隧道塌方、涌水往往发生在地质条件差的地段,有必要从地质角度研究该类灾害发生机制.文章以十房高速(十堰—房县)通省隧道塌方、涌水为例,分析了灾害发生过程,归纳总结了其典型的围岩大变形—塌方—涌水—突泥四阶段特征.在此基础上,结合隧道地质条件分析、隧洞内及地表地质调查、TRT探测等,从工程地质和水文地质角度探讨了隧道塌方、涌水灾害机理,认为主要有四个方面的原因:(1)隧道穿越压性断层破碎带,断层破碎带由含水破碎岩块及粘土构成,直接导致隧道开挖后塌方、涌水、突泥的发生;(2)推覆构造导致围岩呈层状-碎裂结构;(3)片岩中粘土矿物含量较高,遇水易泥化;(4)断层破碎带中含有承压地下水.最后,提出了加强超前地质预报及地质分析等风险规避建议,研究结果可为同类工程提供借鉴.%Collapse and water inflow often occurs in regions with unfavorable geological conditions, and it is necessary to study this mechanism from a geological point of view. Taking the collapse and water inflow event in the Tongsheng Tunnel of the Shiyan-Fangxian Highway as an example, the development process of the disaster is analyzed and the typical phase characteristics of the deformation, collapse, water inflow and mud bursting in the surrounding rock are summarized. Based on the geological condition analysis, the geological survey for inside the tunnel and on the ground surface, and the TRT detection, the mechanism of tunnel collapse and water inflow is discussed from the perspectives of engineering geology and hydrogeology. The following conclusions are reached: 1) the tunnel passes through the compressive fault fracture zone, which is composed of broken rock and clay containing water, and it directly leads to the occurrence of collapse, water inflow, and mud bursts after tunnel excavation;2) the nappe structure causes layering and fracturing in the surrounding rock;3) with a high content of clay minerals in the schist, mud is easily created when water is encountered;and 4) the fault fracture zone contains confined groundwater. Finally suggestions for strengthening geological predictions and geological analyses are proposed.
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