Discrete simulations of shear zone patterning in sand in earth pressure problems of a retaining wall

The intention of the paper is to check the capability of a discrete element method (DEM) to simulate a pattern of quasi-static shear zones in initially dense sand. Discrete calculations were carried out with a rigid and very rough retaining wall, undergoing passive and active horizontal translation, rotation about the top and rotation about the toe. To simulate the behavior of sand, the three-dimensional spherical discrete model was used allowing for grain rolling resistance. The geometry of calculated shear zones was qualitatively compared with experimental results of laboratory model tests using X-rays and Digital Image Correlation technique (DIC), and quantitatively with finite element results obtained with a micro-polar hypoplastic constitutive model. The results show that a discrete model is able to realistically predict the experimental pattern of shear zones in the sand interior. A satisfactory agreement with experiments and finite element calculations was achieved.