Grain-Based Discrete-Element Modeling Study on the Effects of Cementation on the Mechanical Behavior of Low-Porosity Brittle Rocks

This paper presents the results of a series of numerical experiments using a grain-based discrete-element model approach to investigate the effects of cementation on the mechanical behavior of a low-porosity brittle rock. The adopted approach enables the incorporation of multigrains for a given composition and explicit simulation of intergranular and intragranular cracking, which are important features in the simulation of brittle rocks. The results show that cementation has significant effects on the macroscopic behavior of brittle rock in many aspects, including crack-initiation and crack-damage thresholds, stiffness, peak strength, brittleness, and failure patterns. In general, as bond strength increases, the secant Young's modulus, the peak strength, the ratio of crack-initiation threshold to peak strength, and the ratio of crack-damage threshold to peak strength decrease. The lower the bond strength, the earlier the volumetric strain reversal occurs and the earlier the absolute dilation occurs. It is observed that the model with the higher bond strength appears to be more brittle. The significance of those effects is found to decrease as confining pressure increases. The proposed approach provides a very useful tool for simulating granular materials at a microscopic level. (C) 2017 American Society of Civil Engineers.