Hydraulic Characteristics due to Closing Work of Tidal Embankment

Abstract

When a land area is established on top of soft ground on a coast and an estuary though reclamation, the reclamation is carried out by dropping gravel and rubble in order to improve the efficiency in the movement of equipment and the work being done. There is a difficulty with regard to final closing work in the closing section due to the occurrence of scouring. This is because the closing work is carried out with an increased flow velocity as a significant difference in water level occurs during the tidal embankment construction work for developing the inner side of the embankment by blocking seawater. In this study, the distribution of layer velocity and particle tracking according to the phased closing work with the high water level (DL(+)9.17 m) as the normal tidal condition were carried out. In addition, the flow velocity field was cross-correlated through the numerical simulation and hydraulic model test. When the tidal embankment was constructed using the combined deep and high critical method through the experiment, an increase in the flow velocity occurred in the closing section as the closing width became narrower. The flow velocity decreased due to a decrease in the cross sectional area of flow within 20 m of the closing width. The layer velocity reached a maximum near the bottom layer due to the installation of a sill and reached a minimum in the middle layer.