Εκτίμηση συντελεστή ασφαλείας για την ταπείνωση της στέψης χωμάτινων φραγμάτων

The crest settlements of embankment dams with a central clay core are usually described as an exponential function of time. They play a major role in the safety and operational capacity of the dam, especially when taking into account that extreme crest settlements that have been observed for some of these dams have resulted in a significant reduction of the storage capacity of the reservoir and maintenance works at large scales and cost (e.g. Ataturk dam, Turkey). We studied the crest settlements of > 40 embankment dams, 10-41 years old, located at different parts of the world. Our analysis shows that the safety threshold for the crest settlements should not be a constant but increase with the age of the dam and that most of suggested thresholds in the literature are too conservative. A safety threshold of 1% (crest settlement to dam height ratio) appears to be realistic for the whole operational life of the dam. The Kremasta dam, whose age and size places it to a most critical situation, has a crest settlement to dam height ratio value well below the above threshold.