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<p>Through impact dynamics experiments conducted on coal samples with different sizes, it was observed that, under identical impact load, increasing the sample size from 30 to 70&#xa0;mm led to a reduction in strain rate from 41.3 to 18.39&#xa0;s<sup>-1</sup>, a decline in dynamic strength from 28.8 to 15.82&#xa0;MPa, and a decrease in absorbed energy from 0.56 to 0.13&#xa0;J/cm<sup>3</sup>. The extent of damage within the coal samples diminished as the size increased, demonstrating a consistent decreasing trend. Both the energy reflection coefficient and absorption ratio gradually decreased with larger sample sizes, while energy transmittance rose correspondingly. The failure-related dynamic strength, fractal dimension, and absorbed energy all showed negative correlations with sample size, whereas the critical crack size at failure exhibited a positive correlation with increasing coal sample dimensions. Larger coal samples generally required more energy to reach failure, which may have facilitated the likelihood of structural breakdown. Gaining insight into how coal samples with different sizes respond mechanically under dynamic impact loading provides important theoretical support for mitigating rockbursts in deep mining environments and optimizing the design of coal-rock structural systems.</p>

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Dynamic Behavior and Fracture Mechanism of Coal Samples with Different Sizes Under Impact Load

  • 期刊论文

  • 发表日期：

    2025年11月26日

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  • Siqing Zhang,
  • Xiaofei Liu,
  • Zhoujie Gu,
  • Xin Zhou,
  • Xiaoran Wang,
  • Ruilin Tan

摘要

Through impact dynamics experiments conducted on coal samples with different sizes, it was observed that, under identical impact load, increasing the sample size from 30 to 70 mm led to a reduction in strain rate from 41.3 to 18.39 s-1, a decline in dynamic strength from 28.8 to 15.82 MPa, and a decrease in absorbed energy from 0.56 to 0.13 J/cm3. The extent of damage within the coal samples diminished as the size increased, demonstrating a consistent decreasing trend. Both the energy reflection coefficient and absorption ratio gradually decreased with larger sample sizes, while energy transmittance rose correspondingly. The failure-related dynamic strength, fractal dimension, and absorbed energy all showed negative correlations with sample size, whereas the critical crack size at failure exhibited a positive correlation with increasing coal sample dimensions. Larger coal samples generally required more energy to reach failure, which may have facilitated the likelihood of structural breakdown. Gaining insight into how coal samples with different sizes respond mechanically under dynamic impact loading provides important theoretical support for mitigating rockbursts in deep mining environments and optimizing the design of coal-rock structural systems.