Influence of roof cutting parameters on stability of surrounding rock of gob-side entry retaining

As one of the core issues of roof cutting pressure relief gob-side entry retaining technology, roof cutting parameters have a great influence on the stability of surrounding rock.Taking the 1226 working face of Shuguang Mine as the engineering background, the reference values of cutting top height and cutting top Angle are 7.1~9.5 m and 11.4° respectively through theoretical analysis.Through numerical simulation, the roof collapse form, roof subsidence and stress distribution of solid coal side are analyzed when the roof cutting height is 4 m, 7 m, 10 m, 13 m and the roof cutting Angle is 0°, 10°, 15°, 20° and 30° respectively from two angles of roof cutting effect and surrounding rock deformation.The results show that the optimal cutting top parameters are the cutting top height 10 m and the cutting top Angle 15°.The optimum hole spacing, blasting method and charge quantity are determined by field blasting test.The surrounding rock deformation of the rear roadway of the working face was monitored after the roadway retaining.The deformation of the surrounding rock of the roadway was small and the effect of the roadway retaining was good.