Abstract: In order to effectively extract charge induction precursor of coal-rock dynamic disaster and improve the prediction accuracy, uniaxial loading fracture experiments were carried out on samples of composite coal-rock taken from a coal mine in Shanxi province at loading rates of 0.1, 0.3, 1 mm/min. Variation law and mechanism of charge induction signal in the process of deformation and rupture of composite coal-rock were studied. The results show that there are significant paroxysmal and discontinuous charge induced impulse precursory signals before deformation and fracture of the composite coal-rock, that the charge induction signal increases with the increase of the loading stress level, and reaches the strongest before the peak stress,that the charge induction signal is the strongest at the loading rate of 0.1 mm/min, that the charge signal of coal sample is more obvious than that of the top plate, and that the charge induction signal is related to the internal rupture, friction and thermal effect.

Key words: composite coal-rock, deformation and fracture, charge induction, variation routine, precursory extraction