Study On The Clogging Mechanism Of Tailings Material And Its Influence On The Permeability Of The Dam Body

The tailing dam is a mine facility for storing tailing.As the tailing dams become higher and the storage capacity becomes larger,they gradually become major a hazard source of man-made debris flow with high potential energy and some of them contain heavy metals,chemical reagents and other toxic substances.Based on the above factors,in case of dam-break,it will not only cause casualties and huge property loss and environmental pollution problems that are difficult to restore,also can cause negative social effects.There are many factors that cause an accident of dam-break,and the seepage is one of the more important ones.Clogging is a common phenomenon occurring in the seepage process of porous media that will reduce the permeability of the dam.If tailing dam is clogging,it will reduce the permeability of the dam,resulting in poor drainage of the tailing dam,thereby reducing its stability and safety.Therefore,in this paper,study on the physical clogging during the seepage progress of tailing dams is the main research content.Based on theoretical analysis and laboratory experiments,this study explores the occurrence progress and distribution characteristic of siltation under the conditions of different media particle sizes,different suspended particle sizes,and different suspension concentrations,and analyzes the clogging mechanism of tailing materials and takes the actual project as a background,using the numerical simulation software MODFLOW to analyze the change laws of the seepage field of tailing dam under the clogging action.The main research contents and conclusions include:(1)Carry out the clogging tests of tailing material under different influencing factors,explore the clogging characteristics and analyze the clogging mechanism.The test results show: The particle size ratio is an important factor affecting the spatial characteristics of the clogging,when the particle size ratio is relatively large,the particle migration range is wider,resulting in a wider clogging range,and the final clogging degree will be deeper;the suspension concentration is an important influence factor affecting the clogging time characteristics,when the concentration is higher,the faster the clogging occurs,and the higher the concentration,the shorter time forclogging of the surface layer,and the surface clogging will accelerate the occurrence of clogging.(2)Under current conditions,it is very difficult for fine tailing particles to migrate through the tailing media without being trapped or precipitated,therefore,combining with theoretical analysis of clogging and analysis of the results after indoor clogging tests,the tailing clogging is summarized as two types of surface clogging and surface-internal clogging.(3)Takes the actual project as a background,using the numerical simulation software MODFLOW to analyze the change laws of the seepage field of tailing dam under the clogging action.The results show: In the case of clogging,the drainage capacity of the initial dam gradually decreases,and the location of the saturation line will gradually increase,which will seriously affect the stability of the dam;As the clogging degree of the fill dam deepens,the drainage capacity of the fill dam will gradually decrease and decrease,which will reduce the water discharge per unit time,shorten the length of the dry beach,and will also reduce the safety and stability of the dam.For the analysis of the results of the numerical simulation,it is recommended to consider the clogging effect on the stability of the tailing dam and to obtain a more practical and reasonable stability analysis result.