穿越软硬地层的盾构区间隧道三维地震时程响应分析  

Analysis of Three-dimensional Seismic Time-History Response for Shield Tunnel through Soft-hard Stratum Junction

作　　者：赵继 林放 ZHAO Ji;LIN Fang(National Engineering Laboratory for Green&Safe Construction Technology in,Urban Rail Transit,Beijing Urban Constructioh Design&Development Group Co.Ltd.,Beijing 100037,China)

机构地区：[1]北京城建设计发展集团股份有限公司城市轨道交通绿色与安全建造技术国家工程实验室,北京市100037

出　　处：《公路》2019年第1期278-284,共7页Highway

基　　金：国家重点研发计划;项目编号2017YFB1201104;国家自然科学基金资助项目;项目编号51508477

摘　　要：以徐州一穿越软硬地层的区间隧道为工程背景,研究和分析穿越软硬地层的盾构区间隧道结构在设防地震和罕遇地震作用下的结构抗震性能。利用Midas GTS/NX大型有限元程序建立三维有限元"地层-结构"动力模型,采用时程分析法,把地震运动视为一个随时间变化的过程,并将地下结构物和周围土体介质视为共同受力变形的整体,通过直接输入地震加速度记录,分析了结构的径向变形和结构动力力学特性。基于场地条件下的穿越软硬地层的盾构区间,在设防地震下最大径向变形率为0.122%,小于1/250;罕遇地震下,最大径向变形率为0.231%,小于0.6%,满足结构变形要求;结构断面最大弯矩值为121.6kN·m,结构轴向内力最大值为583kN/m,满足断面配筋承载能力要求。研究结果表明:内力和变形较大处都发生在土体刚度变化较大处,盾构环的下半部呈现区间最大受拉状态;应在土层性质急剧变化处设置变形缝。A section of tunnel project which goes through soft and hard stratum in Xuzhou is taken as project background,the seismic behavior of shield tunnel structures passing through soft and hard strata under the action of fortified earthquakes and rare earthquakes are studied and analyzed.The Midas GTS/NX large-scale finite element program is used to establish a three-dimensional finite element "stratumstructure"dynamic model,by means of time-history analysis method,the seismic motion is regarded as a time-varying process,and the underground structure and surrounding soil medium are treated as a whole body which deforms together due to common force,the radial deformation and structural dynamics of the structure are analyzed by directly inputting the seismic acceleration record.Based on the shield section crossing the soft and hard stratum under the site conditions,the maximum radial deformation rate under the fortified earthquake is 0.122%,less than 1/250;the rare radial deformation rate is 0.231%,less than 0.6% under rare earthquakes,which meet the structural deformation requirements;the maximum bending moment value of the structural section is 121.6 kN·m,and the maximum axial internal force of the structure is 583 kN/m,which satisfies the requirements of the section reinforcement capacity.The results show that the internal force and deformation occur in the soil stiffness change,and the lower half of the shield ring presents the maximum tension state.The deformation joint should be set at the sharp change of soil properties.

关 键 词：隧道 软硬地层 盾构 抗震性能 三维时程 分析 

分 类 号：U455.43[建筑科学—桥梁与隧道工程]