Guidance System

System that locates the actual position of the MTBM relative to the laser or other device. The laser or other device should be referenced to the design line and grade.

Guide Rail

Device used to support or guide, first the shield and then the pipe within the drive shaft during a pipe jacking operation.

Guided Auger Boring

A term applied to auger boring systems which are similar to microtunneling, but with the guidance mechanism actuator sited in the drive ShaftA pit or wall sunk from the ground surface into a tunnel for the purpose of furnishing ventilation or access to the tunnel. (e.g. a hydraulic wrench which turns a steel casing with an asymmetric face at the cutting head). The term may also be applied to those auger boring systems with rudimentary articulation of the casing near the head activated by rods from the drive pit.

Guided Boring

Method for the installation of pipes, conduits and cables using a surface-launched drilling rig. A pilot bore is drilled using a rotating drill string and is then enlarged by a back reamer to the size required for the product pipe. The necessary deviation during the pilot boring is provided by a slanted face to the drill head, an asymmetric drill head, eccentric fluid jets or a combination of these, usually in conjunction with a locator.

Guided Boring Method

Another term for the pilot tube method, in which an auger boring power unit is used with a pilot tube’s guidance and steering system.