| The coastal area is a zone with dense population and fast economic growth. Due to the interaction of climate change and human activities, the erosion hazard in coastal areas is increasingly severe. Emerged as the disadvantages of rigid structures for coastal protection, the concept of shore nourishment had been put forward and develops at pace. Shoreface beach nourishment, dumping sand offshore under the mean low tide level, is one effective form of shore nourishment. However, researches on the evaluation of effectiveness and lifetime in shoreface nourishment project are in great demand. Therefore for guiding the engineering application, this paper conducts experimental and numerical simulations for purpose of analysis on lee and feeder effect and of a longevity prediction method which consists of transmission coefficient empirical formula and XBeach model for shoreface nourishment based on the artificial sandbar.A 3D basin experiment was used to simulate a shoreface nourishment project composed of three sandbars reaching an understanding of the impact on wave transformation and profile changes. The shoreface nourishment project reduces the wave height and energy behind the sand bar. Besides, the beach foreshore suffering from erosion turns to sedimentation at low tide level with backshore from erosion to no-change. At high tide level, the beach erosion decreases significantly under the protection. Thus the degree of lee and feeder effect is demonstrated by these experiment data.Considering the lee effect of sandbars, a design criterion is given to demarcate project failure that transmission coefficient exceeds a threshold. A transmission coefficient empirical formula is derived from a 2D flume experiment to get the relative water depth at crest when the threshold is reached. XBeach, a process-based model, is chosen to establish a 1D profile numerical model to simulate profile changes in a storm process and the lifetime of the sandbar in one shoreface nourishment project. |
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