Study On The Technology Of Increasing The Rate Of Lump Coal In Large Mining Height Fully Mechanized Of Hydraulic Fractured Coal Seam

Ordos Jurassic coal field is a national coal chemical base,coal mining conditions are good,good quality coal,coal mining is the concentration of China.Production,due to the thick coal seam,cracks are not developed,shearer cutting energy consumption,small amount of coal,coal is too large,causing serious pollution,poor production safety environment.Based on the actual method of hydraulic fracturing,the fracturing coal seam formed by the reconstruction of hard and thick coal seam is analyzed.Through the field research,laboratory experiment and numerical simulation analysis,this paper analyzes the coal seam Fracture distribution,fracturing coal seam cutting process and parameters were studied.The main research contents and conclusions are as follows:(1)Through the field measurement of fractured coal seam wall crack distribution law.The fractal law of coal wall fractures is studied by using fractal theory,and the relationship between fracture and fractal dimension of fractured coal seam is obtained.The physical and mechanical properties of coal under different fractured coal seams are given,Fractal Evolution of Parameters.(2)Based on the analysis of coal seam fracturing model and the shape of coal cutting machine,the mechanics model of fracturing coal seam was established.Based on the simplified analysis of fracturing mechanics model,the horizontal wedge force T and rupture The expression of the prying force F on the surface.The FLAC3D numerical simulation software was used to simulate the variation of the length and range of the maximum cutting depth and the collapse line under different fractured coal seam conditions.Through the numerical simulation and theoretical analysis,the expression of cutting area of fractured coal seam is established,and the change of cutting area from the fractured area to the double-hole fracturing area is gradually increased and the lump coal rate is gradually increasing.(3)In this paper,the fully mechanized coal mining face of fractured coal seam is studied,and the fully mechanized mining technology such as coal cutting,drum loading and scraper transport is studied.Coal machine traction speed,drum speed and other process parameters.The results of the study are applied to the mining practice of fully mechanized coal mining face with 5 m mining height.The best way to get the shearing machine is to cut the incision of the two-way cutting coal tip.The reasonable value of the shearer’s traction speed The rate of traction is 8.5～9.2m/min,and the speed of the shearer is 3.4%～12.1%higher than that of the original coal seam,and the drum speed is reduced to 28.78r/min and decreased by 10.51%.The daily coal mining cycle of the fractured coal seam increased by 1.2 knives,and the average lump coal rate in the working face increased by 18.7%and the dust concentration decreased by about 45.4%.