ABSTRACT
To investigate the fracture characteristics of static pre-load rock under impact disturbance, tests under coupled static pre-loads and impact loads were carried out by adopting the Cracked Straight Through Brazilian Disc specimens (CSTBD) of granite. The conventional static and dynamic fracture tests were also performed by using MTS Landmark material testing machine and SHPB device respectively. Three static pre-load levels (50%, 70% and 90%, i.e. the ratio of pre-load to static fracture peak load) were selected as the initial loading state, and the coupled loads fracture tests were conducted with a modified Split Hopkinson Pressure Bar (MSHPB) device. The results show that, when the static pre-load level is constant, the dynamic fracture toughness will increase with the loading rate and the rate effect is especially obvious. Compared to conventional tests, it will decrease when the static pre-load was applied, and the dynamic toughness decreasing effect can be observed.
