Abstract: In this paper, the impact failure experiment of coal mass was conducted in SHPB experimental system. Meanwhile, the changes of near transient magnetic field were tested by ZDKT-1 Transient Magnetic Testing System, and the generation mechanism was analyzed. The results show that the near magnetic field of coal mass will be mutated suddenly when the coal samples were suffered by high speed impact. In addition, different impact damage characteristics of coal mass were comparatively analyzed through infrared spectrum technique. It is concluded that H-bonds of hydroxyl group are changed at different statuses before and after the impact failure process of coal samples, and the separation and transfer of massive electric charge during the H-bonds rupture is one of the most important reasons for instant mutation of near magnetic field.

Key words: coal mass, impact failure, transient magnetic field, H-bond, electric charge transfer