The evolution of shear zones in initially medium dense cohesionless sand for quasi-static earth pressure problems of a retaining wall was analysed with a 3D discrete element method DEM using spheres with contact moments. The passive sand failure for a very rough retaining wall undergoing horizontal translation was discussed. Attention was paid to vortex and anti-vortex structures appearing in granular shear zones. Three different methods were introduced to find granular vortices
