地下水示踪试验在岩溶隧道勘察中的应用——以利万高速齐岳山隧道为例  

Application of groundwater tracer tests for karst tunnel investigation——taking Qiyueshan Tunnel of Lichuan-Wanzhou Expressway as the example

作　　者：於开炳 徐蔓 严竞雄 李剑 

机构地区：[1]湖北省交通规划设计院股份有限公司,武汉430051

出　　处：《工程勘察》2017年第10期46-51,共6页Geotechnical Investigation & Surveying

摘　　要：利万高速齐岳山隧道穿越的德胜场—响水洞暗河是齐岳山地区规模最大的岩溶地下暗河系统,最大流量可达4.6m^3/s,利万高速穿越该暗河系统有较高的岩土突水涌泥风险。自宜万铁路齐岳山隧道泄水洞建成后,在暗河系统上游形成了一个新的排泄点,将原地下暗河系统分化为由铁路隧道泄水洞和响水洞暗河出口分别排泄的两个地下水系统。本文通过地下水示踪技术确定了原来完整的天阴桥—团坝子—王家坝—陶家新房子—响水洞地下暗河系统分化为南部的天阴桥—团坝子—泄水洞系统和北部的王家坝—陶家新房子—响水洞系统,两个地下水系统的分水岭位于五同庙牛石嵌与王家坝之间的部位,使得利万高速公路齐岳山隧道出口段响水洞岩溶水系统汇水范围大大缩小,由原来的95.52km^2减小到目前的33km^2。此外,本文通过示踪试验进一步识别了响水洞暗河系统含水介质的高度非均质性——岩溶地下暗河附近岩石的含水性及透水性极强,其地下水渗透流速达v=892m/d;垂直于地下暗河的横向小型岩溶管道的渗透性稍差,其地下水渗透流速为v=442m/d;而发育比较普遍的溶蚀裂隙含水层,即非岩溶管道上岩石的含水性及透水性要小得多,其渗透流速一般在150~250m/d。Qiyueshan Tunnel of the Lichuan-Wanzhou Expressway is designed to cross the DeshengchangXiangshuidong subsurface stream,which is the largest underground river system in the Qiyueshan area with the maximum recorded flowrate of 4. 6m^3/s. Therefore,the risk of water or mud debris ingress into the tunnel is very high when the tunnel crosses the underground stream. Since the completion of the Qiyueshan Tunnel drainage point of the Yichang-Wanzhou railway,a new sink has been artificially created on the upstream of this subsurface system. Therefore the original system is divided into two groundwater flow system with two different discharge points,that is the artificial Qiyueshan Tunnel drainage point and the original Xiangshuidong sinkholes. Through the groundwater tracer technique,the study reveals that the original complete underground river system along Tianyinqiao-Tuanbazi-Wangjiaba-TaojiaxinfangziXiangshuidong sinkhole has evolved into two independent groundwater flow systems： the southern one along Tianyinqiao-Tuanbazi-artificial drainage hole and the northern one along Wangjiaba-TaojiaxinfangziXiangshuidong sinkhole,with the groundwater divider in-between Wutongmiao-Niushiqian and Wangjiaba,resulting in the significant decrease of the watershed area from 95. 52km^2 to 33km^2 for the discharge point of Xiangshuidong sinkhole. In addition, the high heterogeneity of the water-bearing medium of theXiangshuidong underground river system is further identified by using the tracer tests. The permeability of the rockmass near the drainages is extremely high with the velocity of 892m/d,while the permeability of the small-scale karst conduits transversal to the major drainage system is relatively low with the velocity of442m/d. The karstic fractured rock without development of karst conduits has the lowest permeability with the velocity ranging from 150m/d to 250m/d.

关 键 词：地下水示踪试验 岩溶隧道勘察 暗河系统 渗透流速 利万高速 

分 类 号：P641.73[天文地球—地质矿产勘探]