大跨度Y形柱地铁车站结构地震反应研究

SEISMIC RESPONSE OF SUBWAY STATION WITH LARGE SPAN AND YSHAPED COLUMN

随着地铁建设的发展,出现了一种新型的结构形式—大跨度Y形柱地铁车站结构,与现有的地铁车站结构完全不同,其空间高大宽敞,环境舒适.为研究该新型地铁车站结构的抗震性能,以北京地铁6号线新华大街站为工程背景,使用FLAC^(3D)软件建立土与地下结构三维有限差分动力模型,模拟其在新华大街人工波作用下的响应过程,重点分析了车站Y形柱和侧墙的加速度、位移、应变的规律,并与试验结果进行了对比分析,结果表明:数值模拟与振动台试验结果基本一致,体现出了相似的规律性;Y形柱加速度最大位置出现于柱顶端稍下位置,并非于柱顶端;Y形柱分叉位置处应变出现突变,此点相对于柱底的位移最大,且变化率较大,是抗震设计中需要加强的部位;Y形柱加速度、位移变化都会大于侧墙.上述研究成果对提高该类地铁车站结构抗震性能的认识及抗震设计水平提供了合理的参考与指导.

Along with the development of subway construction, a new type of structure with long span and Y shaped column comes up. It is dierent from the existing subway station structure, the space is tall and spacious, which shows a comfortable environment. In order to study the seismic performance of subway station structure with this new type,taking Xinhua Street station of the Beijing Metro Line 6 as engineering background, FLAC3D was used to build the soilunderground structure dynamic model of three-dimensional finite dierence to simulate the response process under the Xinhua Street artificial seismic wave excitation. Emphasis is put on the analysis of the law of acceleration, displacement and strain of both Y shaped column and side wall of the station. The numerical results are also compared with the shaking table test. The results show that the numerical results are basically identical with the shaking table test, which reflects the similar structure response. The maximum acceleration of Y shaped column occurred at the position just a little down from the top of the column, not at the top. Strain changes suddenly at the bifurcation position of Y shaped column, where this position also has the largest response displacement relative to the bottom of column and with abrupt change, so this is the part to be reinforced in aseismic design. The acceleration and change of displacement of Y shaped column are both larger than side wall. The results above may provide reasonable reference and guidance to improve the seismic performance and seismic design for similar subway station structure.