Free-surface tracking through non-saturated models

The first filling and the rapid drawdown of the reservoir of an earthdam contribute largely to the stability of it. A coupled mechanical-hydraulic analysis must take into account the effects of partially saturated parts of the dam. To deal with such an analysis three developments implemented in the computer code GEFDYN will be presented in the paper : hydraulic model for the non saturated soil ; an initial hydraulic condition formulated with respect to the initial degree of saturation ; a numerical formulation for the hydraulic boundary conditions on the potential seepage surface. The transient free surface may then be determined automatically. Some applications are presented.