State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400030, China.
School of Resources and Safety Engineering, Chongqing University, Chongqing, 400030, China.
Environ Sci Pollut Res Int. 2020 Mar;27(8):8046-8057. doi: 10.1007/s11356-019-07419-6. Epub 2020 Jan 2.
The co-placement of mine tailings and fly ash (CMF) can reduce acid mine drainage (AMD) production and decrease metal mobilization. This aids in waste management construction. However, few people have studied a large number of tailing sand-fly ash mixtures under the condition of neutral saturated solution in tailing ponds, wherein the pozzolanic reaction is highly gradual. In this study, a series of tests were conducted to determine the monotonic and cyclic shear characteristics of a mixture of fly ash and tailings. In particular, the effects of the fly ash content on the monotonic shear peak, shear strength parameters, dynamic modulus, and damping ratio of the mixture were analyzed. The results reveal that in a monotonic shear test, the peak shear strength of the saturated CMF mixture decreases as the fly ash content increases. The shear strength parameters (cohesion c and internal friction angle φ) were observed to increase and decrease linearly, respectively, as the fly ash content increased. Furthermore, the maximum dynamic shear modulus was observed to decrease by 41.4% as the fly ash content increased from 0 to 50%, during the cyclic cutting process. Moreover, the experimental results fit well with the fitting formula for the variation in shear modulus in the cyclic shear process of the saturated CMF mixture with varying fly ash content. Meanwhile, the initial damping ratio of the cyclic shear was observed to increase from 10.3 to 13.6% as the fly ash content increased. Therefore, when the CMF method is used to treat AMD waste, it is necessary to consider the extent to which the design stability of the tailing pond may be reduced. These experimental results can be used as a reference for similar CMF projects.
共生尾矿和粉煤灰（CMF）的放置可以减少酸性矿山排水（AMD）的产生并降低金属的迁移。这有助于进行废物管理建设。然而，很少有人在尾矿库中性饱和溶液条件下研究大量的尾矿砂-粉煤灰混合物，其中火山灰反应非常缓慢。在这项研究中，进行了一系列测试以确定粉煤灰和尾矿混合物的单调和循环剪切特性。特别是，分析了粉煤灰含量对混合物的单调剪切峰值、剪切强度参数、动模量和阻尼比的影响。结果表明，在单调剪切试验中，饱和 CMF 混合物的峰值剪切强度随粉煤灰含量的增加而降低。随着粉煤灰含量的增加，剪切强度参数（凝聚力 c 和内摩擦角 φ）分别呈线性增加和减小。此外，在循环剪切过程中，当粉煤灰含量从 0 增加到 50%时，最大动剪切模量下降了 41.4%。此外，实验结果与循环剪切过程中饱和 CMF 混合物剪切模量随粉煤灰含量变化的拟合公式吻合较好。同时，随着粉煤灰含量的增加，循环剪切的初始阻尼比从 10.3%增加到 13.6%。因此，当使用 CMF 方法处理 AMD 废物时，有必要考虑尾矿库设计稳定性可能降低的程度。这些实验结果可以作为类似 CMF 项目的参考。
