Experimental Study On Permeability-clogging Of Loose Accumulation Slag From Slag-type Debris Flow Source

The Belt and Road Initiative and the Western Development Strategy are accelerating the development and utilization of mineral resources in Western China,especially the vigorous promotion of industrialization in Northwest China,and the demand for mineral resources is increasing day by day.The slag-type debris flow disaster has become a prominent problem in the mining environment of Western China.In the investigation of mine debris flow in Fengxian County,Shaanxi Province,western Qinling Mountains,it is found that with the accumulation of slag accumulation time,the permeability coefficient of slag in the source area shows a significant downward trend.Through comparison,it is found that the fine grain composition in the slag debris flow accumulation body is richer than that in the accumulation of slag.Therefore,it is worthy of our attention to determine the relationship between fine particles and slag debris flow and how it affects the formation of debris flow disasters.In this study,the slag accumulation pile in Yinmusigou of Fengxian County was taken as the research object.Based on the field investigation of topography,hydrogeological conditions and material source accumulation characteristics in the study area,the permeability characteristics of slag and fine particle migration and clogging were taken as the focus.The slag permeability-clogging test was carried out by using the self-developed slag permeability instrument to explore the permeability-clogging law under the influence of slag characteristics,determine the most dangerous clogging particle size,and then establish the relationship between fine particle clogging and the disaster-pregnant process of slag debris flow.Based on the above analysis and test results,the following research results are obtained:(1)The particle size and density of slag have significant influence on the permeability and clogging law of slag.When the particle size of slag is smaller and the accumulation is denser,the permeability of slag is smaller,the time required to stabilize the flow is less,and the blockage degree of adding fine particles is more obvious;(2)According to the permeability law and clogging situation of slag,three slag clogging forms,namely,surface accumulation,clogging deposition and internal sedimentation,were proposed.Based on the effective aperture method,the criterion suitable for slag clogging was corrected;(3)The main factors affecting the permeability-clogging of slag are summarized as slag particle size,slag bulk density and slag particle morphology.Combined with the three influencing factors and the modified criterion of slag infiltration-clogging,the most dangerous particle size range of slag is obtained,which provides a reference for reducing the disaster risk of slag debris flow and exploring the inoculation and starting law of slag debris flow.