Distribution Of Abutment Pressure And Disaster Prevention In Horizontal Sublevel Mining Of Steeply Inclined Extra-thick Coal Seam

The occurrence of rock burst disaster is closely related to the special abutment pressure and dynamic load disturbance in the working face area during the horizontal sublevel mining of steeply inclined and Extra-thick seam.This paper theoretically analyses the distribution characteristics of abutment pressure in horizontal sublevel working face of steeply inclined and Extra-thick Coal seam,studies the influence law of main control factors on abutment pressure,puts forward the prevention and control technology of rock burst in horizontal sublevel mining of steeply inclined and Extra-thick Coal seam,and applies it in the field.Based on the principle of dynamic and static overlapping induced impulse,the characteristics of rock burst in steeply inclined coal seam face are reflected through the analysis of two impact cases in 5521 working face.The scientific nature of studying the distribution law of abutment pressure is determined.The function expression of abutment pressure in steeply inclined horizontal sublevel mining face is deduced from three directions of strike,inclination and inclination along coal seam,taking distance from coal wall as independent variable.The linear positive correlation between abutment pressure and mining depth,thickness of coal seam and double angle of coal seam is summarized,and it is negatively correlated with index of sublevel mining height.The results of numerical simulation show that the abutment pressure of the coal body on the roof side is relatively concentrated,the peak area is about 2 m away from the coal wall,the stress concentration area is about 12 m away from the coal wall,and the coal body on the floor side is liable to break up in the process of upper slicing mining;the concentration range of the advance abutment pressure of the working face is about 30 m;along the inclined direction of the coal seam,the vertical distance from the upper sublevel goaf is about 30 m,and the abutment pressure is up to 30 m.Minimum value.Through the analysis and comparison of several simulation results,it is concluded that with the increase of mining depth,the inclined abutment pressure of working face increases obviously;with the decrease of sublevel mining height,the peak value of strike and inclined abutment pressure of working face increases slightly;with the increase of coal seam thickness and the decrease of inclination angle,the peak value of inclined abutment pressure along coal seam and working face increases obviously,and the change of stress increases sharply.Law.It is revealed that the probability of occurrence of impact disaster in mining face is far greater than that in roadway,and the probability of occurrence of impact disaster in areas where the coal seam becomes thicker and the inclination becomes slower is greater.Through the analysis of support resistance and micro-seismic data,the results of theoretical and numerical simulation analysis are verified,and the impact disaster prevention technology for steeply inclined and extra-thick coal seam face is put forward,which has better prevention effect.