Micromechanical failure models are new methods for considering the real physics of the problem of microcrack growth and propagation (wing crack nucleation). Given that rock materials have different distributions of primary microcracks in terms of size and direction, most of the intrinsic microcracks in rock materials are activated and grow under dynamic loading. Micromechanical failure models that have been presented so far have been considered failures due to the fin crack mechanism in their formulation. Laboratory studies conducted by various researchers have proven the growth of secondary cracks along primary microcracks. Therefore, in this research, the secondary crack mechanism (failure resulting from secondary crack growth and inelastic strains resulting from asymmetric sliding of secondary shear crack surfaces) along with the wing crack mechanism (failure resulting from wing crack growth and inelastic strains resulting from wedging phenomenon) has been studied. The method Self-consistent homogenization has been used to consider the interaction between microcracks. To validate the results of the micromechanical failure model, a Hopkinson compression test has been performed on Sungun porphyry rock samples for dynamic strain rates. Considering the capability of the FLAC finite difference software in simulating dynamic loading, the formulation of the micromechanical failure model has been coded in the form of Fish commands in the software environment. The results of the numerical simulations are in good agreement with the results of the Hopkinson compression test studies on Sungun porphyry rock samples. Therefore, it can be concluded that the developed micromechanical failure model has good capability in simulating the real physics of the problem under dynamic loading.