基于黏弹性边界的二维沉积盆地非线性地震响应分析  

Nonlinear earthquake response analysis of 2D sedimentary basin using viscous-spring boundary

作　　者：梁佳利 梁建文[1,2] 韩冰[3] LIANG Jiali;LIANG Jianwen;HAN Bing(State Key Laboratory of Hydraulie Engineering Simulation and Safety,Tianjin Univesity,Tianjin 300354,China;Department of Civil Engineering,Tianjin Unversity,Tanjin 300354,China;Departme nt of Civil Engineeing,Nanjing Univesity of Aeronautics and Astronautics,Nanjing 210016,China)

机构地区：[1]天津大学水利工程仿真与安全国家重点实验室,天津300354 [2]天津大学建筑工程学院土木工程系,天津300354 [3]南京航空航天大学土木工程系,江苏南京210016

出　　处：《地震工程与工程振动》2020年第4期108-117,共10页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金项目(51978462)。

摘　　要：建立弹性基岩上覆软土场地中二维沉积盆地非线性地震响应分析的有限元模型。模型截断边界定义为黏弹性人工边界,地震波动以等效结点荷载的形式输入,土体的非线性特征以等效线性法模拟,求解在频域内进行。首先,借助高精度的有限元-间接边界元耦合法,验证模型的可靠性。其次,基于某一沉积盆地开展地震动数值计算,针对其线性与非线性响应的差异性进行分析。最后,通过比较非线性条件下自由场与存在盆地地形场地的响应结果,讨论盆地局部地形对地震动的影响。研究表明,土体的非线性特征对盆地地震响应有显著影响,在盆地中心附近有可能出现非线性地震响应大于线性响应的特殊现象;与自由场相比,盆地内的非线性地震响应普遍明显放大。A finite element model for the nonlinear earthquake response analysis of 2 D sedimentary basin is established in this paper.In the model,the truncated boundary is defined as the viscous-spring boundary,the seismic wave is input in the form of equivalent nodal force,the soil nonlinearity is simulated by the equivalent linear method,and the operation is carried out in the frequency domain.The model accuracy is verified by comparing with the results of finite element-indirect boundary element coupling method.Taking a shallow sedimentary basin for example,the nonlinear earthquake response of the basin is compared with the corresponding linear response,and the effect of the basin topography on the nonlinear earthquake response is investigated.The results show that the soil nonlinearity has significant impacts on the basin earthquake response,and there may be a special phenomenon that the nonlinear earthquake response is larger than the linear response near the basin center,in addition,the nonlinear earthquake response inside the basin is generally significantly magnified compared with the corresponding free-field response.

关 键 词：二维沉积盆地 黏弹性边界 等效结点荷载 等效线性 地震响应 

分 类 号：P315.9[天文地球—地震学]