强降雨条件下某铅锌矿尾矿堆积坝安全稳定性分析

强降雨是影响尾矿坝安全的重要因素之一,同时尾矿堆积坝在建造的过程中随着选矿工艺的改变堆坝尾砂的粒径分布也随之变化。为了研究不同组构尾矿堆积坝在强降雨条件下的稳定性,以湖南某铅锌矿尾矿堆积坝为研究对象,在分析该尾砂坝各级堆积子坝的尾矿砂物理力学性质的基础上,采用数值模拟方法研究了该尾矿坝在强降雨作用下不同时期堆积子坝的稳定性。研究表明:1)不同高度堆积子坝的尾砂组构不同,其不均匀系数、曲率系数以及黏聚力不同,尾矿堆积坝的安全系数与尾砂黏聚力呈正相关关系,与尾砂的不均匀系数呈正比,与曲率系数呈反比;2)相同降雨强度,降雨时长的增加对尾矿堆积坝整体稳定性影响小,但对坝坡表面及一定深度的尾砂有影响,其负孔隙水压力减小,坝体松散,影响坝坡稳定;3)尾矿堆积坝各部位能承受的最大剪应变与尾砂的黏聚力呈正相关关系,且黏聚力大的坝体的最大剪应变在各个区域都较黏聚力小的坝体有较大剪应变。实际堆积坝施工过程中可通过尾砂组构来分析坝体在强降雨作用下的稳定性。

Safety and stability analysis of a lead zinc mine tailings fill dam under heavy rainfall

Strong rainfall is one of the important factors affecting the safety of tailings dams. At the same time, the size distribution of the tailings changes with the change of the beneficiation process during the construction of the tailings dam. In order to study the stability of tailings fill dams with different structures in heavy rainfall conditions, a lead-zinc ore tailings dam in Hunan Province was selected as the research object, and the physical and mechanical properties of the tailings of fill dams at each level of the tailings dam were analyzed. In the above, the numerical simulation method was used to study the stability of the different periods tailings fill dams under heavy rainfall. The results show that, (1)Tailings fill dams with different periods have tailings with different particle size distribution, which have different non-uniform coefficient, curvature coefficient and cohesion force. The safety factor of tailings fill dam is positively related to the cohesion of tailings, and proportional to the non-uniform coefficient of tailings, and inversely proportional to the curvature coefficient of tailings. (2) The increasing rainfall duration has little effect on the overall stability of the tailings dam under the same rainfall intensity, but has an impact on the dam slope surface and a certain depth of the tailings dam. The negative pore water pressure is reduced and the dam body is loose, which affects the stability of the dam slope. (3) The maximum shear strain at each site of the fill dam is positively correlated with the cohesion of the tailings, and the maximum shear strain of the dam with large cohesion force is greater than the dam with small cohesion force in each area. During the actual construction of the dam, the stability of the dam under heavy rainfall can be analyzed through the size distribution of the tailings.