PIPE JACKING & TUNNELING
Tunnel Boring Machines (TBMs) and Boring Shields are used to install 48 - 93-in. (1,219 - 2,362 mm) and 96 - 168-in. (2,438 - 4,267 mm) OD jacking pipe. Both systems are interiorly controlled by an operator. TBMs excavate soil at the face of the bore when hydraulic motors rotate the inner drum, the cutter head excavates and soil is transported via conveyor and haul unit for disposal from the launch shaft. The Boring Shield system excavates soil with a backhoe-type excavator at the face of the bore and is removed in the same manner as the TBMs. With both systems, a passive pipe laser in the launch shaft projects a laser point on the cutter face for the operator to monitor and make steering corrections as necessary. The all-in-one Tunnel Boring System easily adapts to any jacking pipe with an appropriately sized TBM, yoke and skid section(s). A complete Tunnel Boring System is comprised of a TBM, pump unit, yoke, skid, haul unit, conveyor, pipe laser and often a bentonite pump. A Boring Shield system contains a boring shield with excavator, conveyor, haul unit, power pack or pump unit, pipe laser and jacking frame.