Abstract: Probed into the general mechanism of the coal wall failure in thick coal seam, combined with the main failure form of coal wall in 8101 mining face of Ruilong mine, the mechanical model of rib spalling during the topple mining was established, and the sensitivity analysis was also implemented to study the factors influencing the coal wall stability. The results show that the mining height, confining pressure, support strength, angle of topple mining, strength of coal, etc., have a great influence on the stability of coal wall, and reducing the mining height, improving the support strength, and grouting reinforcement of coal wall are the most effective measures to prevent the rib spalling of coal wall. The reasonable drilling diameter of grouting reinforcement was further studied through theoretical analysis and UDEC numerical modeling. As a result, the grouting effect with 15 mm in borehole diameter is the best to control rib spalling of coal wall.

Key words: fully mechanized caving mining face, topple mining face, rib spalling, grouting reinforcement technique