An interacting crack-mechanics based model for elastoplastic damage model of rock-like materials under compression

A micro-mechanical elastoplastic damage model for rock-like materials under compressive loading is proposed based on the growth of pre-existing flaws. Interaction among the cracks is included through the self-consistent approach. The evolution of damage is quantified by the spatial flaw density and the density of the quasi-static spherical region, enclosing the flaw and its wings. The flaw density is defined by the absolute volume strain in the two-parameter Weibull statistical model. Mixed-mode fracture model is adopted to calculate the wing crack length by the strain energy density (SED) criterion. Drucker–Prager yield criterion and Voyiadjis' strain hardening function under compression are employed to represent the equivalent plastic behavior of such materials. This self-consistent scheme is implemented numerically with an implicit updated and a prediction–correction decomposition. Numerical simulations are carried out, and the factors of friction coefficient, confining pressure and initial flaw size are analyzed.

► The wing crack growth rate considering interaction for larger flaw is increasing before failure.
► Compressive strength for mixed-mode fracture is greater than that of mode I fracture.
► The initiation of the wing cracks requires the same strain for different parameter k.
► The stresses for non-interaction/interaction cases almost overlap under high confining pressure.