[Multistep outflow method for determination of unsaturated hydraulic conductivity of municipal solid waste]

Traditional method for soil permeability measurement causes important errors when it is used in municipal solid waste (MSW) experiment. The in-situ saturated water content and hydraulic conductivity were measured at Liulitun landfill. It was tested that the average water content increased downward and the average hydraulic conductivity was 0.0185 mm x s(-1). On the same condition of density, water retention curve and unsaturated hydraulic conductivity were determined with multistep outflow method in laboratory. Multistep outflow method, together with successive simulation, is used in the paper to provide parameter measurement for distribution models. The model is remarkably correlative to experiment data. On the basis of lab data and later simulation, changing rules of water retention curve are disclosed, and the method is proved to be effective to measure unsaturated hydraulic conductivity of municipal solid waste.