In high-temperature rock engineering projects, rocks are subjected to external loads. Studying the cracking behavior of thermally damaged rock under uniaxial loading is of great significance to engineering. In the present study, real-time computed tomography (CT) scanning was performed on thermally damaged granite subjected to compression loading to observe the evolution of spatial three-dimensional (3D) microcracks and planar two-dimensional (2D) microcracks. The porosity and crack length were further introduced to quantify microcracking behavior. The effects of the load on the 3D microcrack volume distribution and the length of 2D microcracks with different orientations were discussed. The results show that real-time CT imaging intuitively presents the evolutionary process of realistic microcrack morphology during loading. As the load level increases, the porosity of the specimen and the total length of 2D microcracks experience stages of slow decrease, slow increase, and rapid increase. The proportion of microcracks with larger volumes decreases and then increases as the load level increases. In the slice parallel to the loading direction, the length of microcracks within an angle range of 30°–90° to the loading direction decreases as the load level increases. In the slice perpendicular to the loading direction, the microcrack length distribution exhibits obvious anisotropy as the load level increases.

在高温岩石工程项目中，岩石承受外部载荷。研究单轴加载下热损伤岩石的开裂行为具有重要的工程意义。在本研究中，对承受压缩载荷的热损伤花岗岩进行实时计算机断层扫描 (CT) 扫描，以观察空间三维 (3D) 微裂纹和平面二维 (2D) 微裂纹的演变。进一步引入孔隙率和裂纹长度以量化微裂纹行为。讨论了载荷对 3D 微裂纹体积分布和不同方向的 2D 微裂纹长度的影响。结果表明，实时CT成像直观地呈现了加载过程中逼真微裂纹形态的演化过程。随着载荷水平的增加，试样的孔隙率和二维微裂纹的总长度经历了缓慢减少、缓慢增加和快速增加的阶段。体积较大的微裂纹的比例随着载荷水平的增加而减少然后增加。在平行于加载方向的切片中，与加载方向成 30°~90° 角度范围内的微裂纹长度随着加载水平的增加而减小。在垂直于加载方向的切片中，随着加载水平的增加，微裂纹长度分布表现出明显的各向异性。在平行于加载方向的切片中，与加载方向成 30°~90° 角度范围内的微裂纹长度随着加载水平的增加而减小。在垂直于加载方向的切片中，随着加载水平的增加，微裂纹长度分布表现出明显的各向异性。在平行于加载方向的切片中，与加载方向成 30°~90° 角度范围内的微裂纹长度随着加载水平的增加而减小。在垂直于加载方向的切片中，随着加载水平的增加，微裂纹长度分布表现出明显的各向异性。