Flume experiment on the sediment-retaining effect of submerged breakwaters under the combined action of waves and currents

Abstract

This research was initiated as design guidance for the extension works of a submerged trapezoidal riprap breakwater protecting the channel towards Huanghua Port in China. Based on flume experiments, the sediment-retaining effect of the breakwater was investigated in two sections under the combined action of currents and waves. We also discussed differences due to two kinds of facing layer-Accropodes and mold bag concrete. Three main observations are provided herein. First, the suspended sediments in front of breakwaters are mainly concentrated in the near-bottom 30% water depth scope and the interface can be seen clearly between the high concentration suspension and the upper clear water. Second, the sediment-retaining ratio of breakwater at-5.7 m isobath position is about 37%-49% and that at-7.3 m isobath position is about 61%-65%. Last, when there are wave breakings in the vicinity of submerged breakwater crest, the facing layers cause some differences of sediment-retaining performances.