Dilatancy-induced surface deformation in dense cohesive granular media

TL;DR

This study investigates how cohesion and dilatancy in dense granular media with liquid bridges cause surface deformation during shear, highlighting the Bond number as a key control parameter.

Contribution

It introduces the Bond number as a unifying parameter to predict surface deformation in cohesive granular materials under shear.

Findings

Surface elevation correlates with cohesion strength and particle density.

Higher shear rates reduce surface deformation due to inertial effects.

Dilatancy effects are enhanced by cohesion, influencing surface profiles.

Abstract

When granular materials with interstitial liquid bridges are sheared in a split-bottom cell, a localized shear band develops, accompanied by a surface elevation. Cohesion, governed by the surface tension of the interstitial liquid, enhances dilatancy in dense cohesive packings, leading to expansion within the shear band and the emergence of a surface elevation. Surface deformation is observed not only in cohesive systems with high particle density and large liquid surface tension, but also in those with lower values of these parameters. The equivalent Bond number arises as a key control parameter for the surface deformation, shaping both the evolution of the surface profile and the packing density. At higher shear rates, inertial effects dominate dilatancy, resulting in less pronounced surface deformation.