提高地铁车站结构抗震能力的理论及数值分析

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

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,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:所提出的理论分析方法可以较好地分析地震荷载与轴力联合作用下柔性动边界梁的动力响应问题;在强震荷载作用下,在地铁车站中柱的端部合理设置隔震支座能够有效减小结构(尤其是柱子)的变形与损伤破坏,提高其抗震能力;柱子上部覆土及结构自重产生的轴力会对柱子的振动响应产生影响,一旦结构交叉部位产生塑性铰,轴力会加剧中柱的破坏,上部覆土及结构自重在地下结构动力分析中必须考虑。

In order to increase aseismic capability of metro stations,an analytical model of beam（or column） with elastic and damping supports subjected to combined action of seismic loading and static axial loading was developed.Based on the secondary Lagrange＇s dynamic equations,an analytical method was established to investigate the dynamic response of the beam.The effect of the axial loading on the dynamic responses of the member and the influences of the stiffness and damping coefficient were analyzed.In order to further investigate the nonlinear responses of the column with elastic and damping supports,taking the Daikai metro station as example,the 3D nonlinear responses of the column of the subway station with isolated supports subjected to the seismic loading in Kobe earthquake were analyzed by finite element software ABAQUS.The main conclusions can be drawn as follows：（1） The proposed analytical model can well predict the dynamic responses of the structural member subjected to combined action of seismic loading and static axial loading.（2） Setting isolators（springs and dampers） at the supports can reduce the deformation and damage of the column effectively,and hence enhance the seismic-resistance of the structure.（3） The static axial loading induced by the gravity of soil and structures provide constraint on the column.But when the plastic hinges are installed at the joints between walls and slabs,the axial loading will accelerate the damage of the whole structure.Therefore,it should not be neglected in the structural dynamic analysis.