云南卡房尾矿库固结试验与机理研究

Consolidation Test and Mechanism Study of Kafang Tailings Reservoir in Yunnan Province

随着国内矿山的开采规模不断扩大,尾矿库的安全问题越来越受到关注,而尾矿颗粒的固结程度又直接影响着尾矿坝体的稳定性,所以对其进行研究十分必要。以云南卡房尾矿库为例,通过室内试验模拟该尾矿库中尾粉砂及尾粉土的淋滤固结过程,分析了固结方式、淋滤方式、淋滤次数对砂土体固结程度的影响。试验结果表明:尾矿液淋滤后的砂土体的沉降量及力学指标比清水淋滤后的砂土体高,固结程度更强;随着单次淋滤时间和总淋滤次数的增加,砂土体的沉降量会逐渐增大,但沉降速率会逐渐降低并最终趋于稳定。通过对尾矿颗粒微观结构的观测和对水化学场的变异分析,推演了卡房尾矿库的化学固结过程。通过对卡房尾矿多种固结作用机理进行综合分析得出:卡房尾矿库存在自重固结、淋滤固结、化学固结等多种固结形式,尾矿砂土的沉降及力学指标的提高是3种形式共同作用的结果,淋滤及化学固结作用往往发生在饱和-非饱和状态交替的区域,无交替状态的区域则由自重固结主导;淋滤固结对于浅部尾矿影响较大,化学固结对深部尾矿影响大。上述分析对于尾矿颗粒固结特性的理论研究及实践应用有一定的借鉴意义。

With the continuous expansion of the mining scale of domestic mines,the safety of tailings reservoir has been paid more and more attention,and the degree of consolidation of tailings particles directly affects the stability of tailings dam,so it is of academic value and practical significance to study it.In this paper,taking Kafang tailings reservoir in Yunnan Province as an example,the leaching consolidation process of tailing silt and tailing silt in the tailings reservoir is simulated by laboratory test,and the influence of consolidation mode,leaching mode and leaching times on the consolidation degree of sand and soil is studied.The test results show that the settlement and shear test indexes of the sand soil after the leaching of tailings liquid are higher and the degree of consolidation is stronger than that of the sand soil after the leaching of clear water;with the increase of single leaching time and total leaching times,the settlement of the sand soil will gradually increase,but the settlement rate will gradually decrease and eventually tend to be stable.In addition,the chemical consolidation process of Kafang tailings reservoir is deduced by observing the microstructure of tailings particles and analyzing the hydrochemical field.The comprehensive analysis of various consolidation mechanism of Kafang tailing show that there are various consolidation forms such as self-weight consolidation,leaching consolidation and chemical consolidation in Kafang tailings reservoir.The settlement of tailing sand and the improvement of mechanical index are the result of joint action of the above three consolidation forms.Leaching and chemical consolidation often occur in the area of alternate saturated unsaturated state,the region of unsaturated unsaturated alternating state is dominated by self-weight consolidation.Leaching consolidation has a greater impact on shallow tailings,while chemical consolidation has greater influence on deep tailings.The above study results have certain reference for the theoretical study and practical application of the consolidation characteristics of tailings.