P波入射下山体-隔震层-隧道的整体响应分析  

Analysis of the overall response of mountain-isolation layer-tunnel under P-wave incidence

作　　者：黄磊 刘翔 刘中宪 段更月[3] 蒋坪临 艾天淳 Huang Lei;Liu Xiang;Liu Zhongxian;Duan Gengyue;Jiang Pinglin;Ai Tianchun(School of Civil Engineering,Tianjin Chengjian University,Tianjin 300384,China;Key Laboratory of Soft Soil Characteristics and Engineering Environment,Tianjin 300384,China;Beijing Zhiyu Tiancheng Design Consulting Co.,Ltd,Beijing 101100,China;Beijing Urban Construction Design and Development Group Co.,Ltd,Beijing 100032,China)

机构地区：[1]天津城建大学土木工程学院,天津300384 [2]天津市软土特性与工程环境重点实验室,天津300384 [3]北京智宇天成设计咨询有限公司,北京101100 [4]北京城建设计发展集团股份有限公司,北京100032

出　　处：《地震学报》2024年第3期526-538,共13页Acta Seismologica Sinica

基　　金：国家自然科学基金(52108466,52278516);天津市教委自然科学基金(2020KJ039)联合资助。

摘　　要：采用高精度间接边界元方法(IBEM)开展了山体-隔震层-隧道的整体响应分析,研究了P波入射下柔性隔震层对高斯形山体内双线隧道地震动响应的减弱作用。在隔震层与围岩之间考虑了碎土的错动滑移,以模拟不完美交界面,并系统讨论了隔震层弹性模量、厚度、P波入射频率等因素对隧道地震动响应的影响。数值模拟结果表明:适当增加隔震层厚度可以显著降低隧道应力,有效提升隔震效果,应力降低幅度约达50%以上,且使得结构受力更为均匀;随着隔震层材料的弹性模量减小,隧道动应力数值明显减小,有效减少了其应力放大区的面积,从而有效避免因地震而导致的衬砌裂缝。As an important transportation facility,the safety and stability of mountain tunnels are of great concern when natural disasters such as earthquakes occur.Seismic wave reflection and coherence effect will occur in the mountain body,and the mountain body,seismic isolation layer,and tunnel as “scattering body” and “secondary source” can change the spatial distribution of ground shaking distribution and values of seismic ground motion.In order to study the influence of isolation measures on seismic wave scattering in double line tunnels within mountains,we uses high-precision indirect boundary element method(IBEM) to analyze the overall response of mountains,isolation layers,and tunnels under P-wave incidence.The isolation effect of flexible isolation layers on double line tunnels crossing Gaussian-shaped mountains.Firstly,a comprehensive computational model was developed.A two-lane lined tunnel is traversed within the Gaussian-shaped mountain,and a seismic isolation layer is set between the tunnel and the mountain site.It is assumed that the mountain site,the tunnel and the seismic isolation layer are all linear isotropic media.In this article,there is not complete consolidation between the tunnel and the surrounding rock,but rather dislocation slip.Therefore,a series of virtual linear springs and dampers are used to connect the isolation layer and the surrounding rock,and a viscoelastic boundary is set to simulate this imperfect boundary.Secondly,wave field analysis was conducted based on elastic wave theory.The formulas for the free field and scattering field are provided in the article,and an equilibrium equation is established based on the displacement and stress continuity conditions at the interface of each computational domain.Solving this equation can obtain the virtual wave source density.Multiplying the concentration of the virtual wave source by the corresponding Green's function can obtain the scattering field of observation points in each domain.The superposition of scattering field and free fi

关 键 词：间接边界元法 山体地形 双线衬砌隧道 隔震层 地震波散射 

分 类 号：P315.31[天文地球—地震学]