Uncertainty Quantification of Transient Unsaturated Seepage through Embankment Dams

Abstract

Sensitivity analysis is conducted to investigate the effects of uncertainty in hydraulic conductivity and van Genuchten parameters on transient seepage. To this end, a random number generator is used to generate random values from probability distributions of each parameter. The generator is coupled with finite-element software that handles seepage analysis in porous media. The Monte Carlo simulation approach is adopted for stochastic seepage analyses. The suggested method is applied on a homogeneous dam made of clayey sand. Uncertainties in each parameter are considered individually in different cases for rapid drawdown and rapid fill conditions. The results show that a variation of hydraulic conductivity has significant effects on transient seepage, and it is suggested that it should be treated as a random variable. However, the effects of the van Genuchten parameters on seepage are found to be insignificant, such that they can be treated as deterministic variables.