防砂壩下游河床沖刷特性之研究

Study on the Scouring Properties of River Bed Below a Sabo Dam

連惠邦(Hui-Pang Lien) ； 陳昶憲(Chang-Shian Chen) ； 林昆志(Kun-Chih Lin)

《中華水土保持學報》 23卷2期 (1992/11) Pp. 123-133

https://doi.org/10.29417/JCSWC.199211_23(2).0011

摘要

為瞭解防砂壩下游面局部沖刷深度之變化，本研究根據一維運動方程式建立相對最大沖刷深度之半對數定律，經初步驗體已獲得良好之結果。由不同研究者之實測資料分析得知，相對最大沖刷深度與相對速度間可表為(方程式略)上式自變數與應變數間不僅具高度相關，同時兩待定常數〔摩擦係數(f_b)與結合係數(φ)〕具有實質之物理意義，尤其證明沖刷坑臨底臨界流速之綜合係數(φ)與楊式泥砂起動公式完全一致。此外，由摩擦係數與綜合係數可得清水流沖刷深度過程線。h = D sin_a/fb 1n(1+f_bU_i/D t)式中h為沖刷坑深度。上式經比較沖刷深度冪次方方程式證實可適度反映沖刷之時間變化。

關鍵字

沖刷深度 ； 防砂壩 ； 摩擦係數

並列摘要

To understand the variation of the local scour depth in the channel bed below a sabo dam. This study is based on the one-dimensional momentum conservation equation to found the semi-logarithmic law of the relative maximum scour depth. The result is quite satisfactory . According to the experiments from different researchers were analyzed. Relationship between the relative maximum scour depth and the relative velocity can be written as (The equation is abbreviated) It was found that the relation between the parameters, f_b and Ψ, are definite, especially the coefficient Ψ value is equal to the grain incipient motion formula of Yang. In addition, from f_b and Ψ value can be found scouring depth hydrograph of clear water flow was related as: (The equation is abbreviated) The result of this equation. semi-logarithmic equation, is proved that on the time dependent of scour depth is better than the power equation of scour depth.

並列關鍵字

scour depth ； saba dam ； friction factor