Scholarlink

<p>With the progressive exploitation of coal resources, open-pit mining operations are increasingly confronted with coal–rock composite formations characterized by variable proportioning, underscoring the imperative for systematic stability evaluations. To address the safety requirements of open-pit mining engineering, this study focuses on investigating the influence of diverse coal–rock ratios on the mechanical properties and failure modes of coal–rock composites. Uniaxial compression tests were performed on composite specimens, integrated with acoustic emission (AE) monitoring systems and digital image correlation (DIC) digital speckle techniques. Concurrently, PFC2D numerical simulation software was utilized to construct two-dimensional coal–rock composite models, facilitating the analysis of the failure process and macroscopic failure patterns. The experimental and simulation results are as follows: (1) Composites exhibit strength reduction dependent on coal proportion, with 90% coal content specimens showing 42.9% lower unconfined compressive strength (UCS) than pure sandstone, consistent with the observed UCS hierarchy: sandstone &gt; composites &gt; coal. The UCS of pure sandstone is 56.52&#xa0;MPa, that of pure coal is 28.05&#xa0;MPa, and the UCS of the composite material is between 29.28 and 51.30&#xa0;MPa. (2) Failure modes transition from tensile-dominant cracking in low-coal-proportion specimens to shear-dominated rupture in high-coal-proportion composites, accompanied by decreasing tensile crack ratios with increasing coal content. (3) Macroscopic cracks always originate at the coal–rock interface, occur during the unstable stage of crack propagation, then spread to the sandstone units, and finally fail within the coal matrix itself. (4) Numerical simulations demonstrate close agreement with experimental stress–strain responses and failure patterns.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Multiscale PFC2D Experimental Assessment of Progressive Failure in Variable-Ratio Coal–Rock Composites

  • 期刊论文

  • 发表日期：

    2026年2月25日

查看全文
  • Yuanzeng Wang,
  • Wen Wan,
  • Wei Chen,
  • Yanlin Zhao,
  • Shuailong Lian,
  • Qiuhong Wu,
  • Wenqing Peng,
  • Yu Zhou,
  • Zhili Peng,
  • Qiang Li

摘要

With the progressive exploitation of coal resources, open-pit mining operations are increasingly confronted with coal–rock composite formations characterized by variable proportioning, underscoring the imperative for systematic stability evaluations. To address the safety requirements of open-pit mining engineering, this study focuses on investigating the influence of diverse coal–rock ratios on the mechanical properties and failure modes of coal–rock composites. Uniaxial compression tests were performed on composite specimens, integrated with acoustic emission (AE) monitoring systems and digital image correlation (DIC) digital speckle techniques. Concurrently, PFC2D numerical simulation software was utilized to construct two-dimensional coal–rock composite models, facilitating the analysis of the failure process and macroscopic failure patterns. The experimental and simulation results are as follows: (1) Composites exhibit strength reduction dependent on coal proportion, with 90% coal content specimens showing 42.9% lower unconfined compressive strength (UCS) than pure sandstone, consistent with the observed UCS hierarchy: sandstone > composites > coal. The UCS of pure sandstone is 56.52 MPa, that of pure coal is 28.05 MPa, and the UCS of the composite material is between 29.28 and 51.30 MPa. (2) Failure modes transition from tensile-dominant cracking in low-coal-proportion specimens to shear-dominated rupture in high-coal-proportion composites, accompanied by decreasing tensile crack ratios with increasing coal content. (3) Macroscopic cracks always originate at the coal–rock interface, occur during the unstable stage of crack propagation, then spread to the sandstone units, and finally fail within the coal matrix itself. (4) Numerical simulations demonstrate close agreement with experimental stress–strain responses and failure patterns.