Overview
Earth pressure type box shield
The Box Shield Method is a method of constructing underground tunnels using rectangular face shields. When the cross section is rectangular, such as in road tunnels and community ditches, this method is superior to conventional circular face shields in that there is no waste in the excavation cross section and no unnecessary space is created. It is also possible to construct large cross-section tunnels by using combining box shield machines (MMB method). The box shield method is available in both the slurry shield machine and the earth pressure balanced shield machine.