Appendix H Simi Valley Double Track and Platform Project Preliminary Geotechnical Design Report Draft EIR – Simi Valley Double Track and Platform Project Appendix H. Simi Valley Double Track and Platform Project Preliminary Geotechnical Design Report March 2021 Appendix H Simi Valley Double Track and Platform Project Preliminary Geotechnical Design Report Draft EIR – Simi Valley Double Track and Platform Project This page is intentionally blank. March 2021 CTO 48 SCORE Ventura Corridor Segment 1 - Simi Valley Double Track and Platform Preliminary Geotechnical Design Report SIMI VALLEY, CALIFORNIA January 2020 Prepared for: Southern California Regional Rail Authority (SCRRA) 2704 North Garey Avenue Pomona, CA 91767 Prepared by: HDR Engineering, Inc. 3230 El Camino Real, Suite 200 Irvine, CA 92602 January 31, 2020 METROLINK Mr. Colm McKenna 270 E. Bonita Ave Pomona, CA 91767 Attn: Mr. Colm McKenna, Senior Railroad Civil Engineer Dear Mr. McKenna, We are pleased to present this preliminary geotechnical design report summarizing the results of our geotechnical study for the proposed CTO 48 SCORE Ventura Corridor, Segment 1 - Simi Valley Double Track and Platform project located at Simi Valley, California. This report summarizes the work performed, data acquired, and our preliminary findings, evaluations, and recommendations for preliminary design of the project. We appreciate the opportunity to provide geotechnical services on this project and trust the information in this report meets the current project needs. If you have any questions regarding this report or if we may be of further assistance, please contact the undersigned. Respectfully submitted, HDR ENGINEERING, INC. Mario Flores, EIT Mahdi Khalilzad, PhD, PE Geotechnical Designer Senior Engineer - Geotechnical Reviewed by: Reviewed by: Jim Starick, PE Gary R. Goldman, PE, GE 2587 Senior Engineer - Geotechnical Geotechnical Section Manager Table of Contents Table of Contents Introduction .................................................................................................................... 1-1 1.1 Project Description ............................................................................................. 1-1 1.2 Project Location .................................................................................................. 1-1 1.3 Purpose and Scope ............................................................................................ 1-1 Geotechnical Investigation and Laboratory Testing ....................................................... 2-1 2.1 Subsurface Exploration ...................................................................................... 2-1 2.2 Geotechnical Laboratory Testing........................................................................ 2-2 Geology and Faulting ..................................................................................................... 3-1 3.1 Regional Geology ............................................................................................... 3-1 3.2 Site Geology ....................................................................................................... 3-1 3.3 Faulting and Seismicity ...................................................................................... 3-1 Site Conditions ............................................................................................................... 4-1 4.1 Existing Surface Conditions ............................................................................... 4-1 4.2 Subsurface Earth Materials ................................................................................ 4-1 4.3 Engineering Properties of Subsurface Materials ................................................ 4-1 4.3.1 Shear Strength .......................................................................................................... 4-1 4.3.2 Density and Compaction ........................................................................................... 4-2 4.3.3 Expansive Soils ......................................................................................................... 4-2 4.3.4 Corrosion Potential .................................................................................................... 4-2 4.3.5 Compressible Soils .................................................................................................... 4-3 4.4 Groundwater ....................................................................................................... 4-3 Geologic and Seismic Hazards ...................................................................................... 5-1 5.1 Seismic Hazards ................................................................................................ 5-1 5.1.1 Fault Rupture ............................................................................................................. 5-1 5.1.2 Liquefaction ............................................................................................................... 5-1 5.1.3 Seismically-Induced Settlements .............................................................................. 5-1 5.1.4 Lateral Spreading ...................................................................................................... 5-2 5.1.5 Seiches and Tsunamis .............................................................................................. 5-2 5.1.6 Earthquake-Induced Flooding ................................................................................... 5-2 5.2 Flooding .............................................................................................................. 5-2 5.3 Landslides .......................................................................................................... 5-2 5.4 Expansive/Collapsible Soils ............................................................................... 5-2 5.5 Subsidence ......................................................................................................... 5-2 Segment 1 - Simi Valley Double Track and Platform i Preliminary Geotechnical Design Report Table of Contents Preliminary Geotechnical Recommendations ................................................................ 6-1 6.1 Foundations and Bearing Capacity .................................................................... 6-1 6.1.1 Pedestrian Underpass Bearing Capacity .................................................................. 6-1 6.1.2 Minor Structures Bearing Capacity ............................................................................ 6-1 6.2 Seismicity and Preliminary Seismic Design Criteria ........................................... 6-1 6.3 Earthwork ........................................................................................................... 6-2 6.3.1 Site Preparation ......................................................................................................... 6-2 6.3.2 Overexcavation .......................................................................................................... 6-2 6.3.3 Engineered Fill ........................................................................................................... 6-4 6.3.4 Fill Material ................................................................................................................ 6-4 6.3.5 Expansive Soils Mitigation ......................................................................................... 6-4 6.4 Slope Geometry ................................................................................................. 6-5 6.5 Lateral Earth Pressures ...................................................................................... 6-5 6.6 Enviroblock Retaining wall ................................................................................. 6-6 6.7 Consolidation Settlements .................................................................................. 6-6 6.8 Pavement Design ............................................................................................... 6-7 6.9 Ballast and Sub-ballast ....................................................................................... 6-8 6.10 Trench Backfill .................................................................................................... 6-8 6.11 Corrosion Measures ........................................................................................... 6-9 Construction Considerations .......................................................................................... 7-1 7.1 Groundwater Control .......................................................................................... 7-1 7.2 Temporary Excavations and Shoring ................................................................. 7-1 7.3 Additional Geotechnical Services ....................................................................... 7-1 Limitations ...................................................................................................................... 8-1 References ..................................................................................................................... 9-1 List of Tables Table 2-1. Subsurface Exploration Information .............................................................. 2-1 Table 3-1. Nearby Faults ................................................................................................ 3-2 Table 4-1. Preliminary Soil Design Parameters ............................................................. 4-2 Table 4-2. Summary of Corrosion Test Results ............................................................