岩溶地区某尾矿库尾砂渗漏探查与治理

Exploration and control of tailings leakage in a tailings reservoir in karst area

某尾矿库位于岩溶地区,雨季库区出现塌陷,且下游溶洞口尾砂泄漏,造成当地水土体污染。经现场调查及库区水文地质条件初步分析,认为库区岩溶塌陷导通岩溶管道是尾砂泄漏的主要原因。采用EH4连续电导率剖面仪与五极纵轴测深相结合的综合物探方法,先进行EH4探测,再在EH4圈定的异常部位进行五极纵轴测深,发现在库区岩溶洼地中间发育一条北东向断层及其次生构造,且沿构造附近地表以下80m范围内有大量低阻区,推测为库区的主要过水通道。采用地面帷幕注浆方法,利用钻探查清了尾砂渗漏的主要岩溶通道;利用理论公式计算确定了骨料投入量,并采用“投骨料-注双液浆-注水泥单液浆”的动水注浆技术对大型溶洞或岩溶管道进行了有效封堵。经帷幕注浆治理后,库区内未再出现塌陷情况,下游也未见尾砂泄漏。实践表明,综合物探探测技术与地面帷幕注浆方法能有效解决尾砂渗漏通道探查与治理问题,可为今后类似尾矿库渗漏治理提供借鉴。

A tailings reservoir is located in the karst area,and the tailings leakage in the downstream of the rainy season causes local water and soil pollution.After field investigation and preliminary analysis of the hydrogeological conditions in the reservoir area,it is believed that the main cause of tailings leakage is karst collapse in the reservoir area connecting to karst pipelines.Using a comprehensive geophysical prospecting method combining EH4 continuous conductivity profiler and five-pole electrical sounding,EH4 detection is carried out firstly,and then five-pole electrical sounding is conducted at the abnormal location delineated by EH4.It is found that a northeast trending fault and its secondary fault structure are developed in the middle of the karst depression in the reservoir area,and there are large number of low-resistance areas within 80 m below the surface along the structure,which are presumed to be main water channels.Using the ground curtain grouting method,the main karst channels of tailings leakage are identified by drilling.The aggregate input is determined by theoretical formula calculation,and the dynamic water grouting technology of adding aggregate firstly,then injecting double slurry and then injecting cement single slurry is used to effectively block large karst caves or karst pipelines.Other karst and fault structures are grouted and blocked by ordinary grouting technology.After the curtain grouting treatment,there is no collapse in the reservoir area and no tailings leakage in the downstream.The practice shows that the comprehensive geophysical prospecting technology and the ground curtain grouting method can effectively solve the problem of the exploration and control of the tailings leakage channels,and can provide a reference for similar tailings leakage control in the future.