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Smoothbore Tunnel Linings

  • FP McCann Precast Concrete Shafts and Tunnels Smoothbore Tunnel Lining
FP McCann Smoothbore Tunnel Linings
 
FP McCann has launched and is developing a comprehensive range of smoothbore shaft and tunnel linings. Each size is specifically designed to meet the tunnelling industry’s exacting and varied needs, recognising the key criteria as being strength, stability and the capability of performing in all types of ground conditions.
 
Tunnel segments can be modified to suit a variety of joint fixings, segment thickness and tunnel diameter’s.  The latest manufacturing techniques incorporate steel fibre dosing to guarantee a high quality, reliable product.  The wedge shape design of individual segments eliminates the requirement for a special closure segment.
 
Design Features
All rings, with the exception of the cutter choker comprise of ordinary segments and two top segments. The top segments have one tapered cross joint in order that they can be installed with EPDM gasket. The cutter choker comprises all ordinary segments.
 
Sealing
FP McCann are the only precast concrete manufacturer to supply pre-fitted, tailor made EPDM rubber gaskets on the complete range of smoothbore shaft and tunnel linings. The gaskets provide an immediate water tight seal on construction and are fully compliant with the requirements of the British Tunnelling Society specification. Speed of build, safety and increase in site productivity are key benefits.
 
Connection
Cross joint connections are made using a spear bolt passing through a pocket in one segment and a plastic socket in the adjacent segment. Circle joint connections are made using a T bolt passing through a hole in one segment and into a T box in the adjacent segment. Bolts are designed to fully compress the gasket. All connections are sheradised. (Other finishes to fittings, including galvanised, are available on request). Additionally, FP McCann offer a safer and more efficient back bolting system for the caisson build method.
 
Ring Types
Segmental ring types provided by FP McCann:
Segmental rings in stock are front or back bolted.
1. Standard rings
2. Corbel rings
3. Recessed rings (standard, choker or cutter choker)
4. Choker rings
5. Combined cutter choker rings
 
Mix and reinforcement
Each segment is wet cast to achieve a smooth internal finish. The concrete mix provides a Design Chemical Class 4 (DC4) with a minimum 28 day characteristic strength of 55 N/mm2. Alternative mixes are available. The segments are reinforced with either a reinforcing cage or structural synthetic and steel fibres to suit both design and customer requirements.
 
Build Methods
The segmental rings are suitable for underpinning, caisson and chimney construction methods.

 

FP McCann Precast Concrete Shafts and Tunnels Smoothbore Tunnel Lining

Trapezoidal Segmental Tunnel Linings

Developed in conjunction with leading consultants and contractors, these single pass smoothbore linings have been designed for use with the latest closed-face tunnelling machines.
The linings can be designed to accommodate elastomeric compression gaskets or hydrophilic seals. Individual segments are wedge shaped thus eliminating the need for a special closure or key segment.
 

Trapezoidal Segment

FP McCann Precast Concrete Shafts and Tunnels Smoothbore Tunnel Lining

 

Trapezoidal Lining

 

FP McCann Precast Concrete Shafts and Tunnels Smoothbore Tunnel Trapezoidail Linning

 

Trapezoidal Tunnel Lining 

FP McCann Precast Concrete Shafts and Tunnels Trapezoidal Tunnel Linings Table

* Nominal weights. Increase by 5% for sizing of lifting equipment and reduce by 5% for floatation design. 

 

Expanded Lining

FP McCann Precast Concrete Shafts and Tunnels Smoothbore Tunnel Expanded Linning

Expanded Tunnel Lining

 

P McCann Precast Concrete Shafts and Tunnels Expanded Tunnel Linings Table

* Nominal weights. Increase by 5% for sizing of lifting equipment and reduce by 5% for floatation design.