Modeling shear behavior and strain localization in cemented sands by two-dimensional distinct element method analyses

This paper presents a numerical investigation of shear behavior and strain localization in cemented sands using the distinct element method (DEM), employing two different failure criteria for grain bonding. The first criterion is characterized by a Mohr–Coulomb failure line with two distinctive contributions, cohesive and frictional, which sum to give the total bond resistance; the second features a constant, pressure-independent strength at low compressive forces and purely frictional resistance at high forces, which is the standard bond model implemented in the Particle Flow Code (PFC2D). Dilatancy, material friction angle and cohesion, strain and stress fields, the distribution of bond breakages, the void ratio and the averaged pure rotation rate (APR) were examined to elucidate the relations between micromechanical variables and macromechanical responses in DEM specimens subjected to biaxial compression tests. A good agreement was found between the predictions of the numerical analyses and the available experimental results in terms of macromechanical responses. In addition, with the onset of shear banding, inhomogeneous fields of void ratio, bond breakage and APR emerged in the numerical specimens.