Insight into the fracture evolution behavior of pre-flawed hollow-cylinder granite under multi-stage increasing-amplitude cyclic loads: A lab-scale testing

The structural deterioration and associated fracture evolution behavior of pre-flawed hollow-cylinder granite subjected to multi-stage increasing-amplitude (MSIA) cyclic loads are studied herein. The influences of rock structure on volumetric deformation, damage accumulation, energy dissipation, and failure pattern were investigated. It is shown that the volumetric deformation is relatively large for rock having high flaw angle, and it is the minimum and maximum for rock having a 10 degrees and 70 degrees flaw angle. A damage evolution model that can describe a first fast and then steady damage propagation was proposed based on the irreversible axial strain. Much energy needs to be consumed to drive crack propagation and hole collapse for rock having high angle flaws. A series of 2D computed tomography (CT) images reveal the different crack network pattern and how it is affected by the rock structure. A more complicated crack network is found for rock having a high flaw angle.

Automated summary

The study focused on the structural deterioration and fracture evolution behavior of pre-flawed hollow-cylinder granite subjected to multi-stage increasing-amplitude cyclic loads, revealing that rock with high flaw angles exhibit larger volumetric deformation and requires more energy for damage propagation. The research proposed a damage evolution model and analyzed the influence of rock structure on crack network patterns.