To study the dynamic mechanical properties and rupture mechanism of laminated composite rock mass under the action of impact loading

we carried out loading tests of laminated soft and hard coal rock composites consisting of coal monomer and white sandstone under different rates and impact directions by using the split Hopkinson pressure bar (SHPB) device and LS-DYNA finite element analysis software combined with Holmquist-Johnson-Cook (HJC) constitutive model. Results show that the strength of the laminated coal-rock composite did not change with the loading direction under static loading. The peak stress and dynamic increase factor (DIF) of the laminated coal-rock composite under dynamic loading increased linearly with the impact velocity. The mechanical properties of HS (H and S represent white sandstone and coal monomer respectively) composite with better wave impedance matching were always better than those of SH composite

and this phenomenon gradually decreased with the increase in the impact velocity. The dissipation energy density and incident energy density of the laminated coal-rock composite showed a quadratic growth relationship. The fractal dimension increased with the velocity

and the effect obtained when the stress wave transferred from hard into soft was better than that from soft into hard. The degree of fragmentation of the laminated coal-rock composite became more and more intense with the increase in the impact velocity

the degree of destruction of HS composite was greater than that of SH composite under the same conditions

the white sandstone presented more shear-like fragmentation

and the coal monomer presented more crushed conical destruction. The strength at the interface of the laminated coal-rock composite was not consistent with that in other regions

resulting in a change in the order of destruction of the composite. The overall strength law of the composite from small to large was: coal monomer non-interface region

coal monomer interface region

white sandstone interface region

and white sandstone non-interface region.