A novel 3D clumped particle method to simulate the complex mechanical behavior of rock

Abstract

This paper presents a novel 3D clumped particle method for a more realistic prediction of the complex mechanical characteristics of rock. In the proposed method, a clump originates from a randomly picked particle and grows from inside to outside, similar to the real growth process of mineral particles. Clumps characterized by representative random-irregular shapes are used to achieve a close-packed microstructure which significantly strengthens grain interlocking. A detailed parametric study shows that the clump particle number and parallel bond strength ratio significantly influence the UCS/TS ratio and the strength envelope. In addition, it is shown that, in the current approach, the friction coefficient also has a significant influence on the UCS/TS ratio. The effect of contact stiffness ratio on strength and failure was also investigated. A calibration procedure is proposed and applied to simulate the behavior of Lac du Bonnet granite. Results indicate that the UCS/TS ratio and nonlinear strength envelope of Lac du Bonnet granite can be replicated. The crack initiation stress and crack damage stress are also accurately predicted. Finally, the bimodularity and failure transition from splitting to shear is investigated and observations indicate very good agreement between predictions and experiments.