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Coal Engineering ›› 2026, Vol. 58 ›› Issue (1): 68-75.doi: 10.11799/ce202601009

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Study on Modification and Control Techniques for Fractured Roofs in Fully Mechanized Mining Faces under Shallow Burial and Intense Weathering Conditions

  

  • Received:2025-05-20 Revised:2025-08-20 Online:2026-01-12 Published:2026-03-04
  • Contact: LIANG mingming E-mail:tb25020050a41@cumt.edu.cn

Abstract:

In working faces with shallow burial depth and thin bedrock where the roof is severely weathered and fractured, it remains a widespread technical challenge in mining engineering to effectively control roof stability during roadway excavation support and face retreat operations. Taking the 3209 shallow-buried working face in the severely weathered zone of the Fengjiata Coal Mine as the engineering background, this study employs field measurements, numerical simulation, theoretical analysis, and industrial-scale testing to investigate the full-cycle surrounding rock stability control problem during excavation and mining in the shallow weathered zone of the 3209 working face. The reinforcement effect of grouting anchor cables on the roof during roadway excavation is evaluated, and the mine pressure manifestation mechanism under the coupled influence of surface gully topography and roof weathering in shallow-buried working faces is revealed. The results show that during the working face retreat, the maximum vertical stress in the roof of the 3209 transportation roadway reaches 2.45 MPa, the maximum roof subsidence is approximately 248 mm, the maximum development range of the plastic zone is about 20 meters, and the fractures within the roof are predominantly tensile-shear fractures. Under the gully landform, the maximum surface subsidence above the working face reaches 1.76 meters, the peak value of the abutment pressure is 5.40 MPa, and the stress concentration factor reaches 1.8; after the working face advances more than 80 meters, the number of fractures tends to increase steadily. The study proposes a safe mining control technology scheme for the “reconstruction” of strongly weathered and fractured roof through grouting in the working face. Field implementation results indicate that the roof grouting measures effectively improved the overall stability and deformation resistance of the surrounding rock. During face retreat, only localized issues such as coal wall spalling and end-face spallation occurred, while the working face advanced smoothly overall, with no instances of support frame crushing. The grouting reconstruction technology for fractured roof effectively addressed the full-cycle surrounding rock control problem in the shallow-buried weathered zone of the working face, providing technical support and reference for the safe mining of shallow-buried coal resources under similar conditions in the mine.

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