Probabilistic analysis of seepage that considers the spatial variability of permeability for an embankment on soil foundation

In this study, probabilistic analysis of seepage through an embankment on soil foundation was performed. The traditional seepage analysis method was extended to develop a probabilistic approach that accounts for the uncertainties and spatial variation of the hydraulic conductivity in a layered soil profile. The hydraulic conductivity of soil shows significant spatial variations in different layers because of stratification; further, it varies on a smaller scale within each individual layer. It was assumed that the statistics of the hydraulic conductivity is different for different layers and that the hydraulic conductivity in a layer is uncorrelated with that in the other layers. Two-dimensional random fields were generated on the basis of the Karhunen–Loève expansion in a manner consistent with a specified marginal distribution function and an autocorrelation function. A series of seepage analyses of embankment–foundation systems were performed using the generated random fields to study the effects of uncertainty due to the spatial heterogeneity of the hydraulic conductivity on the seepage flow. The results showed that the probabilistic framework can be used to efficiently consider the various flow patterns caused by the spatial variability of the hydraulic conductivity in seepage assessment for an embankment on soil foundation.

► Probabilistic seepage analysis through an embankment–foundation system was performed.
► The hydraulic conductivity of two-layered soil profile was considered as a random field.
► Predicted μ and σ in Q were always smaller than those for a single layered profile.
► Influence of autocorrelation distances depends on the dominant flow component.
► Probabilistic analysis enables consideration of various flows by spatial variability.