为研究海域围堰内孤石和基岩地层中超大直径泥水盾构在浅覆土条件下的掘进变形规律，以汕头海湾隧道盾构始发段为背景,加固区采用密钻孔疏松，回填区采用钻孔爆破，通过监测二者地表沉降、地层土体压力和隧道周边深层土体位移变化，结合盾构泥水舱顶部压力、总挤压力、掘进速度和刀盘转速等掘进参数，得出如下结论: 1）加固区的掘进参数变化明显大于回填区。2）加固区受盾构掘进挤压作用小，地表沉降和深层土体位移变化都在6 mm以内； 回填区受盾构掘进挤压作用明显，地表沉降达到27 mm，深层土体位移为17.6 mm。3）深层土体位移呈现出先远离后靠近隧道并最终稳定的规律。4）地层土体压力在盾构掘进和回填注浆中变化明显，且加固区土体压力大于回填区。5）加固区位于隧道开挖面侧向底部，回填区位于隧道开挖面侧向上部，隧道顶部压力均较小。

The reinforcement area of the shield launching section of the Shantou Bay Tunnel is loosened because of dense boreholes, and the backfill area is blasted by the boreholes. The surface settlement, ground soil pressure, and deep soil displacement around the tunnel in these two areas are monitored. Moreover, the deformation law of boulder formation induced by the slurry shield tunneling with superlarge diameter in the sea area cofferdam is investigated based on shield tunneling parameters such as the pressure of the slurry chamber top, total extrusion pressure, tunneling speed, and cutterhead rotation speed. The following conclusions are drawn. (1) The variations in the tunneling parameters in the reinforcement area are more pronounced than those in the backfill area. (2) The extrusion effect of the ground in the reinforcement area induced by shield tunneling is small, and the surface settlement and deep soil displacement are both within 6 mm. Conversely, the extrusion effect in the backfill area is considerably larger, with surface settlement and deep soil displacement reaching 27 and 17.6 mm, respectively. (3) The deep soil displacement exhibits the phenomenon of first receding from the tunnel, approaching the tunnel, and finally stabilizing. (4) The soil pressure varies during shield tunneling and backfill grouting. The reinforcement area shows a greater soil pressure than the backfill area. (5) The reinforcement and backfill areas are located at the lateral lower parts of the tunnel face. The pressure at the tunnel top is low.