【摘要】 为查明场地结构和填挖分布对西昌昔格达组沉积地层三维地基地震动响应规律的影响,利用有限元软件模拟了地震作用下2个三维计算模型表面的加速度分布情况。从场地平台结构、标高突变和填挖分区3个方面讨论地基地震动响应差异。研究表明:场地平台标高越高,竖直方向加速度放大系数变化越显著;标高突然增大引起竖直方向加速度放大系数骤增,向平台内侧延伸,加速度放大系数有减小的趋势;填方区加速度放大系数大于挖方区;地震动响应的地形放大效应具有方向性,数值分析应该采用三维计算模型。研究结果为西昌昔格达组地层场地地基方案比选和抗震设计提供重要依据。更多还原

【Abstract】 In order to find out the effect of site structure and distribution of cut-fill area on the seismic responses rules of Xigeda formation three-dimensional subgrade in Xichang,finite element method software is used to simulate the acceleration distribution on the surface of three-dimensional calculation models under seismic load. This paper discusses differences of subgrade seismic response from three aspects,including platform structure of the site,elevation mutation,and excavation and filling area. And there are four conclusions can be drawn. Firstly,the higher the elevation sites platform is,the greater the acceleration amplification factors are,especially in the changes of vertical acceleration amplification factors. Secondly,a sudden increase of elevation causes a sudden increase of vertical acceleration magnification factors,and acceleration amplification factors is getting smaller while extending to the platform inside. Thirdly,the acceleration amplification factors of filled area are greater than those of the excavation area. Fourthly,because terrain amplification of the seismic response is directional,three-dimensional calculation models should be used to numerical analysis. The results provide an important basis for the Xigeda subgrade base plan selection in Xichang and seismic design.更多还原