Shield Tunneling

Shield Tunneling

Excavator shield tunneling is a trenchless method used for larger diameter utility and crossing tunnels. This specialized form of tunneling includes a steerable forward shield with a hood that extends beyond the excavating face for ground stabilization. The material at the face is excavated by a digger arm that is controlled by an operator inside the shield. As the pipe string advances in the pipe jacking mode or propelled by a jacking can in a ring building mode, the leading edge of the shield scarifies the ground while the excavator’s arm moves material onto the conveyor belt for removal. A hydraulically controlled steering joint allows the onboard operator to make line and grade adjustments when dictated by the tunnel laser mounted in the launch shaft.

Case Studies

Blacks Run Interceptor Division 1B Replacement

The Blacks Run Interceptor – Division 1B –Replacement project scope included 3,700-lf. of 48-in. sanitary sewer installed by open-cut and trenchless methods.

A 200-lf. section that crossed under Stone Spring Road requiring a tunnel boring machine to maintain traffic on a busy arterial roadway.

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Tunneling