Settlement analysis of the Mornos earth dam (Greece): Evidence from numerical modeling and geodetic monitoring

This paper studies the long-term (>30 years) settlement behavior of the Mornos dam on the basis of finite element analysis and vertical displacement data. It compares actually measured deformations resulting from a continuous geodetic monitoring record of the dam behavior with a numerical back analysis. Our aim is to explain the actual deformation history on the basis of the mechanical behavior of the dam. The deformation monitoring record consists of precise leveling data of a large number of control stations established along the crest and the inspection gallery of the dam, as well as settlements derived by magnetic extensometers placed inside the dam body. Overall, the available data cover the phases of construction, first filling of the reservoir and most of the operational time of the dam. The numerical modeling assumes 2D plane-strain conditions to obtain the displacement and the stress–strain characteristics of the abutments and the dam at eleven equally-spaced cross sections. Comparative evaluation of the results of the geodetic monitoring analysis against the findings from the finite element back analysis simulating characteristic stages in the lifetime of the structure, shows a very good agreement (on average 0.03 m) between the measured and computed displacements, which testifies to the correctness of the geotechnical parameters and loads used in the analysis.