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<p>Efficient fragmentation of ultra-hard rocks in deep excavation environments has long been a challenge in mining and tunneling, limiting operational efficiency and safety. High-pressure abrasive water jetting shows significant promise for ultra-hard rock excavation, but its breaking performance is heavily governed by the complex in situ stress conditions. To investigate the rock-breaking mechanisms under stress–jet coupling, abrasive jet cutting experiments were conducted under stress-free, uniaxial stress, and biaxial stress conditions, with real-time strain monitoring. Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and numerical simulations were employed to analyze the internal damage and fracture characteristics of the rocks, revealing the mechanical evolution during the fracturing process and exploring the effects of high stress and mineral composition on stress-induced rock failure. The results indicate that low stress inhibits rock fragmentation, with damage reduced by 20.52% to 74.22%, while high stress promotes fragmentation, with damage increased by 52.11% to 319.21%. A novel parameter, the “Jet Stress Threshold,” was identified to characterize this transition, determined to be 20.88&#xa0;MPa for granite and 16.43&#xa0;MPa for limestone under uniaxial loading. Comparatively, biaxial stress exerts a stronger inhibitory effect than uniaxial stress. Dynamic strain monitoring indicates that granite exhibits predominantly brittle elastic responses, whereas limestone displays complex non-linear deformation characteristics. Microscopic observations further indicate that fracture modes are stress-dependent: a transition from intergranular fracture (dominant at low stress) to transgranular fracture occurs under high confining stress, driven by the “locking effect” of grain boundaries. This study enhances the understanding of ultra-hard rock fragmentation and offers practical guidance for optimizing abrasive water jet technology in stress-laden environments, potentially improving efficiency and safety in mining and tunneling operations.</p>

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Understanding Stress-Induced Fragmentation of Ultra-hard Rocks in Abrasive Water Jet Cutting

  • 期刊论文

  • 发表日期：

    2026年3月3日

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  • Lei Liu,
  • Zhaolong Ge,
  • Zhe Zhou,
  • Qinlin Deng,
  • Zhongtan Li,
  • Xiaoxiao Li

摘要

Efficient fragmentation of ultra-hard rocks in deep excavation environments has long been a challenge in mining and tunneling, limiting operational efficiency and safety. High-pressure abrasive water jetting shows significant promise for ultra-hard rock excavation, but its breaking performance is heavily governed by the complex in situ stress conditions. To investigate the rock-breaking mechanisms under stress–jet coupling, abrasive jet cutting experiments were conducted under stress-free, uniaxial stress, and biaxial stress conditions, with real-time strain monitoring. Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and numerical simulations were employed to analyze the internal damage and fracture characteristics of the rocks, revealing the mechanical evolution during the fracturing process and exploring the effects of high stress and mineral composition on stress-induced rock failure. The results indicate that low stress inhibits rock fragmentation, with damage reduced by 20.52% to 74.22%, while high stress promotes fragmentation, with damage increased by 52.11% to 319.21%. A novel parameter, the “Jet Stress Threshold,” was identified to characterize this transition, determined to be 20.88 MPa for granite and 16.43 MPa for limestone under uniaxial loading. Comparatively, biaxial stress exerts a stronger inhibitory effect than uniaxial stress. Dynamic strain monitoring indicates that granite exhibits predominantly brittle elastic responses, whereas limestone displays complex non-linear deformation characteristics. Microscopic observations further indicate that fracture modes are stress-dependent: a transition from intergranular fracture (dominant at low stress) to transgranular fracture occurs under high confining stress, driven by the “locking effect” of grain boundaries. This study enhances the understanding of ultra-hard rock fragmentation and offers practical guidance for optimizing abrasive water jet technology in stress-laden environments, potentially improving efficiency and safety in mining and tunneling operations.