TRANSPORTATION AGENCY FOR MONTEREY COUNTY GEOTECHNICAL EVALUATION REPORT FOR THE MONTEREY PENINSULA LIGHT RAIL PROJECT November 16, 2010 GEOTECHNICAL EVALUATION REPORT FOR CONCEPTUAL ENGINEERING PHASE MONTEREY PENINSULA LIGHT RAIL PROJECT TRANSPORTATION AGENCY FOR MONTEREY COUNTY (TAMC) MONTEREY COUNTY, CALIFORNIA November 16, 2010 Copyright 2010 Kleinfelder All Rights Reserved Unauthorized use or copying of this document is strictly prohibited by anyone other than the client for the specific project. 109205/GEOL (SAL10R205)/es Page i of v November 16, 2010 © 2010 Kleinfelder TABLE OF CONTENTS 1 INTRODUCTION .................................................................................................. 1 2 PROJECT DESCRIPTION ................................................................................... 3 2.1 GENERAL ................................................................................................. 3 2.2 SUMMARY OF KEY PROJECT FEATURES ............................................ 4 2.2.1 Track Restoration or Replacement, and Street/Grade Crossings ... 4 2.2.2 Bridges / Track Structures ............................................................... 5 2.2.3 Passenger Stations / Stops ............................................................. 6 2.2.4 Maintenance Facility and Operations Center .................................. 7 2.2.5 Recreation Trail Restoration ........................................................... 8 2.3 ENGINEERING DESIGN STANDARDS .................................................... 9 3 COMPILATION AND REVIEW OF AVAILABLE GEOLOGIC AND GEOTECHNICAL DATA SOURCES ................................................................. 10 4 GEOLOGIC AND GEOTECHNICAL RECONNAISSANCE ............................... 12 5 GENERAL GEOLOGIC CONDITIONS .............................................................. 14 5.1 REGIONAL GEOLOGIC SETTING ......................................................... 14 5.2 SEISMIC SETTING AND HISTORICAL SEISMICITY ............................. 15 5.3 HISTORICAL SEISMICITY ...................................................................... 18 5.4 HYDROGEOLOGY AND GROUNDWATER ........................................... 18 5.5 ALIGNMENT GEOLOGIC CONDITIONS ................................................ 19 6 GEOLOGIC AND SEISMIC HAZARDS ............................................................. 22 6.1 FAULTING AND GROUND SURFACE RUPTURE................................. 22 6.2 EARTHQUAKE GROUND MOTIONS ..................................................... 23 6.3 LIQUEFACTION, LATERAL SPREADING, AND LURCHING ............... 23 6.4 TSUNAMI, SEICHE, AND FLOODING .................................................... 24 6.5 LANDSLIDES AND SLOPE INSTABILITY ............................................. 25 6.6 VOLCANIC ERUPTIONS ........................................................................ 25 6.7 EROSION, SEDIMENTATION, AND SCOUR ......................................... 25 6.8 COMPRESSIBLE SOILS ........................................................................ 26 6.9 EXPANSIVE SOILS................................................................................. 26 6.10 SEA LEVEL RISE AND COASTAL RECESSION .................................. 27 7 DESIGN CONSIDERATIONS FOR THE CONCEPTUAL ENGINEERING PHASE ............................................................................................................... 28 7.1 IMPACT OF IDENTIFIED GEOLOGIC AND SEISMIC HAZARDS ......... 28 7.1.1 Faulting and Ground Surface Rupture .......................................... 28 7.1.2 Earthquake Ground Motions ......................................................... 28 7.1.2.1. AREMA Seismic Parameters for Conceptual Design ....... 28 7.1.2.2. 2007 CBC Seismic Parameters for Conceptual Design ... 31 7.1.3 Liquefaction, Lateral Spreading, and Lurching .............................. 32 7.1.4 Tsunami, Seiche, and Flooding ..................................................... 33 109205/GEOL (SAL10R205)/es Page iii of v November 16, 2010 © 2010 Kleinfelder 7.1.5 Landslides and Slope Instability .................................................... 33 7.1.6 Volcanic Eruptions ........................................................................ 33 7.1.7 Erosion, Sedimentation, and Scour ............................................... 34 7.1.8 Compressible Soils ....................................................................... 34 7.1.9 Expansive Soils ............................................................................. 34 7.1.10 Sea Level Rise and Coastal Recession ........................................ 35 7.2 POTENTIAL MITIGATION ALTERNATIVES FOR GEOLOGIC AND SEISMIC HAZARDS ................................................................................ 