Finite element analysis of earth dam settlements due to seasonal reservoir level changes

This paper presents a nonlinear finite-element analysis of the long-term (>25 years) deformations of an earth dam. The Kouris earth dam, which is largest dam in Cyprus and for which comprehensive monitoring data is available, is taken as the case study. The study attempts to examine the effects of reservoir level variation and transient soil consolidation on the long-term settlements of earth dams. Two-dimensional plane-strain coupled transient hydro-mechanical nonlinear finite-element analyses of the dam are conducted. The numerical model considers soil plasticity, nonlinear stiffness and permeability of the different earth and dam materials. The entire stress history of the dam is modelled, which includes staged construction, reservoir impounding, consolidation and seasonal reservoir level changes. This study shows that seasonal reservoir level changes induce small fluctuations of crest settlements and that the majority of the total settlements is due to soil consolidation. The effect of different material properties (e.g. stiffness and permeability) on the dam deformations are examined along with the applicability of different constitutive models. The results are useful in understanding the mechanisms governing the long-term settlements of earth dams.