Definition - What does Jacking mean?
Jacking is the pushing of pipe or tunnel casing forward through an excavated hole. The procedure can be done with various technologies, including mechanical, hydraulic or air jacks. It is a common practice in trenchless construction.
The term is sometimes used interchangeably with pipe jacking or pipe ramming.
Trenchlesspedia explains Jacking
With trenchless construction, workers can dig tunnels in places never thought possible before. They can go under streets and streams -- even whole neighborhoods. But once the hole is excavated, they still have to get the pipe in somehow. That’s where jacking comes in.
Manufacturers have learned to make pipe and casing materials extremely strong - enough for the pipe and casing to be forced into an excavated hole using a great amount of force. Without the strength of the materials, they might break or fall apart when force is applied.
Jacking occurs when equipment with sufficient thrust advances the pipe or casing through a bore hole. Calculation of required thrust is important when designing the project. When a section of pipe or casing is fully ensconced in the ground, a new piece is attached and the jacking resumes.