35 7.2.1 Faulting and Ground Surface Rupture .......................................... 35 7.2.2 Earthquake Ground Motions ......................................................... 35 7.2.3 Liquefaction, Lateral Spreading and Lurching ............................... 36 7.2.4 Tsunami, Seiche, and Flooding ..................................................... 36 7.2.5 Landslides and Slope Instability .................................................... 36 7.2.6 Erosion, Sedimentation and Scour ................................................ 37 7.2.7 Compressible Soils ....................................................................... 37 7.2.8 Expansive Soil ............................................................................... 37 7.2.9 Sea Level Rise and Coastal Recession ........................................ 38 8 GEOTECHNICAL EVALUATION AND RECOMMENDATIONS FOR CONCEPTUAL DESIGN PHASE ....................................................................... 39 8.1 EMBANKMENTS AND TRACK SECTIONS ........................................... 39 8.1.1 Roadbed Subgrade ....................................................................... 41 8.1.2 Sub-Ballast .................................................................................... 43 8.1.3 Ballast ........................................................................................... 43 8.1.4 General Engineered Fill ................................................................ 45 8.1.5 Material Borrow Sources ............................................................... 46 8.2 TRACKWAY BRIDGES AND STRUCTURES ........................................ 46 8.2.1 Recommended Foundations for Bridge Structures ....................... 48 8.2.2 Retaining Walls ............................................................................. 50 8.3 PASSENGER STATIONS, AND MAINTENANCE FACILTY BUILDING 53 8.3.1 Foundations .................................................................................. 53 8.3.2 Slabs-on-Grade – General ............................................................ 54 8.3.3 Interior Concrete Slabs ................................................................. 55 8.3.4 Exterior Concrete Slabs ................................................................ 56 8.4 DRAINAGE AND GROUNDWATER ....................................................... 57 8.4.1 Surface Drainage .......................................................................... 57 8.4.2 Sub-Surface Groundwater Considerations .................................... 59 8.5 PAVEMENT RECOMMENDATIONS FOR CONCEPTUAL DESIGN...... 60 8.6 EXPANSIVE SOILS – RECOMMENDATIONS FOR CONCEPTUAL DESIGN ................................................................................................... 67 8.7 CORROSIVE SOILS – RECOMMENDATIONS FOR CONCEPTUAL DESIGN ................................................................................................... 68 8.8 RECOMMENDATIONS FOR FUTURE GEOLOGIC AND SEISMIC HAZARD EVALUATION INVESTIGATIONS .......................................... 69 8.9 PRELIMINARY RECOMMENDATIONS FOR FUTURE SUBSURFACE EXPLORATION PROGRAM ................................................................... 70 109205/GEOL (SAL10R205)/es Page iv of v November 16, 2010 © 2010 Kleinfelder 9 LIMITATIONS ..................................................................................................... 71 10 REFERENCES ................................................................................................... 72 PLATES Plate 1 Alignment Location Plate 2 Geologic Map Plate 3 Regional Fault Map Plate 4 Liquefaction Susceptibility Map Plate 5 Tsunami Inundation Map (Seaside Quadrangle) Plate 6 Tsunami Inundation Map (Marina Quadrangle) Plate 7 Soil Erosion Map 109205/GEOL (SAL10R205)/es Page v of v November 16, 2010 © 2010 Kleinfelder 1 INTRODUCTION This report presents the results of Kleinfelder’s Geotechnical and Geologic evaluation in support of the conceptual engineering phase for the Monterey Peninsula Light Rail Project along the existing Monterey Branch Line (MBL) planned by the Transportation Agency for Monterey County (TAMC). Kleinfelder is a subconsultant to Parsons that is leading the project in preparation of conceptual engineering (approximate 10 to 20% level of design completion) studies and cost estimates to add ‘definition’ to the project for TAMC. This report was revised in November 2010 to include updated project description information and address review comments provided by Parsons’ planning and design staff for the project. The primary engineering objectives of the Parsons team for the conceptual design phase include (1) defining the major construction elements and to update the project cost estimates