沖刷對河岸穩定之影響分析

Abstract

本研究以動床試驗方式，探討不同入流量及岸壁坡度下，床型沖刷變遷對灘地崩塌時間與退縮距離之影響。岸壁試驗材料採用矽conducted砂與高嶺土混合之凝聚性土壤，底床試驗材料採用矽砂之非凝聚性土壤，以此鋪設方式類比真實河川的情況。此外，本研究透過謝(2003)所發展的二維水深平均RESED2D水理動床模式，並加入Arulanandan et al.(1980)之凝聚性岸壁沖刷經驗式及懸臂型岸壁之安全係數公式(姜,2011)，進行試驗案例之比對模擬分析。

In this study, a movable bed flume was set up. To make the conditions close to the natural rivers, the channel bank was paved with the cohesive material composed of the mixture of silica sand and kaolinite; the channel bed was paved with the noncohesive material of the silica sand. Several experimental cases with various inflows and angles of channel bank were conducted to investigate the influence of bed scouring to the time and distance of bank collapsing. Moreover, this study adopted a 2D Depth-Averaged Model (Hsieh, 2003) with adding bank scouring formula for cohesive material(Arulanandan et al., 1980) and safety factor of cantilever failure formula (Chiang, 2011) to simulate experiment cases. The simulation results were analyzed and compared with measured data.