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<p>We investigated the mechanical and energy dissipation characteristics of coal-rock combinations under varying high-humidity conditions, which is a critical factor in deep mining environments. Using a humidity control device, we exposed coal-rock specimens to dry, 80%, 90%, and 100% relative humidity (RH) for 49&#xa0;days, followed by uniaxial compression tests. Acoustic emission (AE) and digital image correlation (DIC) techniques were employed to monitor failure modes, while scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to analyze microstructural changes. Our results reveal that increasing humidity significantly weakens the mechanical properties of the combination, reducing peak strength by up to 57% and elastic modulus by 45%. Notably, the coal section exhibits a transition from tensile to mixed tensile-shear failure, whereas the sandstone section shifts from mixed tensile/shear to shear failure as humidity increases. High humidity induces significant pore structure modifications, with micropores in sandstone evolving into macropores, while coal retains its micropore structure. Energy dissipation during the failure process increases with humidity, with the combination under 100% RH exhibiting a 68% higher cumulative AE count compared to dry conditions. The coal section contributes more to energy dissipation in tensile failure, while the sandstone section plays a dominant role in shear failure. This study provides critical insights into the physical and chemical deterioration of coal-rock combinations under wet conditions, offering a foundation for safer deep mining operations.</p>

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Energy dissipation and mechanical stability of coal-rock combination in roadways under high-humidity conditions

  • 期刊论文

  • 发表日期：

    2025年11月14日

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  • Wei Chen,
  • Bowen Liu,
  • Qiuhong Wu,
  • Yanlin Zhao,
  • Wen Wan,
  • Jie Liu,
  • Wenqing Peng

摘要

We investigated the mechanical and energy dissipation characteristics of coal-rock combinations under varying high-humidity conditions, which is a critical factor in deep mining environments. Using a humidity control device, we exposed coal-rock specimens to dry, 80%, 90%, and 100% relative humidity (RH) for 49 days, followed by uniaxial compression tests. Acoustic emission (AE) and digital image correlation (DIC) techniques were employed to monitor failure modes, while scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to analyze microstructural changes. Our results reveal that increasing humidity significantly weakens the mechanical properties of the combination, reducing peak strength by up to 57% and elastic modulus by 45%. Notably, the coal section exhibits a transition from tensile to mixed tensile-shear failure, whereas the sandstone section shifts from mixed tensile/shear to shear failure as humidity increases. High humidity induces significant pore structure modifications, with micropores in sandstone evolving into macropores, while coal retains its micropore structure. Energy dissipation during the failure process increases with humidity, with the combination under 100% RH exhibiting a 68% higher cumulative AE count compared to dry conditions. The coal section contributes more to energy dissipation in tensile failure, while the sandstone section plays a dominant role in shear failure. This study provides critical insights into the physical and chemical deterioration of coal-rock combinations under wet conditions, offering a foundation for safer deep mining operations.