FOLKESTONE RELIEF DRAIN: FROM JACKING TO SEGMENTS IN THE SAME DRIVE

The scheme described will carry surface drain water from the Cheriton Channel Tunnel Terminal area under Folkestone to a sea outfall. It is believed to be the first time that a slurry shield has been converted from pipe jacking to performing a segmental lining in the same drive. Access was from four shafts, 9m to 38m deep, three of which required ground freezing. The possible conversion to segmental lining was considered in case ground conditions prevented pipe jacking. After good progress for some 250m of the 695m long, 2.1m internal diameter drive high jacking forces were experienced and segmental lining used. The special inner sleeve of the Crunchingmole shield allowed hydraulic rams, a double row of wire brush seals and a segment erector to be installed. Symmetrical lining was then installed without losing the protection of the machine's tail seal. The slurry treatment system is designed so that the pumped slurry circuit is virtually 'closed' with little make-up water necessary. Steering the Crunchingmole became more difficult in the changed mode of operation; this problem was overcome by using a reverse rotation facility to correct for wander. A 2.5m extension to the shield is expected to reduce steering problems. (TRRL)

  • Availability:
  • Corporate Authors:

    Morgan-Grampian (Construction Press) Limited

    Morgan-Grampian House, 30 Calderwood Street
    London SE18 6QH,   England 
  • Authors:
    • Jones, M
  • Publication Date: 1990-12

Language

  • English

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00617625
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Nov 30 1991 12:00AM