基于有限元方法研究岫岩罗圈里陨石坑地形对地震反应的影响

FEM-BASED RESEARCH INTO THE INFLUENCE OF CRATER-TERRAIN ON SEISMIC RESPONSE IN XIUYAN LUOQUANLI

基于有限元方法对岫岩罗圈里陨石坑地形对地震反应的影响进行了探索。结合文献资料、岩土勘察工作建立了岫岩罗圈里陨石坑二维有限元分析模型。选用粘弹性人工边界和等效节点力输入方法解决了有限元模拟半空间无限域时的边界问题和地震动输入问题。为了突出地形因素的影响,采用弹性材料介质进行数值模拟分析,并与水平场地模型的分析结果进行了对比。数值模拟结果和对比表明:罗圈里陨石坑地形对于陨石坑中部的地震动有显著的放大作用,远高于水平场地模型。此外,盆地中部短周期部分的反应谱也明显高于盆地边缘和水平一维场地模型,这是导致海城地震中盆地中部自振周期较短的单层房屋破坏明显严重的主要原因。

The paper presents a research, which is based on the finite element method, into the influence of Crater-terrain on seismic response in Xiuyan Luoquanli. Xiuyan Luoquanli crater two-dimensional finite element analysis model was established by literature and geotechnical investigation work. The viscous-spring artificial boundary and the equivalent nodal force input method are used to solve the boundary problem and the ground motion input problem in finite element simulation. Elastic material medium and the comparation with the result of horizontal site model are used to focus on the influence of terrain factors. The results and comparison show that Luoquanli crater terrain has significant amplification effect for crater central vibration, and much higher than the level of horizontal site model. Moreover, the acceleration response spectrum values during short periods in centre are significantly higher than that the level of in the edge of the basin and the horizontal site, that is the primary reason for the serious damage of one-storey house with short natural period of vibration in centre of crater.