Study On Roof Rock Fracture Structure And Control Of Fully Mechanized Coal Mining In Thick Coal Seam In Deep Mine

Full-mechanized top-coal caving has become the preferred coal mining method for thick coal seam mining in China,which has not only achieved great economic benefits,but also made breakthroughs in theoretical and technological research.But for the deep well fully mechanized top coal caving face,the roof pressure is large.In the process of coal mining,the roof breaking structure and the distribution of supporting pressure around the stope are different from those of the fully mechanized top coal caving face(less than 800m).Especially when the length of the working face is different,the roof breaking structure and the supporting strength of the working face are also different.In view of this,in this paper,the field monitoring,numerical simulation and theoretical analysis are used to study the movement law of the top,slate strata of the adjacent unequal wide caving face,the law of the rock pressure,the distribution of the forward support pressure,the relationship between the support and the surrounding rock,and the design of the front support of the mining face.The main contents and achievements of the paper are as follows:(1)Based on the theory of mine pressure and using microseismic monitoring technology,I obtained the movement range of the top slate in deep well fully mechanized caving face,and compared and analyzed the difference of the movement range of the roof strata in the adjacent unequal width fully mechanized caving face(the length of the working face of the upper section is 70m,the length of the lower working face is 120m).Through the pressure monitoring of the hydraulic support on the working face,we get the cycle pressure and the strength and the support pressure of the fully mechanized top coal caving face.(2)By comparing and analyzing the results of the microseismic monitoring data and the field monitoring results of the support pressure,I have revealed the corresponding relationship between the broken height of the roof and the pressure of the support.(3)Using the on-line real-time monitoring technology of the borehole stress meter,I obtained the characteristics of the pre support pressure distribution in the deep well fully mechanized caving face,determined the front support range of the working face,and discussed the influence of the upper working face mining on the distribution of the Presupport pressure in the lower working face.(4)Through the simulation study of the roof breaking law of deep well fully mechanized caving face and the evolution characteristics of the advanced support pressure,I have obtained the broken structure form of the roof rock and the distribution range of the overbearing pressure.(5)On the basis of the above research,I established the mechanical model of the roof breaking structure of the deep well fully mechanized caving face,and obtained the calculation formula of the working resistance of the support of the deep well fully mechanized caving face,and found that the calculated results are basically consistent with the field measured results.By calculating the support resistance of the advance support of coal mining face,the advanced support parameters of the mining face are designed.