Study On Fracture Evolution Law And Application Of Overburden Rock In Fully Mechanized Caving Mining In Inclined Coal Seam

When the high-level drilling field is adopted to control the gas in the goaf,the drilling effect is best when the drilling is arranged in the fracture zone of the overburden.In order to analyze the evolution law of overburden fissure,this paper analyzes the law of fissure evolution by using physical similarity simulation experiment and numerical simulation experiment with the geological prototype of Xinjiang as a geological prototype and the theory of fracture evolution and gas extraction.The results of the test results and the field test results were analyzed,and the application method of the spatiotemporal evolution law of overburden fractures in high drilling was studied.Based on the evolution law of existing overburden fissures,combined with the geological background of the mine,the physical similarity simulation experiment is designed and carried out to simulate the evolution of the cracks in the direction and tendency of the coal seam during the mining process.The results show that the height of the rock zone is 26m and the height of the fracture zone is 75.8m.The fractal theory is introduced into the "three zones" And the fractal dimension of the fractured network is obtained.The relationship between the fractal dimension and the mining width and the peak of the bearing pressure is obtained.The fissure evolution and distribution characteristics of the different regions are studied quantitatively,and the elliptical zone is developed.Based on the fluent numerical simulation software and the similarity simulation and fractal theory,the change of the gas concentration in the mined-out area before and after the high-level drilling and the comparison of the gas concentration at different horizons before and after the mining is carried out.The results show that the high-The effect of hole extraction is remarkable,especially the gas concentration on the side of the return air is greatly reduced.Based on the mechanism of gas drilling and the formation of high gas concentration in overburden fractures,the change rule of gas volume fraction at different locations was analyzed based on the actual situation of the mine area in Xinjiang and the data and effect of high drilling It is reasonable to conclude that the gas concentration of the high-level drilling in the mining fissure ointment is reasonable and can ensure that the gas concentration in the fully mechanized top-coal caving face is not limited.