二维土层地震反应分析的时域等效线性化解法  

Time-domain equivalent linearization method for two-dimensional seismic response analysis

作　　者：杨笑梅[1] 赖强林 YANG Xiao-mei LAI Qiang-lin(Faculty of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, Guangdong 510006, China)

机构地区：[1]广东工业大学土木与交通工程学院,广东广州510006

出　　处：《岩土力学》2017年第3期847-856,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.51178123)~~

摘　　要：考虑非线性特征的局部复杂场地地震反应分析,一直是工程场地地震动预测中需解决的关键问题。借鉴目前一维成层场地地震反应分析中广泛使用的频域等效线性化思想,将其推广至时域及二维问题,提出了可用于考虑非线性特征的时域显式有限元方法,适用于复杂工程场地地震反应分析。本方法内域主要采用可实现显式算法的低阶有限元格式,人工边界处采用与显式算法相匹配的透射边界模拟无限域,单元内先通过求取平面应变状态下的最大切应变替代一维模型中的最大切应变,再依据整个时间过程的切应变求取等效切应变。每次整体求解采用时域中心差分的递推过程,并通过迭代完成非线性特征分析。为了验证本方法,选取水平成层场地及二维盆地两个典型场地模型进行模拟分析,将计算结果与传统的一维等效线性化模型及二维差分非线性计算结果做了对比,计算结果显示本文解与参考解非常吻合,证明了本文方法的可靠性。进一步采用该方法对美国Turkey Flat试验场地进行地表地震动模拟,计算结果与应用广泛的一维等效线性化模型及实测记录比较,探讨该方法的可靠性及与现有分析模型的差异,并阐述了非线性特征对地震动影响的规律。The seismic response analysis of local complex sites with nonlinear characteristics has been the key problem to solve in prediction of seismic motion. Frequency domain equivalent linearization, widely used in the seismic response analysis of one-dimensional stratified sites, is extended to time domain and two-dimensional problems. A time-domain explicit finite element method can be used to consider nonlinear characteristics and it is suitable for seismic response analysis of complex engineering sites.In this method, the inner domain of the method is mainly used to realize the low-order finite element scheme of the explicit algorithm. The boundary of the artificial boundary is simulated by the boundary of the transmission boundary. The maximum tangent strain in the one-dimensional model is replaced by the maximum tangent strain in the plane strain state, and the equivalent shear strain is obtained according to the tangent strain of the whole time process. Each time the whole solution is solved by the time domain center difference, and the nonlinear characteristic analysis is done by iteration. In order to verify this method, two typical site models of horizontal stratified and two-dimensional basins are selected for simulation analysis. The results are compared with solutions of the traditional one-dimensional equivalent linearization model and the two-dimensional differential nonlinear calculation. The results show that the solution is in good agreement with the reference solution, and prove the reliability of the method. This method is used to simulate the surface vibration of the US Turkey Flat test site. The results are compared with one-dimensional equivalent linearization model and the measured record. The reliability of the method and the difference with the existing analysis model are discussed, and the influence of the nonlinear characteristics on the seismic motion is illustrated.

关 键 词：非线性特征 等效线性化 时域显式有限元 地震反应 

分 类 号：TU435[建筑科学—岩土工程]