YUAN R F，LI H，DONG Z，et al. Study on failure evolution mechanism of ends hanging roof under static fracturing［J］.Journal of Henan Polytechnic University（Natural Science），doi:10.16186/j.cnki.1673-9787.2024120020

doi: 10.16186/j.cnki.1673-9787.2024120020

Received：2024-12-09

Revised：2025-04-24

Online：2025-04-24

Study on failure evolution mechanism of ends hanging roof under static fracturing

YUAN Ruifu^1,2,3，LI Hui^1,2，DONG Zhuo¹，ZHANG Qunlei¹

(1. School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, Henan, China; 2. State Collaborative Innovation Center of Coal Work Safety and Clean-efficiency Utilization, Jiaozuo 454000, Henan, China; 3. Zhengzhou Institute for Advanced Research of Henan Polytechnic University, Zhengzhou 451464, Henan, China)

Abstract: [Objective] To reveal the failure evolution mechanism of end-hanging roofs in mining faces and achieve rational mine pressure control, and to explore the static fracturing failure mechanism of end-hanging roofs and the optimal drilling spacing. [Methods] A numerical model of end-hanging roof failure was established using the Continuous-Discontinuous Element Method (CDEM) to analyze the static fracturing failure mechanism. A numerical model of the strata in the end area of the working face was constructed based on the geological conditions of the 5-2 coal seam in a specific mine to investigate the deformation and breakage process of the end-hanging roof before and after static fracturing during excavation, revealing the failure evolution mechanism under the action of static cracking agents. [Results] The results show that the expansion pressure of the static cracking agent is proportional to the tensile strength of the end-hanging roof. When the tensile strength is below 8 MPa and the expansion pressure is ≥30 MPa, the optimal fracturing effect is achieved. The optimal drilling spacing for fracturing the end-hanging roof is 1.25 m. Before static fracturing, the periodic caving step distance of the end-hanging roof at the working face ranges from 37.5 m to 22.5 m, with an average step distance of 27.5 m. After static fracturing, the caving step distance range reduces to approximately 17 m to 12 m. On-site tests of support pressure and roof displacement further confirm the feasibility of the static fracturing technology. [Conclusion] Static fracturing technology effectively avoids safety hazards caused by sudden mine pressure changes by controlling the caving step distance and fracture sequence of the end-hanging roof. The research findings provide theoretical guidance for applying static fracturing technology to hard roof engineering.

Key words: ends hanging roof; static fracturing; cutting roofs and relieving pressure; numerical simulation; failure evolution mechanism

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