Effects of grains characteristics and geogrid shape and rigidity on the behaviour of reinforced granular soil − 3D DEM study

This study explores the impact of granular properties and geogrid characteristics on the behaviour of reinforced soil techniques, through DEM numerical simulations of triaxial compression tests. Three particle shapes (spheres, two different clumps) were examined, as well as two geogrid types (biaxial and triaxial). The results show that geogrids significantly increase peak strength and reduce lateral deformations, mainly due to better particle confinement. Clumps generally exhibit better shear strength, creating a more stable granular structure that interacts more effectively with geogrids. The study also reveals that particles interlocking in geogrid apertures predominates friction at the soil-geogrid interface. The stiffness of geogrids influences their effectiveness: above a certain threshold, geogrids offer near-saturated benefit performance. On the other hand, the shape and size of geogrid openings present a secondary impact when stiffness and effective area are maintained constant. This research highlights the importance of selecting geogrids according to soil granularity and can provide practical recommendations for the use of geogrids in geotechnical applications.