本研究使用動床渠道進行均勻橋墩加裝套環之局部沖刷研究，並藉此闡明其沖刷特性。除了分析最大刷深與沖刷坑範圍外，並針對套環不同的置放高度所造成之沖刷變化進行了一系列比較。
研究結果顯示，無論套環的形狀為何，最大刷深隨著套環置放高度愈接近底床而愈小。套環形狀的選擇乃根據其可減少之刷深及範圍為重要的效益考量。當套環置放位置位於套環頂端與底床切齊處可將渦流系統從底床處抬升，不僅可有效減少刷深且可將沖刷坑最大刷深遠離主要結構物。向下射流與馬蹄形渦流成功的被導引至橋墩結構物下游後方處。故橋墩裝置圓形之套環為橋墩基礎保護工法最佳選擇。

This study uses experimental mobile channel to examine the characteristics of local scour around uniform piers with collar protection. The maximum scour depth and the range of the scour hole is analyzed. Furthermore, the change of scour at different exposure elevation is compared by performing a series of case studies.
No matter what kinds of the collar shape is,the maximum scour depth is decreased with the position of the collar set close to the bed.The importance of the collar shape chosen is according to the best benefit of redusing scour depth and the range of the scour hole. Setting the collar which it’s top is flush with the bed would lead the vortex system rise away from the bed,and it can not only reduce the depth of the scour hole,but lead the maximum depth of the scour hole away from the main structure.The downflow and horseshoe vortex is guided to the downstream successfully far away from the bridge pier structure.It can be accepted that the circular collar is the best choice of the pridge foundation protection.

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