 California Building Code. • Preparation of this report, compiling our previous exploratory borings and laboratory test data pertinent to this area and providing our preliminary geotechnical recommendations for foundation design and earthwork construction. - 1 - 601914-002 January 11, 2008 2.0 PROJECT DESCRIPTION 2.1 Site Description The proposed mixed use development, located south of Murrieta Hot Springs Road, between the I-15 and I-215 Freeways, encompasses approximately 64.3 acres, “Golden Triangle”, within the City of Murrieta, California, (see Figure 1, Site Location Map). Site topography slopes gently downward and away from the east central highpoint elevation toward the low- lying drainage crossing the southerly area and toward the west and I-15. Total relief on the site is on the order of 50 feet. The site was partially graded in 1998 for a previously planned entertainment center (RogersDale U.S.A.) under the observation and testing by Leighton and Associates, Inc. (Leighton, 1998c). The recent past grading resulted in the creation of several graded pads and a large (excavation depression) for a previously planned arena. Several large stockpiles associated with previous site grading are still present until this date. A minor natural drainage channel was also filled and a storm drain constructed in the northwest corner of the site. This work was performed under the observation and testing by others and documentation of this grading was not available for our review. Remnants of past improvements such as a residential trailer park, some building foundations and slabs, well pumps, and several power poles for an active power line remain on the site as well as several areas of stockpiled debris associated with