Uncertainty based analysis of seepage through earth-fill dams

Çalamak, Melih
The steady-state and transient seepage through embankment dams are investigated considering the uncertainty of hydraulic conductivity and van Genuchten fitting parameters, α and n used for unsaturated flow modeling. A random number generation algorithm producing random values for these parameters is coupled with a finite element software, SEEP/W to analyze seepage through earth-fill dams. Monte Carlo simulation is adopted for stochastic seepage analyses. The variability effects of the random parameters on seepage are investigated conducting sensitivity analyses. The variation effects of hydraulic conductivity are found to be significant, whereas those of fitting parameters are shown to be negligible or minor. Considering these, the statistical and probabilistic properties of the seepage are assessed for different embankment dam types and boundary conditions. The degree of uncertainty and statistical randomness of the seepage are evaluated. In general, it is found that the seepage through embankment dams can be characterized by generalized extreme value or three-parameter log-normal distributions.