Fundamental Study on Fracture Process Analysis of Rocks under Quasi-Static Loading Based on Hybrid FEM-DEM Using Extrinsic Cohesive Zone Model

Abstract

In this study, FDEM (ECZM), which is the combined finite-discrete element method (FDEM) based on an extrinsic cohesive zone model (ECZM), was improved by incorporating a novel algorithm that makes it easier to insert the cohesive elements than the conventional adaptive remeshing and a scheme to avoid the generation of dormant cohesive element, which is generated as a result of inserting a single cohesive element within the FDEM mesh. The improved FDEM (ECZM) was implemented in a self-developed 2-dimentional code, and it was first validated against a numerical experiment assuming a virtual rock. Subsequently, the proposed FDEM was applied to model the uniaxial compression and the Brazilian tests of siliceous mudstones under quasi-static loading. The results of the proposed FDEM simulations reasonably captured the trends of fracturing and stress-strain curves observed in the experiments well. The proposed scheme can also be extended to parallel computation based on general-purpose-graphic-unit (GPGPU) and 3-dimentional FDEM (ECZM) with minimal efforts.