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<p>Dynamic pressure accidents frequently occur during the mining of near-vertical coal seams, posing significant challenges to mine safety and production efficiency. This study employs a combination of laboratory-scale similar simulations and numerical modeling to systematically investigate the failure characteristics of the roof and floor, as well as the ground pressure behavior during the mining of near-vertical coal seams. It clarifies the correlation between roof collapse and energy evolution, revealing the underlying mechanism of dynamic pressure accidents and providing theoretical guidance for the safe and efficient extraction of these seams. The research findings indicate that in the early stages of mining, due to shallow burial depth, the roof remains largely intact and ground pressure behavior is mild. However, as mining depth increases, the roof develops cracks that topple toward the goaf, eventually expanding to a critical state and inducing roof collapse. The roof caving occurs with a step distance of 40–60&#xa0;m and fracture Heights ranging from 50to 70&#xa0;m. Alternating mining of the two coal seams causes deflection of the interlayer rock pillar, significantly raising the risk of dynamic pressure events. Digital Image Correlation monitoring shows that once the mining depth exceeds 140&#xa0;m, the rock pillar experiences prying forces, and the roof’s strain concentration zones enlarge. These conditions intensify the dynamic impact load and raise the likelihood of pressure disasters. Energy evolution patterns also shift with depth: in shallow zones, the high integrity of coal and rock mass leads to longer energy cycles; as depth increases, the cycles shorten due to the enhanced prying effect from the rock pillars. This trend underscores the need for stronger disaster prevention measures in deep mining. Strain measurements show localized roof fluctuations that vary with mining progress. Increased mining depth and extent exacerbate disturbance to surrounding rock and pose greater challenges to overall stability. In dual-seam mining scenarios, roof principal stress evolution is influenced by the dip angle-related gravitational forces and the expanding span of the goaf. This evolution follows a typical “concentration-fracture-unloading” pattern. As the working face advances, stress concentration zones migrate forward, eventually leading to tensile failure and caving of the roof. The findings provide crucial theoretical and engineering guidance for the safe, stable, and efficient mining of complex geological conditions.</p>

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Study on Caving Characteristics of Roof and Floor and Law of Ground Pressure Behavior in Near-Vertical Coal Seams Mining: A Three-Dimensional Similarity Simulation Experiment

  • 期刊论文

  • 发表日期：

    2025年9月15日

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  • Qiang Li,
  • Shengli Yang,
  • Hao Yue,
  • Dezhong Kong

摘要

Dynamic pressure accidents frequently occur during the mining of near-vertical coal seams, posing significant challenges to mine safety and production efficiency. This study employs a combination of laboratory-scale similar simulations and numerical modeling to systematically investigate the failure characteristics of the roof and floor, as well as the ground pressure behavior during the mining of near-vertical coal seams. It clarifies the correlation between roof collapse and energy evolution, revealing the underlying mechanism of dynamic pressure accidents and providing theoretical guidance for the safe and efficient extraction of these seams. The research findings indicate that in the early stages of mining, due to shallow burial depth, the roof remains largely intact and ground pressure behavior is mild. However, as mining depth increases, the roof develops cracks that topple toward the goaf, eventually expanding to a critical state and inducing roof collapse. The roof caving occurs with a step distance of 40–60 m and fracture Heights ranging from 50to 70 m. Alternating mining of the two coal seams causes deflection of the interlayer rock pillar, significantly raising the risk of dynamic pressure events. Digital Image Correlation monitoring shows that once the mining depth exceeds 140 m, the rock pillar experiences prying forces, and the roof’s strain concentration zones enlarge. These conditions intensify the dynamic impact load and raise the likelihood of pressure disasters. Energy evolution patterns also shift with depth: in shallow zones, the high integrity of coal and rock mass leads to longer energy cycles; as depth increases, the cycles shorten due to the enhanced prying effect from the rock pillars. This trend underscores the need for stronger disaster prevention measures in deep mining. Strain measurements show localized roof fluctuations that vary with mining progress. Increased mining depth and extent exacerbate disturbance to surrounding rock and pose greater challenges to overall stability. In dual-seam mining scenarios, roof principal stress evolution is influenced by the dip angle-related gravitational forces and the expanding span of the goaf. This evolution follows a typical “concentration-fracture-unloading” pattern. As the working face advances, stress concentration zones migrate forward, eventually leading to tensile failure and caving of the roof. The findings provide crucial theoretical and engineering guidance for the safe, stable, and efficient mining of complex geological conditions.