一般下游底床會有設置護坦和尾檻的保護工設施，以防止底床的嚴重淘刷。本研究通過清水流渠槽試驗，控制在一固定之流量及閘門開口下，改變兩種不同的粒徑，分別比較邊牆射流、邊牆射流護坦保護工及邊牆射流尾檻保護工等三種不同的試驗模型在深、淺尾水流況下，探討沖刷坑的沖刷機制與型態。且利用理論分析配合實驗結果，建立沖刷坑特徵尺度(最大沖刷深度、最大堆積丘高度、最大刷深位置、沖刷坑長、和基礎趾處刷深)預測模式，可用於推估並比較護坦保護工和尾檻保護工下游端之沖刷坑。以期能進一步瞭解保護工在邊牆射流作用下，下游河床之互制作用，達到最佳保護水工結構物設計之參考。 Aprons and sills are the common countermeasures for protecting the downstream riverbed. In this study the local scour behavior downstream of aprons and sills are examined by employing laboratory experiments. The scour characteristics of two homogeneous sand beds caused by the wall jet, the wall jet with apron, and the wall jet with end sill, are compared. By using theory and experimental data, a prediction model is developed, and is used to explore the characteristics of local scour near those structures.
