Analysis and strength statistical damage constitutive model of coal under impacting failure

Using Split Hopkinson Pressure Bar (SHPB) experimental system,the experiments on the failure character- istics of coal samples taken from Weiding coal mine under impact loading were carried out. Then the coal dynamic me- chanical properties were analyzed in detail. According to the experimental data,it is clear that coal is a typical rate-de- pended material. Moreover,both the coal elastic modulus and compressive strength increase with the strain rate increa- ses. Besides,a strength statistical damage constitutive model of coal was built based on the strength theory and statisti- cal damage theory,a method to determine the model parameters was proposed,and the model correctness was verified by the testing data. The model is proved to be accurate and reasonable compared with the component statistical damage constitutive model. The research results show that the strength statistical damage constitutive model not only can effec- tively describe the coal dynamic mechanical properties,but also has several advantages,such as simple construction, few parameters and clear physics meaning. Therefore,the model with high relevance is more suitable and universal to describe the coal dynamic mechanical properties than the component statistical damage constitutive model.