Structural deterioration and instability in grouted reinforcement crushed rock masses subjected to increasing-amplitude fatigue loading

• Increasing Talbot grading index (n-value) first enhances then degrades the mechanical properties of grouted reinforcement specimens under fatigue loading. • Acoustic emission parameters (cumulative ring counts, energy counts) and spectral characteristics correlate strongly with crack evolution and damage progression. • The cumulative AE ring counts damage model reveals a three-phase fatigue damage behavior, with b-value showing sensitive correlation with volumetric strain growth rate. • Findings support prediction of destabilization in grouted reinforcement under fatigue and provide theoretical basis for stability control in fragmented rock excavations.