Volume 23, Issue 3 (September 2000)
Model for Capillary-Induced Radial Flow in Cohesionless Soils
Capillary phenomena in cohesionless soils play an important role in the migration of liquids through the unsaturated zone above and close to groundwater sources. The purpose of this paper is to present the results of a theoretical and experimental study of capillary flow in the radial direction. A closed-form solution for the time-dependent advance of wetting front radius is derived as a function of porosity, degree of saturation, hydraulic conductivity, and capillary head. A laboratory test called the “radial horizontal capillarity test” was developed to measure the radial movement of the wetting front as a function of time and experiments were conducted. Values of capillary-induced hydraulic conductivity and capillary head from the theory and experiments on sands and silt are close to those obtained from linear horizontal capillarity tests.