Effects of grain size-to-particle size ratio on micro-cracking behavior using a bonded-particle grain-based model

The strength and deformation behavior of rocks is an important topic in rock mechanics. A good understanding of the rock strength and deformation will facilitate cost-effective design and long-term stability maintenance of engineering structures constructed in or on rocks. Numerous laboratory test results have revealed that the deformation (failure) of rocks is mainly controlled by its inherent microstructure and the associated micro-cracking process. The microstructures are usually associated with the different mineral aggregations and varying amounts of micro-defects such as micro-cracks, voids and cleavage planes. It is, therefore, of vital importance to comprehensively study the influence of inherent microstructures on the failure behavior and the induced micro-crackling process of rocks. The grain size of minerals for the generated numerical model is slightly larger than that obtained from the microscopic observation of thin sections. This is because some voids exist in the assembled particles in the initial particle packing stage.