Abstract: To investigate the directional independence of multi-stage stress memory in granite under different loading rates, uniaxial cyclic loading and unloading tests were performed at five loading rates and different deflection angles. Acoustic emission technology was employed to reveal how different loading rates affect the rock’s multi-stage stress memory, including the Kaiser effect (KE) and the incomplete erasion phenomenon (IEP). The results indicate that granite shows directional independence of multi-stage stress memory at different loading rates. The critical angle of directional independence for KE is higher than that for IEP at each loading rate. As the loading rate increases, the KE critical angle of granite gradually increases. When the loading rate is below 10 kN/min, the IEP critical angle also increases, but it decreases to 0º−5º when the loading rate exceeds 10 kN/min. The results offer an experimental foundation for a more systematic and in-depth understanding of the directional independence of multi-stage stress memory in rocks.

Key words: acoustic emission method, stress memory, Kaiser effect, incomplete erasion phenomenon, different loading rates, deflection loading