隧道拱部隐伏溶洞下地铁隧道施工地层响应分析  

Strata Response Analysis of Subway Tunnel Construction Under Hidden Karst Caves in the Tunnel Arch

作　　者：黄松 HUANG Song(Guiyang Public Transport Investment and Operation Group Co.,Ltd.,550081,Guiyang,China)

机构地区：[1]贵阳市公共交通投资运营集团有限公司,贵阳550081

出　　处：《城市轨道交通研究》2024年第12期206-212,218,共8页Urban Mass Transit

基　　金：国家自然科学基金项目(51991394)。

摘　　要：[目的]在城市地铁隧道工程中,常会遇到隧道拱部浅埋隐伏溶洞的情况,因此有必要对隧道拱部隐伏溶洞工况下的地铁隧道施工地层响应进行研究。[方法]采用室内模型试验对隧道开挖过程进行模拟,通过分析监测隧道施工过程中的地层围岩变形、土压力释放、初支拱架内力及地面沉降规律,研究隧道施工对岩溶地层的扰动影响。[结果及结论]Ⅳ级围岩下,当开挖隧道跨度为6.52 m、隧道拱部溶洞直径为4 m、溶洞底与隧道顶部净距为2 m时,隧道机械开挖下,隧道拱部隐伏溶洞围岩能够保持稳定,不会发生围岩失稳破坏。拱顶溶腔工况下,隧道拱顶处的围岩土压力变化量明显小于无溶腔工况下的围岩土压力变化量,其最终量值为无溶腔时的53.8%。拱部隐伏溶腔的存在会增大地面沉降范围,开挖隧道顶部正上方处的地面沉降峰值是无溶腔工况下的1.73倍。隧道拱顶发育溶腔时,拱架拱顶处的轴力值为无溶腔工况下的120.3%,拱顶处弯矩值为无溶腔工况下的53.3%。[Objective]In urban subway tunnel projects,it is common to encounter shallow-buried hidden karst caves in the tunnel arch.Therefore,it is necessary to study the strata response of subway tunnel construction under such condition.[Method]The indoor model test is used to simulate the tunnel excavation process.By analyzing and monitoring the deformation of surrounding rock,release of soil pressure,internal force of primary support arch and ground settlement laws during tunnel construction,the disturbance effect of tunnel construction on karst strata is studied.[Result&Conclusion]Under Grade IV surrounding rock,when the excavation tunnel span is 6.52 m,the tunnel arch cave diameter is 4 m,and the net distance from cave bottom to metro tunnel top is^(2) m,the surrounding rock of the hidden cave in the tunnel arch could maintain stability under mechanical excavation of the tunnel,with no surrounding rock instability and damage.Under the condition with vault cavity,the change amount of surrounding rock soil pressure at the tunnel vault is significantly smaller than that under the condition without cavity,and the final value of surrounding rock soil pressure in the former condition is 53.8%of that in the latter condition.The existence of hidden cavity in the arch will increase the range of ground settlement,and the peak ground settlement value directly above the top of the excavation tunnel is 1.73 times that under the condition without cavity.When the tunnel vault develops cavity,the axial force value at the arch vault is 120.3%of that under the condition without cavity,and the bending moment value at the vault is 53.3%of that under the condition without cavity.

关 键 词：地铁隧道 隐伏溶洞 施工地层响应 

分 类 号：U451.5[建筑科学—桥梁与隧道工程] U231.3[交通运输工程—道路与铁道工程]