Centrifugal Model Test on the Failure Mechanism of Barrier Dam Overtopping

In order to study the failure mechanism of barrier dam overtopping, centrifugal model tests of dam failure were conducted in this research. A calculation method of rectangular weir flow in the centrifugal field was derived. The process and mechanism of barrier dam overtopping were intensively analyzed. They were further verified by the breach flow curve and the development curve of the breach top width acquired from model tests. Results showed that the barrier dam breach developed during the entire process of overtopping in the width direction. The development of the barrier dam breach in the depth direction, however, ceased at an earlier time on account of the large particles accumulated in the downstream slope. Moreover, coarsening in the downstream slope could be clearly observed in the last stage of overtopping. Thus, it was concluded that the bottom part of the barrier dam could survive after dam breaching and that a full dam failure is relatively rare for a barrier dam. Furthermore, the size of the remaining breach would be less than that of a homogeneous earth dam under the same conditions.