Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

Accurate estimates of the hydraulic properties are needed for any quantitative description of multiphase flow in an unsaturated zone. A hysteretic model is described for the prediction of relative permeability-saturation- pressure(k-S-p) relations in two-phase (air-water) porous media systems subject to arbitrary saturation paths. A representation of hysteretic soil hydraulic properties is given based on a combination of van Genuchten\'s parametric model, statistical model to predict relative permeability, and empirical hysteresis model to account for fluid entrapment. Predictions of k-S-p relations for a hypothetical medium are presented using model parameters for a sandy soil. Simulations were performed for the water flow through unsaturated soil columns during infiltration or evaporation under gravity. The numerical results indicate that hydraulic properties without consideration of hysteresis and entrapment may produce highly unacceptable results, especially for cases including reversals of various flow paths.