隧道涌水段不良地质探测及围岩变形规律研究

Research on Unfavorable Geological Condition Prediction and Rock Mass Deformation In Tunnel Section with Water Inflow

在富水地层中开挖隧道出现涌水事故后,若继续盲目施工易引发隧道坍塌,此时应停止开挖,探明涌水段周围地质条件与岩体变形。以大奎隧道右线出口处涌水事故为背景,从地质雷达和变形监测2方面进行研究分析。地质雷达探测结果显示隧道底板左下方2.5 m处存在承压水层,且隧道衬砌背后存在巨大暗道。变形监测表明多个里程断面岩体变形超过50 mm,高于规范要求的安全界限。基于探测结果,提出了混凝土回填、超前注浆止水及架立钢支撑支护的处理方案,涌水段围岩变形最终得到了控制。

Collapse may occur to if water inflow occurs during tunneling. In such case, the excavation should be stopped and the geological conditions and rock mass deformation in the water-inflow section should be predicted. Water inflow occurs near the exit of the right tube of Dakuishan tunnel. Ground penetrating radar （GPR） is used to predict the geological conditions of the water-inflow tunnel section. Analysis is made on the predicted geological conditions and the measured deformation data. The geological prediction results show that there is a confined water aquifer 2.5m below the tunnel floor and there is a huge cavity behind the tunnel lining. The deformation monitoring results show that the rock mass deformation exceeds 50 mm, which is higher than the limit value specified in relevant standards. Countermeasures, including concrete backfilling, advance grouting and steel rib installing, are taken on basis of the prediction results. In the end, the deformation of the tunnel section with water-inflow is brought into effective control.