化学淤堵作用下尾矿砂孔隙分布及渗透特性试验研究

对石板沟尾矿库调研采样,分析尾矿砂表面化学元素并确定钙离子为造成该库化学淤堵的主要元素.添加氯化钙溶液改变尾矿砂中的钙离子含量,采用渗流试验装置及核磁系统观测不同溶液浓度和水力梯度作用下尾矿砂孔隙分布、孔隙率和渗透系数的时序变化规律,分析其影响因素.结果表明:核磁共振系统能准确地获得尾矿砂在不同条件下的孔隙率和孔隙分布...

Experimental study on the pore distribution and permeability characteristics of tailing sand under chemical clogging

The chemical elements on the surface of tailing sand were analyzed and calcium was found to be the main element causing the chemical clogging in Shibangou Tailing Reservoir. Calcium chloride solution was added to the samples to change the calcium content. The seepage test equipment and the nuclear magnetic resonance (NMR) system were used to observe the time series changing pattern of the porosity, pore distribution and permeability coefficient of the tailing sand under the action of different solution concentrations and hydraulic gradients, and then the influencing factors were analyzed. The results show that the NMR system can accurately obtain the porosity and pore distribution of the tailing sand under different conditions. The larger the solution concentration and the longer the action time, the more obvious the clogging effect gets, the smaller the porosity, pore size and permeability coefficient become. The permeability damage caused by high hydraulic gradient will slow down the clogging process. There is an obvious negative exponential relationship between the permeability coefficient and the action time under different concentrations. The established empirical model for the prediction of the permeability coefficient can provide some reference for the seepage control analysis and safe operation of tailing reservoirs.