隧道纵向整体抗震分析的近似方法

根据隧道工程的特点，考虑隧道与围岩的相互作用，依据抗震动力学理论、结构-围岩相互作用理论及当量半径的思想，建立隧道结构动力平衡方程，该方程从理论上考虑了隧道的自重惯性力。从方程可以看出，经典反应变位法是该方法的特例。通过算例分析了隧道埋深、地层剪切波速、基岩剪切波输入方向、上覆地层的特征周期、弹性地基系数及围岩弹性模量对衬砌纵向应力的影响。通过算例分析可知，（1）围岩-结构相互作用对隧道抗震分析具有较大的影响，不考虑相互作用得到的结果是相对保守的；（2）隧道的自重惯性力只有在超浅埋结构中有一定的影响，随着隧道埋深的增加，自重惯性力的影响完全可以不计；（3）本方法实际上是隧道纵向抗震分析的一种工程算法，所得的结论对于深埋隧道结构的整体抗震概念分析提供了一定的理论参考。

Approximation method of tunnel longitudinal seismic analysis

According to the features of tunnel engineering,interaction between tunnel and wall rock is considered.Based on structural dynamics theory,interaction theory and the idea of equivalent radius,a dynamic equilibrium equation of tunnel structure is established.The equation takes into account the action of inertial force of the tunnel structure.As can be seen from the equation,classical displacement response method is a special case of the method.Factors effecting on longitudinal stress of tunnel lining have been studied.Those factors contain tunnel depth,strata shear wave velocity,shear wave direction,elastic foundation coefficient,elastic modulus and the characteristic period of the overlying strata.The case studies show that:(1) Interaction between structure and wall rock has a greater impact on lining.Without considering the interaction,the results are relatively conservative.(2) Inertial force has a great effect on the ultra shallow structure;but with the tunnel depth increases,the impact of inertial force can be neglected.(3) The method is actually an engineering algorithm for solving tunnel longitudinal stress.In the preliminary design of tunnel,the method could provide theoretical reference for seismic concept design of the overall tunnel.