Experimental study of wave generated dynamic load on coastal embankment

Abstract

Coastal embankment is a structural measure usually taken near coastline to protect inland habitat and crops. This research work considers only those embankments which are located along the coast line directly facing the sea. The general practices in Bangladesh for the design of coastal embankment normally consider high tide level as the design high water. Based on the design criteria it can be said that, the consideration of periodicity of small waves while designing an embankment is one of the most important parameter. For accurate design consideration, the main parameters are wave height, wave direction, current and soil properties. The effects of the above considerations might result in changes in the alignment, crest level, slope or drainage system of the embankment. The study analyzes the effect of dynamic loading due to wave associated with submerged, floating breakwater and CC block condition on coastal embankment. An experimental investigation was conducted to study the behaviour of wave parameters with different loading conditions in the laboratory flumes of Hydraulics and River Engineering Laboratory of the Department of Water Resources Engineering, BUET. Test runs were conducted for different wave periods, water depths with loading conditions such as by providing CC block, submerged breakwater and floating breakwater. Before the test runs, instrumental setup of wave generator had been done and pointed for individual condition runs. Total 36 test runs were conducted. All the above performances have been done by two different slopes of 1:2 and 1:3 against the wave action by changing the wave period, water depth and protection work. Wave loads, especially dynamic loads were calculated from the experimental values of wave parameters by using Sainflou’s formulae (1928). The study shows that presence of breakwater in front of the coastal embankment resulted in a change in the loading distribution. Breakwater position (submerged or floating) individually affect the wave loads further more.