软弱隧道围岩拱顶塌方模型试验及其数值模拟

Model Test and Numerical Simulation of Tunnel Collapse in Weak Rock Mass

在软弱岩体中修建隧道,塌方是常见的事故之一,严重威胁施工人员安全、阻碍施工进度,从而增加工程投资成本。以Ⅳ级围岩为研究对象,采用模型试验和数值模拟手段对软弱岩体拱顶塌方破坏机理开展了研究,并得出结论,隧道开挖后,软弱围岩塌落破坏成拱,表明围岩具有一定的自承能力;随着隧道开挖的进行,围岩应力重分布呈现出阶段性特征,拱顶上方约一倍洞径高度范围内的围岩受扰动明显,是施工应重点加强支护的区域;隧道塌方破坏会引起地层的位移,故在施工中应对地层活动进行实时监控量测,并以此为依据反馈指导设计和施工。

Tunnel collapse is one of the most common accidents during tunneling construction in weak and soft rock,which seriously causes threat to the safety of workers,hinders the construction schedule,thereby increases the cost of project.In this paper,the weak rock mass of grade IV is taken as research object,and the collapse mechanism of rock mass above tunnel arch is studied with model test and numerical simulation.Following conclusions are drawn：（1）after the tunnel excavation,the weak surrounding rock mass collapses into arch shape,which indicates that the surrounding rock has a certain self-bearing capacity.（2）During the process of tunnel excavation,the stress redistribution of surrounding rock shows the stage characteristic,and the surrounding rock within the range of one times of tunnel span above the arch is disturbed obviously,which should be strengthened in the construction.（3）Tunnel collapse will cause the ground movement,so it is necessary to carry out real-time monitoring on ground deformation,which can be used to guide the tunnel design and construction activities.