基于无限元和波场分离方法的-同济大学学报.docVIP

基于无限元和波场分离法的地震响应数值分析 阳 栋1, 2， 王志亮1, 2 （1.同济大学 岩土与地下工程教育部重点实验室，上海 200092；2. 同济大学 地下建筑与工程系，上海 200092） 摘 要：用无限元模拟远场地基，有限元模拟近场区域，并在有限元和无限元接触处施加等效荷载以输入地震作用，从而求解半无限地基的地震响应。通过算例对边界和地震动输入方式进行了验证，并探讨了剪切波作用下，重力和土与结构相互作用对场地地震响应的影响。结果表明：基于无限元边界和波场分离法的地震动输入，能够有效仿真波动在半无限地基中的传播过程，且重力对水平地震运动无影响。土与结构相互作用效应使短周期段的加速度反应谱值降低，而长周期段的加速度反应谱值增加。土与结构相互作用对地基水平位移无影响，但使结构底部土体的最大主应力和最小主应力幅值增大。 关键词：无限元；波场分离；地震动输入；土与结构相互作用；地震响应 中图分类号：O242；TU 478 文献标识码：A Numerical analysis of seismic response based on infinite element and wave field separation method Yang Dong1, 2， Wang Zhiliang1, 2 （1. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092,China；2. Department of Geotechnical EngineeringTongji University，Shanghai 200092，China)Abstract：ses the infinite element to model the far field and the finite element to model the near field of foundation, and the equivalent load is artificially applied onto the interface between the finite element and the infinite element meshes to replace the seismic action. The seismic responses of semi-infinite foundation are then simulated. A numerical example is performed to verify the boundary mode and seismic input. Besides, the effects of gravity and soil-structure interaction on the seismic response of field under incident shear wave are investigated. It shows that the proposed method based on the infinite element and the equivalent load method is feasible and can effectively simulate the process of wave propagation in semi-infinite foundation. Gravity has on impact on the horizontal seismic motion. The influence of soil-structure interaction reduces the acceleration response spectrum at short period, but increases the acceleration response spectrum at long period instead. Again, the influence of soil-structure interaction produces no effect on the horizontal displacement of foundation, but it may increase the major and minor principal stresses of soils under structural bottom. K