近断层地震动作用下地铁车站中柱减震效果研究

为研究近断层地震动作用下地铁车站中柱减震效果，本文首先从PEER 强震数据库中选取我国台湾集集大地震中典型近断层地震动记录，进行了近断层地震动频谱特性分析．然后，以某地铁车站为背景，分别建立中柱安装橡胶隔振支座和没有安装橡胶隔振支座的土-地铁车站结构相互作用体系有限元模型．在此基础上，选取4 条具有明显脉冲特性的近断层地震动记录和El Centro 波作为输入，对土-地铁车站结构相互作用体系进行了地震反应分析，对比分析了减震模型和原型结构的位移响应和应力响应等结果，探讨了近断层地震动作用下地铁车站中柱的减震效果．结果表明：近断层脉冲型地震动具有较大的加速度、速度和位移时程幅值，并有明显的速度脉冲效应，0.1~1 Hz 的低频成分丰富；在地铁车站中柱柱端安装橡胶支座后，改变了车站结构的传力机制，使得顶板的内力及变形不能有效的传递到中柱上，起到了非常明显的减震效果；中柱增设橡胶支座后结构整体刚度变小，车站结构侧墙内力和水平变形较原型结构有明显增大．

Seismic Mitigation Effect Analysis of Subway Station Center Column Subjected to Near-Fault Ground Motions

In order to analyze the seismic mitigation effect of subway station center column subjected to near-fault ground motions, this paper firstly selects typical near-fault ground motion records of Chi-Chi earthquake in Taiwan based on PEER strong earthquake database and analyzes the frequency spectrum characteristics of near-fault ground motion. The finite element models of the subway station system considering soil- structure interaction with and without rubber bearing in the center column are established, respectively. On this basis, four near-fault ground motion records with obvious pulse-like characteristics and El Centro wave are selected as input to analyze the seismic response of the system. The seismic mitigation effect of the subway station center column under the near-fault ground motion is discussed, the displacement response and the stress response of the modified structure and the prototype structure are analyzed and compared. The results show that the near-fault pulse-like ground motion has large acceleration, velocity and displacement amplitude in time history, with obvious velocity pulse effect and abundant low frequency components between 0.1~1Hz. After installing rubber bearing at the end of center column, the force transmission mechanism of station structure is changed, and the internal force and deformation can not be effectively transferred from the roof to the center column. Compared with the prototype structure, the overall stiffness of the structure is decreased, while the internal force and the horizontal deformation of the side wall will increase to a certain degree.