Publication Abstract

Proceedings - Fourth International Conference - Piling and Deep Foundations, 1991, Stresa, Italy, (DFI)

55 Channel Tunnel: Foundation Engineering at the UK Portal
J.C. Duggleby Transmanche Link, Balfour Beatty Construction Ltd, UK P.J. Avgherinos & A.J. Powderham Mott MacDonald Consulting Engineers, UK

This paper provides an overview of the design and construction for the cut and cover tunnels at the U.K. Portal of the Channel Tunnel. These major works, constructed in difficult ground conditions within an ancient landslip, cover an area of 130 x 30 m with a maximum excavation depth of 20 m. The need to maintain stability of the landslip was a major factor in the planning and excavation of the works. A carefully phased sequence of top-down construction, which minimized changes in overburden pressure, was adopted using contiguous bored pile walls. Control of ground movements and groundwater levels were essential requirements and deep internal piles were also used to limit heave. Emphasis was placed on the relationship between analysis, soil/structure interaction and construction methods. For this fast-track design and construct contract, close co-ordination between designers and constructors combined with effective monitoring permitted substantial reductions in temporary support works using the observational method.

 article #495; publication #37 (IC-1991-IT)