竖向地震动对大跨度高断面Y形柱地铁车站地震响应分析研究

Influence of the Vertical Seismic Wave on the Seismic Response of an Large-span High-section Y-shaped Column Subway Station

以北京地铁6号线新华大街站公共区Y型柱地铁车站为工程背景,利用FLAC3D有限差分程序数值模拟分析,研究超浅埋大跨度、高断面、Y形柱地铁车站结构分别在仅输入水平向地震动和同时输入水平向与竖向地震动情况下的地震响应特性。结果表明:(1)与仅输入单向地震动相比,双向地震动耦合作用下车站各测点的峰值加速度和应力值均增大,而相对水平位移减小,且随着输入地震动强度的增加,竖向地震动影响率呈递减趋势;(2)双向地震动作用下,同一工况Y形柱叉支处各测点的竖向位移明显增大,且各测点的竖向位移值较为均匀,而单向水平地震动作用下各测点竖向位移差异较大;(3)与单向水平地震动相比,竖向地震动的输入对各测点间的水平方向地震动特性规律影响较小。

In this study,the Y-column subway station of the Xinhua Street Station in public areas of the Beijing Metro Line 6was used as an engineering background to develop a numerical model with the FLAC3 Dfinite difference program.The model was used to analyze and research the seismic response characteristics of the large-span high-section Y-shaped column subway station under only ground horizontal vibrations as well as under a combination of both horizontal and vertical seismic waves.The results showed that compared with inputting only one-way seismic waves,the peak acceleration and stress value of the station increased and the relative horizontal displacement decreased under the two-way seismic coupling.When the strength of the seismic wave input increased,the impact rate of vertical ground motion showed a decreasing trend.Under the combined action of the two-way seismic waves,the vertical displacement of the Y-shaped column fork branch was significantly increased under the same conditions and the vertical displacement of the measuring point was more uniform,whereas the vertical displacement of the measuring point in the one-way horizontal motions was quite different.Compared with the oneway horizontal motion,the vertical seismic wave input was less affected by the horizontal-direction vibration characteristics law among each measuring point.