A new strategy for discrete element numerical models: 2. Sandbox applications

[1] Here we present a series of numerical experiments using a new formulation of the discrete element method (DEM) that improves performance in modeling faults and shear zones. In the new method, named the stress-based discrete element method (SDEM), which is introduced in the companion paper by Egholm, stress tensors are stored at each circular particle. Further, SDEM includes rotational resistivity of particles and elastoplastic constitutive rules for governing particle deformation. When combining these new features, the SDEM is capable of reproducing the friction properties of rocks and soils, without the need for the ad hoc calibration routines normally associated with DEM. In contrast to the conventional DEM, the friction properties of a SDEM particle system are in agreement with the Mohr-Coulomb constitutive model with friction angles specified on a particle level. "Benchmark'' sandbox models show that unlike most commonly used numerical methods, SDEM faults and shear zones develop at angles in agreement with general observations from structural geology and analogue modeling studies.