GROUND CONDITONS OF THE BERMONDSEY AREA OF LONDON: A GEOTECHNICAL REPORT FOR PACKAGE 4 OF THE JUBILEE LINE EXTENSION Student No: 701890 NOVEMBER 21, 2016 UNIVERSITY OF PORTSMOUTH Contents 1.0 INTRODUCTION ......................................................................................................................................... 1 2.0 THE SITE .................................................................................................................................................... 1 2.1 Topography ........................................................................................................................................... 1 2.2 Geology ................................................................................................................................................. 2 2.2.1 Stratigraphy ................................................................................................................................... 2 2.2.2 Groundwater ................................................................................................................................. 3 2.2.3 Made Ground ................................................................................................................................ 3 2.2.4 Alluvium ......................................................................................................................................... 3 2.2.5 Kempton Park Gravel Member ...................................................................................................... 3 2.2.6 Thames Group ............................................................................................................................... 4 2.2.7 Lambeth Group .............................................................................................................................. 4 2.2.8 Thanet Sand Formation ................................................................................................................. 5 2.2.9. Upper Chalk Formation ................................................................................................................ 5 2.3 Potential Ground Hazards ..................................................................................................................... 5 2.3.1 Groundwater levels ....................................................................................................................... 5 2.3.2 Seepage and Chemical Damage..................................................................................................... 6 2.3.3 Subsidence ..................................................................................................................................... 6 3.0 GROUND INVESTIGATION ......................................................................................................................... 6 3.1 General ................................................................................................................................................. 6 3.2 Boreholes .............................................................................................................................................. 6 3.3 In Situ Testing ....................................................................................................................................... 7 3.4 Installations........................................................................................................................................... 7 3.5 Sampling ............................................................................................................................................... 7 3.6 Laboratory Testing ................................................................................................................................ 8 3.7 Groundwater Monitoring ..................................................................................................................... 8 4.0 GROUND CONDITIONS .............................................................................................................................. 9 4.1 Stratigraphy .......................................................................................................................................... 9 4.2 Groundwater Conditions .................................................................................................................... 10 4.3. Results of the Laboratory and In Situ Testing. ................................................................................... 10 4.4 Geotechnical Characterisation ........................................................................................................... 10 4.4.1 Made Ground .............................................................................................................................. 11 4.4.2 Alluvium ....................................................................................................................................... 11 4.4.3 Kempton Park Gravel Member .................................................................................................... 12 4.4.4 London Clay ................................................................................................................................. 13 4.4.5 Blackheath Beds .......................................................................................................................... 14 4.4.6 Upper Shelly Clay ......................................................................................................................... 14 4.4.7 Upper Mottled Clay ..................................................................................................................... 15 4.4.8 Laminated Beds ........................................................................................................................... 16 4.4.9 Lower Shelly Clay ......................................................................................................................... 17 4.4.10 Lower Mottled Clay ................................................................................................................... 18 4.3.11 Pebble Bed ................................................................................................................................. 18 4.4.12 Glauconitic Sands ...................................................................................................................... 19 4.4.13 Thanet Bed ................................................................................................................................ 20 4.4.14 Bullhead Bed .............................................................................................................................. 21 4.4.15 Upper Chalk ............................................................................................................................... 21 5.0 CONCLUSION ........................................................................................................................................... 22 6.0 REFERENCES ............................................................................................................................................ 23 APPENDIX 1 – Engineering Descriptions ....................................................................................................... 33 List of Figures 1 Site Location Map ...................................................................................................................................... 24 2 Borehole Location Map .............................................................................................................................. 25 3 Geological Map .......................................................................................................................................... 26 4 Geological Cross Section ............................................................................................................................ 27 5 Standard Penetration Test vs Level ........................................................................................................... 28 6 Plasticity Index Chart ................................................................................................................................. 29 7 Moisture Content vs Level ......................................................................................................................... 30 8 Undrained Shear Strength vs Level ............................................................................................................ 31 9 pH vs Level ................................................................................................................................................. 32 List of Tables 1 A summary of the geological strata of the London Basin ............................................................................ 2 2 A summary of the groundwater piezometer data ....................................................................................... 8 3 A summary of the soil succession beneath the site ..................................................................................... 9 4 Summary of geotechnical properties for Made Ground ............................................................................ 11 5 Index test summary for Made Ground ...................................................................................................... 11 6 Summary of geotechnical properties for Alluvium ...................................................................................