盾构隧道联络通道冻土帷幕设计计算方法探讨

Discussion on Calculations of Frozen Wall for Cross Passage in Shield Tunnels

盾构隧道联络通道冻结法施工时冻土帷幕的流行计算方法是平面应变问题的荷载-结构模型,按框架结构用结构力学法计算。为考察该方法的准确性和适用性,将考虑土层作用的结合弹性地基梁的结构力学法与荷载-结构、土层-结构模型的平面应变问题数值计算以及联络通道和集水井整体三维数值计算进行比较。结果表明,上述方法所得的应力分布规律基本一致,但数值差异较大。综合分析表明,传统结构力学法在一定程度上降低安全储备后比结合弹性地基梁的结构力学法更具适用性,但三维数值计算更为准确。

The popular calculation method for the frozen wall for cross passage in shield tunnels is the method of Structural Mechanics for the problem of plane strain with load - structure model to calculate the frame structure. Considering the veracity and applicability of the method, another method of Structural Mechanics for a frame structure with beam on elastic foundation with effect of the strata is applied. A comprehensive comparison among the two meth ods, the numerical computation of the load- structure and the soil -structure and the 3D model of cross passage with drainage sump is done. The calculation results by these methods are generally consistent in stress distribution. Analysis shows that the method of Structural Mechanics with lower safety coefficient by contrast with the method of Structural Mechanics with beam on elastic foundation is more proper for engineering calculation. On the other hand, 3D numerical calculation should be applied to analyze the cross passages and flare openings to ensure the safety of the projects of this type.