The hydraulic roof control theory and its application in contiguous hard roof roadway

In order to study the hydraulic roof control theory in contiguous hard roof roadway, the distribution of coal seam load and roadway stress during hydraulic roof control and pressure relief were investigated through theoretical analysis and numerical simulation.The mechanism of the influence of hydraulic roof control and pressure relief on the stability of roadway surrounding rock has been revealed, and the associated technological process has been elucidated.The results show that when the 81403 return airway is not excavated, the periodic weighting step of the working face is 19 m, the immediate roof thickness is 4.84 m, the main roof thickness is 10.64 m, and the range of internal stress zone is 5.2 m.Compared to the excavation of the roadway and the single roof cutting, the load of No.15 coal seam away from the side of 81401 goaf is reduced by 20% and 15%, respectively.The convergence rate of roadway height and width in the on-site observation of the top cutting drilling test area is 33.7% and 23.0%, respectively.The convergence rate of roadway height and width is 39% and 32% lower than those in the comparison area.The use of unilateral high-pressure abrasive jet drilling and roof cutting can timely collapse the roof rock layer, cut off the stress transmission path between the roof rock layers.Therefore, it can effectively improve the stress state of the surrounding rock of the roadway, reduce the deformation of the roof, floor, two sides of the roadway in the later stage of mining, and the difficulty of roadway maintenance.