考虑地基土体参数空间变异性隔震结构的SSI效应可靠性分析  

Reliability analysis of SSI effect of the isolated structure considering spatial variability of foundation soil properties

作　　者：方泓杰 刘禹彤 张丰宇 吴应雄[1] FANG Hong-jie;LIU Yu-tong;ZHANG Feng-yu;WU Ying-xiong(College of Civil Engineering,Fuzhou University,Fuzhou 350108,China;Shenzhen Capol International&Associates Co.,Ltd.,Shenzhen 518000,China)

机构地区：[1]福州大学土木工程学院,福建福州350108 [2]深圳市华阳国际工程设计股份有限公司,广东深圳518000

出　　处：《振动工程学报》2023年第5期1380-1389,共10页Journal of Vibration Engineering

基　　金：国家自然科学基金资助项目(51778149);中国地震局工程力学研究所基本科研业务费专项(2021D03);福建省建设科技研究开发项目(2020,2021)。

摘　　要：土体弹性模量的空间变异性不仅影响输入地震波的特性,考虑SSI效应后还会增加隔震结构动力响应的随机性,影响结构的可靠度。为探究土体弹性模量的空间变异性对隔震结构地震动力响应的影响,将随机场模拟技术与有限元分析结合,实现基于蒙特卡罗模拟的动力“非侵入”随机有限元计算。以典型大底盘隔震结构振动台试验为例,进行确定性与随机有限元分析,计算结构相关响应参数,并使用AIC(Akaike Information Criterion)准则判定响应参数的最优边际分布。结果表明:考虑土体参数空间变异性后,不均匀软土对低频率地震波幅值的放大效应比均质软土更加明显,傅氏谱的峰值增大约14.2%,且谱值分布整体向低频集中;确定性分析低估了SSI效应对隔震结构隔震层加速度的放大作用及隔震层以上楼层的位移响应;经AIC准则检验,使用正态或对数正态分布描述数据的分布并不总是可靠的,需判定最优的拟合边际分布,从而为结构隔震提供更加合理的设计依据。The spatial variability of soil elastic modulus not only affects the characteristics of input seismic waves but also increases the randomness of structure dynamic response and affects the reliability of structure in terms of considering the SSI effect.In order to explore the influence of the spatially variable soil elastic modulus on the seismic response of isolated structures,the random field simulation technology is combined with finite element analysis to conduct the dynamic"non-intrusive"random finite element calcula-tion based on Monte Carlo Simulation.Taking the shaking table test of a typical large chassis isolation structure as an example,the deterministic and random finite element analyses are carried out.The relevant response parameters of the structure are calculated,and the AIC value is used to determine the best-fit marginal distribution of the response parameters.The results reveal that when the spatial variability of soil is considered,the amplification effect of non-homogeneous soft soil on the amplitude of the low-fre-quency seismic wave is more obvious than that of homogeneous soft soil.The peak value of the Fourier spectrum increases by about 14.2%and the distribution of spectral value concentrates to low-frequency.The deterministic analysis underestimates the am-plification impacts of SSI effects on the acceleration of the isolation layer and the displacement response of floors above the isolation layer.According to the AIC value,it is not always reliable to use normal or lognormal distribution to describe the distribution of da-ta.It needs to determine the best-fit marginal distribution of response parameters,so as to provide a more reasonable design basis for structural isolation.

关 键 词：层间隔震 SSI效应 地基空间变异性 随机有限元法 

分 类 号：TU352.12[建筑科学—结构工程] TU317.1