Assessment of grain-boundary crack evolution in intact Wombeyan marble using a continuum grain-based model

ABSTRACT: It is well-known that during an unconfined compression test on rock, tensile cracks initiate first and then grow and coalesce into a macroscopic axial fracture leading to ultimate rock failure. Recent years have seen an advancement in the use of continuum grain-based models (CGBM) for studying such rock damage processes. While CGBM in RS2 effectively captures grain-boundary fracturing, RS2-CGBM inability to differentiate between tension and shear joint failure modes poses as a limitation. To address this, a post-processing methodology is developed and presented in this work which can facilitate quantitative estimation of the evolution in the shear and tensile cracks under applied compressive loading. For this, intact Wombeyan marble was chosen for the investigations and for validation of the proposed methodology. The study found that the progressive yielding of joints under unconfined compression provides critical insights into the underlying damage mechanisms. Based on the qualitative and quantitative results, it is concluded that the proposed post-processing methodology effectively classifies the mode of joint failure.