提高地铁车站结构抗震能力的理论及数值分析

1995年阪神地震中，地铁车站等地下结构遭受了严重的破坏，其中大开地铁车站破坏尤为严重，一半以上的中柱发生坍塌，为了提高地铁车站结构的抗震能力，本文基于第二类拉格朗日方程首先建立了地震荷载和轴力联合作用下柔性动边界梁动力响应的分析方法，并讨论了轴力和弹簧刚度与阻尼系数对动力响应的影响特点与规律，然后利用ABAQUS软件对阪神地震荷载作用下大开地铁车站在有无设置隔震器时进行了三维非线性动力分析。研究结果表明：)

Theoretical and numerical investigations on enhancement of aseismic capability of metro stations

During 1995 Kobe earthquake, the metro stations suffered serious damage. The Daikai station was the first well-documented underground structure not crossing an active fault that has completely collapsed during an earthquake without liquefaction of the surrounding soil. Most columns of the Daikai metro station collapsed, including mid-column shear failure, which had never been observed in the past. In order to increase aseismic capability of metro stations, an analytical model of an elastically supported and damply supported beam (or column) subjected to combined action of seismic loading with static axial loading was developed. Based on the secondary Lagrange’s dynamic equations, an analytical method was established, which could be used to investigate the dynamic response of the beam. The effect of the axial loading on the dynamic responses of the member, the influences of the stiffness and damping coefficient were analyzed. In order to further investigate into the nonlinear response of an elastically supported and damply supported column, taking the Daikai metro station as an example, the 3D nonlinear responses of the column of the subway station with isolator supports subjected to the seismic loading in Kobe earthquake were analyzed by finite element software programme ABAQUS. The main conclusions can be drawn as follows: (1) The proposed analytical model of an elastically supported and damply supported beam (or column) can predict the dynamic response of the structural member subjected to action of combined seismic loading with static axial loading. (2) Setting isolators (springs and dampers) at the supports could reduce the deformation and damage of the column effectively, and hence the seismic-resistance of the structure could be also enhanced. (3) The axial static loading induced by the gravity of soil and structures provide the constraint on the column. But when the plastic hinge occurred at the joint between walls and slabs, the axial loading would accelerate the damage of the whole structure. Therefore, it could not be neglected in the structural dynamic analysis.