Comparison analysis on dynamic mechanics features of coal and rock under shock load

In order to study failure mechanism of coal and rock under explosion,impact and other dynamic load,a 050 mm separation type Split Hopkinson Pressure B ar test system was applied to impact load test under different impact speed on anthracite and sandstone samples. Based on stress wave theory and fractal theory,a study was conducted on differences of the anthracite and sandstone from dynamic stress and strain,failure mode, dissipated energy and block fractal. The results showed that dy namic mechanics performances of anthracite and sandstone were different obviously. The dynamic stress and strain of anthracite at initial rising stage would be nonlinear 0 bviously. The smaller impact speed,the nonlinear would be more obvious. The dynamic stress and strain curve of sandstone was a straight line with linear elasticity at initial stage. With impact speed increased,both the plastic deformation and ultra strength would be in increasing tendency. The plastic deformation of the sandstone would be les s than the plastic deformation of the anthracite coal. Finally,with calculation of anthracite and sandstone on dissipated energy and fractal dimension,both dissipated energy would be increased with the impact speed increased. The increased speed of anthracite would be fast. The fractal dimension of the anthracite coal sample broken size wou Id be more concentrated.The fractal dimension of sandstone would be in a decreased tendency with the impact speed increased.