城市地下变电站非线性地震反应分析

为研究城市地下变电站结构及其内部电气设备的动力特性及地震反应规律,以西安市快速轨道交通二号线张家堡地下变电站为工程背景,依据黏弹性人工边界理论及有限单元法,建立考虑土体-结构-设备动力相互作用的三维有限元计算模型,首先通过半空间自由场模型验证了地震动输入方法的有效性,继而开展地下变电站系统的模态分析和动力时程分析,得到了该类结构的动力特性及地震响应规律。研究结果表明,结构上覆土体及电气设备在地震作用下产生的惯性力是结构构件应力增长的主要原因,8度罕遇地震作用下地下变电站内电气设备的加速度放大系数明显超出规范要求,需要采取相应保护措施。

Nonlinear seismic response analysis of urban underground substation

As far as the Zhangjiapu underground substation of Xi’an urban rapid rail transit line two is concerned, the dynamic characteristics and seismic response of urban underground station are analyzed. Based on the theory of viscous-spring artificial boundary and finite element method, a 3 D model considering soil-structure-equipment dynamic interaction was built. Firstly, the correctness of the earthquake input method was verified by the half-space free field model. Then the model analysis and seismic time-history analysis were performed to study the dynamic characteristics and seismic response of the model. The research results showed that the inertial force generated by the overlying soil and electrical equipment is the main reason for the stress growth of structural components. The acceleration amplification factor of the electrical equipment under 8-degree rare earthquake is obviously greater than the value recommended by corresponding standard, so corresponding protective measures need to be taken.