Abstract
Finite element saturated and unsaturated seepage flow analysis was done in this paper to study distribution of the residual pore water pressure generated in an embankment dam during a rapid drawdown and its influence on safety evaluation in the up-stream slope. The accuracy of FEM solutions was first examined by comparing them with the observed results from centrifuge model tests. Parametric studies were then conducted on several model fills with different inclinations of slope by varying the decreasing rate of the reservoir level, to understand the mechanism of seepage flow during drawdown and variation with time of the residual pore water pressure accumulated in the embankment. Instability of embankment slopes was studied for two different patterns of failure, sliding failure along circular slip surfaces due to a large residual pore water pressure and seepage erosive failure due to a large difference of pore water pressure in space, i.e. hydraulic gradient.
