Analytical analysis of coupled seepage in unsaturated soils considering varying surface flux

Based on the assumption that water content and permeability coefficient are exponential functions of pore-water pressure, the Fourier transform is used to obtain an analytical solution to one-dimensional coupled rainfall infiltration and deformation in unsaturated soils with varying surface rainfall flux. When the gradually increasing rainfall intensity is less than the saturated coefficient of permeability, a flux boundary condition is adopted. When the rainfall intensity is larger than the infiltration capacity of the saturated soils, a pore-water pressure boundary condition is used. The analytical solution can consider varying flux boundary conditions, pressure boundary conditions and arbitrary initial conditions. The calculated results of a case study show that the coupling effect has a markable effect on the pressure distribution for the transient unsaturated seepage. The coupling effect dissipates if the steady-state infiltration occurs.