Sivertown Tunnel Tunnel Engineering
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TRANSPORT FOR LONDON RIVER CROSSINGS: SILVERTOWN TUNNEL SUPPORTING TECHNICAL DOCUMENTATION This report is part of a wider FURTHER DEVELOPMENT suite of documents which OF TUNNEL ENGINEERING outline our approach to traffic, environmental, optioneering Mott MacDonald and engineering disciplines, July 2013 amongst others. We would like to know if you have any This report builds upon previous studies comments on our approach to to develop the bored tunnel concept and this work. To give us your addresses design development of key views, please respond to our areas. consultation at www.tfl.gov.uk/silvertown- tunnel Please note that consultation on the Silvertown Tunnel is running from October – December 2014. Silvertown Tunnel Further development of Tunnel Engineering 298348/MNC/TUN/002 July 2013 Transport for London Silvertown298348 MNC TunnelTUN 002 A Document3 15 April 2013 Further development of Tunnel Engineering 298348/MNC/TUN/002 July 2013 Transport for London Mott MacDonald, Mott MacDonald House, 8-10 Sydenham Road, Croydon CR0 2EE, United Kingdom t +44 (0)20 8774 2000 f +44 (0)20 8681 5706, W www.mottmac.com Silvertown Tunnel Content Chapter Title Page Executive Summary i 1. Introduction 1 1.1 Background ________________________________________________________________________ 1 1.2 Scope of this report __________________________________________________________________ 1 1.3 Report structure ____________________________________________________________________ 1 1.4 Contributors _______________________________________________________________________ 1 2. Project Constraints 2 2.1 Introduction ________________________________________________________________________ 2 2.2 Land Use, Ownership and Greenwich Peninsula Development ________________________________ 2 2.3 Emirates Air Line (London Cable Car) ___________________________________________________ 2 2.4 Gas Works Foundations and Existing Gas Holder __________________________________________ 4 2.5 River Flood Walls ___________________________________________________________________ 4 2.6 Land Ownership ____________________________________________________________________ 4 2.7 Connections to A102 Blackwall Approach ________________________________________________ 4 2.8 DLR Thames Wharf Station ___________________________________________________________ 4 2.9 Jubilee Line Future Extension __________________________________________________________ 4 2.10 Royal Victoria Dock Western Entrance ___________________________________________________ 5 2.11 DLR Viaduct _______________________________________________________________________ 5 2.12 Royal Victoria Dock Drainage __________________________________________________________ 6 3. Geotechnical 7 3.1 Introduction ________________________________________________________________________ 7 3.2 Ground and Groundwater Conditions ____________________________________________________ 7 3.2.1 Topography ________________________________________________________________________ 7 3.2.2 Regional Geology ___________________________________________________________________ 7 3.2.3 Scour Hollows ______________________________________________________________________ 8 3.2.4 Hydrogeology _____________________________________________________________________ 10 3.2.5 Expected Ground Conditions _________________________________________________________ 10 3.2.5.1 Made Ground _____________________________________________________________________ 12 3.2.5.2 Alluvium _________________________________________________________________________ 12 3.2.5.3 River Terrace Deposits ______________________________________________________________ 13 3.2.5.4 London Clay ______________________________________________________________________ 13 3.2.5.5 Harwich Formation _________________________________________________________________ 15 3.2.5.6 Lambeth Group ____________________________________________________________________ 15 3.2.5.7 Thanet Sand ______________________________________________________________________ 16 3.2.5.8 Upper Cretaceous Chalk _____________________________________________________________ 16 3.3 Additional Ground Investigation _______________________________________________________ 17 3.4 Unexploded Ordnance (UXO) _________________________________________________________ 17 3.5 Geotechnical Implications for Bored Tunnel ______________________________________________ 18 3.5.1 TBM Selection & Specification ________________________________________________________ 18 3.5.2 Cross Passages ___________________________________________________________________ 18 3.5.3 Low Point Sump ___________________________________________________________________ 19 3.5.4 Cut and Cover _____________________________________________________________________ 19 298348/MNC/TUN/002 17 July 2013 Silvertown Tunnel 3.5.5 Retained Cut Ramps ________________________________________________________________ 19 4. Tunnel and Civil Engineering Considerations 20 4.1 Introduction _______________________________________________________________________ 20 4.2 Alignment Development _____________________________________________________________ 21 4.3 Design Criteria ____________________________________________________________________ 21 4.3.1 Design Speed and Stopping Site Distance _______________________________________________ 21 4.3.2 Super Elevation ____________________________________________________________________ 21 4.3.3 Gradient _________________________________________________________________________ 22 4.4 Minimum Alignment Plan Radius ______________________________________________________ 22 4.5 Minimum Tunnel Crown Cover ________________________________________________________ 22 4.6 Tunnel Clearances and Diameter ______________________________________________________ 22 4.6.1 Vertically _________________________________________________________________________ 22 4.6.2 Horizontally _______________________________________________________________________ 23 4.7 Tunnel Linings _____________________________________________________________________ 24 4.8 Tunnel Ventilation __________________________________________________________________ 25 4.9 Cladding considerations _____________________________________________________________ 25 4.10 Phase I Settlement Assessment _______________________________________________________ 26 4.10.1 General __________________________________________________________________________ 26 4.10.2 Potential Damage Assessment Procedure _______________________________________________ 26 4.10.3 Results of the Stage 1 Potential Damage Assessment ______________________________________ 29 4.10.4 Preliminary Mitigation Measures _______________________________________________________ 30 4.11 Cross-passages ___________________________________________________________________ 30 4.12 Service Diversions _________________________________________________________________ 31 5. Environmental Issues 32 5.1 Introduction _______________________________________________________________________ 32 5.2 Flood Risk ________________________________________________________________________ 32 5.3 Ground Contamination ______________________________________________________________ 32 5.3.1 Potential Contaminants of Concern ____________________________________________________ 34 5.3.2 Gas Holder Area Considerations ______________________________________________________ 35 5.3.2.1 General __________________________________________________________________________ 35 5.3.2.2 COMAH designation ________________________________________________________________ 35 5.3.2.3 Land contamination _________________________________________________________________ 37 5.3.2.4 Development of scheme in this area ____________________________________________________ 38 5.3.3 Potential for ground contamination at tunnel depth _________________________________________ 40 5.4 Waste Management ________________________________________________________________ 41 5.5 Air Quality ________________________________________________________________________ 41 5.6 Archaeology ______________________________________________________________________ 42 5.7 Biodiversity _______________________________________________________________________ 43 5.8 Heritage _________________________________________________________________________ 44 5.9 Landscape & Townscape ____________________________________________________________ 44 5.10 Noise & Vibration __________________________________________________________________ 45 5.11 Sustainability ______________________________________________________________________ 46 6. Fire Life Safety 48 6.1 Introduction _______________________________________________________________________ 48 6.2 Design Criteria ____________________________________________________________________ 48 6.3 Consultations with London Fire Brigade _________________________________________________ 49 298348/MNC/TUN/002 17 July 2013 Silvertown Tunnel 6.4 Green Wave Traffic Plan _____________________________________________________________ 51 6.5 Design Fire Size ___________________________________________________________________ 52 6.5.1 Range of Vehicle Fire Sizes __________________________________________________________ 52 6.5.2 Summary of practices adopted in different countries _______________________________________ 52 6.5.3 Comparison with selected UK tunnels __________________________________________________ 53 6.5.4 Recommended Fire Size for Ventilation Design ___________________________________________ 54 6.5.5