Study on pre-reinforcement technology of roadway affected by contugous overhead mining

Under the combined action of the in-situ stress and advanced dynamic pressure， the maintenance of contugous roadway affected by overhead mining becomes very difficult.Aiming at the difficulty of controlling the surrounding rock of the contugous roadway affected by overhead mining， this paper takes the haulage rise-entry of No.Ⅱ4 mining area in Taoyuan Coal Mine as the research background.Through the theoretical analysis of the distribution law， the mining support pressure distribution law and surrounding rock deformation and failure characteristics of the cross mining roadway during the overlying No.1042 work face mining were obtained， and the targeted roadway pre-reinforcement technology was proposed.The research results show that with the advancement of the overlying working face，a stress-increasing area is formed on the floor of the working face and a stress-reducing area is formed below the gob.The vertical stress peak caused by the mining of the overlying working face is gradually away from the working face as the burial depth increases，and the stress concentration coefficient also gradually decreases as the burial depth increases.The horizontal stress concentration along the advancing direction of the working face is much smaller than the vertical stress concentration， and the horizontal stress caused by the mining of the overlying working face has less influence on the stability of the surrounding rock of the roadway affected by overhead mining.When the overlying face is advanced to a distance of 50 m from the roadway affected by overhead mining， it will be affected by the advanced dynamic pressure.When the overlying working face is advanced to a distance of 15 m from the cross mining roadway，the peak value of vertical stress is located directly above the roadway affected by overhead mining.At this time，the roadway affected by overhead mining is most affected by the advanced dynamic pressure.Therefore， it is decided to use grouting anchor cable and floor grouting to pre-reinforce the support of the surrounding rock and floor of the roadway.The designed pre-reinforcement technology can effectively control the surrounding rock deformation of the roadway affected by overhead mining and ensure the stability of the surrounding rock during the mining of the cross mining roadway so that the safe and efficient production of the coal mine can be achieved.