Experimental study on gob-side entry formed by roof cut of broken roof at shallow depth of Hecaogou No. 2 Coalmine

For the key problem that the broken roof in caving zone of gob is not easy to fall and dynamic pressure of the gob-side entry is violent for the shallow depth and thin coal layer under broken roof, the technology of automatic gob-side entry formed by roof cut of shallow buried depth, thin coal layer, and broken roof is investigated through theoretical analysis, numerical simulation and engineering geological analysis. Through the numerical simulation, the distribution of stresses and the displacements of the surrounding rock are analyzed and compared when the roof cut is deficient or enough. The result shows that when the roof cut is enough, the effect of the roof of the goaf on the dynamic pressure of roadway roof is greatly weakened, and the deformation of the surrounding rock is small, which can guarantee the effects of the gob-side entry. And it is applied in the air-return way of 1105 working face of Hecaogou No.2 Coalmine. According to its motion patterns and behavioral characteristics of mine pressure, key parameters angle of seam and such as support of constant resistance cable are determined, and it lays a foundation for the successful application of the proposed technology of automatic gob-side entry formed by roof cut of shallow buried and broken roof. The relevant design pre-splitting blasting parameters and pressure relief are put forward. Through the analysis of engineering geological conditions of air return way of 1105 working face of Hecaogou No.2 Coal Mine, the key parameters are designed according to the technical principles of the gob-side entry formed by roof cut. The proposed technology is applied in practice, and good results are achieved.