非可溶岩隧道突涌灾害预测研究及工程应用

 隧道等地下工程施工过程中，突涌事故一般发生在可溶岩隧道中，然而近些年非可溶岩隧道发生突涌事故的案例越来越多，给隧道施工带来重大灾难和经济损失。首先，通过3个突涌事故案例的剖析，揭示非可溶岩隧道突涌的本质是开挖或爆破扰动触发赋存在破碎带或软弱带中的水和碎屑物在自身压力作用下涌入隧道，其孕险环境必须同时具备物质条件、空间条件和触发条件，三者缺一不可。物质条件是充足的水和砾石、砂、泥等原地性或外源性的碎屑物；空间条件是突涌物的存储和运移的破碎带或软弱带等；触发条件是岩体的开挖扰动和爆破扰动。非可溶岩隧道施工过程中突涌灾害的预测就是对掌子面前方能够赋存潜在突涌物的破碎带或软弱带及其带内物质组成、固结程度的辨识。然后，针对突涌灾害的物质和空间条件给出基于地质、物探和钻探的综合超前预报体系；结合实践，重点建立地震波反射法(TGP)成果中的反射幅度比、波轴相似度等参数对异常地质体的地震动态响应特征。最后，将上述成果应用到岩前隧道的F17断层破碎带的预报中，通过宏观工程地质分析和已开挖段的地质调查及试验，全程动态追踪隧道揭露围岩的统计及力学特征；通过未开挖段长距离的TGP探测和短距离的地质雷达和水平钻孔探测，辨识隧道即将揭露区段突涌灾害的孕险环境，实现对断层破碎带位置、规模、空间展布的精确定位，对带内物质组成及胶结程度的确认，成功预测突涌事故的发生。实践证明，上述综合预报技术体系能够预测非可溶岩隧道的突涌灾害，其结果准确可靠，可为类似工程提供参考和借鉴。

PREDICTION OF INRUSH DISASTER IN NON-SOLUBLE ROCK TUNNEL AND ITS ENGINEERING APPLICATION

Inrush accidents generally happen in soluble rock tunnels during underground constructions. However，the number of inrush disasters reported in non-soluble rock tunnels have been increasing recently. They can lead to serious disasters and huge economic losses in tunnel construction. Cases studies were thus carried out and the analysis of three inrush accidents revealed that the causes of the inrush in non-soluble rock tunnels were due to the effects of excavation and blasting disturbance leading to the water and fragmental materials occurred in the fractured and weak zones flowing into the tunnels under their own pressures. The risks carrying environment must have the required physical，spatial and triggering conditions simultaneously：the physical conditions refers to the existence of abundant water and in-situ or exogenous fragments including gravel，sand and mud，etc.；the spatial condition refers to the fracture zone and the weak zone storing and transferring the inrushing materials；The triggering condition is the disturbance to the rock caused by excavation and blasting during the tunnel construction. The predication of inrush disaster in the construction of non-soluble rock tunnels is therefore to identify the fracture and weak zones containing the potential inrushing materials and the components and cementation level of material in two zones a head of the front face of tunneling. A comprehensive geological and geophysical detection and drilling scheme was then carried out to according to the material and spatial conditions in inrush disaster；The characteristics of seismic dynamic response of the parameters such as the reflection amplitude ratio and the wave axis similarity to anomaly geological objects in tunnel geologic prediction(TGP) were constructed. The approach was applied to the fault fracture zone F17 in anterior tunnels. The macro engineering geological analysis，geological investigation and experiments in excavated sections and the trends tracking were performed to reveal the statistical and mechanical characteristics of the surrounding rocks. The long range TGP and the short range ground penetration radar detections and the horizontal drilling were performed to identify the risks containing environment of inrushing disaster in the section unexcavated. The precise locating of the position，the scale and the spatial distribution of the fault fracture zone were thus be achieved. The material components within the zones and the cementation level were detected and the occurrences of inrush accidents were predicted successfully.