三维贯通节理对大跨隧道围岩稳定性的影响  

Influence of three‐dimensional persistent joints on surrounding rock stability of large-span tunnel

作　　者：林聪波 俞缙[1] 常方强[1] 付晓强 姚玮 蔡燕燕[1] LIN Congbo;YU Jin;CHANG Fangqiang;FU Xiaoqiang;YAO Wei;CAI Yanyan(Fujian Research Center for Tunneling and Urban Underground Space Engineering,Huaqiao University,Xiamen 361021,China;School of Civil Engineering,Sanming University,Sanming 365004,China)

机构地区：[1]华侨大学福建省隧道与城市地下空间工程技术研究中心,福建厦门361021 [2]三明学院建筑工程学院,福建三明365004

出　　处：《中南大学学报（自然科学版）》2023年第3期1141-1152,共12页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(42077254,51874144)。

摘　　要：为了探究贯通节理对大跨隧道围岩稳定性影响规律,运用3DEC软件结合离散元强度折减法,以剪切滑移区面积指标为稳定性判据计算大跨隧道围岩安全系数,分析三维状态下节理的走向、倾角、间距、力学参数对围岩稳定性的影响规律。研究结果表明:在大跨隧道围岩中,节理倾向影响稳定性程度由大到小依次为X向、Z向、Y向,仅有单向节理时,ψ>60°时围岩较不稳定;在双向节理组合下,节理倾角致使隧道失稳的经验判别式;节理间距对大跨隧道稳定性的影响程度根据不同块体形状而产生差异,拱顶分布长条形块体时影响最大,洞周分布尖条形块体时影响最小;节理力学参数对大跨隧道稳定性影响程度由大到小依次为内摩擦角、法向刚度、切向刚度、黏聚力;大跨隧道围岩节理倾角由水平到垂直的过程中,围岩变形破坏由拱顶沉降、拱底隆起转变为以拱顶、拱肩大变形及滑移为主。研究结果可为节理岩体中大跨隧道围岩稳定性判定及支护优化提供借鉴。In order to explore the regularity of influence of variation through joint characteristics on the stability of surrounding rocks of large-span tunnels,3DEC software and discrete element strength reduction method were used.The surrounding rock safety factor of large-span tunnel was calculated based on shear slip zone area index as stability criterion.The influence of joint strike,joint dip,and joint spacing on the surrounding rock stability in the three-dimensional state were analyzed.The results indicate that the influence degree of joint tendency on the stability of surrounding rocks of large-span tunnels from large to small is X−direction,Z−direction and Y−direction.The surrounding rock is unstable when the inclination is greater than 60°with only one direction joint.The empirical discriminant of tunnel instability caused by joint inclination with the two-direction joints combination is obtained.The degree of influence of joint spacing on the stability of large-span tunnels varies according to the shape of the blocks,with the greatest influence occurring when long blocks are distributed around the vault and the least when pointed blocks are distributed around the cavern perimeter.The influence degree of joint mechanical parameters on stability of long-span tunnel from large to small isφJ,Kn,Ks and cJ.During the process of joint inclination from horizontal to vertical in the surrounding rock of large−span tunnels,the deformation and damage of surrounding rock are transformed to be dominated by large deformation and slippage of vault and arch shoulder.The research results can provide a reference for the determination of rock stability and support optimization of large-span tunnels in jointed rock masses.

关 键 词：贯通节理 大跨隧道 稳定性 离散元 强度折减法 

分 类 号：U45[建筑科学—桥梁与隧道工程]