The erection is described of precast concrete tunnel lining rings designed so that their diameter and hoop thrust could be controlled when they were used as an expanded lining. The adjustment also allowed the same rings to be expanded inside a shield, where they were locked together, the lining standing without lateral support from the ground or the use of former rings. The external cavity was filled with grout, as in the construction of bolted rings. Both modes of use produced a smooth bore tunnel. The rings, which consisted of wedge-blocks differed from the conventional form. For erection as a tied and grouted ring two holes were formed in each block, parallel with the longitudinal axis of the tunnel, and positioned so that the adjacent holes on either side of the cross joint were a constant distance apart. For the trials reported here, the concrete blocks were cast with their inner face downwards, the extrados being finishing by trowelling. Each ring was 610 mm long, and 114 mm thick and comprised 10 symmetrial wedge-shaped blocks, tapered longitudinally at 1 in 10 on two faces, with a mean arc length of either 630 mm or 650 mm. Details are outlined of the method of excavation and erection. During erection, the longitudinal holes were found to be an aid to lifting the blocks by inserting bars as handles. The trials demonstrated that using the same type of segment and similar methods of erection, either an expanded or a grouted wedge block lining could be constructed.

  • Availability:
  • Corporate Authors:

    Morgan-Grampian Limited

    30 Calderwood Street
    London SE18 6QH,   England 
  • Authors:
    • Collins, S P
  • Publication Date: 1974-11

Media Info

  • Features: Figures; Photos; References;
  • Pagination: p. 52-54
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00265360
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jan 29 1975 12:00AM