隧道穿越断层破碎带突水突泥机理模拟试验研究

Experimental Study on Simulating Mechanism of Water and Mud Inrush in Tunnel Crossing Fault Fracture Zone

为研究隧道穿越断层破碎带突水突泥灾害发生机理,研发了隧道穿越断层破碎带突水突泥三维模拟试验系统,该系统可同时实现隧道开挖揭露断层破碎带过程的有效模拟、水压恒定加载及围岩位移、渗流压力、涌出物流量的实时监测功能,通过该系统开展了突水突泥物理模拟试验,再现了隧道穿越断层破碎带突水突泥灾害演化发生过程,进一步揭示了突水突泥灾害发生机理。结果表明:从隧道涌出物方面来看,隧道穿越断层破碎带突水突泥灾害为揭露型灾害,当隧道掌子面直接揭露断层破碎带时,突水突泥灾害即发生,突水突泥通道瞬间形成,隧道涌出物由清水转变为泥水混合物,涌出物流量快速增长。从隧道围岩位移及渗流压力方面来看,当隧道揭露断层破碎带发生突水突泥灾害时,隧道拱顶围岩位移、拱顶及拱底渗流压力均发生突变,拱顶围岩位移发生突然增加,拱顶及拱底渗流压力发生突然降低,均反映了隧道穿越断层破碎带突水突泥灾害的瞬发特征。地下水对断层破碎带突水突泥灾害具有重要影响,主要体现在地下水对断层的物理化学弱化和渗流诱发通道扩展两个方面。

In order to study the mechanism of water and mud inrush in tunnel crossing fault fracture zone,a 3D simulation test system for water and mud inrush in tunnel crossing fault fracture zone is developed.The system can simultaneously realize the effective simulation of the process of exposing fault fracture zone during tunnel excavation,the constant water pressure loading,and real-time monitoring the displacement of surrounding rock,the seepage pressure and the flow of effluent.Through this system,the physical simulation experiment of water and mud inrush is carried out,the evolution process of the water and mud inrush disaster when tunnel crossing fault fracture zone is reproduced,and the mechanism of water and mud inrush disaster is further revealed.The research result shows that(1)From the perspective of tunnel effluent,the water and mud inrush disaster of the tunnel crossing fault fracture zone is an exposing disaster.When the tunnel excavation surface directly exposes the fault fracture zone,the water and mud inrush disaster occurs,the water and mud inrush passage is formed instantly,the tunnel effluent changes from clear water to mud-water mixture,and the flow of the effluent increases rapidly.(2)From the perspective of tunnel surrounding rock displacement and seepage pressure,when the water and mud inrush disaster occurs during the tunnel exposing the fault fracture zone,the vault surrounding rock displacement,vault and springing seepage pressures of the tunnel all change suddenly,the vault surrounding rock displacement increases suddenly,and the seepage pressures at vault and springing decrease suddenly,reflecting the instantaneous characteristics of the water and mud inrush disaster in tunnel crossing fault fracture zone.Groundwater has an important influence on the water and mud inrush disaster in fault fracture zone,which are mainly reflected in the physical and chemical weakening of the fault by groundwater and the expansion of seepage induced passage.