Functions

The push-shield method is a construction technique that combines pipe jacking and shield tunneling. Depending on the alignment of the project, pipe jacking is used for the initial short, straight sections; when construction reaches a curved section or the thrust force reaches its limit, shield tunneling is initiated. The push-shield machine is the equipment used to implement this method.

Initial tunneling will be carried out using the pipe jacking method, with the main shield machine assembly, commissioning, and jacking operations completed within the existing launch shaft. Pipe segments will be prefabricated as complete rings, and both installation and jacking will take place within the launch shaft. The excavation, muck removal, and jacking processes in this pipe jacking method are identical to those of conventional pipe jacking techniques. Once the pipe jacking reaches its maximum advancement point, the operation switches from pipe jacking to shield tunneling mode: First, dual-component grout is injected behind the walls of the pipe jacking sections to reinforce them and provide reaction force for the shield tunneling advancement. Next, tracks are laid, and the rear support carriage is installed, followed by the installation and commissioning of the shield tunneling rear support system.

During shield-driven tunneling, the installation and advancement of tunnel segments follow a process similar to the shield method. A segment erector is used to assemble the segments. Once assembly is complete, the shield is advanced using thrust cylinders, while grouting is performed simultaneously with a grout pump. Grease is applied to the shield tail to ensure a tight seal. Construction proceeds using the shield method until the shield reaches the reception shaft, at which point the advancement is completed.

Applicable Projects

Construction of medium- and long-distance underground pipeline networks for water supply and drainage systems, power supply, and natural gas distribution.