Advances in numerical modelling for quantifying the role of cohesion in clogging of granular materials

Clogging represents a critical challenge in various engineering and geotechnical applications, particularly impacting the functionality and longevity of granular media such as filters and stone columns. Despite the growing interests in clogging problems, the mechanisms underlying the migration and clogging of cohesive fines within porous media are not well understood. This is due to the complex interactions at fine-coarse domain interfaces, necessitating a critical need for in- depth investigation from a more fundamental perspective. In this context, this study develops an advanced numerical approach that captures fluid-solid phases combining the discrete element method (DEM) with the computational fluid dynamics (CFD) to assist with the design process. This technique is able to monitor the time-dependent changes in clogged regions, permeability and filtration ratios associated with particle migration and clogging in granular columns. Key governing attributes including the fluid flow condition and the presence of interparticle cohesive forces between fine particles are examined in detail. Our findings indicate that interparticle cohesion profoundly alters the trajectory and migratory patterns of fine particles within the coarse medium, significantly decreasing the infiltration capability and increasing the likelihood of particle deposition and clogging. Moreover, the temporal and spatial distribution of cohesive fines within the column can be quantified over time to elucidate the characteristic depth of clogging effect (i.e., unclogged column radius), enabling a more precise determination of time-dependent clogging parameters. These clogged parameters are crucial for the development of constitutive models that incorporate the clogging effect into the consolidation and settlement responses of granular columns used in geotechnical applications. The innovation of this study aims to not only capture the time-dependent clogging process but also investigate the critical role of microscale cohesion in governing the clogging potential of granular columns, which has not been explored in depth previously.