Study on the static mechanical behavior and energy evolution of layered sandstone after impact-disturbed

Dynamic disturbances induced by drill-and-blast excavation often cause damage to layered rock masses, yet the static mechanical response of such damaged layered rock remains inadequately studied. This investigation examines the effects of impact disturbance and bedding angle on the static mechanical behavior and energy evolution of layered rock masses by combining split Hopkinson pressure bar pre-damage treatment with conventional triaxial compression tests. The results show that: 1) Both undamaged and impact-damaged rock samples exhibit U-shaped trends in dynamic/static peak strength, dynamic/static elastic modulus, total peak energy, and energy storage limit as bedding angle increases, with minima consistently occurring 60°. 2) The effect of impact disturbance on static mechanical behavior of layer rock masses exhibit the orientation-dependent evolution: at 0°, the impact primarily produces a strengthening effect, while at 30°, 45°, 60°, 90°, it induces cumulative damage and leads to degradation of mechanical performance. 3) Impact disturbance does not significantly alter the characteristic failure patterns of layered rock masses, and the final failure pattern remains dominated by the bedding angle. These findings lay a theoretical foundation for optimizing stability control in layered rock tunnels subjected to blasting-induced disturbances.