Parameter design and practice of retaining roadway along goaf for roof cutting and pressure relief in medium thick coal seam

In order to solve the problems of tense mining and excavating, low resource recovery rate and stress concentration in goaf caused by setting coal pillars between mining faces, the technology of roof cutting and pressure relief along goaf retaining roadway in 97214 roadway of 97307 working face in No.2 well of Sihe Coal Mine is studied by means of laboratory experiment, numerical simulation and field practice.Based on laboratory experiments, the physical and mechanical parameters of coal and rock mass are given, and then the main parameters such as roof cutting height, roof cutting angle, blast hole spacing and reinforcement support are given through numerical simulation analysis.Finally, in field practice, 97214 gob side entry retaining is divided into four areas, and different support schemes and measures are adopted in different areas.The monitoring data of gob side entry retaining effect by roof cutting and pressure relief show that after adopting the roof cutting and pressure relief technology, the support pressure at the top cutting side of 97307 working face is not only lower than that at the side entry without roof cutting, but also lower than that at the middle support pressure, and the roadway surface deformation and separation layer are basically constant when they lag behind the working face 170 m and 200 m respectively.The technology of roof cutting and pressure relief gob side entry retaining has achieved good results in the field practice of 97214 roadway of 97307 working face.