Discrete-Element Modeling of Cemented Granular Material Using Mixed-Mode Cohesive Zone Model

Abstract

This paper presents an energy-controlled fracture model to simulate mechanical behavior of cemented granular material (CGM). A modified mixed-mode cohesive zone model is developed to describe the damage behavior of the cementitious bond, which consists of Mohr-Coulomb yield criterion and strain-softening formula controlled by fracture energy. This developed constitutive model is implemented in a three-dimensional discrete element method (DEM) simulation. Three-point bending tests are used to calibrate model parameters. A group of uniaxial compression tests are carried out to study the mechanical behavior and fracture propagation. The study investigates how cementation can influence the strength parameters at the peak and postpeak states that govern softening behavior of CGMs. Strong agreement between experimental and numerical stress-strain curves was achieved. The numerical simulation presents strong and weak force chains and quantifies the bond damage process as well as the damage distribution. A comprehensive sensitivity analysis is provided by varying parameters in the mixed-mode cohesive zone model, and their influence on the stress-strain behavior of CGM is also illustrated.