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Coal Engineering ›› 2026, Vol. 58 ›› Issue (4): 145-154.doi: 10.11799/ce202604018

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Evolution law and monitoring-warning method of water-conducting fractures in surrounding rock under repeated multi-seam mining #br#

  

  • Received:2025-05-08 Revised:2025-07-29 Online:2026-04-10 Published:2026-05-12

Abstract:

To address the engineering challenges of unclear surrounding rock failure and water-rich characteristics in multi-seam mining, this study, based on the multi-seam mining background of Yangjiacun Coal Mine at Shuangxin Mining, comprehensively employed numerical simulation, theoretical analysis, and field testing. A FLAC3D numerical model for multi-seam mining was established to investigate the nonlinear evolution law of water-conducting fractures in surrounding rock during multi-seam mining. The "mechanical-electrical" response relationship of water-bearing rocks was clarified, and a coupled "mechanical-electrical" monitoring and early warning model was constructed and applied in field measurements. The results indicate that the overburden load-bearing structure evolution during multi-seam mining exhibits high-level transfer characteristics, and under the superimposed damage effects of repeated mining, water-conducting fractures demonstrate nonlinear expansion characteristics. The integrated monitoring and early warning method, combining fiber Bragg grating and direct current resistivity, can simultaneously determine the extent of surrounding rock failure and identify water-rich features in the roof and floor, effectively warning of water hazards during mining. The failure zone height of the roof in the 351-upper 07 goaf was 18 m, connecting with the floor failure zone of the 4-1 coal seam goaf. Two water-rich anomaly areas-old goaf water and roof sandstone water-were identified in the 24109 goaf. Given the overall small water inflow (0.2~1.5 m3/h) during the mining of the 351-upper 07 working face, it was inferred that the overlying sandy mudstone roof still retains its water-resisting properties. The research findings provide theoretical and technical support for ensuring production safety in multi-seam mining faces at Shuangxin Mining and similar geological mining areas.

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