Home – Home – Jornals – Journal of Mining Sciences 2018 number 5

With the increasing depth of mineral resources exploration, hard rock can have a strong impact on the effect and cost of resource exploration. Due to the particularity of rock, including un-predictable damage such as joints, cracks and holes, the development of mesoscopic defects in the rock under the action of vibration load will lead to the deterioration of its macroscopic mechanical properties. At present, the research about the effect of ultrasonic vibration time on rock crushing is almost blank. In this paper, the method of theoretical analysis, finite element numerical simulation and experimental research is used to explore the damage and the strength degradation law of granite under ultrasonic vibration over time. It is of great significance to improve the effect of rock crushing, and to provide theoretical guidance for the application of ultrasonic vibrators in hard rock drilling and devel-opment of ultrasonic vibration rock drilling. The finite element method is used to establish the practical heterogeneous rock model to analyze the law of rock crack propagation in different time periods, and the ultrasonic vibration time threshold (during 15-20 min) is proposed to provide theoretical guidance for the experiment. The porosity and strength of the rock samples are measured by nuclear magnetic resonance and uniaxial compressive strength after vibration, and the influence of vibration time on rock damage is analyzed.