海灘在波浪作用下會有不同變化，主要是受到漂沙的支配。本文主要研究在沙質海攤， 原始底床為單一坡度的向離岸漂沙，對沙丘侵蝕量影響程度。利用實驗水槽進行沙丘輸沙實驗，漂沙由外海隨波浪運動向前灘區傳輸，當波浪溯升時(uprush) 碰到沙丘造成沙丘侵蝕， 使沙丘位置後退;波浪回降時(backwash) 將侵蝕沙量攜入海灘內，在沙丘前端形成堆積性， 一部份沙量被帶離到外海，如此持續不斷造成海灘地形變化。實驗時，起初由於波浪作用使海灘地形產生劇烈變化，隨著實驗時間延長其海灘地形變化漸趨平緩，而接近平衡狀態。在不同的入射波被高、海灘坡度、沙丘位置和波浪週期情況下，輸沙量及沙丘侵蝕量會有不同結果，波浪尖銳度與沙洲尖銳度之關係及與胡(1994) 之斜坡上輸沙量比較本文將分別加以討論。 The incident waves on the beach and the fOllowing uprush and bckwash phenomenon change the beach
profile due to the sedimentation. The mainpurpose of this study is to investigate the on-offshore
sedimentationon a slopingbeach and its effect to the quantities of the eroded dune. By using the flume experiments,We examined the dune erosion and the sediment-ation on the slope. The sediments were transported from the offshore to the foreshore region in according to the wave shoreward propagation. The dune was eroded when the waves collide dune. That makes the dune backward. As waves backwash, some eroded sands were carried offshore and some were stored in fr'ont of dune. Therefore the opography was changed by the action of these waves.ln the beginning, the beach topography was changed intensively because of the waves action. The longer the experiment took, the closer the equilibrium beach was reached. We will discuss the quantities of the sedimentation and the eroded dune for different wave heights, beach slopes, dune locations and wave periods. The relation between wave steepness and bar steepness have also been studied.
Relation:
第十六屆海洋工程研討會論文集=Proceedings of the 16th Ocean Enginnering Conference in Taiwan，頁C 202-215
