Abstract: Aiming at the stability problem of filling body under dynamic disturbance in deep high-temperature mines,taking
the -675 m level (ground temperature 40 ℃) of a mining area as the engineering background,the effects of cement and cementitious powder (water-quenched slag-based cementitious material) on the dynamic characteristics of tailings cemented filling body at different temperatures were systematically studied. Through the dynamic impact test of split Hopkinson pressure bar,combined with scanning electron microscope observation and PCAS image analysis,the dynamic mechanical properties,
failure characteristics and microstructure evolution of the two cementitious materials under 20 ℃ and 40 ℃ curing conditions
were compared and analyzed. The results show that the dynamic stress-strain curve of the filling body shows obvious three-stage
characteristics,and the dynamic compressive strength is positively correlated with the strain rate. The increase of temperature
significantly promotes the hydration reaction. At 40 ℃,the dynamic compressive strength of the cemented powder filling body is
significantly better than that of the cement filling body at each impact speed. The microstructure analysis shows that the formation
of a more developed ettringite network with optimized spatial distribution in the cemented powder backfill is the key microscopic
mechanism for the dynamic mechanical properties of the cemented powder tailings backfill to be significantly better than
that of the cement system. This study provides an important theoretical basis and practical guidance for the selection of filling
materials in deep high-temperature mines.