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<p>This investigation was conducted to analyze the weakening mechanism of bearing capacity of sandstone under wet-dry cycles conditions. The effects of wet-dry cycles on the mechanical properties and acoustic emission characteristics of sandstone with varying mineral particle sizes were studied. Through systematic experiments—including uniaxial compression tests, acoustic emission monitoring and microscopic fracture morphology analysis—the evolution of physical properties (porosity, wave velocity), mechanical characteristics (peak strength, peak strain, and elastic modulus), and fracture modes under 5–20 wet-dry cycles were analyzed. Results show that increased porosity and decreased wave velocity correlate with progressive internal microcrack propagation, particularly in coarse-grained sandstone that it was exhibited the highest porosity increase 2.2% and strength loss 56.97% after 20 cycles. As the number of cycles and particle size increase, the failure patterns become more complex, with more secondary cracks and slight spalling around the specimens. In terms of acoustic emission response, there will also be dense acoustic emission signals and frequent high amplitudes, indicating a higher likelihood of crack coalescence and increased macroscopic damage. Scanning electron microscope observations indicate that particle size differences lead to distinct fracture modes, while increased wet-dry cycles weaken the cementing ability between minerals, promoting intergranular fracture-dominated failure, significantly reducing mechanical bearing characteristics of sandstone. Research reveals that one of the key reasons for the weakening of its mechanical bearing capacity caused by wet-dry cycles is the synergistic effect of mineral cementation and intergranular fracture, and this phenomenon becomes increasingly significant with the increase of wet-dry cycles and particle size. These insights advance the prediction of sandstone stability in cyclic hydration environments, supporting resilient rock engineering design.</p>

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Mechanical and Acoustic Responses of Sandstone with Varying Particle Sizes Under Wet–Dry Cycles

  • 期刊论文

  • 发表日期：

    2025年7月7日

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  • Qianlong Jin,
  • Hailong Wang,
  • Houli Fu,
  • Zhenlong Zhao,
  • Xiaoyong Yang

摘要

This investigation was conducted to analyze the weakening mechanism of bearing capacity of sandstone under wet-dry cycles conditions. The effects of wet-dry cycles on the mechanical properties and acoustic emission characteristics of sandstone with varying mineral particle sizes were studied. Through systematic experiments—including uniaxial compression tests, acoustic emission monitoring and microscopic fracture morphology analysis—the evolution of physical properties (porosity, wave velocity), mechanical characteristics (peak strength, peak strain, and elastic modulus), and fracture modes under 5–20 wet-dry cycles were analyzed. Results show that increased porosity and decreased wave velocity correlate with progressive internal microcrack propagation, particularly in coarse-grained sandstone that it was exhibited the highest porosity increase 2.2% and strength loss 56.97% after 20 cycles. As the number of cycles and particle size increase, the failure patterns become more complex, with more secondary cracks and slight spalling around the specimens. In terms of acoustic emission response, there will also be dense acoustic emission signals and frequent high amplitudes, indicating a higher likelihood of crack coalescence and increased macroscopic damage. Scanning electron microscope observations indicate that particle size differences lead to distinct fracture modes, while increased wet-dry cycles weaken the cementing ability between minerals, promoting intergranular fracture-dominated failure, significantly reducing mechanical bearing characteristics of sandstone. Research reveals that one of the key reasons for the weakening of its mechanical bearing capacity caused by wet-dry cycles is the synergistic effect of mineral cementation and intergranular fracture, and this phenomenon becomes increasingly significant with the increase of wet-dry cycles and particle size. These insights advance the prediction of sandstone stability in cyclic hydration environments, supporting resilient rock engineering design.