Macro-meso failure characteristics of circular cavity-contained granite under unconventional cyclic loads: A lab-scale testing

This work aims to investigate the macro-meso failure and instability mechanism of cavity-contained granite subjected to increasing-amplitude and decreasing-frequency cyclic loads combined with acoustic emission (AE) and X-ray computed tomography (CT) technique. Testing results show the cavity orientation affects rock lifetime, strength, deformation, damping ratio, AE activities and the internal failure pattern. The sudden increase of volumetric strain and abrupt decreases of b-value and damping ratio can issue the fast damage propagation, and their relationships were established. The rock having high cavity orientation has lower AE b-value, volumetric strain and damping ratio. A damage evolution model considering the damage accumulation was proposed based on AE energy that can well fit the experimental data. Post-test CT images highlight the influence of cavity orientation on rock internal failure modes. It is found that shear failure is liable to occur for rock having high cavity orientation.

Automated summary

The cavity orientation affects the lifetime, strength, deformation, damping ratio, and failure modes of rocks, with higher cavity orientation leading to faster damage propagation and lower AE b-value, volumetric strain, and damping ratio. Shear failure is more likely to occur in rocks with high cavity orientation, highlighting the importance of cavity orientation in rock failure analysis.