Abstract: As the dynamic destruction of mixed rock strata are increasingly observed in engineering, it is indispensible to study the mechanism of dynamic destruction. A numerical model of split Hopkinson pressure bar (SHPB) was established by PFC^2D to simulate the dynamic failure process of mixed rock strata specimens with different dip angles of rock strata at varied strain rates. The conclusions are drawn from numerical simulation as follows: 1) as the dip angle of mixed rock strata increased, the dynamic compressive strength and dynamic elastic modulus reduced at first and then surged, displaying a “V”-shaped curve; 2) dynamic compressive strength increased correspondingly with the climbing of strain rate, while dynamic elastic modulus is less affected by strain rate; 3) the cracks of mixed rock strata were dominantly tensile cracks, and dynamic fragmentation exacerbated with the increasing of strain rate; 4) the macroscopic failure mode of specimen was affected by the number and coalescence of cracks. The research findings are conducive to understanding the dynamic failure mechanism in mixed rock strata.

Key words: mixed rock strata, rock dynamics, split Hopkinson pressure bar (SHPB), dip angle of rock strata, strain rate