M. OULAPOUR - Civil Engineering Department, Shahid Chamran University of Ahwaz, Iran
E. MOHAMMADIAN - Manager, Department of Dam Engineering, Dez-Ab Consultants Co., Ahwaz, Iran
M. GHATEI - Civil Engg. Dept., Sh. Chamran University of Ahwaz, Ahwaz, Iran

The probabilistic approach, as an alternative to traditional deterministic approaches, includes the uncertainties due to the spatial variability of material properties and loading cases and presents a reliability based design including reliability index, β. Therefore, each parameter is assumed to be a probabilistic variable. Also, the output parameter follows the same probability distribution, the parameters of which should be calculated. This will provide a probability or risk factor for each safety factor. A simulation method, such as Monte-Carlo, is used for calculations and acceptable risk levels must be provided for each different loading condition. In this research the probabilistic and deterministic approaches are used to evaluate the stability of an earthfill dam under water pressure loading and the results are compared. The results show that this new approach is more realistic and can lead to economic optimization via accepting a certain tolerable risk for a steeper slope rather than the old conservative deterministic one.

Reliability, Probabilistic analysis, Slope stability, Embankment dams