大断面黄土隧道变形特征分析  

Analysis on Deformation Characteristics of Large-section Loess Tunnel

作　　者：扈世民[1,2] 张顶立[1] 郭婷[2] 杨秀仁[2] 苏洁[1] 

机构地区：[1]北京交通大学隧道及地下工程实验研究中心,北京100044 [2]北京城建设计研究总院有限责任公司,北京100037

出　　处：《铁道学报》2012年第8期117-122,共6页Journal of the China Railway Society

基　　金：国家重点基础研究发展计划(973计划)(2010CB732100);铁道部科技研究开发计划重大项目(2009G005)

摘　　要：以兰渝铁路大断面黄土隧道为工程背景,采用三维数值模拟结合现场试验,对台阶法施工中围岩深部变形特征进行分析;研究围岩纵向变形规律并预测先期位移;研究预留核心土对围岩变形的控制效果。结果表明:围岩拱部竖向位移弱化较慢,而边墙水平位移弱化较快,水平收敛普遍小于拱顶沉降;隧道纵向先期位移约占总位移的31%～38%,预留核心土可有效控制围岩纵向变形;纵向位移与围岩弹性模量成反比,Hoek曲线与数值计算结果较接近,特别是掌子面前方较好吻合,数值计算先期位移占总位移的33%;预留核心土有效降低掌子面的临空范围,有利掌子面稳定;核心土适宜预留长度为2R/3(R为隧道换算半径);数值计算和实测的围岩变形规律基本一致。Taking the large-section loess tunnel of the Lanzhou-Chongqing Railway as the engineering background,site monitoring and 3D numerical simulation were conducted to analyze the deep-depth deformation features of the loess surrounding rock in the process of bench-method construction. The law of longitudinal deformation of surrounding rock was studied and displacements were predicted. The control effects of reserved core soil on deformation of surrounding rock were researched. The results show as follows .Vertical displace- ments of the crown of arch weaken slowly whereas horizontal displacements of the side wall weaken rapidlyl horizontal convergence is generally less than crown settlement; previous longitudince displacements occupy 31% ~38% of the total of displacements,longitudinal deformations are controlled effectively by reserved core soil; the longitudinal deformation is inversely proportional to the elastic modulus of surrounding rock; the results are closer between the Hoek curve and the numerical simulation, especially in front of the working face; previous displacements are accounted for 33% by numerical simulation; the range of free working face is effectively reduced with reserved core soil,which is beneficial to stability of the working face,the suitable reserved length of core soil is 2R/3, R is the conversion radius of tunnel;the law of deformation of surrounding rock remains basically the same in site measurement and in numerical calculation.

关 键 词：大断面 黄土隧道 纵向变形 三维数值模拟 

分 类 号：TU443[建筑科学—岩土工程]