Abstract: In order to solve the gushing problem of shield screw conveyor caused by high pressure rich water in the waterrich sandy soil, sandy pebble, and upper soft and lower hard composite strata, according to the relationship and the inversely proportion principle between the flow rate that mud water passing through the gate and the cross section, a kind of construction technology is proposed. It adopts the opening differential of the double gates of screw conveyor to enlarge the cross section of deslagging and reduce the pressure step by step. The technology can ensure continuity of mucking for the screw conveyor during shield tunneling, which avoids the risks of the pileup in chamber caused by slag gushing, the cutterhead wear caused by loss of pressure, surface subsidence and so on. The technology was applied in the section between Mingxiu Road station and Xiuxiang station of Nanning metro line 2, realizing rapid and continuous excavation for shield tunneling in the sandy pebble waterrich strata, reducing the disturbance to the stratum and effectively controlling the ground subsidence. In all, the construction technology has obvious advantages in efficiency, economy, operability, safety, and practicability.

Key words: shield construction, opening differential, gushing control, pileup in chamber, double gate, stepbystep pressure reduction, stress characteristics