固體邊界之泥砂輸送行為研究

Abstract

近年來，石門水庫存在著洪水挾帶大量泥砂與流木進入庫區之問題。因此，增設防洪防淤隧道，提升水庫排洪與防淤功能為當下最重要之課題。現今國內研究輸砂之風氣雖然興盛，但並無專門探討管道、隧道相關之輸砂研究。本研究欲探討在不同的管徑及不同的流速之下，其泥砂輸送行為對固體邊界造成之影響與差異。 本研究先以迪聖凡南(de Saint Venant)方程式建立起一維水理模式，然後加入泥砂傳輸方程式，合併為一維水砂方程式。數值方法採用顯式有限體積法並結合WENO增加數值解之穩定性。本研究以Banasiak and Verhoeven (2008)試驗案例以及Creaco and Bertrand - Krajewski (2009)模擬法國里昂(Lyon)拉卡薩涅(Lacassagne)地下水道之現場案例進行模式之檢定與驗證。最後，模式以艾利颱洪事件對石門水庫防洪防淤隧道進行模擬，並由結果得知在高速流況下，隧道不會產生淤積，並且有可能造成固體邊界磨損，因此，加入了Bitter磨損理論以探討固體邊界磨損之問題。

In recent years, the severe problem existing in Shihmen Reservoir is the flood with a lot of sediment and driftwood flow into the Reservoir. As the result, the most important thing is building sediment bypass tunnels and enhancing the function of reservoir on preventing drainage and silting. The research in sediment is flourish in Taiwan, but not particularly focuses on the area in pipe, tunnel, and sewer. This study is to explore sediment transport behaviour caused by the impact of solid boundary in different diameters and velocities. First, we establish a one-dimensional model combined with de Saint Venant equations and sediment transport equations in this study. This numerical model uses explicit finite volume method with WENO method to increase stability of the numerical solution. In this study, we use the test cases, the case of Banasiak and Verhoeven (2008), and the on-site case of Creaco and Bertrand - Krajewski (2009) simulating the drain in Lyon and Lacassagne, France, to verify and validate the model. Finally, the model applies the case of Aere Typhoon to simulate the sediment bypass tunnels in Shihmen Reservoir. From the result, we find that sediment transport in high velocity flow condition may wear and tear on the solid boundary instead of depositing. To model the study more accurate, we combine the Bitter theory and our model to analyze problems about wearing on the solid boundary.