Analysis of rock failure under dynamic loading based on a micromechanical damage model

A micromechanical constitutive damage model accounting for micro-crack interactions was developed for brittle failure of rock materials under compressive dynamic loading. In this study the Self-Consistent homogenization Scheme was used in developed damage model in which each micro-crack inside the elliptical inclusion experiences a stress field different from that acting on isolated cracks. The developed model has been programmed, and it was used as a separate and new constitutive model in the commercial finite difference software (FLAC). The dynamic compressive test of a brittle rock was simulated numerically and the simulated stress-strain curves under dynamic loading were compared each other. The proposed model predicts a macroscopic stress-strain relation and a peak stress (the materials compressive strength) with an associated transition strain rate beyond which the compressive strength of the material becomes highly strain rate sensitive. Results also show that as the strain rate increases, the peak strength increases and the damage evolution becomes slower with strain increment.