Abstract: As a key material for controlling the deformation of surrounding rock and buffering dynamic disasters in mining,
the dynamic mechanical properties of gangue cemented fill are crucial for stope stability. In order to explore the mechanical
properties and failure characteristics of gangue cemented backing under impact load,the uniaxial impact test under different
impact air pressures was carried out by using the separate Hopkinson pressure bar test system(SHPB). The test results show
that the dynamic stress-strain curve of the gangue cemented filling body under different impact air pressures shows significant
nonlinear characteristics,and with the increase of impact air pressure,the peak stress of the gangue cemented filling body increases
significantly,and the peak point shifts to the left. With the increase of impact pressure,the reflected energy in the proportion
of incident energy of gangue cemented filling decreases from 78. 3% to 69%,and the absorption energy increases from
21. 6% to 30. 5%,indicating that the energy dissipation ability increases with the increase of impact pressure. With the increase
of impact load,the damage degree of gangue cemented filling gradually deepens,only a small amount of debris falls at
low impact load,internal cracks begin to develop and spread under medium impact load,and appear in a serious fracturing state
under high impact load.

Key words: dynamic load,gangue cemented backfill,mechanical properties,energy dissipation,macro-microscopic failure
characteristics