Definition - What does Jacking Shield mean?
A jacking shield is a steel cylindrical structure at the front end of an excavation carried out by a tunnel or microtunnelling boring machine during pipe jacking. Contained in the confines of the jacking shield are the cutting head with associated equipment and machinery necessary for the advancement of the excavation.
Trenchlesspedia explains Jacking Shield
Initially, at the launch shaft, the jacking shield is pushed forward by a system of hydraulic jacks. Once the jacks have advanced the shield to the required distance, a singular pipe section is then lowered into position behind the shield.
The hydraulic jacks continue to push the concrete pipes behind the shield until the shield has reached the desired end point. The shield is then removed from the reception point to complete the pipe installation.