Abstract: Coal or rock dynamical disaster poses grave threats to the coal mine safety and high efficiency production. So, research on dynamic properties of coal under the complex stress state is significant. By using the software LS-DYNA, the Φ50 mm split Hopkinson pressure bar(SHPB) tests for coal have been numerically simulated by using the Holmquist-Johnson-Cook (HJC) constitutive model. Based on the finding that the numerical simulation results were similar to the experimental results, passive confined pressure SHPB of coal has been simulated. It is demonstrated that elasticity modulus of sleeve, thickness of sleeve, friction coefficient of contact surface, interval between sleeve and specimen significantly have significant impact on dynamic properties of coal. According to the research results, a new layer to the coal pillar can be added. It can improve shock resistance of coal pillar by designing optimal parameters of additional layer: elasticity modulus, thickness, friction coefficient of contact surface interval.

Key words: coal, SHPB experiment, passive confined pressure, Holmquist-Johnson-Cook constitutive model