Influence of Different Cohesive Contact Models on Micro-to-Macro Response of Geomaterials: A DEM Investigation

Cohesive contact between soil particles plays a key role in the micro- and macroscale responses of geomaterials, but the contact behavior can vary widely depending on different contexts. As our understanding of cohesive contact and the use of appropriate models when simulating cohesive materials is still limited, this study provides a comprehensive assessment of the most commonly used cohesive contact models, such as the Johnson–Kendall–Roberts (JKR), Simplified JKR (SJKR), Easo liquid bridge (ELB), and Derjaguin–Muller–Toporov (DMT) models. Not only are extensive reviews and analyses made to highlight crucial differences in the concept and mechanisms that different models utilize to govern cohesive bonds, but a series of 369 DEM simulations of the drawdown (DD) tests used by these models is also implemented. Cohesion and rolling friction degrees are varied in tandem, followed by detailed analyses of micro and macroscale features ranging from interparticle contact to bulk deformation characteristics across different cohesive models. The results show there are large differences in interparticle behavior depending on how the attractions are formed and developed, despite yielding similar macroscale responses. Soft bond models like ELB and DMT, whose attraction concentrates around the border of the contact region, result in weak bonds and less impact on structural features such as the contact network and porosity, especially under different dynamic contexts. This study significantly enhances understanding of different forms of cohesions and suggests criteria that can be used to select cohesive models, promoting accurate predictions of micro-to-macroscale responses.