Effects of Grain Shape and Orientation on the Dynamic Mechanical and Damage Characteristics of Crystalline Rocks

Abstract

Grain shape and orientation considerably affect the dynamic mechanical and damage characteristics of engineering projects related to crystalline rocks. In this study, a transformed grain-based model (TGBM) based on the transformation algorithm and the correction grouping algorithm is proposed to construct the model with different grain shapes and preferred orientation. Then, a novel calibration procedure is presented to determine the microparameters with respect to the TGBM dynamic simulation. Several methods are innovatively combined to reveal the mechanism of grain aspect ratio and preferred orientation on dynamic mechanical and damage characteristics of crystalline rocks. The results show that the preferred orientation is the main factor affecting crack characteristics, whereas the aspect ratio dominates the dynamic strength. Intragranular fracturing carries much weight and is the main failure mode in the high-strain-rate field; the occurrence frequency increases as the preferred orientation increases. Crystalline rocks with different preferred orientations have varying damage status on account of diverse failure modes. The dynamic strength of crystalline rock shows a strong sensitivity to the aspect ratio due to the changes in the proportions of different contact types.