Full Length ArticleDynamic mechanical behaviors of Fangshan marble

Dynamic strength parameters are extensively used in mining engineering and rock mechanics. However, there are no widely accepted dynamic failure models for rocks. In this study, the dynamic punching shear strength, uniaxial compressive strength (UCS) and tensile strength of fine-grained Fangshan marble (FM) are first measured by using a split Hopkinson pressure bar (SHPB) system. The pulse-shaping technique is then implemented to maintain the dynamic force balance in SHPB tests. Experimental results show that the dynamic punching shear strength, UCS and tensile strength increase with the loading rate. A recently developed dynamic Mohr-Coulomb theory is then used to interpret the testing data. In this model, the angle of internal friction ϕ is assumed to be independent of loading rate and is obtained using the static strength values. According to the dynamic Mohr-Coulomb theory, the dynamic UCS and the dynamic tensile strength are predicted from the dynamic punching shear strength. Furthermore, based on this dynamic theory, the dynamic UCS is predicted from the dynamic tensile strength. The consistency between the predicted and measured dynamic strengths demonstrates that the dynamic Mohr-Coulomb theory is applicable to FM.