Study on Reasonable Parameters of Roof Cutting and Pressure Relief in Gently Inclined Coal Seam with Narrow Coal Pillar
In order to solve the problem of large deformation of surrounding rocks in gob-side entry driving with narrow coal pillars in gently inclined coal seam,based on the 020203 working face in Qingyun Coal Mine,the mechanical model of roof cutting and pressure relief in gob-side entry driving with narrow coal pillar in gently inclined coal seam was established.It is calculated that the roof cutting angle should not be less than-1.3° and the roof cutting height should not be less than 9.51 m.FLAC3D numerical simulation software was used to simulate the stress and deformation failure law of surrounding rocks in the roadway with different roof cutting heights and different roof cutting angles under leaving a narrow coal pillar of 8 m.The results show that when the roof cutting height is 10 m and the roof cutting angle is 0°,the basic roof can be completely cut off,the stress of narrow coal pillar is small and uniform and the control effect of surrounding rocks is the best.The field test shows that there are many cracks in the borehole,the degree of fragmentation of the borehole wall is high,and the blasting effect is ideal when the spacing of blasting boreholes is 600 mm.After adopting the roof cutting and pressure relief technology,the deformation of surrounding rocks of the 020205 track crossheading has been significantly reduced compared to that in the area without roof cutting,which indicates that roof cutting and pressure relief is beneficial to improve the stability of surrounding rocks in gob-side entry driving in gently inclined coal seam.
Roof cutting and pressure reliefGob-side entry drivingGently inclined coal seamRoof cutting parameterDeformation of surrounding rock
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