Research on Fatigue Damage and Affecting Factors of Defected Rock Mass Based on Ultrasonic Wave Velocity

摘要

In this paper the fatigue-loading test of defected rock-like specimen has been carried out by electro-hydraulic servo fatigue testing machine. At the same time, the ultrasonic data has been collected and analyzed by the digital ultrasonic instrument. The fatigue damage and influencing factors of the defective rock mass under dynamic load are studied. According to the experimental research and analysis, this paper chooses to define the damage variable by ultrasonic velocity, and the inverse function of the Logistic equation was used to describe the evolution curve of fatigue damage sample. The experimental data fitting results show that the damage model and the experimental data fit well. In addition, this paper analyzes the main influencing factors of fatigue damage in the test. The initial damage represents the damage state before the sample is cyclically loaded. Different initial damages have a significant effect on the fatigue life of the sample. In the case the initial damage is substantially the same, the upper limit stress is larger, the fatigue life of the sample is shorter, and conversely, the fatigue life is longer.