Information of ground motion records.

Investigations from past earthquakes have shown that underground subway stations can suffer excessive deformation under strong seismic loads, leading to the damage of critical components and the collapse of structures. This study presents the results of finite element analyses on the seismic damage of underground subway stations installed under different soil constraint conditions. The plastic hinge distribution and damage characteristics of cut and cover double-storey and three-storey subway stations are analyzed using the finite element method software ABAQUS. Combined with the static analysis results of the column sections, a discriminant method for bending plastic hinges is presented. The numerical results show that the collapse of the subway stations begins with the failure of the bottom columns’ bottom sections, which leads to the bending of the plates and the destruction of the whole structure. The bending deformation at the end section of columns has an approximatively linear relationship with the inter-storey drift ratio, and the change in soil conditions shows no apparent influence. The sidewall deformation behavior varies significantly under different soil conditions, and the bending deformation at the bottom section of sidewalls increases along with an increase in the soil-structure stiffness ratio at the same inter-storey drift deformation level. The sidewall bending ductility ratio of the double-storey and three-storey stations at the elastic-plastic drift ratio limit increases by 61.6% and 26.7%, respectively. In addition, the fitting curves between the component bending ductility ratio and inter-storey drift ratio based on the analysis results are also presented. The findings may provide a helpful reference for the seismic performance evaluation and design of underground subway stations.

过往地震调研结果表明，地下地铁站在强地震荷载作用下易发生过度变形，进而造成关键构件损坏与结构坍塌。本研究针对不同土体约束工况下修建的地下地铁站震害展开有限元分析，采用有限元软件ABAQUS分析了明挖双层与三层地铁站的塑性铰分布及震害特征，并结合柱截面静力分析结果，提出了弯曲塑性铰的判别方法。数值模拟结果显示，地铁站的坍塌起始于底部柱脚截面失效，随后引发楼板弯曲变形并最终导致整体结构破坏。柱端截面的弯曲变形与层间位移角近似呈线性相关关系，且土体条件变化对此无显著影响。不同土体工况下，侧墙变形行为差异显著；在相同层间位移变形水平下，侧墙底部截面的弯曲变形随土-结构刚度比的增大而增大。在弹塑性层间位移角极限状态下，双层与三层地铁站的侧墙弯曲延性比分别提升61.6%与26.7%。此外，本研究还基于分析结果给出了构件弯曲延性比与层间位移角之间的拟合曲线。本研究成果可为地下地铁站的抗震性能评估与设计提供有益参考。