富水黏土地层盾构隧道开挖面稳定性

富水黏土地层盾构隧道施工过程中，确定合理的开挖面支护力对于安全掘进至关重要。针对富水黏土地层盾构隧道，对不排水条件下的开挖面稳定性展开了研究。通过数值模拟研究，分析了直径D、埋深比C/D与内聚力c对极限支护力的影响规律；推导已有的适用于不排水分析的开挖面主动破坏模式并分析其功率构成，结合黏土不排水离心试验得到破坏区域范围，对极限分析法获得的极限支护力进行了修正。最后，利用理论解析法与数值模拟方法对常州地铁工程某标段区间盾构隧道段进行开挖面稳定性分析，结果表明，理论解析法与数值模拟所得极限支护力相互印证，但理论解析法计算更为便捷。研究结论为富水黏土地层盾构隧道的工程实践提供借鉴与指导。

Study on Face Stability of Shield Tunnel in Water-rich Clay Stratum

During the construction of shield tunnels in water-rich clay strata, it is very important to determine the reasonable support force of the tunnel face for safe excavation. In this paper, the stability of tunnel face under undrained conditions is studied for shield tunnels in water-rich clay strata. Through numerical simulation research, the influence law of various parameters on the limit support pressure is analyzed; the existing active failure mode of tunnel face suitable for undrained analysis is deduced and its power composition is analyzed. Combined with the clay undrained centrifugal test, the failure area is obtained. The limit support force obtained by the limit analysis method is corrected. The correctness of the limit support force correction is verified by comparing with previous researches and numerical simulations. Finally, the stability analysis of the tunnel face of a shield tunnel section in a section of Changzhou Metro Project is carried out by using the theoretical analysis method and numerical simulation method. For convenience, it provides reference and guidance for the engineering practice of shield tunnels in water-rich clay strata.