Support Technology of Limestone Roof Roadway in Qiuji Coal Mine

The safety production pressure in coal mines is huge, and there is a general phenomenon of over-supporting in roadways. Even hard and dense thick limestone roofs do not dare to be unsupported. 1102 track roadways of Qiuji Coal Mine is taken as the engineering background, by constructing a hard roof deformation analysis model, quantifying the role of the fifth layer limestone thickness in controlling roadway deformation, using numerical simulation to verify theoretical calculation results, using field test and monitoring reinspection research results. The research shows that as the thickness of limestone increases, the roof deformation decreases continuously and the self-stability of the roadway increases. When the thickness of the fifth layer limestone reaches 1.5 m, the deformation of the roof is reduced by 77.4% compared with the thickness of 0.2 m, and the plastic zone is reduced by 40.5%. The thickness of the fifth layer of limestone in 1102 track roadway is greater than 1.5 m. The scheme of without supporting in the roadway roof and the anchor net supporting on both sides of the roadway is adopted. The results show that the vertical convergence of the roadway is extremely small, and the convergence on both sides of the roadway is less than 15 mm. The cables on both sides of the roadway are under stable force. The roof force measuring bolt (cable) does not rise but falls back after applying the pre-tightening force and no cracks and separation can be seen in the roof peep to meet the safety requirements.