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<p>This study employed a series of experiments, including drying, weighing, P-wave velocity measurement, saturation, freeze–thaw (F-T) cycles, and pore structure distribution (PSD) analysis, to examine the impact of F-T cycles on the microstructural and macromechanical behavior of saturated sandstone under Brazilian splitting and uniaxial compression conditions. A detailed investigation was conducted into the damage mechanisms and their progression in the sandstone samples exposed to varying numbers of F-T cycles. The results demonstrate that the pore structure, both before and after F-T cycles action, can be categorized into nanopores, micropores, mesopores, and macropores. Following F-T cycles, an increase in the signal strength and peak area was observed for all the pore categories, accompanied by a rightward shift in the PSD curves, indicating irreversible damage. The uniaxial compressive strength, tensile strength, and elastic modulus of the sandstone exhibited a negative correlation with the number of F-T cycles. Conversely, the Brazilian splitting displacements, peak strain, P-wave velocity, porosity, and defined damage variables showed a positive correlation. Various damage variables and damage models, evolving with F-T cycles, were developed and validated based on changes in the P-wave velocity, static elastic modulus, porosity, P-wave velocity–porosity coupling (P-P couple), total energy, pore size distribution (PSD), and a porosity–static elastic modulus–tensile strength coupling (P-E-B couple). A novel damage factor and corresponding model were formulated, incorporating the effects of F-T cycles by considering mutual pore transformation and the evolution of the porosity–elastic modulus–tensile strength relationship. This approach integrates microstructural evolution with macro-physico-mechanical characteristics, providing a more comprehensive reflection of the damage mechanism. The predictive accuracy of the newly proposed PSD couple damage model and P-E-B couple damage model was confirmed through comparisons with experimental uniaxial compressive strength (UCS) and peak strain data.</p>

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Study on Damage Mechanism and Damage Evolution Model of Sandstone Subjected to Freeze–Thaw Cycles

  • 期刊论文

  • 发表日期：

    2026年1月8日

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  • Jingjing Huang,
  • Yanlin Zhao,
  • Shuailong Lian,
  • Wen Wan,
  • Qiuhong Wu,
  • Lianyang Zhang

摘要

This study employed a series of experiments, including drying, weighing, P-wave velocity measurement, saturation, freeze–thaw (F-T) cycles, and pore structure distribution (PSD) analysis, to examine the impact of F-T cycles on the microstructural and macromechanical behavior of saturated sandstone under Brazilian splitting and uniaxial compression conditions. A detailed investigation was conducted into the damage mechanisms and their progression in the sandstone samples exposed to varying numbers of F-T cycles. The results demonstrate that the pore structure, both before and after F-T cycles action, can be categorized into nanopores, micropores, mesopores, and macropores. Following F-T cycles, an increase in the signal strength and peak area was observed for all the pore categories, accompanied by a rightward shift in the PSD curves, indicating irreversible damage. The uniaxial compressive strength, tensile strength, and elastic modulus of the sandstone exhibited a negative correlation with the number of F-T cycles. Conversely, the Brazilian splitting displacements, peak strain, P-wave velocity, porosity, and defined damage variables showed a positive correlation. Various damage variables and damage models, evolving with F-T cycles, were developed and validated based on changes in the P-wave velocity, static elastic modulus, porosity, P-wave velocity–porosity coupling (P-P couple), total energy, pore size distribution (PSD), and a porosity–static elastic modulus–tensile strength coupling (P-E-B couple). A novel damage factor and corresponding model were formulated, incorporating the effects of F-T cycles by considering mutual pore transformation and the evolution of the porosity–elastic modulus–tensile strength relationship. This approach integrates microstructural evolution with macro-physico-mechanical characteristics, providing a more comprehensive reflection of the damage mechanism. The predictive accuracy of the newly proposed PSD couple damage model and P-E-B couple damage model was confirmed through comparisons with experimental uniaxial compressive strength (UCS) and peak strain data.