Assessing the effect of layered spatial variability on soil behavior via DEM simulation

Motivated by the spatial variability observed in geological profiles, this study explored the feasibility of using discrete element method (DEM) to capture the effect of layered spatial variability into overall soil performance. The spatial variability of packing densities, particle Young’s modulus (E), and frictional properties (μ) within specimens was studied. It was observed that samples with similar overall void ratios exhibited comparable small-strain stiffness and shearing behaviors. In contrast, the coordination number and particle stress transmission demonstrated significant sensitivity to the layer-wise spatial variability in packing densities. Regarding the spatial variability effect of particle-scale E values, this study illustrates that spatial variability strongly affects the stiffness contributions of individual layers. Specifically, layers with higher E values are capable of transferring much stress and stiffness. For the spatial variability effect of frictional property, a degree of consistency in shearing behaviors was observed among specimens with similar average frictional characteristics, while layers with lower frictional property were identified as potential initial failure junctures. Overall, this study validates the utility of employing a DEM code for analyzing both the macroscopic behavior and localized vulnerabilities within complex granular systems, presenting profound implications for engineering practices.