土层非线性地震反应分析方法及其检验

Development and verification of a method for analyzing the nonlinear seismic response of soil layers

针对现行土层地震反应方法在大震情况不适用的问题,基于所提出的指数形式土体动力本构模型(UE模型),结合时空交叠积分格式和多次透射边界条件,提出了一种新的一维土层非线性地震反应分析方法.利用共振柱试验的结果检验了UE模型的可靠性,并利用该方法对唐山响嘡三维强震台阵的资料进行了计算,通过对地表加速度时程和放大系数以及土层阻尼特性的计算结果进行分析,可知该方法较等效线性化方法更为合理可靠.检验结果表明该方法能够较好地反应土体在强震作用下的非线性特性,可用于土层地震反应分析计算.

The current method used to analyze the seismic response of soil layers is inappropriate for forces in strong earthquakes.A one-dimensional method for seismic response analysis of nonlinear soil layers was proposed.It is a constitutive model of soil dynamics with an exponential form,combining a time-space overlapping integration scheme and the multi-transmitting artificial boundary condition.This emerged from a UE model,and its reliability was verified by the results of resonant column tests.The new method was used with the strong motions recorded by the Xiangtang three-dimensional strong motion array in Tangshan.By analyzing the results of time histories and amplification factors for ground acceleration and the results of damping characteristic of soil layers,the conclusion can be drawn that the new method is more reasonable and reliable than the equivalent linearization method.The test results indicated that the method can simulate the nonlinear characteristics of soil layers experiencing heavy thrusts,and it can be applied to the analysis of seismic response in soil layers.