Prévision de l'hydrogramme de rupture par submersion d'un barrage en enrochement avec masque amont de béton

Safety standards about dam security predict a30 minute long failure of embankment dams by overflowing and a breach width equal to four times the dam height. In this thesis « Évaluation du gain de sécuritérelié au rehaussementd'unediguemunie d'un élémentd'étanchéitérigide », Laurent Masson gives a method to calculate the flooding failure hydrograph of an embankment dam with a concrete seal curtain. The purpose of this thesis is to make a calculation model to predict the impact of overflow on arockfill dam with a concrete mask in the upstream facing. Beginning with the « Multiple Wedge Analysis » method used by the U.S. Bureau of Reclamation, this model has geotechnical components which are used to establish a model of sliding line, hydraulic components to study of incipient movement of rocks by high velocity gradients and drag forces, and finally structural components with the calculation of stresses in the mask and the parapet. With the different models which give security factors for each failure mechanism, we study how these mechanism interfere with each other and once the failure scenario are done, we calculate failure hydrographs. In order to evaluate the applicability of safety standards used by Hydro-Québec, we compare these hyrographs with the one we obtain by using the (4H, 30 min) standards. The results tend to invalidate the (4H, 30 min) norm by giving faster failures. A better knowledge of failure mechanism and scenarios for embankment dams and hybrid dams using both soil and concrete properties allows to improve the resources management and the efficiency of safety measures.