<p>The shape of underground chambers in deep mining varies due to their geological environment and intended use, which results in different failure modes under the influence of mining activities. However, the effect of chamber shape on the mechanism of structural integrity under dynamic load is still unclear. In this paper, granite samples with circular (C), rectangular (R), long ellipse (EL), and short ellipse (ES) holes were prepared. The dynamic mechanical response and cracking mechanism of granite were systematically analyzed using the split Hopkinson pressure bar (SHPB) test system and the hybrid finite and discrete element method (HFDEM). The results indicate that the dynamic strengths of granite with EL and ES represent the maximum and minimum values within the range of close strain rates, respectively. When EL granite is subjected to dynamic load, the axial stress concentration (in the load direction) is weak, and the transverse stress shows relative dispersion, which is the primary reason for its highest dynamic strength. The failure of granite with various holes primarily involves a tensile-shear mixed fracture, with relatively few pure type II cracks. The chamber’s transverse span is the primary factor influencing the distribution range of the fracture area.</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

Dynamic fracture mechanism of granite with different shape holes under high strain rates based on HFDEM

  • Fu-qiang Ren,
  • Zhao-guo Zhang,
  • Tian-zuo Huang,
  • Chun Zhu,
  • Ming Huang,
  • Fei Wu,
  • Chuan-qi Zhu

摘要

The shape of underground chambers in deep mining varies due to their geological environment and intended use, which results in different failure modes under the influence of mining activities. However, the effect of chamber shape on the mechanism of structural integrity under dynamic load is still unclear. In this paper, granite samples with circular (C), rectangular (R), long ellipse (EL), and short ellipse (ES) holes were prepared. The dynamic mechanical response and cracking mechanism of granite were systematically analyzed using the split Hopkinson pressure bar (SHPB) test system and the hybrid finite and discrete element method (HFDEM). The results indicate that the dynamic strengths of granite with EL and ES represent the maximum and minimum values within the range of close strain rates, respectively. When EL granite is subjected to dynamic load, the axial stress concentration (in the load direction) is weak, and the transverse stress shows relative dispersion, which is the primary reason for its highest dynamic strength. The failure of granite with various holes primarily involves a tensile-shear mixed fracture, with relatively few pure type II cracks. The chamber’s transverse span is the primary factor influencing the distribution range of the fracture area.