Establishment of a Dynamic Mohr–Coulomb Failure Criterion for Rocks

Abstract Static Mohr–Coulomb Failure Criterion for rocks has been used extensively in various rock engineering applications. In this model, the compressive strength, tensile strength, and shear strength are related. To investigate the applicability of the Mohr–Coulomb model to dynamic failures, we studied the correlation of the three dynamic rock properties: compressive strength, tensile strength and punch shear strength. The strengths are quantified using a split Hopkinson pressure bar (SHPB) system. The methods for acquiring these strengths were briefly discussed. A fine-grained sandstone, Longyou sandstone (LS) was studied using these methods. The results showed that the compressive strength calculated from the punch shear strength of LS matched well with the experimental UCS results, thus the punch shear strength could be effectively used to predict the UCS of rocks. The tensile strength calculated from the punch shear strength of LS also has exhibited a good trend with the experimental results of Brazilian tensile strength. We concluded that the famous Mohr–Coulomb criterion can be extended to the dynamic range. However, caution has to be taken in determining the loading rates for different strength results.