Abstract
Failures of old small earth dams occur frequently due to concentrated heavy rainfall, and it is necessary to reinforce these dams. On the other hand, lowering reinforcement costs is needed in terms of the Japanese financial situation. In this study, we developed a countermeasure to protect small earth dams against heavy rainfall and wave erosion at a low cost and a short-term construction period, namely the “Surface Cover Method”. In this method, erosion protection mats with impermeable sheets are spread from the upstream slope to the downstream slope of an embankment. We performed several model tests and revealed that this method effectively protects against rainfall infiltration, erosion by overtopping and wave erosion of the upstream slope, so is able to protect a dam from sliding, overtopping and wave erosion failure. From a construction test, the construction costs appear to be one third of conventional repair methods and the construction period is several weeks.
