Research on Caving Mechanism and Key Governance Technologies for through Strata Roadways in Composite Coal Seams

In view of the situations of roof fracture and caving, collapse of two sides and others in the 8232 high-level extraction roadway strata through the igneous rock zone in Tashan Coal Mine, the surrounding rock fracture mechanism in the through strata section is deeply analyzed from multiple aspects such as excavation process, geological structure, coal seam occurrence and so on, a joint support scheme of "artificial false roof+curtain grouting+self-locking yielding pressure anchor rod+shotcrete surface protection+C-shaped steel shed" is proposed. The on-site application effect verifies that after the construction of artificial false roofs, the range of caving zones is effectively controlled, and the concentration of gas accumulation is significantly decreased from 2.9% to 0.3%; After adopting joint support measures for the fracture zone, the occurrence of roof caving phenomenon is successfully prevented, the maximum roof subsidence amount in the fracture zone is only 0.17 m, the maximum convergence amount of the two sides is 0.24 m, and the permanent support failure rate for the surrounding rock is decreased to below 5%, obtaining significant application results.