NORTH DOWNS TUNNEL TECHNICAL OVERVIEW

Technical innovations, value engineering and integrated observational techniques led to estimated savings of $14 million on the North Downs Tunnel, a 3.2-km high-speed rail tunnel on Section 1 of the U.K.'s Channel Tunnel Rail Line. It is the only tunnel in the route to be built with New Austrian Tunneling Methods (NATM). It cross chalk beds up to 100 m. below the ground. Construction is five months ahead of schedule and substantially under budget. To account for geological variations along the route, the job was divided into eight principal design zones. Construction monitoring of the performance of the primary lining was a critical aspect of design verification in order to obtain real-time interpretation of ground conditions, lining deformation and stress buildup. Changes in the tunnel design included adoption of a flat invert for the majority of the tunnel. Excavation rates were excellent, especially where a surface planing miner was used to trim chalk in the invert section. Laser monitors and guides enabled an exceptionally accuracy. The article includes tables summarizing excavation rates and monitoring threshold levels, and figures showing tunnel design.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/0041414X
• Corporate Authors:

  Polygon Media Limited

  Tubs Hill House, London Road
  Sevenoaks, Kent TN13 1BY,   United Kingdom 
• Authors:
  • WARREN, C
• Publication Date: 2003-3

Language

• English

Media Info

• Features: Figures; Photos; References; Tables;
• Pagination: p. 36-39
• Serial:
  • Tunnels & Tunnelling International
  • Volume: 35
  • Issue Number: 3
  • Publisher: Progressive Media Markets, Ltd
  • ISSN: 0041-414X

Subject/Index Terms

• TRT Terms: Chalks; Construction scheduling; Cost effectiveness; Excavation and tunneling; Ground settlement; Shotcrete; Tunnel lining
• Geographic Terms: United Kingdom
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 00941519
• Record Type: Publication
• Source Agency: UC Berkeley Transportation Library
• Files: BTRIS, TRIS
• Created Date: May 1 2003 12:00AM