Dam-break waves over an erodible embankment: experiments and simulations

The paper investigates the impact of a dam-break wave on an erodible embankment with a steep slope. Both experimental and numerical analyses were carried out. The laboratory experiments have been specifically designed and performed, varying the storage water level, the elevation and the slope of the embankment. The simulations were carried out using a recent two-phase depth-integrated model, supplemented with a geofailure operator to account for the possible occurrence of geotechnical collapses. The comparison between the numerical and experimental results indicates that the two-phase model permits to fairly reproduce the experimental free surface elevation, with or without the geofailure operator. Conversely, especially for high embankment slopes, this operator appears to be crucial for predicting the observed morphological evolution. Moreover, the results show that, due to the geotechnical collapses, water and sediment velocities may have opposite sign. While models based on equal direction of the liquid and the solid motion cannot reproduce this issue, the proposed two-phase approach easily accounts for such a peculiarity of the investigated process.