Ground Investigation Chester Road, Stonnall Walsall
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GROUND INVESTIGATION CHESTER ROAD, STONNALL WALSALL, WS9 9DE Report No: 17291/1 Date: November 2017 Prepared for RESTFUL HOMES GROUP PROJECT QUALITY ASSURANCE INFORMATION SHEET GROUND INVESTIGATION CHESTER ROAD, STONNALL WALSALL, WS9 9DE Report Status: Final Report No: 17291/1 Issue Date: November 2017 Prepared For: Restful Homes Group 5 Manor Road WALLINGTON Surrey SM6 0BU Prepared By: Georisk Management Limited Summit Point Summit Crescent Industrial Estate Smethwick BIRMINGHAM B66 1BT Telephone: 0121 553 4044 Written by: Martina Young Title: Principal Geoenvironmental Engineer Contact: martina.young@georisk‐uk.com Reviewed by: Mark Gill Title: Director Contact: mark.gill@georisk‐uk.com TABLE OF CONTENTS EXECUTIVE SUMMARY FOREWORD 1. INTRODUCTION ........................................................................................................................................... 1 2. INFORMATION SOURCES .............................................................................................................................. 1 3. REFERENCE SOURCES ................................................................................................................................... 2 4. THE SITE ...................................................................................................................................................... 2 5. SITE HISTORY ............................................................................................................................................... 3 6. GEOENVIRONMENTAL SETTING .................................................................................................................... 4 6.1 GEOLOGY AND MINING .............................................................................................................................. 4 6.2 HYDROLOGY ........................................................................................................................................... 5 6.3 HYDROGEOLOGY ...................................................................................................................................... 5 6.4 WASTE MANAGEMENT .............................................................................................................................. 5 6.5 POLLUTION ............................................................................................................................................. 5 6.6 RADON ................................................................................................................................................. 6 6.7 SUPPORTING INFORMATION ........................................................................................................................ 6 7. INITIAL CONCEPTUAL MODEL AND INVESTIGATION STRATEGY ....................................................................... 6 7.1 ENVIRONMENTAL SETTING .......................................................................................................................... 6 7.2 INITIAL CONCEPTUAL MODEL AND PRELIMINARY RISK ASSESSMENT ......................................................................... 7 7.3 INVESTIGATION STRATEGY ......................................................................................................................... 10 8. FIELDWORK, MONITORING AND LABORATORY TESTING .............................................................................. 10 8.1 FIELDWORK .......................................................................................................................................... 10 8.2 SOIL‐GAS AND GROUNDWATER MONITORING ................................................................................................ 11 8.3 CHEMICAL TESTING ................................................................................................................................. 11 8.4 GEOTECHNICAL TESTING ........................................................................................................................... 11 9. GROUND AND GROUNDWATER CONDITIONS .............................................................................................. 12 9.1 GENERAL ............................................................................................................................................. 12 9.2 TOPSOIL .............................................................................................................................................. 12 9.3 MADE GROUND ..................................................................................................................................... 12 9.4 CHESTER FORMATION .............................................................................................................................. 12 9.5 EVIDENCE OF CONTAMINATION .................................................................................................................. 13 9.6 GROUNDWATER ..................................................................................................................................... 13 9.7 SOIL‐GAS ............................................................................................................................................. 13 9.8 DEVELOPMENT OF CONCEPTUAL MODEL ....................................................................................................... 13 10. HUMAN HEALTH RISK ASSESSMENT ............................................................................................................ 13 10.1 GENERAL ............................................................................................................................................. 13 10.2 HUMAN HEALTH RISK ASSESSMENT DESIGN ................................................................................................... 14 10.3 GENERIC QUANTITATIVE HUMAN HEALTH RISK ASSESSMENT ............................................................................... 15 10.4 MATERIAL CLASSIFICATION ........................................................................................................................ 16 10.5 RISK EVALUATION ................................................................................................................................... 16 11. SOIL‐GAS RISK ASSESSMENT ....................................................................................................................... 17 11.1 RISK ASSESSMENT PROTOCOL .................................................................................................................... 17 11.2 MONITORING RESULTS ............................................................................................................................ 17 11.3 RISK ASSESSMENT AND PROTECTION STRATEGY RECOMMENDATIONS ..................................................................... 18 12. ENGINEERING CONSIDERATIONS ................................................................................................................ 18 12.1 PREPARATORY WORKS ............................................................................................................................. 1 8 12.2 FOUNDATION DESIGN .............................................................................................................................. 19 12.3 FLOOR SLABS ........................................................................................................................................ 19 12.4 ROAD/PAVEMENT DESIGN ........................................................................................................................ 19 12.5 BURIED CONCRETE REQUIREMENTS ............................................................................................................. 20 12.6 EXCAVATIONS ....................................................................................................................................... 20 12.7 SOAKAWAYS ......................................................................................................................................... 20 TABLES Table No. Table Title 1 Summary of Historical Land Usage 2 Coal Mining Risk Assessment 3 Risk Matrix 4 Pollutant Linkages 5 Investigation Strategy 6 Summary of SPT Results in Made Ground 7 Summary of SPT Results in Chester Formation 8 Human Health Risk Assessment Criteria 9 Summary of Chemical Test Results 10 Summary of Soil‐Gas Monitoring Results 11 Summary of Infiltration Test Results APPENDICES APPENDIX A DRAWINGS Drawing No. Drawing Title 3378‐06 Rev. A ‘Proposed Care Home’ by Robothams Architects dated November 2016 17291/1 Exploratory Hole Location Plan APPENDIX B HISTORICAL MAP EXTRACTS APPENDIX C COAL AUTHORITY MINING REPORT APPENDIX D EXPLORATORY HOLE RECORDS APPENDIX E INFILTRATION TEST RESULTS APPENDIX F SOIL‐GAS AND GROUNDWATER MONITORING RESULTS APPENDIX G CHEMICAL TEST RESULTS APPENDIX H ENVIROCHECK SUPPORTING INFORMATION EXECUTIVE SUMMARY GROUND INVESTIGATION CHESTER ROAD, STONNALL WALSALL, WS9 9DE Georisk Management Limited has been commissioned to carry out a ground investigation of the above site, which is to be redeveloped with construction of a residential care home facility. Phase I Comments The Site The site is situated off Chester Road in Stonnall near Walsall, West Midlands and can be located approximately by National Grid Reference 406410, 303430. It is an irregular shaped plot of land covering an area of approximately 0.8 hectares of a former pit/quarry. The site was densely vegetated until recently when it was cleared in preparation