水平壩體內滲流表面及滲出點之研究

The Phreatic Surface and Exit Point of Seepage Flow through Horizontal Embankment Dams

周憲德(Hsien-Ter Chou) ； 李伯亨(Bo-Heng Lee) ； 陳主惠(Chu-Hui Chen)

《中國土木水利工程學刊》 21卷3期 (2009/09) Pp. 307-318

https://doi.org/10.6652/JoCICHE.200909_21(3).0007

摘要

本文以理論解析及實驗探討水平土壩內之自由滲流液面（簡稱滲流表面）及滲出點特性。理論解加入β參數，此參數於無尾水位時隨壩寬－上游水深比呈冪次增加，且本無因次公式較Kashef模式及Dupuit模式符合實驗流況。本實驗採用Hele-Shaw模型，利用兩板間距、流體密度、上游定水頭高度－壩體寬度比值等參數控制滲流表面及滲出點有無受毛細高度及出口阻力之影響，並以鋁粉粒子流線軌跡產生可視化滲流線。實驗結果顯示靜壓水頭符合由表面向下遞減之拋物線假設。本理論解之滲流表面及滲出點高度與實驗結果頗相近。當上下游水深度比大於0.9與上游水深－壩寬比小於0.1時，Dupuit解與本理論解相近。本研究成果有助於了解現場堆積顆粒或邊坡之破壞機制。

關鍵字

滲流表面 ； 滲出點 ； Hele-Shaw模型 ； 粒子流線軌跡

並列摘要

The development and validation of an analytical solution for the flow through horizontal embankment dams was proposed in this study, and the analytical solution is in fair agreement with experimental data. Under the condition of negligible downstream depth, the parameter, β, shown in the analytical solution increases with the increasing ratio of embankment-dam width to upstream depth. The Hele-Shaw model is employed to examine the phreatic (free) surface and exit point of seepage flow by adjusting gap width and fluids density. Aluminum powders were used to as tracking particles inside the gap and the flow visualization was performed. The phreatic surfaces and exit points are in good agreement between experimental data and the analytical solution. The assumption of a parabolic piezometric head was verified by experimental data. When the ratio of down-upstream water depth is large than 0.9 or the ratio of upstream depth -width is less than 0.1, the solution based on Dupuit model is close to the analytical solution. This model has the advantage to predict the seepage point for understanding the seepage-induced sloping failure.

並列關鍵字

phreatic surface ； exit point ； Hele-Shaw model ； tracking particles