This study provides an analysis of the water-table configuration and pore-pressure distribution in layered hillsides. A finite-element model was used to simulate two-dimensional, saturated–unsaturated, steady-state flow through layered slopes. A laboratory sand-tank experiment was used to verify the physical foundation of the mathematical model. It is shown that layered slopes feature multiple seepage faces, perched water tables, and wedge-shaped unsaturated zones. The pore-pressure distribution and the distribution of multiple seepage faces are strongly dependent on the position of the impeding layers and their hydraulic properties. Predictions of pore-pressure fields based on homogeneous, saturated analyses may be significantly in error when applied to problems on layered slopes. Slope-stability analyses on layered slopes that do not take into account the presence of unsaturated wedges beneath the impeding layers can lead to overdesign of the stable slope angle. Key words: groundwater conditions, unsaturated zone, layered slopes, seepage face, slope stability.
Rulon et al. (1985) studied this question.