Roof failure mechanism of gob-side entry retaining by roof cutting and pressure releasing and its control technology

In order to solve the problems of roof deformation and cracks in roadway by roof cutting and pressure releasing in Ningtiaota Coal Mine, by establishing a roof cutting mechanical model, the mechanism of roof failure and the main influence factor when by roof cutting and pressure releasing were studied in the paper, the roadway of by roof cutting and pressure releasing were classified into three regions, the criterion condition of fissure development were also proposed in the paper.The results showed that the development of cracks was main concentrated in area with dynamic pressure.Based on the above results, corresponding measures were propos ed from the aspects of controlling dynamic pressure, improving roof supporting intensity and the optimization of roof kerf parameters. The in-situ monitoring results sho wed that, in the middle of the roadway, the quantity of the roof and floor movement was reduced from 320 mm to 200 mm, and the cracks in the fracture area were no |o nger expanded, the roof stability control effect was good.