Abstract: The fracture defects in granite produced by long-term exposure to various loads can change the stability of the rock, endangering the project and personnel safety. In this paper, the effects of confining pressure, dynamic load frequency, dynamic stress amplitude and cycle times on the dynamic properties of prefabricated defective granite are studied by using triaxial dynamic load cycle test. It is found that with the increase of the degree of defect, the dynamic elastic modulus of rocks decreases, while the dynamic damping ratio increases. With increasing frequency, the dynamic elastic modulus of rocks with different defects increases at an accelerating rate, and the dynamic damping ratio also increases gradually. With the increase of the dynamic stress amplitude, the dynamic elastic modulus of rocks with different defects increases, while the dynamic damping ratio decreases. The dynamic elastic modulus and dynamic damping ratio of defective rocks initially decrease with the number of cycles and then tend to stabilize. As the confining pressure increases, the dynamic elastic modulus of rocks with different defects increases at an accelerating rate, while the dynamic damping ratio decreases. The multivariate tests were carried out, yielding well-rounded findings. It provides a reference for the study of the dynamic properties of defective granites and a preparation for the inverse analysis of the dynamic properties of granites.
Keywords: triaxial load; prefabrication defects; confining pressure; frequency; dynamic stress amplitude; cycle times; dynamic properties