tailieunhanh - Modelling sea dike toe erosion during storms

Toe erosion, especially in stormy conditions, is one of the common mechanism causing the failure and instability of the sea dikes and revetments. The erosion intensity becomes more serious at the beaches which is under the impacts of typhoons. Reliable forecasts about the intensity of toe erosion of sea dikes in stormy conditions have important ecnomomic and technical meaning in the design and construction of sea dikes. | Modelling sea dike toe erosion during storms Thieu Quang Tuan1 Nguyen Quang Luong1 Le Ngoc Anh1 Abstract Toe erosion especially in stormy conditions is one of the common mechanism causing the failure and instability of the sea dikes and revetments. The erosion intensity becomes more serious at the beaches which is under the impacts of typhoons. Reliable forecasts about the intensity of toe erosion of sea dikes in stormy conditions have important ecnomomic and technical meaning in the design and construction of sea dikes. This study considers and evaluate the extent of the scour in front of the dike toe during the typhoon using the numerical model WADIBE-TC. The protective structures for dike toes consist of buried toes cylinders and coarse rock apron. Keywords sea dike toe erosion storm numerical model WADIBE 1. Introduction In the North and Central provinces of Vietnam toe erosion or foreshore loss is a dangerous and common mechanism causing the failure of the sea dikes especially when the dikes are constructed in the area having strong erosion development. During storms the cross-shore sediment transport due to the impacts of waves and storm surges are main causes of the formation of scours in front of the toes and foreshore sink. There are differences with respect to the phenomena process as well as the training solution between erosion occurring in stormy conditions due to cross-shore sediment transport processes and erosion cause by the deficiency of supplementary sediment for the longshore sediment transport. The latter process causes the chronic erosion and it is very expensive to control while the first process is the cause of acute erosion occuring only during stormy conditions. Up to now in the design of sea dikes toe erosion calculations all have been based on the empirical formulas set up for vertical walls. Field observations have shown that these formulas have not taken all the influence of the parameter into consideration and they often produce .