Fracture Characteristics of Transparent Rock Materials With Eccentric Cracks Under High‐Temperature Three‐Point Bending

ABSTRACT Controlling fracture propagation is imperative for the safety of deep geothermal engineering. This study investigates transparent rock‐like semicircular bend specimens containing eccentric cracks by integrating high‐temperature bending tests with numerical simulations. The results reveal that fracture mechanisms evolve distinctly across different stages. Specifically, thermal exposure initially drives damage dominated by Mode I propagation, which manifests as circular, “U”, and “S”‐shaped morphologies. In contrast, the subsequent three‐point bending stress field shifts the failure behavior to a complex mixed Mode I–II–III mechanism. These findings elucidate three‐dimensional crack evolution under thermo‐mechanical coupling and provide a theoretical basis for predicting geothermal rock failure.