Abstract

This paper systematically deduces the alluvial river excavation length by hydraulic and river dynamics relative knowledge. The results be shown that the channel excavating length is relative to both the ratio-θ of the cross section which is dug and the fall height-y of water level. The restriction relationship exists between these factors. Through the practice of the model experiment of river dredging startup engineering of river dredging for dyke strengthening in the lower Yellow River and maths model calculation, the techno-parameters was testified which was the excavation reduction ratio, the back-deposition volume and the retrogressive erosion-ratio of flow. It is shown that there is a critical river excavation length to reach the optimize the effect in the certain quantity of dredging sediment and income water and sediment. From the preliminary analyzing, it obtains the optimization effect when the river excavation length is about 10~12km.

Keyword: the Lower Yellow river, the channel excavation length, deposition reduction ratio, the fall height of water level, the effect of reducing deposition