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In this paper, stability of slopes with a shallow foundation located on top including the shape of the failure mechanism is investigated in static and seismic states. This is a three dimensional problem which is analyzed two dimensionally because 3D analyses are complex and appropriate softwares are not available.
The conventional method of bearing capacity evaluation of foundations on top of slopes is reviewed and results are compared with those obtained from using a specific three dimensional slope stability algorithm based on upper bound limit analysis theorem.
It is concluded that increasing the foundation load to a threshold level, the effect of the load on the stability of the slopes is negligible, a phenomenon which can not be observed in two dimensional analyses. Determination of this threshold by 3D analyses is a useful criterion for selection of the adequate safety factor in static and seismic slope stability analyses.