Large-diameter shield tunnel displacement control device and working method thereof

The invention discloses a large-diameter shield tunnel displacement control device and a working method thereof. The device comprises a dewatering and drainage pipe, a dewatering and drainage pump, a water storage and drainage tank and a control system. Under the combined action of the dewatering and drainage pipe and the water storage and drainage tank, the pressure of pore water in a soil layer at the bottom of a shield tunnel is reduced through dewatering and drainage to reduce the buoyancy of the shield tunnel, meanwhile, the water storage capacity of the water storage and drainage tank is increased to increase the dead weight of the shield tunnel, and floating of the shield tunnel is comprehensively prevented; the self weight of the shield tunnel is reduced by reducing the water storage capacity in the water storage and drainage tank, underground water is recharged into the soil layer at the bottom of the shield tunnel through the dewatering and drainage pipe when necessary, so that the pressure of the p