2017年6月上第46卷第11期
DI:10.7672/sgjs2017110071
施工技术
CONSTRUCTION TECHNOLOGY
隧道临近下伏承压溶腔开挖稳定性施工工法比选
刘书斌,方勇
（西南交通大学交通隧道工程教育部重点实验室，四川成都610031）
[摘要】临近承压溶腔对隧道开挖不利影响显著，合理的施工工法对保证隧道开挖稳定性至关重要。以某3车道公路隧道为依托，对隧道临近下伏承压溶腔时，运用全断面法、上下台阶法等6种工法开挖进行模拟。监测隧道洞周位移、隧道与溶腔间围岩竖向位移及初期支护内力，分析不同施工工法对隧道开挖稳定性的影响。计算结果表明：工法不同，拱顶下沉、水平收敛增大趋势不同，出现小幅增大的次数也不同；当前溶腔尺寸及内压条件下，最终拱项下沉与水平收敏量大小顺序为全断面法>上下台阶法>三台阶法>侧壁导坑法>弧形导坑法>双侧壁导坑法；地层与隧道间距越大，隧道开挖对地层的影响越小，影响范围向左下、右下方扩散，隧道与溶腔间围岩的稳定性最差；双侧壁导坑法控制拱顶下沉、水平收敛、隧道与溶腔间地层竖向位移效果最好，且能降低仰拱处弯矩与初期
支护偏心距，有利于洞周围岩及初支结构稳定性。【关键词］隧道工程；承压溶腔；施工工法：数值模拟
【中图分类号］U452.2*7
【文献标识码］A
[文章编号】1002-8498(2017)11-0071-06
ConstructionMethods Comparison ofTunnel ExcavationStability
forKarstCaveNearbywithInternalPressure
LIU Shubin,FANG Yong
(MOE Key Laboratory of Transportation Tunnel Engineering, Southwest Jiaotong Uniersity
Chengdu,Sichuan 610031, China)
Abstract :Karst cave with internal pressure nearby has significant adverse effect on tunnel excavation, a reasonable construction method is very important to ensure the stability of tunnel excavation. Based on a three-lane highway tunnel, full section method, benching tunneling method and other four methods are used to simulate the excavation when it is above a karst cave with internal pressure. By monitoring the displacement of the circumference of tunnel,the displacement of the rock between tunnel and cave and the internal force of initial support, the effects of different methods on the stability of tunnel excavation are analyzed. The calculation results show that with the change of method, the increase trends of vault subsidence and the horizontal convergence are also changed, the number of slight increase is also different; under this condition of the karst cave size and internal pressure, the order of final vault subsidence and horizontal convergence size is as follows: full section method > benching tunneling method > three-step method > side heading method > arc heading method > double side heading method; the greater distance between the stratum and the tunnel, the smaller impact of tunnel excavation on the stratum, when it spreads to lower left and lower right, the stability of the surrounding rock between the tunnel and the rock salt caverns is the worst; double side heading method controls the vault subsidence, the horizontal convergence and the vertical displacement of the stratum between the tunnel and the rock salt cavern is best, it can reduce the bending moment at the inverted arch and the eccentricity of the
initial support, it is conducive to the stability of surrounding rock and initial support structure. Key words : tunnels ; karst cave with internal pressure; construction; simulation
【作者简介］刘书斌，硕土研究生，E-mail：52175856@qq-com[通讯作者］方勇，副教投，博士，E-mail：fy980220@swjtu.en【收糖目期]分芳数据
71
本文运用三维数值模拟研究隧道临近下伏承压溶腔时，采用不同施工工法开挖，承压溶腔对隧