二维土层地震反应分析的时域等效线性化解法

发布时间：2018-01-13 04:32

本文关键词：二维土层地震反应分析的时域等效线性化解法　出处：《岩土力学》2017年03期 　论文类型：期刊论文

【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。
[Abstract]:Analysis of seismic response of complex site local nonlinear characteristics of ground motion, has been the key problems needed to be solved in the prediction of currently widely used as reference. The one-dimensional analysis of site earthquake response thought in the frequency domain equivalent linearization, is extended to the time domain and the two-dimensional problem, put forward to consider the nonlinear characteristics of time domain explicit finite element method for seismic response analysis of complex engineering. This method is mainly used in domain can realize low order finite element scheme explicit algorithm, artificial boundary by matching with the explicit algorithm transmission boundary to simulate the infinite element, first by calculating the maximum shear strain under plane strain replacement the maximum shear strain in one-dimensional model, and then based on the shear strain in the whole time course of calculating equivalent shear strain. The recursive process of time difference by each center and through the whole problem. Nonlinear characteristics analysis of complete iteration. In order to validate the method, select the horizontal layered site and two-dimensional basin two typical site model is simulated and analyzed, the calculation results of one-dimensional equivalent linear model and the difference with the traditional two-dimensional nonlinear calculation results were compared. The results show that this solution and the reference solution that very well. The reliability of this method. Further using the method of field test on the surface Turkey Flat ground motion simulation, comparing the calculated record one-dimensional equivalent linearization model and the measured results and wide application, the reliability of the method and discuss the differences with the existing analysis model, and describes the nonlinear characteristics of the ground motion law.

【作者单位】：广东工业大学土木与交通工程学院;
【分类号】：TU435
【正文快照】： 局部场地条件对地表地震动产生显著影响。研究表明[1-2]产生这样影响的主要原因来自场地地形和土体非线性两个重要因素。然而,目前局部复杂场地地震动分析预测通常只建立如下两类分析模型。一类是水平成层场地模型,即将覆盖土层及下卧基岩假设为力学性质沿竖向水平成层变化,而

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