Creep instability rock burst mechanism and prevention technology of isolated coal mass in roadways of high-stress thick coal seam
摘要
In view of the present situation of frequent rock burst appearances of isolated coal body in coal pillar areas of high-stress roadways without obvious mining disturbance, taking the coal pillar of the high-stress thick coal seam in the seventh mining area of Zhaolou Coal Mine in Shandong Province as the engineering background, creep instability rock burst mechanism and prevention technology of isolated coal mass in roadways of high-stress thick coal seam are investigated though theoretical analysis, numerical simulation and on-site investigation. Firstly, the stress evolution laws induced by unstable creep instability of the surrounding rock and the isolated coal body in the roadways of high-stress thick coal seam are studied. Secondly, the mechanism of rock burst induced by creep instability of isolated coal in high-stress roadways is revealed. The results show that the overall instability rock burst is easily induced, when the concentrated stress in the elastic bearing zone of isolated coal body exceeds its ultimate bearing capacity. Thirdly, the creep instability and rock burst mechanical model for isolated coal body in roadways of high-stress thick coal seam is established, and the mechanical criterion of creep instability and rock burst of isolated coal body in roadways is deduced. Finally, the relevant measures are put forward to prevent and control this type of rock burst. The rationality of the theoretical analysis is verified through field practices.