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<p>To elucidate the mechanical behaviour of rock during actuated disc cutting (ADC) and clarify the rock-breaking mechanism, a composite loading method—ramped cyclic uniaxial compression (RCUC) was designed as a mechanical equivalent to ADC. Red sandstone with a distinct damage stress threshold was used to investigate the mechanical behaviour of rock&#xa0;under typical loading parameters. The mechanical response under RCUC is jointly controlled by constant-rate uniaxial compression (CRUC) and constant-amplitude cyclic uniaxial compression (CACUC), which&#xa0;results in a compression-dominated, fatigue-assisted composite failure mode. The deformation and failure process can be divided into three stages: initial crack closure, stable crack propagation, and unstable crack propagation. With decreasing loading rate, increasing frequency, and decreasing amplitude, the damage stress threshold increases significantly; under extreme conditions, unstable crack propagation does not occur even at the peak stress. The degree of failure is determined by the onset time and duration of the unstable crack propagation stage rather than the total input energy or dissipated damage energy. Under the studied&#xa0;parameters, the rock exhibits progressive fatigue failure with low damage energy conversion efficiency, displaying a high-energy-consumption, low-efficiency fatigue&#xa0;process. Therefore, ADC-based rock breaking should transition from fatigue damage accumulation to an impact failure mode characterized by direct single-cycle cracking. The critical conditions for this shift are 2<i>e</i> ≥ <i>δ</i> and <i>v</i> = <i>δf</i>. This study provides theoretical support for understanding the ADC rock-breaking mechanism and for the rational selection of cutting parameters.</p>

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Mechanical Behaviour of Sandstone Under Ramped Cyclic Uniaxial Compression: Implications for Actuated Disc Cutting

  • 期刊论文

  • 发表日期：

    2026年8月4日

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  • Zhengyu Sun,
  • Wenjun Meng,
  • Wenhao Dai,
  • Xiaoxia Sun,
  • Zeping Liu

摘要

To elucidate the mechanical behaviour of rock during actuated disc cutting (ADC) and clarify the rock-breaking mechanism, a composite loading method—ramped cyclic uniaxial compression (RCUC) was designed as a mechanical equivalent to ADC. Red sandstone with a distinct damage stress threshold was used to investigate the mechanical behaviour of rock under typical loading parameters. The mechanical response under RCUC is jointly controlled by constant-rate uniaxial compression (CRUC) and constant-amplitude cyclic uniaxial compression (CACUC), which results in a compression-dominated, fatigue-assisted composite failure mode. The deformation and failure process can be divided into three stages: initial crack closure, stable crack propagation, and unstable crack propagation. With decreasing loading rate, increasing frequency, and decreasing amplitude, the damage stress threshold increases significantly; under extreme conditions, unstable crack propagation does not occur even at the peak stress. The degree of failure is determined by the onset time and duration of the unstable crack propagation stage rather than the total input energy or dissipated damage energy. Under the studied parameters, the rock exhibits progressive fatigue failure with low damage energy conversion efficiency, displaying a high-energy-consumption, low-efficiency fatigue process. Therefore, ADC-based rock breaking should transition from fatigue damage accumulation to an impact failure mode characterized by direct single-cycle cracking. The critical conditions for this shift are 2e ≥ δ and v = δf. This study provides theoretical support for understanding the ADC rock-breaking mechanism and for the rational selection of cutting parameters.