中文摘要：

以上海地铁盾构隧道为例，建立盾构隧道渗流模型，设置不同渗流程度及水位边界条件，分析长期渗流条件下隧道周围土体的孔压分布规律、地表沉降规律和管片内力变化规律。分析结果表明：渗流越严重，孔压降低越明显，地表沉降越大；孔压、地表沉降和管片内力的变化规律一致，且在保持地下水位不变的条件下，三者达到稳定状态的时间几乎相同；渗流使管片内力发生明显改变，管片内力的改变量与渗流的严重程度和地下水位变化情况密切相关；在渗流严重且没有外部水源补给情况下，长期渗流使地下水位不断下降，导致隧道拱腰处的管片内力增加量最显著，对地铁盾构隧道的安全运营造成严重威胁。

英文摘要：

Taking the shield tunnel of Shanghai Metro as an example, the seepage model of shield tunnel was developed. The distribution of pore water pressure of soils around the tunnel, ground surface settlement and inner force of segments under long-term seepage were investigated by considering different seepage degrees and water level boundary conditions. Results indicate that pore water pressure decreases more significantly and ground surface settlement is greater with more obvious seepage of shield tunnel. The variations of pore water pressure, ground surface settlement and the inner force of segments with time are similar. At constant water table, the time for reaching the steady state of pore water pressure, ground surface settlement and inner force of segments is nearly the same. The inner force of segments changes significant- ly with the seepage of tunnel. And it is closely related with the variations of tunnel seepage and water table. In the context of serious seepage and no extra supply of groundwater, long-term seepage makes water table decline continuously. The inner force of segment at tunnel hance increases most significantly after long-term seepage, which may pose a severe threat on the safe operation of subway shield tunnel.