Mechanism elucidation of embankment failure due to overflow and assessment of slope protection

摘要

Experiments concerning failure of embankments due to overflow have been carried out to investigate the processes and to assess effects of slope protection, constructing models of embankments. The results revealed two distinct processes, creation of an erosional scarp (the embankment from which the downstream slope is removed due to erosion) after erosion of the downstream slope and upstream or upward advance of the scarp. The downstream slope was eroded quickly, while the scarp migrated upward slowly. The theory of the scarp migration in breaching due to overflow was developed, considering erosion of the nearly vertical surface of a scarp and mechanical stability of the top end of the scarp. The mechanism of scarp migration plays an important role in assessing the effects of slope protection. The theory allows the profile of a scarp to be determined under the condition of imposed parameters. In the light of the mechanism, two types of slope protection against breaching were assessed.