中文摘要：

研究目的：舟山沈家门海底隧道南岸深基坑最大开挖深度14.8 m,采用SMW工法桩和混凝土、钢管支撑围护,为浙江省内最深的临海沉管隧道基坑,周边环境极为复杂。本文对临海深基坑施工过程中的支护结构内力和水土压力进行实测分析,为类似工程提供宝贵经验。研究结论：（1）随着土层的开挖,支撑轴力增加,而且该土层对应的支撑所受的影响最大,各道支撑轴力的大小表现出不均匀性;（2）围护桩弯矩也随基坑开挖深度的增而增加,内支撑可有效降低桩身弯矩最大值;（3）基坑开挖初期,开挖面以上的实测土压力随着开挖深度的增加而减小,基坑开挖后期,土压力随着施工的进行渐渐增加,较深土层的土压力变化比浅层土层的土压力变化要滞后;（4）随着施工的进行,孔隙水压力先减小后稳定,孔隙水压力变化与基坑开挖及降水紧密相关;（5）本研究成果对于邻近海岸沉管隧道深基坑施工及设计具有参考价值。

英文摘要：

Research purposes： The maximum excavation depth of the deep foundation pit at south shore of Shenjiamen port Zhoushan subsea tunnel is 14. 8m. SMW piles, concrete supports and steel supports are used to support the foundation pit. It is the deepest waterfront immersed tube tunnel pit in Zhejiang province, and the surrounding environment is extremely complex. This paper studied the stress of retaining structure, earth pressure and pore water pressure during the pit construction, which can provide valuable experience for the similar projects. Research conclusions： （ 1 ） The supports axial force increases with the excavation of the foundation pit, and the corresponding support is affected most seriously, the force of the upper supports are uneven. （2）Pile moment also increases with the excavation of the foundation pit, the supports can effectively reduce the maximum pit moment. （3）Measured earth pressure above the excavation face decreases when excavation depth increases during initial excavation, while measured earth pressure above the excavation face increases with excavation advancement during post -excavation; the earth pressure changes in deeper soil layers lags behind changes in shallow soil layers. （4）The pore water pressure reduces before they are stable during the related to excavation and dewatering. （ 5 ） The research construction advancement; pore pressure changes are closely in this paper has a reference value for the construction and design of the deep foundation pit of the shore immersed tube tunnel.