Abstract:Purpose: In order to investigate the effects of the dual action of F-T cycles and dynamic perturbation on the stability of slopes in open pit mines in cold regions. Method: we use the pendulum impact-loaded Split Hopkinson Pressure Bar (SHPB) test system to explore dynamic peak loads, loading rate sensitivity, and damage modes of intact granite and prefabricated single-crack granite specimens under dry, water-saturated, and frozen conditions. Additionally, we modeled dynamic Brazilian splitting tests of saturated specimens with empty cracks to verify their accuracy and subsequently simulate the damage patterns and strength-rate effects of crack-filled saturated specimens under different loading rates. Result: The results indicate that, under identical loading rates, the dynamic tensile peak load of frozen specimens is the highest, then the dry specimens, the saturated one is the lowest. The peak load of intact specimens exceeds that of specimens containing cracks, suggesting that pre-existing cracks reduce the peak load of specimens. Furthermore, the dynamic tensile peak load of specimens under different water contents and freezing states is positively correlated with the loading rate, demonstrating a rate-strengthening effect. Specifically, the rate of increase for the dynamic tensile peak load of intact and cracked specimens under dry, water-saturated, and frozen conditions is 0.465, 0.456, 0.445, 0.479, 0.438, 0.480, respectively. This implies that freezing enhances dynamic strength, saturation weakens strength, and pre-existing cracks amplify loading rate sensitivity. Additionally, crack saturation increases the strength of saturated specimens and expands the range of crack propagation. Conclusion: The research findings provide experimental and simulation support for revealing the dynamic fracture mechanism of rocks with single fractures under freezing conditions.