The first segmental linings of tunnels, in the UK in the 1860s, were made of cast iron. Precast concrete was not used for tunnel linings until 1947. Linings then developed to suit ground conditions. By the 1970s, they were mainly of four types: (1) standard bolted linings; (2) smoothbore grouted linings; (3) expanded linings; and (4) expanded grouted linings. Although designs using these methods are still relevant today, a steady flow of innovations has transformed the performance of concrete linings. They include mechanically jointed steel connections, the introduction of tapered rings and gaskets, bolted smoothbore designs with gaskets and curved bolts, and six-segment smoothbore trapezoidal rings. Several possible future developments are being investigated. Several companies have developed non-ferrous circle joint connectors to overcome problems with connecting curved bolts. The latest innovation here is the locking nylon dowel, which is self-aligning, high-strength, durable, non-corrodable, and suitable for use with compression gaskets. There have been better mix designs and reinforcements to improve concrete strength and durability. Other innovations include the use of monofilament polypropylene fibres in a concrete mix to improve fire resistance, and cast plastic lifting sockets to prevent grout ingress.

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  • Corporate Authors:

    Miller Freeman

    Calderwood Street
    London,   United Kingdom  SE18 6QH
  • Authors:
  • Publication Date: 1999-1


  • English

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Filing Info

  • Accession Number: 00767205
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Aug 6 1999 12:00AM