The strength of liquid bridges in random granular materials

The strength of capillary bridges in randomly packed granular media was analyzed by means of computer simulations. A novel simulation method, based on the tracking of moving interfaces, has been implemented and used for determining the equilibrium shape of capillary bridges in a granular medium under a range of liquid saturations and solid-phase geometry. The net force acting on each grain due to the capillary bridges was evaluated, as well as the aggregate force acting between two wet granular media during their separation in the normal directions. The simulation results are consistent with previous experimental observations and reveal interesting phenomena such as the existence of a maximum in the tensile strength of a wet granular medium as function of liquid saturation.