Sediment Control Mechanism of Debris Dam

本文从泥沙水力学角度分析了土石坝的拦沙机理。本文从实际河道资料分析、土石坝防冲机理和土石坝上下游输沙机理三个方面进行了研究。结果表明：（1）收集和分析了天龙江支流越子江的河床变化资料，为泥石流坝的修建提供了有价值的河床变化信息。在津津江支流芦来川对泥石流在拦石坝内的运动进行了观测研究，阐明了泥石流的泥沙淤积情况。(2)本文从试验和理论两方面讨论了坝前河床变化与坝前排沙率的关系。本文提出了一个可用于预测河床变化和出、入沙比的数学模型。(3)从各种敞开式土石坝的角度，探讨了其防治泥石流的机理，并阐明了其防治机理。

This project has been made to analyze the sediment control mechanism of debris dam in terms of sediment hydraulics. Three subjects, which are concerning the data analysis of actual river, the erosion control mechanism of debris dam and the mechanism of sediment transportation upstream and downstream of the dam, are chosen for consideration. The results show(1) Data on bed variation of the Koshibu River, tributary of the Tenryu River, are collected and analyzed, and give a valuable information of bed variations in rivers where debris dams are constructed. Observational study is made in the Ashiarai River, a tributary of the Jintsu River, for the behavior of debris flow in the crib dam, and clarifies the sediment deposition from the flow.(2) The relation between bed variations upstream of dams and sediment discharge rates from dams is discussed experimentally and theoretically in terms of widths of opening and heights of dams. A mathematical model, which is useful for the predictions of bed variation as well as of the ratio of outflowing sediment discharge to the inflowing one, is presented.(3) The mechanisms of debris flow control are discussed in terms of open type debris dams of various kinds, and are clarified.