Deformation-Based Limit State Analysis of Embankment Dams Including Geometry and Water Level Effects

Abstract

The research presented in this paper is focused on the effect of various parameters on the deformation response of embankment dams and the corresponding performance limit states. The parameters considered include the geometry of the embankment and hydraulic loading in terms of intensity, duration, and cycles of loading and unloading as a result of the rise and fall of the water level in the reservoir. The analysis of a model embankment dam is conducted using the finite-element approach and the results are incorporated into simplified deformation-based probabilistic analyses. The effect of the change in geometry on shear strains and horizontal deformations and the corresponding probabilities of exceeding three predefined limit states are presented. The analyses are also used to demonstrate the importance of taking into account the storm loading history when assessing the stability of the flood protection earth structures under future flood events. In a larger embankment model, the shear zone propagates deeper for failure to occur. The time to exceed Limit States I, II, and III increases as the size of an embankment model becomes longer. For example, failure occurs after 4.6 days in a model with a size factor of 0.1 compared with 12 days for a model with a size factor of 0.2. This is mainly because the advancement of the saturation front to a critical level occurs in less time in the smaller embankment.