Experimental investigations on the stability of riprap layers on overtoppable earthdams

Abstract

In Germany small dams (<10 m) on flood retention reservoirs are often provided with an overtoppable dam section for flood relief. In case of overtopping a protection of the dam body is absolutely mandatory as the mainly cohesive dam material is not capable to withstand the affecting erosive forces of the flow. There is a big number of possibilities how to protect the dam whilst overtopping. Some of the most common construction types of slope protection layers for a sufficient dam protection such as riprap and placed stones, have been tested in large scale physical models at the Hydraulic Laboratory at Universitat Stuttgart. Thereby different experiments for the failure scenarios “erosion of single stones”, “sliding of the protection layer” as well as “disruption of the protection layer” have been conducted and analysed aiming to find some design criteria for the construction of such dams.