In Situ Study on Fracture Process of Sandstones With Internal Flaws Using X-Ray Microtomography

To investigate the damage patterns and crack mechanisms in pre-flawed sandstones, in situ compression experiments were conducted using an X-ray CT scanning system equipped with a loading device. Sandstones with varying flaw inclinations were scanned at different loading stages, and 2D CT images underwent image processing and volume filtering to extract flaw and crack evolution. Quantitative and visual analyses were performed on crack initiation, volume evolution, damage progression, and 3D fractal characteristics. The findings reveal that flaw inclination significantly influences crack development, with a linear correlation between flaw angle and crack initiation angle. Crack volume remains stable before failure and increases exponentially post-failure. A negative linear relationship is observed between rock strength and post-failure 3D fractal dimensions. These insights contribute to understanding the fracture behavior of brittle rocks under loading.