Abstract: In order to analyze the dynamic damage characteristics and energy transport law of magnetite under water immersion effect,the magnetite was immersed in water for different times,and the dynamic compression tests with different impact load values were carried out by using the Hopkinson pressure bar test system (SHPB). The results show that the dynamic failure deformation process of magnetite under water immersion is divided into three stages:elastic deformation,yield damage deformation and instability failure. The dynamic compressive strength of magnetite decreases with the increase of immersion time, and the relationship between them is exponentially decreasing. The decreasing value of the dynamic compressive strength of magnetite first increases and then decreases,and the decreasing value of the dynamic compressive strength is the largest when the immersion time is 14 d. With the increase of immersion time,the fragmentation degree of magnetite increases,but the overall fragmentation uniformity is the best when the immersion time is 14 d. The energy evolution process of immersed magnetite is divided into three stages:elastic storage stage,energy conversion stage and energy dissipation stage. Increasing the dynamic load value can improve the energy utilization rate of magnetite with immersion time of 14 d,and the energy consumption density of magnetite is the largest under this water immersion time,which indicates that the magnetite with water immersion treatment can effectively improve the uneven degree of ore fragmentation,reduce the workload of secondary fragmentation,and decrease the blasting energy consumption to a certain extent. The research results provide certain theoretical guidance for the safe and efficient mining of water-rich orebodies.

Key words: water immersion effect,magnetite ore,dynamic damage,energy evolution