Scholarlink

<p>To study the impact of different prefabricated crack geometries on the microscopic fracture mechanisms and fractal characteristics of sandstone, this paper presents indoor uniaxial compression tests on intact sandstone samples and sandstone samples with prefabricated cracks at various angles (0°, 20°, 45°, 70°, and 90°). The tests employed acoustic emission (AE), particle flow simulation (PFC<sup>3D</sup>), and 3D optical scanning analysis methods. The results indicate that as the angle of the prefabricated cracks decreases, the peak strength, peak strain, and the time required to reach peak stress all decrease progressively, with all of these values significantly lower than for the intact samples. The acoustic emission events during the compression of sandstone with prefabricated cracks can be divided into three stages: a quiet stage, a development stage, and a peak stage. The larger the crack angle, the more time it takes to reach the peak stage, the longer the peak stage lasts, and the greater the number of AE events and accumulative ring down counts. As the crack angle increases, the formation of the rock fracture surface evolves from the coexistence of wing cracks and anti-wing cracks to a predominance of wing cracks, accompanied by the development of secondary cracks. During compression, the sandstone with prefabricated cracks experiences both tensile and shear failure, as the inclination angle of the crack increases, the tensile failure modes gradually weaken, while the shear failure modes progressively intensify. Finally, based on the box-counting dimension algorithm, a fractal study of the fracture surfaces formed after the compression failure of sandstone with different prefabricated crack geometries reveals that the fractal dimension of the upper and lower fracture surfaces is positively correlated. As the crack angle increases, the fractal dimension of the fracture surface first increases and then decreases. Fractal analysis of the fracture path also shows a regular pattern in the impact of different prefabricated crack shapes on the fractal characteristics of regions parallel and perpendicular to the cracks. The findings provide important insights for further research into the engineering properties and failure modes of cracked rock masses.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Microfracture Mechanism and Fractal Characteristics of Sandstone with Various Prefabricated Cracks

  • 期刊论文

  • 发表日期：

    2025年5月6日

查看全文
  • Liu Jiang,
  • Rui Peng,
  • Chunyang Shen,
  • Xuehong Yang

摘要

To study the impact of different prefabricated crack geometries on the microscopic fracture mechanisms and fractal characteristics of sandstone, this paper presents indoor uniaxial compression tests on intact sandstone samples and sandstone samples with prefabricated cracks at various angles (0°, 20°, 45°, 70°, and 90°). The tests employed acoustic emission (AE), particle flow simulation (PFC3D), and 3D optical scanning analysis methods. The results indicate that as the angle of the prefabricated cracks decreases, the peak strength, peak strain, and the time required to reach peak stress all decrease progressively, with all of these values significantly lower than for the intact samples. The acoustic emission events during the compression of sandstone with prefabricated cracks can be divided into three stages: a quiet stage, a development stage, and a peak stage. The larger the crack angle, the more time it takes to reach the peak stage, the longer the peak stage lasts, and the greater the number of AE events and accumulative ring down counts. As the crack angle increases, the formation of the rock fracture surface evolves from the coexistence of wing cracks and anti-wing cracks to a predominance of wing cracks, accompanied by the development of secondary cracks. During compression, the sandstone with prefabricated cracks experiences both tensile and shear failure, as the inclination angle of the crack increases, the tensile failure modes gradually weaken, while the shear failure modes progressively intensify. Finally, based on the box-counting dimension algorithm, a fractal study of the fracture surfaces formed after the compression failure of sandstone with different prefabricated crack geometries reveals that the fractal dimension of the upper and lower fracture surfaces is positively correlated. As the crack angle increases, the fractal dimension of the fracture surface first increases and then decreases. Fractal analysis of the fracture path also shows a regular pattern in the impact of different prefabricated crack shapes on the fractal characteristics of regions parallel and perpendicular to the cracks. The findings provide important insights for further research into the engineering properties and failure modes of cracked rock masses.