Stability Analysis Of Molybdenum Mine Tailings Dam Under The Action Of Dry And Wet Circulation

Mineral resources are a very important substance for the survival of human society and play an important role in promoting national economy.With the continuous expansion of the scale of mining,more and more tailings are produced.However,the tailings dam is in a dry and wet cycle state due to the constant variation of the position of tailings infiltration line caused by precipitation infiltration and tailings drainage,In the process of wet and dry circulation,the physical and mechanical properties of tailings are related to the safe operation of tailings dam.Therefore,in this paper based on the relevant literature,combined with the existing data mining area,taking Shangluo city of Shaanxi Province in a tailings dam as the research object,from the scene investigation and indoor physical and mechanical tests,indoor dry wet cycling experiment and numerical simulation analysis of the four aspects of the dry wet circulation effect of mechanical properties of ore and tailings under the tail of dam stability analysis,The main research results and conclusions of this paper are as follows:(1)Matrix suction is a nonlinear inverse relationship with water content,The drying and wetting cycle makes the soil water characteristic curve move to the left.In the first three times of the dry-wet cycle,the characteristic curve of soil water changes greatly.After the fourth time of the dry-wet cycle,the soil water characteristic curve tends to be stable.Under different cycle times,the same water content corresponds to different matrix suction,and the same matrix suction corresponds to different water content.The Van&Genuchten model has a better match for the soil water characteristic curve(SWCC),which is more than 0.97.(2)With the increase of the number of dry and wet cycles,the cohesive force and internal friction Angle of the tail ore sample gradually decreased,the shear strength of the first two wet cycles was the largest,and after three dry and wet cycles,the shear strength of tailings was stable.(3)In the case of increasing matrix suction,the shear strength of tailings is increased and then decreases,which is the peak occurrence.During the first three dry and wet cycles,the shear strength of the tail sand at the substrate suction of 50 kpa is greater than that of the matrix suction force of 100 kpa.As the number of cycle increases,the effect of matrix suction on the size of the tail mining sand is also changed under high stress conditions.(4)The stability of the tailings dam was 1.64,1.52,1.43,1.37,1.29,1.21,respectively,as the number of wet cycles increased,indicating that the dry-wet cycle has a certain effect on the safe operation of tailings dam.With the increase of the number of dry and wet cycles,the stability coefficient of tailings dam decreases gradually.(5)The establishment of evaluation index system of tailings dam risk,using the analytic hierarchy process(AHP)and fuzzy comprehensive evaluation method to evaluate the risk of dam failure of tailings dam,the evaluation results show that the tailings dam is in a stable state,which is consistent with the actual.