Fracture evolution and failure mechanism of granite considering flaws and microstructure using a grain-based model

An integrated experimental–numerical approach was employed to elucidate how ligament angle influences fracture evolution and failure in flawed granite. Digital image correlation (DIC) under uniaxial compression provided full‐field strain data, while a grain‐based model (GBM) captured the stress distribution and microcrack propagation. Results showed that specimens with ligament angles below 90° (e.g., 45–60°) experienced pronounced shear stress concentrations in the ligament region, leading to lower peak strengths. Conversely, angles above 90° (e.g., 120–150°) promoted tensile stress concentrations and a “self‐locking” phenomenon, resulting in relatively higher strengths. Full‐field strain analysis revealed localized deformation primarily at the flaw tips, with horizontal strains peaking near the specimen center. Early damage stages were dominated by intergranular tensile microcracks, which eventually coalesced with intragranular tensile and shear microcracks to form macroscopic fractures. Moreover, increasing the friction coefficient enhanced post‐peak microcrack formation and boosted overall rock strength. These findings highlight the critical role of ligament inclination in dictating failure patterns in flawed granite, offering valuable insights for the design and monitoring of rock engineering applications, such as slope stabilization and tunnel construction.