The Consolidation Behavior of the Clay-Core in a Rock Fill Dam — Atatürk Dam Case Study

Unexpectedly large settlements occurred in the 165 meter high clay core of Atatürk Dam during the reservoir filling stage. An investigation was conducted based on laboratory experiments and numerical analysis. Consolidation tests were performed on compacted samples under stress levels expected to take place in the field by considering the possible factors affecting the consolidation behavior. The experimental findings were used to model the observed settlements based on a parametric study and by back-calculation. The total expected settlements were determined to be in the order of 16.0 m. While a good fit was captured between the observed and modeled settlements prior to the reservoir filling, it was not possible to model the significantly large settlements observed within the clay core located approximately 120 meter below the crest following the reservoir filling. Evaluating other observations and findings, it was concluded that this phenomenon could be attributed to the lateral displacement of the core material into the filter and shell zones that were prone to instabilities due to disintegration under water