Pipe thrusting is also known as micro-tunnelling or pipe jacking.
- The minimum specification for pipe thrusting shall be:
- Pipes shall be fitted behind a micro-tunnelling boring head and driven through the ground by hydraulic rams.
- Excavation of the face shall be carried out by the tunnelling head, with the spoil removed by slurry pumping, conveyor or auger (there is no pilot hole).
- The applied jacking force shall be distributed between the tunnelling head and the last pipe in the pipe string.
- The micro-tunnelling head shall be equipped with individual steering jacks for directional control.
- Intermediate jacking stations shall be introduced to reduce the jacking force where necessary.
- Where PVC-U pipes are used for thrusting, the maximum length of thrusting shall be two pipe lengths or as recommended by the pipe manufacturer. Only one joint shall be allowed between thrust pits. The minimum length of the pits shall be 6m to allow thrusting without damage being caused by bending of the pipes.
- Any bending of the pipes, bursting or tensile loads applied to the pipe during insertion into the bored hole shall not exceed the manufacturers recommendation.
Definitions in this section