尾矿砂物理力学性能测试及坝体稳定性分析

Physical and mechanical properties test of tailing sand and stability analysis for tailings dam

为测试某上游式尾矿库内尾矿砂的物理力学性能,并论证坝体当前稳定性,通过室内土工试验和BI-90Plus型激光粒度分析仪对原状尾矿砂进行全面测试与分析,得到尾矿砂13项基本物理性质指标和4项力学性质指标,同时计算3种工况下的坝体稳定性安全系数。研究结果表明:铜尾矿为细粒尾矿,渗透性差、可塑性强且膨胀性和收缩性显著,粒径大小及其含量近似呈Gauss分布;细粒尾砂含量越高,黏聚力越强,而内摩擦角和渗透系数越小,且差异达数倍至数十倍,分析认为这可能与尾矿颗粒中黏粒含量有关;3种工况下计算出的最小安全系数均明显大于规范要求值,表明其稳定性较好;按照尾矿颗粒级配和物理力学特性科学、合理的放矿,对坝体稳定性至关重要。试验结果可为研究尾矿砂的工程力学特性和坝体稳定性提供详实的数据支撑。

It is to test the physical and mechanical properties of the tailings in an upstream tailings pond and to demonstrate the current stability of the dam. Through the indoor soil test and the BI-90Plus laser particle size analyzer, the original tailings were thoroughly tested and analyzed. Thirteen basic physical property indexes and four mechanical property indexes of tailings sand were obtained. At the same time, the safety coefficient of dam stability under three conditions was calculated. The results show that copper tailings are fine tailings with poor permeability, strong plasticity, and significant swelling and shrinkage. The particle size and its content approximate Gauss distribution. As the content of fine tailings increases, the cohesion tends to be stronger, whereas the internal friction angle and the permeability coefficient seems to decrease gradually. The difference reached several times to dozens of times. This may be related to the amount of clay in the tailings. The minimum safety factor calculated under the three conditions is obviously greater than the specification requirements, indicating that the stability is better. According to the science of grading and physical and mechanical properties of the tailings, and reasonable ore discharge, it is crucial to the stability of the dam body. The test results provide detailed data support for studying the engineering mechanical properties of tailings and the stability of the dam.