Deformation and Failure Modes of Large-Span Roadway Roof and Critical Time-Effective Roof Control Principle Based on Area Support

To address the challenges of controlling coal roadway roofs with large spans, this study employed theoretical analysis, mechanical modeling, numerical simulation, and field testing to investigate the deformation and failure modes of large-span roadway roofs. An elastic foundation beam model for roof deformation under area support was established. The critical time-effective roof control principle and technology based on area support were proposed. Numerical simulation research and field trials of critical time-effective roof control using area support were conducted in the tailgate (open-off cut) of Panel II513 at the Huaibei Shuanglong Coal Mine. The results indicate that roof stability decreases with decreasing rock beam thickness and increasing span. The deformation and failure modes of large-span roadway roofs include anchor failure within the anchored zone and delamination outside the anchored zone. Case studies based on the mechanical model, numerical simulations, and field tests all demonstrate that the critical time-effective roof control technology utilizing hydraulic support for area support can significantly reduce roof deflection deformation.