HS2 Tunnel Extension: Reducing the Environmental, Social and Economic Burden in Hillingdon
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HS2 Tunnel Extension: Reducing the Environmental, Social and Economic Burden in Hillingdon On behalf of London Borough of Hillingdon Document Control Sheet Project Name: HS2 in Colne Valley Project Ref: 30780/001 Report Title: Tunnel Feasibility Assessment Doc Ref: R01 Date: December 2014 Name Position Signature Date B Blaine Technical Lead BB C Edmonds Geology CE Prepared by: Dec 14 D Page Tunnelling DP S Ring Railway SR Reviewed by: S Witchalls Project Director SW Dec 14 Approved by: For and on behalf of Peter Brett Associates LLP Revision Date Description Prepared Reviewed Approved Peter Brett Associates LLP disclaims any responsibility to the Client and others in respect of any matters outside the scope of this report. This report has been prepared with reasonable skill, care and diligence within the terms of the Contract with the Client and generally in accordance with the appropriate ACE Agreement and taking account of the manpower, resources, investigations and testing devoted to it by agreement with the Client. This report is confidential to the Client and Peter Brett Associates LLP accepts no responsibility of whatsoever nature to third parties to whom this report or any part thereof is made known. Any such party relies upon the report at their own risk. © Peter Brett Associates LLP 2014 Office Address: Caversham Bridge House, Waterman Place, Reading, Berkshire RG1 8DN T: +44 (0)118 950 0761 F: +44 (0)118 959 7498 E: [email protected] HS2 in the Colne Valley ii Tunnel Feasibility Assessment Contents 1 Scope of Study ............................................................................................................................ 1 1.1 Introduction .................................................................................................................... 1 1.2 The Brief ........................................................................................................................ 3 2 Route Options .............................................................................................................................. 5 2.1 General constraints ....................................................................................................... 5 2.2 Colne Valley Tunnel ...................................................................................................... 8 3 Technical Constraints - Ground Conditions .......................................................................... 15 3.1 Introduction .................................................................................................................. 15 3.2 The HS2 Reference Route .......................................................................................... 15 3.3 Proposed tunnel route Options A and B. ..................................................................... 17 3.4 Groundwater impacts .................................................................................................. 18 4 Technical constraints - Rail ..................................................................................................... 21 4.1 Introduction .................................................................................................................. 21 4.2 Heathrow Spur and potential maintenance sidings ..................................................... 21 5 Technical Constraints – Tunnels ............................................................................................. 24 5.1 Introduction .................................................................................................................. 24 5.2 Tunnel Spoil ................................................................................................................. 24 6 Impact and Cost Estimates ...................................................................................................... 25 6.1 Introduction .................................................................................................................. 25 6.2 Significant Impacts – Construction .............................................................................. 25 6.3 Significant Impacts – Operations ................................................................................. 27 6.4 Cost estimates ............................................................................................................. 28 7 Other options ............................................................................................................................. 29 7.1 General ........................................................................................................................ 29 7.2 Westward extension of Northolt Tunnel ...................................................................... 29 7.3 Alignment running between Harefield and South Harefield ........................................ 29 7.4 Extend the Chilterns Tunnel to West Ruislip ............................................................... 29 7.5 Extend the Northolt Tunnel to West Hyde ................................................................... 29 7.6 Required Mitigation for Reference Route .................................................................... 30 8 Conclusions and Recommendations ...................................................................................... 32 8.1 Tunnel options ............................................................................................................. 32 8.2 Other mitigation ........................................................................................................... 32 Figures Figure 1.1: Locations of Key Features on HS2 Reference Route .......................................................... 2 Figure 2.1: Reference Alignment and associated features .................................................................... 7 Figure 2.2: Locations of Sustainable Placement Areas ......................................................................... 9 Figure 2.3: HS2 Reference Route ......................................................................................................... 14 Figure 2.4: Proposed Colne Valley Tunnel ............................................................................................ 14 Figure 3.1: Illustration of TBM types ...................................................................................................... 20 Figure 4.1: London facing turnouts ........................................................................................................ 22 Figure 4.2: Birmingham facing turnouts - Plan ...................................................................................... 22 HS2 in the Colne Valley iii Tunnel Feasibility Assessment Tables Table 2.1: Summary of key aspects of comparative routes ................................................................. 13 Table 6.1: Comparison of costs between HS2 and CVT Option B........................................................ 28 Table E1 : Cost Estimates for HS2 Reference Route and Colne Valley Tunnel Alternative ................... 6 Table E.2: Indicative Overview Programme ........................................................................................... 8 Appendices Appendix A Drawings Appendix B Delivering the Colne Valley Tunnel Appendix C Alignment and Track Maintenance through the Tunnels Appendix D Correspondence Appendix E Cost Estimate HS2 in the Colne Valley iv Tunnel Feasibility Assessment HS2 in the Colne Valley v Tunnel Feasibility Assessment 1 Scope of Study 1.1 Introduction 1.1.1 The government proposes to construct a high speed railway between London (Euston) and Birmingham (Curzon Street), known as HS2. The route has been the subject of consultation at defined stages over the past 3 years and culminating in a Hybrid Bill before Parliament. The Bill has received its Second Reading and will now be scrutinised by a Select Committee. 1.1.2 As part of its formal responses to the consultation over this period the London Borough of Hillingdon has made representations to place HS2 in a tunnel through the whole of the borough to minimise the construction and operational impacts, particularly given that the borough and its residents believe they will receive very little benefit from the line. 1.1.3 From central London, the proposed railway will run in tunnel for most of the urban areas, but will emerge at the surface route at Ickenham High Road in West Ruislip and travel at the surface in cuttings, on embankments and on a viaduct over the Colne Valley before entering the Chiltern Tunnel at its South Portal near the M25. The locations of the key features are identified on the Figure 1.1 below. 1.1.4 The emergence of the route at Ickenham High Road is the first section above ground after the proposed Old Oak Common station. The area west of Ickenham High Road has therefore been selected for a large scale construction operation that will subject the area to 10 years of significant construction impacts and permanently change the character and use of the tract of land along its corridor. 1.1.5 In addition to the construction impacts, the Environmental Statement prepared by HS2 confirms there are permanent adverse impacts from the operation of the surface route. Noise, landscape, ecology, the reduction of available agriculture and the loss of important recreational facilities will have lasting adverse impacts on the environment from direct loss, changes in character and severance of corridors connecting habitats and residents with no