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<p>The micro-structure of rocks has a considerable effect on their deformation and failure. Consequently, it is crucial to investigate the influence of microstructural heterogeneity on the mechanical behavior and failure process of brittle rocks for engineering applications. Here, a series of grain-based discrete element models (DEMs) of different rocks were built through rock image processing and mineral composition determination, in which the size, geometric shape, and distribution of mineral grains were considered in detail. Numerical coarse-grained granite, fine-grained granite, basalt, and marble experiments were then performed under compression. The strength, deformation characteristics, and macro-microscopic fracture evolution patterns of various rocks with different microstructures were studied throughout the loading process. Effects of microstructural characteristics on the evolution of shear and tensile cracks in rocks were discussed. A comparison of shear and tensile cracks derived from the numerical simulation and acoustic emission measurement was made. Additionally, a digital image correlation technology was introduced to identify transgranular and intergranular cracks during the process of rock failure in numerical experiments. The evolution laws of transgranular and intergranular cracks were analyzed with applied stress and compared with the results of electron microscope scanning of rock fracture surfaces. Results showed that the microstructural characteristics of rocks play a crucial role in their macroscopic failure. Rocks are more susceptible to undergo shear failure subjected to uniaxial compression compared to tensile failure. When the applied stress surpasses the crack damage threshold, numerous shear cracks occur in the rock. After failure, intragranular cracks account for approximately 60% of the total cracks in coarse-grained granite, 65% in fine-grained granite, and 73% in basalt, while there are fewer transgranular cracks in rocks. Our findings in this paper establish a foundation for revealing the mechanism by which the microscopic structure affects the evolution of rock fracture.</p>

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Study on the Effects of Microstructural Heterogeneity on the Mechanical Behavior and Failure Process of Brittle Rocks Based on DEM

  • 期刊论文

  • 发表日期：

    2025年1月23日

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  • Zhenghu Zhang,
  • Qihao Zhang,
  • Ke Ma,
  • Jianhui Deng

摘要

The micro-structure of rocks has a considerable effect on their deformation and failure. Consequently, it is crucial to investigate the influence of microstructural heterogeneity on the mechanical behavior and failure process of brittle rocks for engineering applications. Here, a series of grain-based discrete element models (DEMs) of different rocks were built through rock image processing and mineral composition determination, in which the size, geometric shape, and distribution of mineral grains were considered in detail. Numerical coarse-grained granite, fine-grained granite, basalt, and marble experiments were then performed under compression. The strength, deformation characteristics, and macro-microscopic fracture evolution patterns of various rocks with different microstructures were studied throughout the loading process. Effects of microstructural characteristics on the evolution of shear and tensile cracks in rocks were discussed. A comparison of shear and tensile cracks derived from the numerical simulation and acoustic emission measurement was made. Additionally, a digital image correlation technology was introduced to identify transgranular and intergranular cracks during the process of rock failure in numerical experiments. The evolution laws of transgranular and intergranular cracks were analyzed with applied stress and compared with the results of electron microscope scanning of rock fracture surfaces. Results showed that the microstructural characteristics of rocks play a crucial role in their macroscopic failure. Rocks are more susceptible to undergo shear failure subjected to uniaxial compression compared to tensile failure. When the applied stress surpasses the crack damage threshold, numerous shear cracks occur in the rock. After failure, intragranular cracks account for approximately 60% of the total cracks in coarse-grained granite, 65% in fine-grained granite, and 73% in basalt, while there are fewer transgranular cracks in rocks. Our findings in this paper establish a foundation for revealing the mechanism by which the microscopic structure affects the evolution of rock fracture.