Numerical Simulation of the Rainfall Infiltration on Unsaturated Soil Slope Considering a Seepage Flow

Abstract

Frequent failures of river embankments have occurred in the world due to heavy rains. Heavy rainfalls bring about an increase of the ground water level within the soil as well as a rise in the water level of the rivers. As a result, embankments have been failed due to the rainfall infiltration and the generation of seepage flow. A series of two-dimensional numerical analyses of river embankments are carried out using a seepage-deformation coupled method for unsaturated soil. The mechanism of the surface deformation and the strain localization on these soil structures are discussed mainly with respect to the water permeability of the soils. Results obtained by the simulations show that the deformation of the embankments significantly depends on the water permeability of the soil and it is localized on the slope surface at the river sides. The larger the saturated water permeability of the soil, the larger the velocity of the seepage flow and the larger the deformation on the surface of the river embankments. Additionally, numerical simulations of a field experiment are used to show that, the method adopted here, can effectively be used to study the practical seepage deformation coupled problems on unsaturated soils.