隧道在纵向地震作用下的动力响应分析

为了探讨盾构隧道结构在纵向地震动力作用下盾构管片的振动特性。通过将土-结构相互作用简化为等效刚度弹簧建立了模型,并推导了结构在地震作用下的运动方程。然后利用中心差分法求解所得到的运动方程,求得每段管片在不同时刻的位移。进一步研究了土-结构剪切系数、地震纵波速度和结构连接刚度3个因素对隧道盾构管片位移的影响。计算结果表明,随着土-结构之间剪切系数增大,管片最大位移随之增加,结构之间的相对位移减小。而降低结构之间的连接刚度后,土-结构之间的相对位移减小。波的传播速度越小,结构与地层之间相对位移越大,易导致滑移现象出现。因此,选取具有较快波速的坚硬地层、提高土与结构之间的剪切力以及设置合理的抗震缝距离将有助于增加结构的抗震性能。

Dynamic response of tunnel under longitudinal seismic action

The dynamic characteristics of the shield tunnel structure under the longitudinal seismic action was investigated. At first, the soil-structure interaction was modeled by springs with equivalent stiffness, and the motion equations of structure under seismic action were derived. Central difference method was used to solve the obtained motion equations,and the displacement of every section at different moment of time obtained. Furthermore, the effects of three parameters, including soil-structure shear coefficient, seismic P-wave velocity and structural connection stiffness, on shield tunnel segment displacement were investigated. The numerical results show that as the soil-structure shear coefficient increases, the maximum displacement of tunnel segment increases, and that the relative displacement between the structures reduces. After reducing the stiffness of the structure, the relative displacement between the structures and the soil reduces. The lower the wave propagation speed, the larger the relative displacement between the structure and formation becomes, which leads to the slip phenomenon. So choosing rigid foundation with larger wave propagation velocity, increasing interacting shear stress between soil and structure, and setting a reasonable seismic joint distance will help to improve the anti-earthquake performance of underground structures.