Scholarlink

<p>Rock pulverization in fault zones provides insights into earthquake mechanics and off-fault damage distributions. While lithological factors are known to influence this process, the specific role of grain size in governing dynamic deformation remains poorly understood. Here, we investigate the dynamic pulverization of fine- (FG, average grain area of 0.022&#xa0;mm<sup>2</sup> and coefficient of variation of 8.9), medium- (MG, 0.126&#xa0;mm<sup>2</sup> and 14.2), and coarse-grained (CG, 0.146&#xa0;mm<sup>2</sup> and 18.9) granites using Split Hopkinson Pressure Bar tests. The results indicate that grain size controls pulverization thresholds: the CG granite pulverizes at a strain rate of ~ 127&#xa0;s<sup>−1</sup>, whereas the FG granite requires a rate of ~ 296&#xa0;s<sup>−1</sup>. Similarly, the dissipated energy required for pulverization is higher for the FG specimens compared to the CG specimens. Mechanistically, these difference arise because the CG specimens contain larger initial cracks that facilitate crack branching at lower stresses. In contrast, the higher grain boundary density in FG specimens creates tortuous fracture paths, increasing overall resistance to fragmentation. Additionally, the “hinge point” criterion—characterized by a double-peak strain rate pattern, serves as a reliable indicator for the onset of pulverization. These findings suggest that deep-seated, coarse-grained rocks are more susceptible to seismic pulverization than shallow, fine-grained counterparts, with implications for depth-dependent models of off-fault damage.</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

Laboratory Observation of Grain Size Controls on Granite Pulverization Under Dynamic Compression

  • 期刊论文

  • 发表日期：

    2026年5月28日

查看全文
  • Jiazhi Zhang,
  • Yingchun Li,
  • Zhiyi Liao,
  • Fuxin Rui,
  • Chun’an Tang

摘要

Rock pulverization in fault zones provides insights into earthquake mechanics and off-fault damage distributions. While lithological factors are known to influence this process, the specific role of grain size in governing dynamic deformation remains poorly understood. Here, we investigate the dynamic pulverization of fine- (FG, average grain area of 0.022 mm2 and coefficient of variation of 8.9), medium- (MG, 0.126 mm2 and 14.2), and coarse-grained (CG, 0.146 mm2 and 18.9) granites using Split Hopkinson Pressure Bar tests. The results indicate that grain size controls pulverization thresholds: the CG granite pulverizes at a strain rate of ~ 127 s−1, whereas the FG granite requires a rate of ~ 296 s−1. Similarly, the dissipated energy required for pulverization is higher for the FG specimens compared to the CG specimens. Mechanistically, these difference arise because the CG specimens contain larger initial cracks that facilitate crack branching at lower stresses. In contrast, the higher grain boundary density in FG specimens creates tortuous fracture paths, increasing overall resistance to fragmentation. Additionally, the “hinge point” criterion—characterized by a double-peak strain rate pattern, serves as a reliable indicator for the onset of pulverization. These findings suggest that deep-seated, coarse-grained rocks are more susceptible to seismic pulverization than shallow, fine-grained counterparts, with implications for depth-dependent models of off-fault damage.