Failure characteristics of surrounding rock in deep coal roadway with composite roof and cross-boundary anchor-grouting graded continuous support technology

To solve the problem of large deformation of roadway with deep composite roof, based on the material roadway of 3205 working face in Xin’an Coal Mine as the engineering background, the deformation and failure characteristics of roadway with composite roof and its influencing factors were analyzed by combining field analysis and UDEC numerical simulation. Based on the principle of thick layer anchoring of roadway roof, a technical scheme of graded continuous cross-boundary anchoring was proposed. The feasibility of the new scheme is verified by field monitoring and simulation results. The results show that the initial support strength is very important for roadway maintenance. The optimized support scheme can effectively control the deformation of roadway surrounding rock, and the deformation of roof and two sides is reduced by 64% and 63% respectively. The maximumcrack depth decreased from 9.56 m to 3.26 m. The new support scheme constructs the anchor rock beam structure with thick and stable roof, which can maintain the long-term stable bearing capacity of the roadway.