Formulazione semplificata in forma adimensionale dell'idrogramma conseguente al crollo parziale di uno sbarramento di ritenuta

The mathematical modelling of the reservoir emptying process due to a dam break and of the flood wave propagation downstream of the dam can be performed in an effective way on the basis of the de Saint Venant equations. However, this approach is not yet common practice and demands a huge amount of information that often is not available. For these reasons, simplified methodologies have been proposed in the literature to deal with the problem of the characterization of the breach outflow hydrograph following an instantaneous and total dam break. On the other hand, to the authors' knowledge, no satisfactory simplified procedures have been so far developed for the case of partial dam break, although this scenario is specifically considered by the regulations of many Countries for certain types of dams. This paper presents a simplified approach to the characterization of the wave following the partial collapse of concrete gravity dams. The proposed approach is based on the numerical solution of shallow water equations to study the two dimensional evolution of the water surface within the reservoir. The numerical results are made dimensionless and reorganized to allow a straightforward representation of the breach outflow hydrograph.