Study On The Evolution Law Of Gas-stress Field In Coal Bodies Adjacent To The Goaf Of Mengjin Coal Mine

Underground mining operation destroyed the original equilibrium state of coal seam,and the gas and stress of coal seam around the mining space redistributed.The deformation and failure of the coal body near the goaf,the gas flow in the coal seam,and the stress and gas pressure of the coal body decreased significantly.Accurately grasping the evolution law of gas stress field of coal body adjacent to goaf can provide guidance for the prevention and control of coal and gas outburst in gob side entry,which is of great significance to the realization of safe and efficient production of mine.Based on this reason,according to the mining conditions of Mengjin Coal Mine,using the methods of theoretical analysis,numerical simulation and field measurement,this paper studies the evolution law of gas stress field in the adjacent goaf of Mengjin Coal Mine: combined with the actual geological mining conditions of Mengjin Coal Mine,this paper theoretically analyzes the distribution law of internal stress and gas in the working face of the adjacent goaf According to the geological mining conditions of Jincheng coal mine,the COMSOL three-dimensional numerical calculation model is established to simulate the gas and stress distribution of 12050 working face and roadway after excavation,and the evolution law of gas stress field of coal body adjacent to 12050 goaf is obtained;the field measurement of 12070 working face transportation roadway along 12050 goaf is carried out.The results show that: 1(1)Considering the influence of gas and vertical stress,the minimum width of pressure relief zone is 9.78 m.The theoretical calculation results show that the stress relief width of coal along the goaf is 15.77 m,the gas relief discharge range of coal along the goaf is not less than 16 m,and the stress relief width and gas relief discharge range of coal along the goaf are greater than the minimum width of relief zone required for outburst prevention.(2)COMSOL simulation shows that the gas pressure relief range of the coal body near the goaf increases gradually with the increase of time,from 6m in one month to23 m in eight months.It can be seen that the gas pressure relief range of the coal body near the goaf is proportional to the time.The longer the goaf is placed,the more conducive to the gas and stress relief of the coal body along the goaf and the prevention of gas outburst.(3)According to the field measurement of mining stress in 11010 working face,the change of mining stress with time is as follows: first,it is adjusted to a stable state,then it is stable for a period of time,then it increases rapidly,and then it decreases after reaching the peak value.The field measurement of 12070 working face transportation roadway driving along 12050 goaf shows that the gas emission range is less than 20 m around the roadway,and the gas content within 20 m around the roadway gradually decreases with the increase of time.This paper contains 50 pictures,10 tables,and 72 references.