Coupled effects of capillary suction and fabric on the strength of moist granular materials

This paper discusses the coupled effects of capillary suction and fabric on the behavior of partially saturated granular materials at pendular state when discrete liquid bridges form around particle contacts. Experimental results show that the soil–water characteristic curves of granular materials are affected by the internal structure formed during reconstitution of the specimen. The effect of capillary suction on the shear strength of moist sand varies with the direction of shearing relative to the bedding plane which is generally perpendicular to the major principal direction of the fabric tensor. When treating capillary attraction as interparticle forces at particle contacts, a micromechanics analysis shows that the coupling between capillary-attracting forces and fabric results in an additional stress tensor, which describes the anisotropic effect of capillary suction on the behavior of moist sand.