Pre-evaluation for rock burst risks in island longwall panel before mining

In order to investigate the rock burst risk in an island longwall panel, the dynamic evolution and mechanical response of roof structures over goafs are analyzed based on the theory of spatial structures. First of all, the energy mechanical model is adopted to calculate the height of destressed zone above the mined panel. The spatial structures of overburden above the island panel are classified into three categories based on field observations and speculation: long-arm “T”, short-arm “T” and asymetric “T”. Subsequently, the model for calculating the average static and dynamic stresses is established, and the estimation formulas are derived by analyzing theoretically stress transfer mechanisms. Also, the estimation methods for abutment stress are proposed, and the pre-evaluation system is established for rock burst risks in an island longwall panel before mining. Finally, the proposed model is used to determine the stress distribution of the side abutment of longwall panel 3112 in Chaoyang Coal Mine, and the monitoring of ground subsidence verifies the rationality of this model. The findings obtained in this study provide a theoretical guidance for safe mining in coal mines.