Abstract: To reveal the mechanical characteristics and failure modes of stratified rock under combined static-dynamic loads, a split Hopkinson pressure bar device was used to apply one-dimensional load on stratified sandstone specimens. Meanwhile, digital image correlation technique was used to monitor the fracturing process in real time. Fracture evolution and energy consumption characteristics of different dip angles were further summarized. The results show that: under the combined static-dynamic loads, the dynamic strength of stratified sandstone specimens with holes initially increases and then decreases with the increase of bedding angle. The failure modes of the specimens can be divided into four types. The energy consumption characteristics of different dip angles under combined loads show that when the bedding dip angle is 45°, the strength of sandstone specimens and the proportion of absorbed energy reach the maximum values. In underground engineering, reasonable arrangement of breaking position and the angle between the direction of impact load and bedding can significantly improve the efficiency of rock burst, reduce the adverse impact of dynamic disturbance on surrounding rock, and enhance the stability of deep rock engineering.

Key words: split Hopkinson pressure bar device, combined static-dynamic load, digital image correlation, failure mode