Shear mechanical responses and debonding failure mechanisms of bolt-resin-rock anchoring system under dynamic normal load boundary

• Maximum shear load decreases by 36.81% to 46.94% as dynamic normal load amplitude increases from 10% to 70%, with rock type influencing the extent. • Rock type critically controls the localization of shear failure surface, leading to differentiated wear characteristics and failure modes. • DEM simulations reveal nonuniform contact force chains and rock-type-dependent crack propagation pathways under dynamic normal load boundaries. • Anisotropic interface damage factor increases from 34.9% to 56.6% with increasing amplitude, but decreases from 49.6% to 23.4% when rock type changes from coal to limestone.