特大断面铁路隧道施工过程应力特性研究  

A Study of Stress Evolution During Construction of Extra-Large Cross Section Railway Tunnels

作　　者：赵斌[1] 章慧健[1] 仇文革[1] 

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室土木工程学院,成都610031

出　　处：《现代隧道技术》2014年第1期70-76,共7页Modern Tunnelling Technology

基　　金：铁道部科技研究开发计划项目(2010G016-H);国家自然科学基金青年科学基金项目(51208437);中央高校基本科研业务费专项资金资助项目

摘　　要：为了研究隧道施工中围岩的应力特性,采用能够反映围岩三向应力的I1-J2姨曲线来描述应力路径,并结合摩尔库伦准则,定义安全系数。文章以乌蒙山2号隧道为例,采用FLAC3D软件分析了特大断面铁路隧道施工中的应力路径和安全系数的变化规律。研究结果表明:特大断面铁路隧道分部施工中,隧道左右两侧围岩的应力路径和安全系数变化规律表现出一定的"对称性";当开挖至监测点3m范围时,开挖引起监测点应力值、安全系数迅速减小,其主应力方向发生偏转;施作初期支护后,应力值、安全系数得到一定增加,且趋于稳定;及早地施作各部初期支护有利于控制围岩应力变化,边墙处安全系数长时间小于1.0应予以重视;开挖面通过各监测点后,各监测点的安全系数基本趋于稳定并大于1.0,说明该隧道在本次计算中是安全的。In order to study the stress evolution of a rock mass during tunnel construction, the curve, reflecting the three-dimensional stress of the rock mass, was utilized in combination with the Mohr-Coulomb criteria to demonstrate the stress path and define the safety factor. In this paper, using the Wumenshan Tunnel 2 as an example, FLAC3D software is applied to analyze the evolution of the stress path and safety factor during construction of an extra-large cross section railway tunnel. Results show that during construction of extra-large cross section railway tunnels, the following are true： the evolution of the stress path and safety factor of the rock mass at both sides of the tunnel acts with a certain degree of symmetry during partial construction; while advanced to monitoring points spaced at 3m, the stress value and safety factor at the monitoring points are sharply decreased due to excavation and the deflection of the principal stress takes place; after the completion of the primary support, the stress value and safety factor are certainly increased and tend to be stable; earlier installation of all primary supports is useful to control the evolution of rock stress; the safety factor at the sidewalls is less than 1.0 for a long time, to which more attention shall be paid; when the working face passes through each monitoring point, the safety factor measured at each monitoring point tends to be stable and more than 1.0, which shows the tunnel construction is safe based on this computation.

关 键 词：隧道施工 应力路径 FLAC3D软件 安全系数 

分 类 号：U451.2[建筑科学—桥梁与隧道工程]