Impact Energy Absorption Behavior of Cemented Coal Gangue-Fly Ash Backfill

A drop hammer test device is employed to conduct impulse tests on the cemented coal gangue-fly ash backfill (CGFB) samples which have different solid concentrations, dimensions and curing ages. The impacting time of the drop hammer on the CGFB and the maximum rebound height of the hammer are investigated. The acoustic energy loss induced by the impact of the drop hammer on the CGFB and the impact energy absorption power of the CGFB are obtained. The results indicate that, the impact energy absorption power of the CGFB increases with the increases of its solid concentration and dimension. The impact energy also exerts influence on the energy absorption power of the CGFB. When the impact energy is lower than a critical value, the energy absorption power of the CGFB increases with the increase in the impact energy. But when the impact energy exceeds the critical value, the energy absorption power of the CGFB decreases with the increase of the impact energy. The obtained results can provide theoretical and practical guidance for preventing rock burst.