effects of fatigue load amplitude on the mechanical and energy evolution characteristics of stratified rock mass under triaxial cyclic loading and unloading conditions

Rock failure under cyclic loading and unloading has been well studied, however, the mechanical and energy evolution mechanisms of stratified rock mass under triaxial cyclic loading and unloading (tclu) conditions have not been fully elucidated. to reveal the effects of the fatigue load amplitude (fmax) on the mechanical and energy evolution characteristics of rock subjected to tclu tests, triaxial compression tests and triaxial cyclic loading and unloading tests were performed on stratified rock mass. based on the test results, the evolution laws of the mechanical and energy parameters of the stratified rock mass with increasing number of cycles (n) were obtained, and the change laws of the mechanical and energy parameters at peak stress with increasing fmax were analysed. research has shown that under the joint effects of “compaction and consolidation” and “weak structure fracture”, the loading modulus and poisson’s ratio greatly increased during the second cycle and gradually slowed down with increasing n. meanwhile, the unloading modulus and poisson’s ratio changed little, the energy dissipation rate increased, and the growth rate decreased and gradually stabilized. with increasing fmax, the peak stress, peak axial strain, peak circumferential strain, peak volume strain, poisson’s ratio, and energy dissipation rate first increased and subsequently decreased, linearly increased, linearly decreased, linearly decreased, linearly increased, and first decreased and subsequently increased respectively. the critical fmax value of the change laws of peak stress and energy dissipation rate was 0.8. © the author(s), under exclusive licence to the iran university of science and technology 2024.