隧道纵向地震反应分析的反应位移法对比  

Response displacement methods for longitudinal seismic response analysis of tunnel structures

作　　者：刘晶波[1] 王东洋[1] 谭辉[1] 宝鑫[1] LIU Jingbo;WANG Dongyang;TAN Hui;BAO Xin(Department of Civil Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学土木工程系

出　　处：《振动与冲击》2019年第21期104-111,132,共9页Journal of Vibration and Shock

基　　金：国家自然科学基金(51478247)

摘　　要：针对地下隧道结构纵向地震反应问题,《城市轨道交通结构抗震设计规范》(GB 50909-2014)采用了纵向反应位移法,在一定程度上考虑了地震动作用下土体与地下结构的相互作用。而纵向整体式反应位移法,是一种可用于非一致地震动输入时隧道等长线型地下结构抗震分析的实用方法。以北京某地铁区间盾构隧道结构为研究对象,采用规范方法和纵向整体式反应位移法完成了出平面剪切波斜入射下隧道结构纵向地震反应计算,并与动力时程法的计算结果进行对比。结果表明,规范方法计算模型中离散的地基弹簧无法反映地基土体之间的相互作用、可能导致内力(主要是剪力)计算出现较大的误差;假定沿隧道纵向土层位移分布为正弦波式的规范方法由于正弦波型与实际情况不符,导致内力计算结果与动力时程结果相差过大;而以自由场位移时程作为等效地震作用的规范方法计算得到的最大弯矩具有良好的计算精度,但最大剪力与动力时程方法相差较大,同时这一方法需完成所有时间步的静力计算才能获得结构最不利地震反应,影响了计算效率。而纵向整体式反应位移法可以有效模拟地震作用下地基土对结构的约束作用、简便的判断结构最不利地震反应时刻,具有良好的计算精度、较高的计算效率,能够反映地震波作用下非一致地震动输入对隧道纵向地震反应的影响。Aiming at longitudinal seismic response problems of underground tunnel structures, the longitudinal response displacement method is suggested by the "Code for aseismic design of urban rail transit structures". This approach takes the soil-structure interaction into consideration to a certain extent. Here, the longitudinal overall response displacement method was introduced, and it was a kind of the pseudo-static method for seismic response analysis of linear underground structures under non-uniform seismic input. Taking a certain shield tunnel in Beijing as the study object, the specification method and the proposed method were adopted, respectively to perform its longitudinal seismic response computation under SH wave oblique incidence. The results were compared with those using the dynamic time-history method. The results indicated that discrete foundation springs in the computation model of the specification method can’t reflect interactions among ground soil bodies to possibly cause larger errors of internal forces mainly containing shear forces;if assuming the longitudinal soil layer displacement distribution be a sinusoidal wave mode in the specification method, due to the sinusoidal wave mode being inconsistent with real situation, so the computation results of internal forces are too different from those of the dynamic time history method;if taking the free-field displacement time-history as the equivalent seismic action in the specification method, the computed maximum bending moments have good computation accuracy, but the computed maximum shear forces are too different from those of the dynamic time history method, the specification method needs to complete static forces computation in all time steps and then can obtain the most unfavorable seismic response, so its computation efficiency is poor;while the proposed method can effectively simulate constraint action of ground soil on the tunnel structure, it can be easy and simple to determine the time instant of the unfavorable structural seismic respo

关 键 词：隧道结构 纵向地震反应 反应位移法 整体式反应位移法 非一致地震动输入 

分 类 号：TU91[建筑科学—建筑理论]