Research on 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 law of coal seam load and roadway stress during hydraulic roof control and pressure relief were studied 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 technological process of this technology has been elucidated. The research results indicate 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. The load of No. 15 coal seam away from the side of 81401 goaf is reduced by 20% and 15% respectively compared to the excavation of the roadway and the single roof cutting. 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 that 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,effectively improve the stress state of the surrounding rock of the roadway,reduce the deformation of the roof,floor,and two sides of the roadway in the later stage of mining,and reduce the difficulty of roadway maintenance.