Segmental Tunnel Liners
- Linings – transportation tunnels, water transmission
- Direct conveyance for gravity sewer lines
- Segments gasketed to form a ring, universal ring design
- Typically 6 segments per ring
Ring Diameters: 2700mm and greater
Segments are manufactured using moulds. The design for the moulds is developed from the segment design. The quality of the mould, the concrete mix, the reinforcing method and manufacturing process all have to be exact and consistent in order to produce acceptable precast tunnel lining segments. The ring constructed from the segments must be able to fit perfectly in the TBM so that the tunnel can be constructed properly. Tolerances on the dimensions of rings are generally within a few millimeters, making tolerances on precast tunnel lining segments in the sub-millimetre range
Precast tunnel lining segments are designed by consulting engineers specializing in tunnel design. The segments are designed to suit the specific project conditions and the tunnel boring machine (TBM).