Computergestuetzte Analyse des Dammerosionsbruchs

Dams and dikes are commonly regarded as very save structures. People who are living close to big dams do not feel threatened. The trust results from 5000 years experience in building and controlling of dams and dikes. Statistics confirm the intuitive trust in the safety of dams: only 1% of all dams build up to now did break. But there is nevertheless enough reason to be cautious. This holds especially for engineers who are constructing or controlling dams. During the last century hundreds of dam-breaks occurred. Three of these dam-break catastrophes caused the death of more than 2000 men each. At least two of them could have been avoided. Different from other technical structures the collapse of a dam is regarded as a natural catastrophe. The name 'Titanic' implies directly the reminding of a great catastrophe caused by human misjudgement. The name 'Macchu' has meaning only for a few specialists. Every barrage has a certain risk, which is small but not neglectible. This work does not provide knowledge on the increase of safety by the mean of constructional recommendations, but presents mathematical tools for the estimation of what happens, if the dam breaks. There are only earthern and rockfilled dams considered. The sudden collapse of concrete and arc dams can be estimated with known methods. Four different approaches are used. The first model is based on the analysis of 115 real dam-breaks. The second model consists of an analytical solution of the dam-erosion. The third model is similar to the second one, but solves the equations within some discrete time loop. This type of model is called parameter model. Fread calls this approach a simplified model. At least the dam erosion is numerically simulated. The shallow water equations and the sediment continuity equation by Exner are solved in two successive stages. The shallow water equations are solved with two different schemes, the Beam/Warming scheme and an explicit scheme from Nujic. The sediment transport was calculated with implicit and explicit formulations of the Exner equation. The 2d-implementation of the numerical method offers the possibility to simulate time dependent the 3d-shape of the dam surface. (orig.)Available from TIB Hannover: RN 6966(61/1997) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman