随机地震作用下隧道结构抗震可靠度研究  

Research on seismic reliability of tunnel structure under random earthquake

作　　者：陈之毅[1] 姚宜星 CHEN Zhiyi;YAO Yixing(School of Civil Engineering,Tongji University,Shanghai 200082,China)

机构地区：[1]同济大学土木工程学院,上海200082

出　　处：《地震工程与工程振动》2020年第4期1-7,共7页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金项目(51778464)。

摘　　要：地震引起的地面运动是非常复杂的随机过程,具有时间和频率非平稳的特性。用确定性方法对隧道结构抗震性能的评价未能考虑地震动的随机性。本文提出采用概率密度演化法计算隧道结构在随机地震作用下变形响应的概率分布,并引入变形指标计算其在随机地震作用下的可靠度以评估抗震性能。首先根据概率守恒原理的随机事件描述建立概率密度演化方程;其次,根据相应的初始条件与边界条件,采用总变差不增(TVD)格式的有限差分方法求解方程;最后求和得到隧道结构变形指标的概率分布并依据指标限值给出可靠度。结果表明,在随机地震作用下,隧道结构变形响应的概率分布与地震动强度随时间变化规律一致。采用不同变形指标计算得到的可靠度存在差异,直径变形率对应的结构可靠度为0.752 1,隧道倾斜角对应的结构可靠度为0.875 0。The ground motion induced by earthquake is a very complex random process,which has the characteristics of non-stationary of time and frequency.The randomness of ground motion is not considered in the seismic performance evaluation of tunnel structures by deterministic method.In this paper,the probability density evolution method is used to calculate the stochastic deformation responses of a tunnel structure under random earthquakes.In order to evaluate the seismic performance of the tunnel structure,are introduced into reliability under random earthquake is calculated by introducing deformation indexes.Firstly,based on the random event description of principle of probability preservation,the probability density evolution equation is established.Secondly,according to the corresponding initial conditions and boundary conditions,the finite difference method in total variation diminishing(TVD)scheme is used to solve the equation.Finally,the probability distribution of deformation indexes is obtained by summing,and the reliability value of tunnel structure is given according to limit of indexes.The results show that the probability distribution of deformation response of the tunnel structure under random earthquake is consistent with the law of ground motion intensity changing with time.In addition,the reliability calculated by using different deformation indexes is different.The structural reliability corresponding to the deformation rate of diameter is 0.7521,and the structural reliability corresponding to the inclination angle of tunnel is 0.8750.

关 键 词：随机地震 概率密度演化法 抗震可靠度 评估指标 

分 类 号：U451[建筑科学—桥梁与隧道工程]