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<p>Stability of rock faults or fractures can be affected by high temperatures in various underground rock engineering applications such as underground coal gasification, geothermal energy exploitation, and hydrocarbon production. Understanding the sliding stability behavior of rock fractures under a thermal–mechanical coupled environment is of great importance for the evaluation and mitigation of dynamic geo-hazards such as induced earthquakes. In this study, the sliding and stability behavior of rough sandstone fractures under high temperature were investigated by direct shear test, during which acoustic emission parameters were monitored to detect the damage evolution upon shear. Seismic source parameters were also calculated to clarify the correlation between temperature and the stability of sandstone fracture. Results show that the competing effects of normal stress and temperature critically govern stick–slip instability in sandstone fractures. Thermal expansion of asperities increases the real contact area of sandstone fracture, representing an important mechanism for sliding instability at lower temperatures (i.e., 100 °C to 300 °C). At temperature higher than 300&#xa0;°C, the formation of intragranular cracks promotes stable sliding, with no prominent stick–slip. However, increasing normal stress induces compaction of rock fracture that suppresses thermal crack propagation, leading to stick–slip instability at high temperatures. Moreover, increased quartz content was observed to induce a transition from stable sliding to unstable stick–slip behavior for rough sandstone fractures at high temperature. Seismic source parameter analyses show that dynamic slip energy during unstable stick–slip exhibits distinct temperature-dependent responses under varying normal stresses, and stress drops obtained at the laboratory-scale show a range similar to those observed in mining-induced seismicity, with moment magnitude increasing with source dimension. However, this characteristic can be influenced by variations in machine stiffness that affect stress drops at the laboratory scale.</p>

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Frictional Stability and Seismic Response of Sandstone Fractures Under High Temperature

  • 期刊论文

  • 发表日期：

    2026年5月26日

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  • Zhengyang Xu,
  • Fanzhen Meng,
  • Junnan Zhang,
  • Pengyuan Liu,
  • Yuantao Wen,
  • Feili Wang,
  • Hui Zhou

摘要

Stability of rock faults or fractures can be affected by high temperatures in various underground rock engineering applications such as underground coal gasification, geothermal energy exploitation, and hydrocarbon production. Understanding the sliding stability behavior of rock fractures under a thermal–mechanical coupled environment is of great importance for the evaluation and mitigation of dynamic geo-hazards such as induced earthquakes. In this study, the sliding and stability behavior of rough sandstone fractures under high temperature were investigated by direct shear test, during which acoustic emission parameters were monitored to detect the damage evolution upon shear. Seismic source parameters were also calculated to clarify the correlation between temperature and the stability of sandstone fracture. Results show that the competing effects of normal stress and temperature critically govern stick–slip instability in sandstone fractures. Thermal expansion of asperities increases the real contact area of sandstone fracture, representing an important mechanism for sliding instability at lower temperatures (i.e., 100 °C to 300 °C). At temperature higher than 300 °C, the formation of intragranular cracks promotes stable sliding, with no prominent stick–slip. However, increasing normal stress induces compaction of rock fracture that suppresses thermal crack propagation, leading to stick–slip instability at high temperatures. Moreover, increased quartz content was observed to induce a transition from stable sliding to unstable stick–slip behavior for rough sandstone fractures at high temperature. Seismic source parameter analyses show that dynamic slip energy during unstable stick–slip exhibits distinct temperature-dependent responses under varying normal stresses, and stress drops obtained at the laboratory-scale show a range similar to those observed in mining-induced seismicity, with moment magnitude increasing with source dimension. However, this characteristic can be influenced by variations in machine stiffness that affect stress drops at the laboratory scale.