斜入射SV波对地铁车站地震响应的影响

EFFECT OF THE OBLIQUE INCIDENCE OF SEISMIC SV WAVES ON THE SEISMIC RESPONSE OF SUBWAY STATION STRUCTURE

在显式有限元法结合黏弹性人工边界的时域波动方法的基础上,建立了三维平面SV波斜入射的输入方法。半空间算例说明了该文方法具有较好的精度,并基于所建立的斜入射方法研究了地震波斜入射对北宫门地铁车站地震响应的影响。该算例结果表明:在地震波斜入射情况下,地铁车站的地震响应规律与垂直入射时的情况具有明显差异;斜入射角度对水平加速度响应并不敏感,但对竖向加速度影响较大;斜入射使得车站柱子构件的剪力和轴力明显改变,柱子轴力随着入射角增加而明显增大;边墙控制点的应力状态也受入射角的影响较大,各控制点的第一、第三主应力都出现了随着入射角度增加而增大的规律。在地铁车站等地下结构抗震研究中,应考虑地震波斜入射的影响。

Based on the time-domain wave method and the explicit FEM coupled with viscous-spring artificial boundary condition, a 3-D input method for the plane seismic SV waves of oblique incidence is proposed. The numerical results of a half space demonstrates that this approach has a good precision. Then the proposed method is applied to investigate the seismic response of the Beigongmen Subway Station subjected to oblique incidence of seismic waves. The simulation results show that the dynamic responses of the subway station subjected to the action of obliquely incident seismic waves are clearly different from those due to vertically incident seismic waves. Oblique incidence of seismic wave has a significant impact on the vertical acceleration, despite of negligible influence on the horizontal acceleration. It can be found that the axial and shear forces at the columns vary obviously with increasing incident angel. Furthermore, there is significant increase in the first and third principal stresses at some key points of the sidewall. Therefore, the effect of obliquely incident seismic wave should be considered when studying the seismic response of subway stations.