盾构隧道的纵向地震响应

The Longitudinal Seismic Response of Shield Tunnel

基于与盾构隧道纵向变形性能相似的梁单元建立盾构隧道纵向等价连续化模型,通过等价刚度的方法考察管片间接头螺栓对隧道结构刚度的影响。分别采用反应变位法和有限元法进行盾构隧道的地震响应研究和抗震性能分析,并以实例比较2种方法的有效性和应用条件。研究结果表明:在盾构隧道的纵向抗震设计时,应采用螺栓最大张开量作为设计的重要控制指标,并应尽量将隧道设计成可适应其变形的柔性结构;采用等价连续化模型进行盾构隧道纵向受力分析时,其等价弯曲刚度受轴向力的影响较大,故在单元等价弯曲刚度计算中计入轴向作用力的影响是十分必要的;螺栓进入塑性受力状态后,建议采用有限元法计算的结果进行抗震设计。

The longitudinal equivalent continuum model of the shield tunnel was established based on the beam element similar to the longitudinal deformation performance of the shield tunnel.The influence of the joint bolts between the segments on the stiffness of the tunnel structure was investigated by equivalent stiffness method.Displacement response method and FEM was respectively adopted to study the seismic response and analyze the seismic behavior of the shield tunnel.The effectiveness and the application conditions for the two methods were compared by practical example. Results show that the maximum open value of the bolt should be adopted as the important control index for the longitudinal seismic design of the shield tunnel, and the shield tunnel should be designed as the flexible structure adaptable for its motion displacement as possible. When the equivalent continuum model is used to analyze the longitudinal stress of the shield tunnel, its equivalent stiffness is more affected by the axial force. Therefore, it is necessary to take the axial force into account upon calculating the unit equivalent bending stiffness. After the bolt entering the plastic stress state, it is suggested to adopt the FEM calculation results for the seismic design.