Author(s): Dezert Theo; Fjola Guorύn Sigtryggsdottir

Linked Author(s): Fjola Gudrun Sigtryggsdottir

Keywords: Rockfill dams; Riprap; Structure from motion; Toe support; Throughflow

Abstract: Overtopping mechanism being the main factor for embankment dam breakage, enhancing the understanding of riprap resistance against overtopping events is of great importance to improve reinforcement and construction techniques of rockfill dam protection systems. In this work, two 1:10 scale models of rockfill dams with placed riprap supported at the toe were built and exposed to increasing overtopping discharges until their complete failure. Two different construction techniques were used to compare the role of the compaction of the riprap layer in the resistance of the whole structure. 3D models were carried out thanks to the use of Structure from Motion technique to analyze the displacement of riprap stones under overtopping conditions. A buckling deformation, along with the compaction of the placed riprap layer could be demonstrated. This displacement appears to be more important (both in x and z-directions) and occurs at lower discharge for unpacked riprap layer than for the packed one. The resistance of the model with unpacked layer also demonstrated to be less resistant to overtopping than the packed one, failing at lower critical discharge. Finally, the importance of throughflow in the rockfill shoulder of the models is highlighted by comparing the critical discharge values of this study to the ones from previous studies where no throughflow was occurring.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0061-cd

Year: 2023