岩溶台地高压富水特长隧道勘察的精细化探索

Fine Survey of High Pressure and Rich Water Super Long Tunnel in Karst Platform

岩溶台地高压富水特长隧道精细化勘察应在收集和分析区域地质资料、前期勘察成果、前人研究成果及类似工程案例的基础上,找出主要的水文与工程地质问题,针对这些问题进行水文地质与工程地质调绘和地球物理探测,在此基础上构建地质模型,并采用有针对性的水文地质钻探、工程地质钻探、现场监测与测试及数值仿真等方法与手段,对地质模型进行验证、丰富与优化。以G59呼北高速张家界—官庄段沅古坪隧道为研究对象,为了查明岩溶台地高压富水特长隧道的水文地质与工程地质条件,在水文地质与工程地质测绘、地球物理探测、地质钻探及工程评价等方面进行了精细化勘察的探索与研究,提出了精细化勘察技术思路。根据精细化勘察技术思路,细分隧道区域的地下水系统,划为17个地下水系统,隧道穿越9个地下水系统。采用空气潜孔锤(down-the-hole,DTH)-孔内电视复合方法查清了大湖村段水文地质结构,在此基础上,采用解析法和数值法预测了隧道涌水量,隧道涌水量在150 mm降雨量条件下为26.93×10^(4) m^(3)/d,评价了突水突泥风险,在大湖村岩溶泉系统及柏杨坪岩溶地下河系统为高风险区。

Based on the collection and analysis of regional geological data,preliminary survey results,previous research results and similar engineering cases,the main hydrological and engineering geological problems should be found out in the fine survey of super long tunnel with high pressure and rich water in karst platform.In view of these problems,hydrogeology and engineering geology were mapped,and geophysical exploration was also carried out.On this basis,the geological model was constructed.Targeted hydrogeological drilling,engineering geological drilling,on-site monitoring and testing,numerical simulation and other methods and means were used to verify,enrich and optimize the geological model.The Yuanguping tunnel which is from Zhangjiajie to Guanzhuang section of G59 Hubei expressway as the research object was taken as the research subject.In order to find out the hydrogeological and engineering geological conditions of super long tunnel with high pressure and rich water in Karst platform,the exploration and research of fine survey were carried out in the aspects of hydrogeological and engineering geological mapping,geophysical exploration,geological drilling and engineering evaluation.The idea of fine survey technology was put forward.According to the idea of fine survey technology,the groundwater system in the tunnel area is subdivided into 17 groundwater systems,and the tunnel passes through 9 groundwater systems.The hydrogeological structure of Dahu Village section was investigated by using the composite method of air down-the-hole(DTH)hammer and borehole television.On this basis,the tunnel water inflow was predicted by analytical method and numerical method.The water inflow of the tunnel is 26.93×10^(4) m^(3)/d under the condition of 150 mm rainfall.The risk of water and mud inrush was evaluated.The Karst spring system in Dahu village and the karst underground river system in Baiyangping are high-risk areas.