水压条件下盾构隧道双层衬砌力学特性分析

Analysis of Mechanical Properties of Double-layered Lining of Shield Tunnel Under Water Pressure

研究目的:针对国内某些盾构隧道开始出现内部构筑二次衬砌的工程实际,为探明二次衬砌与管片衬砌的相互作用机理,提出相应分析模型,以便正确评价二次衬砌的功能以及为合理地应用二次衬砌提供参考。研究结论:采用提出的双层衬砌抗剪压模型分析了三种典型工况下结构的内力特性,结果表明:增设二次衬砌将加大管片衬砌的弯矩,减小管片衬砌的轴力,这在管片衬砌发生渗漏后更加明显;相对管片衬砌而言,二次衬砌仅发挥了辅助性的承载作用;增设二次衬砌后,双层衬砌的整体受力并非更加合理;理想中的双层衬砌联合承载作用必须在特定荷载和地层结构参数的情况下才能发生。二次衬砌的作用主要体现在管片衬砌完全失效后可立刻发挥承载潜能,担负安全储备的作用。

Research purposes： According to the situation of some of shield tunnels with internal secondary lining in China,in order to prove the interaction mechanism between the secondary lining and segment lining,the corresponding analysis model was offered for the purposes of evaluating the function of the secondary lining correctly and providing the reference to the proper application of the secondary lining.Research conclusions：The analysis model of shearing and compressing resistance for double-layer lining was used to analyze the characteristics of the internal force properties of the structure under three representative kinds of conditions.The result proved that adding secondary lining might increase the moment and decrease the axial force of segment lining,and this effect was especially obvious when water leakage occurred in the segment lining.Compared with segment lining,the secondary lining only plays an assistant role in the load bearing.With adding the secondary lining,the entire load-bearing of the double-layered lining was not more reasonable.The ideal combined bearing effect of double-layered liner only happened under conditions of specific load,ground parameters and structure parameters.The secondary lining could mainly bear the load when the segment lining completely failed and it played an assistant t role in load bearing.