Inverse modelling of two-dimensional water infiltration into a soil containing macropores

Abstract

Two series of axi-symmetric laboratory infiltration experiments were carried out in homogeneous sand and in sand containing artificially made vertical macropores. In the first case the results are compared with numerical solution of the Richards equation. In the second case the results are compared with the double-porosity model obtained by homogenization. The constitutive relations between the capillary pressure, saturation and unsaturated hydraulic conductivity for the sand and macropores are identified via numerical inverse analysis of cumulative infiltration. The applicability of several types of constitutive functions available in the literature is tested. The saturated conductivity and air-entry pressure fitted for the macropores are compared with theoretical predictions. The cumulative infiltration curves fitted by numerical inversion show reasonable agreement with observations for both types of porous media.