Surrounding Rock Control Technology Of Retreating Entry In Extra Thick Coal Seam With Upward Slicing Backfilling Method

This paper focuses on retreating entry surrounding rock control technology in extra thick coal seam with upward slicing backfilling method. By setting forth exploiting extra thick coal seam with upward slicing backfilling method, field research, theoretical analysis, numerical simulation, industrial test and other methods are adopted in this paper. It researches surrounding rock deformation characteristics in retreating entry of different layers using upward slicing backfilling method exploiting extra thick coal seam in excavation process and retreating process. Also support plans for different layers are designed, which has been proved correctly by industrial test. The main results are as follows:(1) It states the fundamental of exploiting extra thick coal seam with upward slicing backfilling method and establishes special mining system for production. The key equipment is selected. All these mentioned make up of the technics of exploiting extra thick coal seam with upward slicing backfilling, which reveals the key technology and difficulty during the mining process.(2) Numerical simulation model of exploiting extra thick coal seam with upward slicing backfilling is established. And surrounding rock deformation characteristics in retreating entry of different layers using upward slicing backfilling method exploiting extra thick coal seam in excavation process and retreating process is simulated by ABAQUS. The stress evolution and deformation laws in surrounding rock of retreating entry is obtained.(3) Based on the theoretical analysis results, different support plans are put forward to control the surrounding rock deformation of different layers and the deformation under different support plans are simulated by ABAQUS.(4) The results have been applied to 0622 backfilling working face, second mining district, Gonggeyingzi Coal Mine, Xilamulun(Group) company, Chifeng City. After monitoring surrounding rock deformation and stress variation in 0622 haulage entry and 0622 return-air entry, the experimental results are basically consistent with the theoretical analysis.There are 56 figures, 7 tables, 91 references attached in this paper.