ABSTRACT
The fracture behavior for rock materials, reflecting the ability of rock to resist the crack initiation and propagation, is largely controlled by water. The fracture behavior of rock affected by water under quasi-static condition has been widely investigated before, however, no data can be found in dynamic fracture test. In order to comprehensively study the effect of water on the dynamic fracture behavior of rock, including fracture toughness and energies evolution, the split Hopkinson pressure bar (SHPB) technique was used to conduct dynamic notched semi-circular bending (NSCB) tests on both dry and saturated sandstone specimens under a wide range of loading rates. A high-speed camera was also adopted to record the fracturing process of rock specimens during dynamic NSCB tests. Test results showed that: both fracture toughness and energies for dry and saturated sandstone were rate dependent. The fracture toughness of saturated sandstone specimen had a higher rate dependency than that of dry one. Water in rock specimens had hardly evident effects on the kinetic energy but a very significant influence on the fracture and damage energy.
