Channel rail tunnel gets underway: Smith, M World TunnlgV1, N1, March 1988, P10–24

Abstract

This article describes the construction of the channel tunnel, now being built by the eurotunnel consortium in collaboration with the TRANS manche link (tml) consortium of British and French companies. Two previous attempts to build the tunnel were made in 1880 and 1975 but soon abandoned. On 12 February 1986, the new project was launched when the British and French governments signed the channel fixed link treaty. The tunnel is scheduled to be fully operational on 15 may 1993; its estimated cost is 4.7 billion after interest payments and inflation, but the total money raised and available is 6 billion. The tunnel will have three bores: twin rail tunnels of about 8.5 km excavated diameter and a central service tunnel of about 5.7 m excavated diameter; cross-passages will link these tunnels at 370 m intervals. There will be two large cross-over sections of up to 14 m diameter, to link the main tunnels and allow rail operations to continue if a section of tunnel is closed temporarily. The total length of each tunnel will be 52 km between the terminals at cheriton, near Dover, and coquelles, near calais, of which about 40 km will be under the sea. The undersea tunnels will be driven predominantly within a chalk marl bed which is easy to bore at high speed. The article gives details of the tunnel design and alignment, tunnel boring machines, ancillary equipment and facilities, spoil handling and disposal, and ancillary operations. Finally, it discusses some of the potential problems.