摩擦摆支座在软弱夹层场地地下结构中的减震效果分析

较一般成层场地而言，软弱夹层场地中地下结构抗震与减震问题更为突出。本文以双层双跨矩形框架地铁车站结构为研究对象，基于有限元软件ABAQUS，建立土-结构体系的静动力耦合有限元分析模型，研究软弱夹层对地铁车站结构的地震响应规律的影响，并对比分析了设置摩擦摆支座的车站结构在均质场地和软弱夹层场地的减震效果。结果表明:软弱夹层穿越地铁车站结构时，结构的整体和中柱的变形以及中柱底部的内力会大幅度增加，且随着夹层厚度增加，结构变形和内力的增加幅度更为明显。在中柱顶部设置摩擦摆支座，中柱的最大位移以及内力值均减小，且软弱夹层场地中摩擦摆支座的减震效果要明显优于一般均质场地，建议在软弱夹层场地地下结构中采用摩擦摆支座进行减震设计。

Seismic Mitigation Effect Analysis on Friction Pendulum Bearings in Underground Structures in Site with Weak Interlayer

Compared to the general layered sites, the seismic resistance and mitigation of underground structures in site with weak interlayer are more prominent. This paper takes the double-story and double-span rectangular frame subway station structure as the research object. Based on the finite element software ABAQUS, a static and dynamic finite element analysis model of the soil-structure system is established. The influence of weak interlayer on the seismic response law of the subway station structure is studied, and the seismic mitigation effect of the station structure with friction pendulum bearings in homogeneous and weak interlayer sites is compared and analyzed. The results show that when the weak interlayer passes through the structure of a subway station, a notable increase in overall deformation, central column deformation, and internal forces at the base of the central column is brought about. Moreover, as the thickness of the interlayer increases, the increase in structural deformation and internal force becomes more significant. The installation of friction pendulum bearings at the top of the central column reduces the maximum displacement and internal force values of the central column, and the seismic mitigation effect of the friction pendulum bearings in sites with weak interlayer is significantly better than that in general homogeneous sites. The friction pendulum bearings are recommended to be used for seismic mitigation design in underground structures in sites with weak interlayer.