Precast Tunnel Liner Segments are specially engineered and fabricated to virtually any diameter and service application. Segments, usually six or more per ring, are assembled and placed by the tunnel boring machine as it excavates the tunnel. Liner segments are generally practical only when the tunnel diameter is too large for precast jacking pipe.
Concrete Tunnel Liner Segments are used for the following applications: Deep water mains
Deep combined sewer overflow systems
Minimum practical diameter is 12 feet. Maximum diameter is limited only to the size and capacity of the tunnel boring machine.
Each segment is gasketed to all adjacent sections to form a watertight core.