Abstract: To conduct chamberentering and operating under high water pressure, tunnel in longdistance bedrock bulge section, control pressure of shallowcovered soft and weak strata, and avoid muck cake phenomenon, targeted designs are proposed for superlarge diameter slurry shield applied in Zhuhai tunnel. Replaceable cutter change under atmospheric pressure can improve the safety of cutter change efficiency under high water pressure. The main drive with telescoping function can realize convenient replacement of disc cutter in hard rock formation under atmospheric pressure. Multiple flushing nozzles and crusher agitation arranged at the bottom of slurry and air cushion chambers minimize the risk of muck stagnation in chamber. The air cushion slurry balance shield minimizes the risk of ground breakdown or settlement. A separate booster pump is used to flush the cutterhead with large flow so as to reduce the mud cake formation on the cutterhead. The targeted designs adopted has received a good application effect in the construction process of Zhuhai tunnel, which significantly improves the geological adaptability and construction safety of the shield.

Key words: shield tunnel, high water pressure, cutter change under atmospheric pressure, muck stagnation in soil chamber, mud cake