ASSET’s Tunnel Liner Plate is a sectional corrugated steel system specifically designed for soft ground tunnelling and culvert reline applications. All elements can be carried to site by hand, and assembly is completed using high-strength nuts and bolts. All assembly is undertaken from inside the completed portion of the tunnel lining, which means an exceptionally safe workplace.
- TUNNEL LINER - Introduction
Tunnel Liner is available in black or galvanised steel. Tunnel Liner Plate is available in a wide variety of shapes and sizes, from as small as 1.3 m diameter to a maximum 8 m diameter.
Tunnelling vs Cut and Cover: Tunnelling is most often used when the surface above the works cannot be open cut.
This may be due to the following:
- traffic above
- existing buildings or structures
- space or clearance restrictions
Typical tunnelling applications would include the installation of drainage or utilities in:
- urban environments
- under highways
- under railways
- Soft ground tunnelling
- Relining existing structures
- Vertical shaft liners
- Rockfall protection (mining applications)
- pipe relines, where access is available only from inside the liner
- pipe relines with vertical or horizontal changes in alignment (sharp turns)
- TUNNEL LINER - Advantages
All underground work can be undertaken from within the assembled shell.
Small sections allow for minimal exposed excavation
Strong corrugated steel plates provide maximum strength at the lowest weight. Two-flange design provides optimum stiffness.
Many shapes are available; liner plate can be installed horizontally for tunnels and relines, or vertically for shafts and caissons.
Can be used with poling plates, full shield or half-shield tunnelling methods
Excavate – muck out – assemble liner – grout. No complex tunnelling equipment is required.
EASY TO HANDLE
With only two basic parts (plates and fasteners), no special skills are required for assembly. All plates can be carried by a single person if required.
Structures are made to order in our central factory and shipped to the customer’s project location. Available in round, elliptical and pipe arch shapes
- TUNNEL LINER - Assembly
Tunnel Liner is assembled completely from within the progressing structure. This is possible due to the bolted flanged circumferential seams and the use of retaining clips and bolts at the longitudinal seams. All components can be safely hand- carried into the assembly area.
Tunnel Liner Plate is one of the safest products available for soft-ground tunnelling due to: a. Full assembly from inside the completed portion of the structure b. Small plates (500 mm wide) allow minimum unsupported excavation. In poor soils this can be as little as the excavation required to install a single plate. For greater efficiency, excavation should permit installation of a complete ring. c. Minimum over-excavation is required: As all connections are made from within the finished portion of the structure, the excavation needs to be only sufficient to allow assembly of the plates. This reduces risk of impact on the structure due to settlement above. d. Bolt torque recommended is 135 to 170 N.m.
COMPLETING THE INSTALLATION
After installation in the excavated tunnel or shaft line, the Tunnel Liner Plate is grouted into place. Grouting is normally undertaken at the end of every shift. Factory-installed grout ports allow work to be completed from within the structure.