NUMERICAL-SIMULATION OF THE WICKING EFFECT IN LINER SYSTEMS

Numerical simulations were carried out to investigate the capillary ba rrier effect and the wicking ability of multilayer earth liner systems . Two specific cases were studied: a two-layer liner composed of a fin e- over a coarse-textured material, and a three-layer liner composed o f a medium-textured material in between a fine- and a coarse-textured material. Results of the simulations show that a quadratic relationshi p exists between the thickness of the fine-textured material and the a rrival time of the wetting front to the interface. At the time the wet ting front reaches the interface, the width of the lateral spreading w ithin the fine material is smaller than the thickness of this material . The lateral spreading and thickness are linearly related. The wickin g ability of the different materials is more significant under relativ ely smaller infiltration rates and is controlled by the magnitude of t he hydraulic diffusivity. For the two-layer liner the criteria of mini mizing the vertical movement and maximizing the wicking effect within the fine-textured material conflict. A three-layer liner satisfies bot h of these criteria. The results for the three-layer system show that the medium-textured material has more superior wicking properties than the fine material does.