An interacting wing-crack based semi-analytical meso-scale model for describing elasto-plastic damage behavior of brittle rocks

An interacting wing-crack based mesoscale model was developed for describing the elastoplastic damage behaviors of brittle rocks under compressive loading. In the present model, the main deterioration process of the rock is assumed to be induced by the wing-crack propagation, attributing the macroscopic inelastic strain to the nucleation and growth of tensile ‘wings’ of the initial flaws. The initial flaws are assumed to follow a periodic distribution in space. To account for the interaction between microcracks, a spatial evolution law as a function of the wing length is introduced, and the influences of the wing-crack propagation on the discontinuous slip of the crack surface are taken into consideration. On this basis, the increment of the compliance tensor caused by wing-crack propagation is proposed, and an incremental-based constitutive model is constructed so that the total stress-strain relations involving post-peak softening and residual behavior can be reproduced. Further, through appropriate parameter selection, the proposed model can reasonably simulate the triaxial test results of Taiwan sandstone, and the correctness of the model is effectively validated. Finally, the intrinsic features of the model are explored through a series of parametric analyses, and the macroscopic mechanical behavior and damage evolution of the rock characterized by the model are investigated. The conclusions show that this model is of significant usage to describe the whole strain-stress relation and inelastic strain analysis. It is full of potential to deem various rock macroscale mechanisms to mesoscale crack evolution.