Research On The Evolution Law Of Mining Fissures And Gas Drainage In The Three-soft Coal Seam Of Weibei Coalfield

The stable operation of my country's industrial system relies on coal resources.In recent years,coal production centers have gradually moved to the central and western regions with the exhaustion of coal resources in the east.The increase in demand for coal resources has increased the intensity and depth of coal mining.We need to face some mining problems such as dynamic disasters,water disasters,spontaneous combustion of coal seams,and gas outbursts.Among them,the disasters caused by gas outbursts are particularly serious.Therefore,in the three-soft coal seam,the evolution of the overburden fissure field in the goaf is used to guide the gas mine.The gas drainage becomes particularly important.The article mainly uses the physical numerical simulation analysis method to determine the evolution of the overburden cracks in the working face.Combined with the on-site industrial experiment,a simplified engineering model is constructed to guide the gas drainage.Finally,the numerical simulation is used to determine the vertical and horizontal distances of the high-level boreholes.Take a step closer to guide gas drainage.Through the research of this article,it is found that the overburden failure characteristics of three-soft coal seam mining is different from that of non-three-soft coal seam mining.The initial pressure is earlier,and the roof falls with the mining after the initial pressure.The cycle pressure step is small;under different pushing speeds The analysis of the amount of stress separation in the key rock layers,etc.,obtains the influence of the pushing speed on the overlying rock in the three-soft coal seam;the results of on-site drilling and microseismic monitoring are consistent with the results of the simulation experiment,and finally the 1508 working face cracks are determined The height of the belt is about 65m,and the height of the caving zone is about 18m.Based on the foregoing analysis,a simplified model of the overburden crack mining engineering for the mining of the three-soft coal seam is constructed.In the displacement ellipse zone of the gas enrichment zone,the pressure is relieved by the three-soft coal seam.Numerical simulation analysis of the key parameters of drainage has determined that the vertical distance of the final hole position of the high drilling hole is 18?27m,and the horizontal distance is 10?25m.After the high-location drilling is used to extract the gas,which ensures the safe production of the working face,the phenomenon of gas concentration is reduced to a safe range in the upper corner and the return airway.The research results in this paper have a positive effect on the evolution law of the overburden cracks in the three-soft coal seam and the pressure relief.The design of the key parameters of gas drainage and the improvement of the efficiency of gas drainage have important guiding significance.