AI Insight
This study uses meso-damage numerical simulation to examine how stress paths and flaw geometry influence the failure mechanisms and mechanical properties of heterogeneous rock masses containing surface, through-going, and internal flaws. The research finds that flaw propagation primarily occurs through wing and anti-wing crack extension, and that the direction of the intermediate principal stress is a decisive factor in determining whether coalescence failure is tensile or transverse. Confining pressure consistently increases peak strength, and the orientation of the intermediate principal stress relative to the flaw plane has a greater influence on embedded and through-going flaws than on surface flaws.
Why it matters
Understanding how three-dimensional flaws propagate and coalesce under varied stress conditions is directly relevant to geotechnical engineering applications such as tunneling, slope stability analysis, and underground excavation design. These findings provide a quantitative basis for improving safety assessments in rock mass engineering projects where complex stress states are present.
by Na Wu, Yu Gan, Jie Hu, Ruixiang Sun, Hongyan Zeng
The macroscopic failure of rock masses is essentially the result of the propagation, interaction, and eventual coalescence of internal defects such as flaws under stress. Given the widespread presence of three-dimensional (3D) flaws in rock mass engineering, it is crucial to investigate their failure mechanisms and mechanical properties. This research employs a meso-damage numerical simulation method to systematically investigate the failure process and mechanical parameters of heterogeneous rock masses containing surface flaws, through-going flaws, and internal flaws under various stresses, focusing on the influence of stress path on flaw propagation behavior and the mechanical properties of the specimens. The study reveals: (1) Rock mass flaw propagation primarily manifests as the extension of wing and anti-wing flaws, and the coalescence of secondary flaws with these or with the pre-existing flaw. (2) Under uniaxial compression test, conventional triaxial and true triaxial compression test with specific intermediate principal stress directions, rock masses exhibit tensile coalescence failure, while changing the intermediate principal stress direction leads to transverse coalescence failure. The direction of the intermediate principal stress plays a decisive role in flaw propagation path. (3) Confining pressure significantly enhances the peak strength of the rock mass. For embedded and through-going flaws, the peak strength is generally higher when the intermediate principal stress direction is oriented towards the flaw plane compared to when it is parallel. Whereas the peak strength of surface flaws is not significantly affected by the intermediate principal stress direction. (4) The magnitude of the intermediate principal stress affects the mechanical properties of rock masses with different flaw types to varying degrees. The results of this study can provide valuable references for theoretical research and physical experiments on the propagation mechanisms of 3D flaws in rock masses.