Mesoscopic damage enhancement in granite under cyclic liquid nitrogen shocks characterized by computed tomography and texture analysis

Abstract

This study investigates the internal damage of granite induced by liquid nitrogen (LN₂) cold shock using X-ray computed tomography (CT) technology. Traditional threshold segmentation methods are subjective and may obscure subtle grayscale variations. In contrast, the Gray Level Co-occurrence Matrix (GLCM), based on second-order statistical measures of grayscale values, quantifies texture features and captures comprehensive fracture information. Uniaxial compression tests were performed on granite samples subjected to cyclic heating and LN₂ treatment, followed by X-ray CT scanning. Image processing techniques and GLCM were employed to extract key features from CT images. Statistical analysis was conducted to quantify the cracks and micro-damages in granite induced by LN₂ cold shock. The results demonstrate that cyclic LN₂ treatment significantly exacerbates cracking in granite, leading to an increase in the number of fracture nodes, thereby intensifying micro-damage. As the number of LN₂ cycles increases, the contrast value typically rises, while the energy and homogeneity values continuously decrease. The correlation values show fluctuating changes, gradually declining. Additionally, as the number of cycles increases, the range of high-frequency feature parameters gradually expands. Parameters associated with the Gaussian main peak steadily increase, and the texture distribution in the CT images becomes increasingly irregular. This work offers a framework for non-destructive quantification of cryogenic-induced rock damage by integrating X-ray CT imaging with GLCM-based texture analysis.