Fatigue behaviour characteristics and life prediction of rock under low-cycle loading

• Lower fatigue upper limit stress delays damage accumulation and extends fatigue life, but leads to more severe ultimate failure. • The damage variable's correlation with relative loading cycles is consistent across different fatigue load upper limits under the same confining pressure. • A modified damage evolution model effectively characterizes the progressive damage trend in rocks under cyclic loading. • The proposed fatigue life prediction method accounts for rock type, confining pressure, loading frequency, and initial damage, matching experimental results closely.