Dynamic response and energy evolution of sandstone under combined dynamic and static loading

Abstract

Impact disturbance and bedding angle have a substantial effect on the mechanical response of sandstone under prestressed loading. Therefore, in this paper, a combined 1D static and dynamic loading test system is employed for examining the compression of sandstone at various bedding angles under a pre-applied axial pressure of 25 MPa. Under these conditions, the strength, stress-strain curves, energy usage ratio, particle size and deformation of sandstone are obtained. The results are as follows. (1) Strain rebound easily occurs in high-strength sandstone under low impact pressure. (2) The peak strength of sandstone is positively correlated with the impact pressure. The peak strength and combined dynamic‒static strength of sandstone change in a "v" shape. (3) The rock's failure particle size is controlled by the bedding plane at low impact pressure. (4) We propose a new energy calculation method in which the energy utilization rate presents an approximately inverted "v" shape. (5) The sandstone with different bedding angles has different bursting liabilities at an identical impact pressure. (6) The impact pressure is proportional to the crack growth rate of sandstone.