Unsaturated Flow

摘要

Unsaturated flow theory, based on Buckingham's capillary potential, the extended Darcy equation and the Richards-Klute flow equation, is the standard model of soil-water transport in the Unsaturated zone. This is a continuum model well suited to the analysis of bulk behaviour and engineering calculation. I discuss the application of this theory to Unsaturated flow in porous inorganic construction materials in general and cementitious materials in particular. I emphasize experimental methods, especially instrumental techniques for determining the moisture distributions in laboratory experiments. Recent work comparing the transport of water and of organic liquids in such materials is presented. Anomalous behaviour in water is related to partial wetting and wetting strain effects. I discuss also the Sharp Front model of capillary absorption and develop a simple model of one-dimensional wick action.