Impact Toughness Influence on the Bending Properties of Rock Bolt

—Abstract: The use of high-strength rock bolt in the underground often occured brittle fracture in the threaded section, this is closely related to bolt material impact toughness. Tested the impact absorbed energy of four manufacturers of the yield strength of 500MPa rock bolt and the impact absorbed energy value ranging from 19J to 165J. Tested bending test of the bolt rod and threaded section that has a different impact absorbed energy, the results showed that: the impact toughness affects the cold bending of the rock bolt thread segment, when the impact absorbed energy value is less than 30J rock bolt thread segment cold bending poor; impact toughness has no obvious affect on the cold bending of rod.