Influence of Layered Angle on Dynamic Characteristics of Backfill under Impact Loading

Abstract

In order to explore the relationship between the filling surface angle and the dynamic characteristics of the filling body under impact load, this paper uses the Hopkinson pressure bar (SHPB) test system to study the influence of different filling surface angles, different cement–sand ratios and different strain rates on the dynamic peak strength, dynamic strength growth factor and failure mode of the filling body. The results show that with the increase in the average strain rate, the dynamic peak strength and dynamic strength growth factor of the layered filling body increase gradually. With the increase in the filling surface angle, the static and dynamic peak strength of the layered filling body decreases gradually, but there is no obvious change law linking the dynamic strength growth factor and filling surface angle. According to the failure mode analysis and the LS-DYNA numerical simulation results for the layered filling body, with the increase in the filling surface angle, the failure mode of the layered filling body changes from splitting failure under tension to shear failure. The research results in this paper can provide theoretical support for the stability of underground layered filling bodies.