Abstract: To reveal the influence mechanism of bursting liability of coal on ultra-low friction type rockburst under dynamic load disturbance, coal samples with different bursting liabilities were studied. Firstly, the bursting liability of coal was measured by uniaxial compression test, and then the self-developed ultra-low friction test device of coal-rock interface was used. Slip displacement and kinetic energy of the coal samples were used to characterize the strength of the ultra-low friction effect during impact. The ultra-low friction tests on coal samples with different bursting liabilities under stress wave disturbance were conducted. The results indicate that: (1) The strength of ultra-low friction effect is influenced by the disturbance frequency, with a significant frequency influence zone. The ranges of significant frequency influence zones for coal with strong, weak and no bursting liability are 2.5−3.5 Hz, 2.0−3.0 Hz and 1.5−2.5 Hz, respectively. The ultra-low friction effect is more likely to occur at the coal-rock interface within the significant frequency influence zone. The significant frequency influence zone shifts to the right as the bursting liability of coal increases. (2) The ultra-low friction effect strength is positively correlated with the disturbance amplitude. Coal with strong bursting liability is more likely to occur ultra-low friction effect under high strength disturbance. (3) The fitting function relationship between the effective elastic energy release rate index and kinetic energy is established, using the coal bursting liability index to comprehensively evaluate the strength of ultra-low friction effect.

Key words: stress wave disturbance, coal-rock block, bursting liability, coal-rock interface, ultra-low friction effect