EPB shield machine uses the full-face cutting cutter head installed in front of the shield to cut the soil in front into the sealed storage bin behind the cutter head, so that there is appropriate pressure in the bin to balance the water and soil pressure on the excavation surface, thus reducing the disturbance of shield propulsion to the stratum soil and controlling the surface subsidence. When unearthed, the soil residue is continuously discharged to the dump by the screw conveyor installed at the lower part of the sealed cabin.

The screw conveyor controls the rotating speed to grasp the unearthed quantity, which should be closely matched with the cutting speed of the cutter head, so as to keep the sealed cabin full of mud all the time and not too full. This kind of shield avoids the main shortcomings of local air pressure shield, and also saves the control system, mud conveying system and mud water treatment equipment with large investment for mud pressure shield.