On the Strain Rate Sensitivity of Coarse-Grained Rock: A Mesoscopic Numerical Study

Abstract

A numerical study on the strain rate sensitivity of coarse-grained rock fracture under dynamic loading is presented. For this purpose, the embedded discontinuity finite element method is employed as a numerical tool. Moreover, a mesoscopic description of grain boundary-grain interior structure of rock is given. Thereby, the present approach is able to account for inter- and intragranular failure types of rock. The numerical simulations carried out here corroborate the conception that in direct tension the dynamic increase of tensile strength of rock is a real material property. Moreover, the simulations agree with the hypothesis that in uniaxial compression the dynamic increase of compressive strength is a structural effect due to lateral inertia. Finally, the numerical simulations of the dynamic Brazilian disc test suggest that structural effects also contribute to the dynamic increase in the apparent indirect tensile strength.