Numerical modeling of saturated - unsaturated seepage flow in porous media and slope stability analysis in an earth dam following rapid drawdown

Abstract

This work was dedicated to study the saturated – unsaturated seepage flow in an earth-dam and slope stability following rapid drawdown which occurs in water-retaining structures (earth-dams, dykes…) characterized by numerical modeling using Geostudio Seep/W and Slope/W Finite Element Software. Seepage flow’s equations in the dam are modeled, the modeling of seepage taking place inside the earth dam infill materials included soil parameters, the negative pore water pressure - hydraulic conductivity relationship as well as the negative pore water pressure - volumetric water content. The drawdown phenomenon was then analyzed and its influence on dam stability assessed by using surface response method and Monte Carlo simulation.  The two-dimensional physical model is built and couples Darcy equation and Richard’s equation in porous media in steady and transient state. The factor of safety values was calculated from Bishop’s simplified method, we took into account mechanical behavior of dam materials which follows the Mohr-Coulomb criterion.