This article describes the construction of the UK undersea crossover cavern in the Channel Tunnel, which is 7km from the English Coast. The depth of the crossover was carefully optimised, to give about 36m cover between the top of the excavation and the seabed. The large crossover cavern was excavated from the undersea chalk strata. Its size was determined by: (1) the clearances needed for the shuttle trains; (2) the trackwork geometry for the 60kph crossing between tracks; (3) design requirements for the structure to support ground and water loads. It is 156m long, 18m wide, and 9.5m high above rail level; allowing for construction tolerance and thicknesses of linings, the excavated cross section is 21.2m wide and 15.4m high. The New Austrian Tunnelling Method was used to excavate the cavern and its associated construction access adits. The cavern was constructed from the service tunnel before the running tunnel drives reached the crossover location, and the service tunnel was diverted, enlarged and located at a lower level in its neighbourhood. Due to its size, the cavern was excavated in several successive stages, and the article describes these briefly. (TRRL)

  • Availability:
  • Corporate Authors:

    Mining Journal Limited

    60 Worship Street
    London EC2A 2HD,   England 
  • Publication Date: 1990-10

Media Info

  • Pagination: p. 338,341,3
  • Serial:
    • Volume: 3
    • Issue Number: 5
    • ISSN: 0956-8700

Subject/Index Terms

Filing Info

  • Accession Number: 00620065
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Mar 31 1992 12:00AM