圖書典藏及影音數位平台

石岡壩位於大甲溪下游，為大甲溪水源調度之總樞紐。民國88年9月21日發生921大地震，地層抬升使左右岸高差達約10公尺，復建修復營運以來，常於洪水過後對於靜水池及副壩下游護坦，皆發生嚴重之沖刷現象。此外，下游河道因下切嚴重，而發生河床面之向源侵蝕現象，對堰體結構安全造成嚴重的威脅。需要進一步進行石岡壩下游之河道穩定設施研擬，借助利用三維水理模式模擬之優勢，並搭配水工模型試驗，進一步詳細探討石岡壩下游河道沖淤情勢及消能設施的消能最佳化設計。

Shigang Dam, located in the downstream of Dajia River, is the most downstream reservoir in the comprehensive development plan of Dajia River, whose function is to adjust the peak power and river water resources. The 921 earthquakes is occurred on 21th Sep. 1999. The ground surface uplift makes the left bank higher than right one about 10 m. Since the restoration operation again, there is serious scouring phenomenon for the static pool and the apron at the downstream of the secondary dam often after the flood. Furthermore, the serious bed erosion is occurred in downstream dam. It will be a serious threat for the safety of dam while the rive. Therefore, the optimal relationship between the size of energy dissipation pool and the total energy head can be analyzed in this project. The 3D flow simulation is used to compute the velocity, total energy head, and the force on hydraulic structures. The bed erosion issue will be discussed on the safety of dam by adding new energy dissipation pool at the downstream of secondary dam as well. The proposed plans will suggest the follow-up improvement project planning and design for a reference.