Abstract:In order to study the evolutionary process of brittle rock damage and fracture under low-velocity impact loading, the dynamic damage was studied by variable angle impact test using compressed gas of SHPB to launch the ball to impact the lateral margin of rock plate. When a source of impact loading was applied to a rock plate specimen, damage cracks were developed from the source to the boundaries, and the surface cracks effectively represened sample internal cracking condition and reflected the impact energy dissipation in these tests. Test results showed that the cracks propagation length and break area are not arbitrary, but are influenced by the angle of dynamic impact loading. The crack length and the break area increase with the increase of the impact loading. When the break area decreases abruptly, the crack length increases suddenly, which shows that there is an obvious incubation period of crack forming, and at first some pits appear on the verge of the rock plate and the propagation rate of crack length and break area decrease with the increase of the impact velocity. According to test results, the scope of impact resistance optimized angle is about 15°~30°.