中文摘要：

目前盾构工法广泛应用于城市地铁的建设之中，而隧道开挖面稳定性是影响隧道施工安全性的重要因素。采用数值模拟的方法，对考虑流固耦合影响的深层盾构隧道砂土层开挖面稳定性进行了模拟研究，并利用自己提出的一套新的判别准则来确定盾构隧道开挖面极限支护压力。相比以前的研究，该准则不仅考虑了盾构隧道开挖面直径对确定极限支护压力的影响，而且也考虑了在开挖面位移曲线突变和近线性两种类型下的极限支护压力如何确定。利用该判别准则，对影响渗流状态下砂土层隧道开挖面稳定性的因素——土体饱和渗透系数、渗流持续时间、地下水位埋深和孔隙率等进行了参数敏感性分析。研究结果表明，土体饱和渗透系数、渗流持续时间、地下水位埋深均与开挖面极限支护压力成正比关系；而随孔隙率变化，开挖面极限支护压力则变化不大。

英文摘要：

At present, the shield method widely applies to the construction of urban subway, and the cut surface stability of the tunnel affects the safety of tunnel construction. In this paper, the surface stability of sandy layer in the deep shield tunnel is studied considering the fluid-solid interface. Then according to a new criterion that applies to determine the limit support pressure of the tunnel face during the numerical simulation. Compared with the previous study, the impact of the face diameter on the limit support pressure is Considered, and also the two forms of the displacement curve including saltatory and near-linear are considered. The fluid parameters （the saturated permeability coefficient of the sand, the seepage duration, the ground water level and the sand porosity） which have influence on the surface stability of soil layers have been carried on the sensitivity analysis. The results of the study show that the saturated permeability coefficient of the sand, the seepage duration, and the ground water level are all proportional to the limit support pressure of the tunnel face, and the change of the limit support pressure is small with the change of the sand porosity. Finally the above conclusions which have been drawn may provide certain reference for the construction of deep shield tunnel.