Capillary Effect on Critical Length of Force Chains in Partially Saturated Granular Materials Within the Pendular Regime

This paper investigates the influence of capillary interaction on critical length of grain columns in partially saturated granular materials at pendular state. When relative rotation between a pair of elliptical particles (2D disks) takes place, the liquid meniscus between the particles is distorted and generates unbalanced capillary forces around the contact, which further induces capillary torque. Both the capillary force and capillary torque have some influence on the characteristic length of grain column or the force chain. The findings imply that the capillary interaction may have some influence on shear band thickness. For engineering soils, however, such effect may be undermined owing to the relative low level of capillary stress in partially saturated granular soils within the pendular regime.