Mechanical behaviors of granite containing two flaws subjected to
uniaxial increasing-amplitude fatigue loading conditions: An insight
into fracture evolution analyses
Abstract
This work aims to investigate the fracture evolution of granite
containing two pre-existing flaws under uniaxial increasing-amplitude
fatigue conditions using GCTS 2000 rock mechanical system and post-test
3D computed tomography (CT) technique. The impacts of flaw arrangement
(i.e., approach angle of 20°, 50°, and 70°) on the stress strain
responses, hysteresis loop shape, damage evolution and crack coalescence
pattern at rock bridge segment were investigated. Results show that rock
structure has obvious impact on macroscopic stress strain responses,
volumetric strain, resilient modulus and damping ratio. The sparse-dense
pattern of hysteresis loop is different at each loading stage caused by
the differential accumulative damage. The resilient modulus decreases
and damping ratio increases with increasing fatigue loading stage as
damage grows. Post-test 3D CT visualization reveal a most striking
finding that crack coalescence is easy for rock having low approach
angle, and complex crack network forms for rock having high approach
angle.