| Gas has always been a major source of hazard that plagued coal mining companies' safe production.Although many mines in my country have low gas levels,high gas gushes out due to mining speed and ventilation methods.It shows that the gas concentration in the upper corner frequently exceeds the limit,which greatly endangers the safe production of the mine.The Yaxing Mine in Inner Mongolia also encountered the same problem of abnormal low gas emission during production.Therefore,this article takes the Yaxing Mine 426 fully mechanized caving face as the research object,aiming at the low gas abnormal emission in the goaf area of the 4# coal seam.From the perspective of theory and practice,the law of gushing out of Yaxing Mine was explored,and the main research results obtained are as follows:Combined with the basic situation of Yaxing Coal Mine,the basic parameters of coal seam gas were measured according to the on-site construction conditions,the gas occurrence index of coal seam #4 was obtained.Equivalently as the working face advances,the gas in the goaf is gradually released,causing gas to accumulate in the upper corner.Combining the field measurement data to analyze the gas emission law in the goaf,the research results provide for the later development of the gas prevention and control measures in the goaf the theoretical basis.Independently set up a dynamic pressure-bearing broken coal and rock mass seepage experiment platform of the goaf.Taking the crushed bituminous coal in the Yaxing Mine as the research object,carried out the evolution test of the permeability characteristics of the broken pressurized coal in the goaf.On the one hand,rock mass compaction-gas permeation experiment method.On the other hand,the gas seepage characteristics during the gradual compaction and deformation of the broken bituminous coal can be obtained.Based on the experimental results,the permeability distribution model of coal and rock mass in the goaf is explored.This new type The permeability model is helpful for further research.Combining the theory of granular mechanics,seepage theory and gas dynamics theory,and based on the actual situation of 426 working face,the fluid-solid coupling model of broken coal and rock mass in the goaf is established,and COMSOL software is used to analyze the internal multiple the field distribution law,and the permeability distribution of the collapsed coal and rock mass inside the goaf is in the form of an "O" shape,which provides theoretical guidance for on-site gas control in the goaf.According to the coal seam occurrence and site conditions of the 426 working face,combined with the principle of economic feasibility,a comprehensive gas control technology for the goaf of the fully mechanized caving face of Yaxing Mine is proposed,and the upper corner concentration distribution under different embedded riser steps is analyzed.From it,it was concluded that the step distance of the pre-hole buried pipe is15 m is more reasonable,and the first test was carried out at the 426 fully mechanized caving face.Through field data investigation,it was found that the gas concentration at the upper corner was greatly reduced,indicating that Group extraction technology can better reduce the gas concentration in the upper corner.The next step is that the technical solution can also be effectively applied in the goaf of the 4# coal seam with similar geological conditions in the Yaxing Mine.This article has 37 pictures,14 tables,and 94 references. |
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