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Excavation Depth Techniques Study SGW-50712 Revision 0 Excavation Depth Techniques Study Prepared for the U.S. Department of Energy Assistant Secretary for Environmental Management Contractor for the U.S. Department of Energy under Contract DE-AC06-08RL 14788 Plateau Remediation Company P.O. Box 1600 Richland, Washington 99352 Approvedfor Public Release; FurtherDissemination Unlimited SGW-50712 Revision 0 Excavation Depth Techniques Study Date Published September 2011 Prepared for the U.S. Department of Energy Assistant Secretary for Environmental Management Contractor for the U.S. Department of Energy under Contract DE-AC06-08RL 14788 P.O. Box 1600 Richland, Washington oved for Public Release; Further Dissemination Unlimited SGW-50712 Revision 0 TRADEMARK DISCLAIMER Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof or its contractors or subcontractors. This report has been reproduced from the best available copy. Printed in the United States of America SGW-50712, REV. 0 Contents 1 Introduction ....................................................................................................................................... 1 Appendix A Excavation Depth Techniques Study ............................................................................................ A-i iii SGW-50712, REV. 0 1 Introduction Fluor Hanford, Inc. contracted Garry Struthers Associates, Inc. (GSAI) to review excavation and mining techniques that are efficient, safe, cost effective, protective of human health and the environment, and applicable to remediation of deep vadose zone contamination at two generic liquid waste disposal sites on the Central Plateau at the Hanford Site: a large crib and a reverse well. The final report prepared by GSAI, Excavation Depth Techniques Study, is provided as Appendix A in this report. The final report includes the specific objectives for the review, detailed information on the applicable excavation techniques, the conclusions of the study, and recommendations. 1 SGW-50712, REV. 0 Appendix A Excavation Depth Techniques Study A-i SGW-50712, REV. 0 FINAL REPORT Excavation Depth Techniques Study Professional Support Services Basic Ordering Agreement (PSSBOA) 28297 Task Order Release 3 PREPARED FOR FLUOR HANFORD, INC. RICHLAND, WASHINGTON July 6, 2007 Prepared by GARRY STRUTHERS ASSOCIATES, INC. 3150 Richards Road, Suite 200 Bellevue, WA 98005 A-1 SGW-50712, REV. 0 FINAL REPORT Excavation Depth Techniques Study for Fluor Hanford, Inc., Richland, Washington Professional Support Services Basic Ordering Agreement (PSSBOA) 28297 Task Order Release 3 July 6, 2007 Prepared by GARRY STRUTHERS ASSOCIATES, INC. 3150 Richards Road, Suite 200 Bellevue, WA 98005 A-2 SGW-50712, REV. 0 CONTENTS EXECUTIVE SUMMARY ............................................................................................................ ES-1 1. INTRODUCTION AND BACKGROUND.................................................................................. 1-1 1.1 Task Goal and Objectives................................................................................................. 1-1 1.2 Background ......................................................................................................................1-2 1.2.1 Large Crib................................................................................................................. 1-2 1.2.2 Reverse Well ............................................................................................................ 1-2 1.2.3 Geology .................................................................................................................... 1-3 1.2.4 Meteorology ............................................................................................................. 1-3 1.2.5 Contaminant Profiles................................................................................................ 1-3 1.2.6 Applicable Federal, State, and Fluor Requirements ................................................. 1-3 2. ASSUMPTIONS ..................................................................................................................... 2-1 3. EVALUATION FACTORS...................................................................................................... 3-1 3.1 Safety................................................................................................................................ 3-1 3.2 Protection of Human Health and the Environment .......................................................... 3-2 3.3 Minimization of Soil Material Removed.......................................................................... 3-2 3.4 Realistic Maximum Depth................................................................................................ 3-3 3.5 Cost-Effectiveness............................................................................................................ 3-3 4. EXCAVATION SUPPORT SYSTEMS...................................................................................... 4-1 4.1 Sloping and Benching ...................................................................................................... 4-1 4.2 Shoring and Shielding Systems........................................................................................ 4-1 4.2.1 Walls......................................................................................................................... 4-3 4.2.2 Piles .......................................................................................................................... 4-6 4.2.3 Shafts...................................................................................................................... 4-11 4.3 Ground Improvement ..................................................................................................... 4-14 4.3.1 Jet Grouting ............................................................................................................ 4-14 4.3.2 Permeation Grouting .............................................................................................. 4-14 Final Report-Excavation Depth Techniques Study i July 6, 2007 A-3 SGW-50712, REV. 0 4.3.3 Chemical Grouting ................................................................................................. 4-15 4.3.4 Ground Freezing..................................................................................................... 4-15 4.3.5 Soil Nailing............................................................................................................. 4-15 5. RESULTS OF VENDOR SURVEYS......................................................................................... 5-1 6. EXCAVATION TECHNIQUES APPLICABLE TO LARGE CRIB............................................. 6-1 6.1 Surface Mining ................................................................................................................. 6-1 6.2 Excavation Using a Structural Diaphragm Wall Soil Support System............................. 6-2 6.2.1 Scenario 1 – Excavation to 20 ft below Crib Bottom............................................... 6-5 6.2.2 Scenario 2 – Excavation to 220 ft Below Crib Bottom ............................................ 6-6 6.2.3 Scenario 3 – Excavation to 220 ft below Crib Bottom With In-Situ Cast Cement/Bentonite as Backfill Material .................................................................... 6-7 6.3 Excavation Using Large Diameter Access Shafts ............................................................ 6-7 6.3.1 Scenario 1-Use of Reinforced Concrete Circular Slurry Wall ................................. 6-7 6.3.2 Scenario 2-Straight Line Grid Orientation ............................................................... 6-8 6.3.3 Scenario 3 – Packed Sphere Orientation ................................................................ 6-11 6.4 Sequential Excavation Depths Using Benching and Vertical Soil Supports.................. 6-11 6.5 Top Down Excavation Using Soil Nails and Internal Brace System ............................. 6-13 7. EXCAVATION TECHNIQUES APPLICABLE TO REVERSE WELL ....................................... 7-1 7.1 Use of Auger Rig.............................................................................................................. 7-1 7.2 Use of Hydraulic Casing Oscillator and Hammer Grab ................................................... 7-1 7.3 Use of Circular Structural Diaphragm Wall Vs. Casing................................................... 7-3 7.4 Sequential Excavation to 200 ft BGS Using Corrugated Metal Pipe for Borehole Stabilization As Proposed by Anderson Drilling ............................................................. 7-3 8. PRELIMINARY COST ESTIMATES....................................................................................... 8-5 9. CONCLUSIONS..................................................................................................................... 9-1 10. RECOMMENDATIONS........................................................................................................ 10-1 Final Report-Excavation Depth Techniques Study ii July 6, 2007 A-4 SGW-50712, REV. 0 APPENDICES Appendix A (Map of Hanford Site and Area Designations) Appendix B (Vadose Zone Stratigraphy) Appendix C (216-B-46) Crib Contaminant Distribution Model of Contaminants of Potential Concern) Appendix
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