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<p>During the construction of coal mines in western China, many boreholes are drilled through artificially frozen Cretaceous and Jurassic formations. After experiencing one freeze–thaw cycle, these water-rich and weakly cemented rocks generally demonstrate significant changes in permeability and mechanical properties, leading to frequent occurrences of water intrusion and flooding accidents. In this study, triaxial compression tests, acoustic emission (AE) tests, and permeability tests were conducted on Cretaceous red sandstone under conditions of both no freeze–thaw cycle and one freeze–thaw cycle. The variation of permeability and mechanical characteristics of red sandstone induced by one freeze–thaw cycle was investigated for different confining pressures. The results indicated that the damage evolution pattern inside red sandstone can be well characterized based on AE cumulative energy. The greater the confining pressure during freeze–thaw, the greater the damage to the red sandstone, and the greater the increase in permeability. At the same time, the permeability of red sandstone decreases with the increase of test confining pressure and increases with the increase of water pressure. After one freeze–thaw cycle, the peak strength and elastic modulus of the red sandstone decreased, but the Poisson’s ratio increased. Under low confining pressures (4 and 6&#xa0;MPa), the permeability of red sandstone exhibited staging characteristics. Enhanced by the freezing–thawing cycle, the permeability of red sandstone significantly increased before the crack initiation stress, and the permeability is negatively correlated with AE signal. In addition, the peak permeability lags the peak stress. Under high confining pressures (8 and 10&#xa0;MPa), the permeability showed a continuous decreasing trend. The correlation between permeability and AE signals of red sandstone varies at different stages during the loading process. The test results from this work are helpful to reveal the deterioration mechanism of permeability and mechanical performance of red sandstone. It can also provide reference for stability analysis of the mine shaft and pre-control of seepage damage after the thawing treatment of the frozen coal mines.</p>

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Effect of Cyclic Freezing and Thawing on Permeability and Mechanical Properties of Red Sandstone Under Triaxial Compression Condition

  • 期刊论文

  • 发表日期：

    2025年11月20日

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  • Bo Liu,
  • Yanqing He,
  • Yanhui Han,
  • Wenhao Li,
  • Jingyuan Zeng,
  • Guoxuan Wang

摘要

During the construction of coal mines in western China, many boreholes are drilled through artificially frozen Cretaceous and Jurassic formations. After experiencing one freeze–thaw cycle, these water-rich and weakly cemented rocks generally demonstrate significant changes in permeability and mechanical properties, leading to frequent occurrences of water intrusion and flooding accidents. In this study, triaxial compression tests, acoustic emission (AE) tests, and permeability tests were conducted on Cretaceous red sandstone under conditions of both no freeze–thaw cycle and one freeze–thaw cycle. The variation of permeability and mechanical characteristics of red sandstone induced by one freeze–thaw cycle was investigated for different confining pressures. The results indicated that the damage evolution pattern inside red sandstone can be well characterized based on AE cumulative energy. The greater the confining pressure during freeze–thaw, the greater the damage to the red sandstone, and the greater the increase in permeability. At the same time, the permeability of red sandstone decreases with the increase of test confining pressure and increases with the increase of water pressure. After one freeze–thaw cycle, the peak strength and elastic modulus of the red sandstone decreased, but the Poisson’s ratio increased. Under low confining pressures (4 and 6 MPa), the permeability of red sandstone exhibited staging characteristics. Enhanced by the freezing–thawing cycle, the permeability of red sandstone significantly increased before the crack initiation stress, and the permeability is negatively correlated with AE signal. In addition, the peak permeability lags the peak stress. Under high confining pressures (8 and 10 MPa), the permeability showed a continuous decreasing trend. The correlation between permeability and AE signals of red sandstone varies at different stages during the loading process. The test results from this work are helpful to reveal the deterioration mechanism of permeability and mechanical performance of red sandstone. It can also provide reference for stability analysis of the mine shaft and pre-control of seepage damage after the thawing treatment of the frozen coal mines.