Microscale analysis of geogrid-aggregate interface cyclic shear behavior using DEM

The performance of a geogrid-stabilized structure affected by dynamic loadings is significant. This study investigates the microscale deformation mechanism of the geogrid-aggregate interface cyclic shear behavior using the discrete element method (DEM). Spheres and nonspherical clumps are generated to form aggregate samples. The DEM models are able to capture the macroscopic dynamic shear laws of the aggregate layers stabilized with a geogrid in a similar way to those tested experimentally. The microscale mechanical responses of the cyclic shear tests (e.g., shear strain, fabric evolution, and confined zone), which vary with the particle shape as well as the measurement volume, are analyzed. The rib flexural rigidity has a minor influence on the peak shear strength of the geogrid-aggregate interface cyclic shear test, but is a key factor influencing the shape of the hysteretic loop, which is closely related to the micromechanical responses at the geogrid-aggregate interface. The particles in the upper and lower shear boxes show different motion patterns in response to the aperture ratio. In the case of A/ D50 = 2.53, the cumulative plastic deformation of the soil layers extending beyond the interface during the loading and reversal loading process is effectively restrained.