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<p>In this study, a new three-dimensional thermo-mechanical damage grain-based model (3D TM-GBM) of granite was established. The model set up 3 minerals, including 9 types of contacts, and can produce 18 different microcracks. Experimental results were used to calibrate the thermal and mechanical parameters, and the root mean square error and determination coefficient of the stress–strain curve fitting can reach 15.003 and 0.91. Subsequently, the 3D evolution and interaction mechanism of thermally induced cracks and thermal stress were investigated, and the effect of thermally induced damage on the mechanical behavior and failure mechanism of granite was analyzed. The research results indicate that thermal stress concentration occurs due to uneven mineral expansion caused by high temperature, which is the main cause of thermally induced cracks. 300&#xa0;°C is the thermal damage threshold temperature of granite in this study. The number of thermally induced cracks increases with rising temperature, predominantly tensile cracks, and is positively correlated with the number and density of force chains. After heat treatment, the maximum contact force increased from 144.55 N at 200&#xa0;°C to 277.25 N at 600&#xa0;°C, while the average contact force increased first and then decreased. High temperatures lead to the deterioration of the mechanical properties of granite, which is reflected in the decrease of peak stress and elastic modulus, while the increase of peak strain. As the temperature increases, more acoustic emissions events are observed in the early stages of loading, which can be explained by crack propagation (thermally induced cracks and stress-induced cracks) and contact force changes (thermal stress and axial stress) and the interaction mechanism between them. The magnitude distribution decreases with increasing temperature, while the <i>b</i>-value first decreases and then increases with temperature, with a minimum of 1.80 at 300&#xa0;°C and a maximum of 2.83 at 600&#xa0;°C. In addition, thermally induced damage aggravates the failure degree of granite specimens and ultimately dominates the failure mode. The research results provide a new insight for the study of the thermo-mechanical behavior of granite from the 3D perspective of numerical analysis.</p>

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Thermo-mechanical Behavior of Granite Rocks Based on the Analysis of 3D Grain-Based Numerical Models

  • 期刊论文

  • 发表日期：

    2025年3月5日

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  • Mohua Bu,
  • Pingye Guo,
  • Xinpeng Li,
  • Peng Zhang,
  • Jiamin Wang

摘要

In this study, a new three-dimensional thermo-mechanical damage grain-based model (3D TM-GBM) of granite was established. The model set up 3 minerals, including 9 types of contacts, and can produce 18 different microcracks. Experimental results were used to calibrate the thermal and mechanical parameters, and the root mean square error and determination coefficient of the stress–strain curve fitting can reach 15.003 and 0.91. Subsequently, the 3D evolution and interaction mechanism of thermally induced cracks and thermal stress were investigated, and the effect of thermally induced damage on the mechanical behavior and failure mechanism of granite was analyzed. The research results indicate that thermal stress concentration occurs due to uneven mineral expansion caused by high temperature, which is the main cause of thermally induced cracks. 300 °C is the thermal damage threshold temperature of granite in this study. The number of thermally induced cracks increases with rising temperature, predominantly tensile cracks, and is positively correlated with the number and density of force chains. After heat treatment, the maximum contact force increased from 144.55 N at 200 °C to 277.25 N at 600 °C, while the average contact force increased first and then decreased. High temperatures lead to the deterioration of the mechanical properties of granite, which is reflected in the decrease of peak stress and elastic modulus, while the increase of peak strain. As the temperature increases, more acoustic emissions events are observed in the early stages of loading, which can be explained by crack propagation (thermally induced cracks and stress-induced cracks) and contact force changes (thermal stress and axial stress) and the interaction mechanism between them. The magnitude distribution decreases with increasing temperature, while the b-value first decreases and then increases with temperature, with a minimum of 1.80 at 300 °C and a maximum of 2.83 at 600 °C. In addition, thermally induced damage aggravates the failure degree of granite specimens and ultimately dominates the failure mode. The research results provide a new insight for the study of the thermo-mechanical behavior of granite from the 3D perspective of numerical analysis.