Mechanical properties of brittle rock governed by micro-geometric heterogeneity

This research presents a new heterogeneity index to describe micro-geometric heterogeneity induced by grain size variation in intact rock. Micro-geometric heterogeneity is considered in a grain-based numerical model to study its effect on the mechanical properties of rock. Characteristic stresses of the specimens with different degrees of heterogeneity such as crack initiation stress, crack damage stress, and peak strength are determined numerically. The result shows that the proposed heterogeneity index measures the micro-geometric heterogeneity effectively in a large range of grain size distribution, even if the mean grain sizes of different constituent minerals are the same.