Q. Why does pipe jacking machine usually get stuck when the ground condition change from soil to very hard rock?

When pipejacking machine moves from anarea of soil to very hard rock, it will be subject to damage of cutting disc. To break and loosen the rock, pipejacking machine applies a large torque on cutting wheels. Though, with the change of soft region to hard region,pipejacking machine is still under the same jacking load. This results in insufficient or little space for the movement of machine against the rock face, resulting in damage and exhaustion of pipejacking machine.