泥沙研究

首先阐述泥沙输移比界定的三个条件一是粒级 ,二是时间 ,三是空间 ,在此基础上讨论了长江上游泥沙输移比研究中存在的主要问题是缺少可靠的侵蚀产沙量 ,对悬移质和推移质的分界线不明确 ,对坡面侵蚀产沙和重力侵蚀产沙在总输沙量中的权重缺少量的概念 ;针对上述问题对河道及沟道泥沙输移比的推理分析 ,再根据反映泥沙输移比的形态指标的定性分析 ,认为长江上游除丘陵宽谷区泥沙输移比会小于 0 .5外 ,高中山区长时段的泥沙输移比都接近 1(不包括泥石流在内的重力侵蚀 )。

Three conditions for defining the sediment delivery ratio are discussed in this paper, including grain size, time, and space. It is found that the main problems in the studies of sediment delivery ratio in the upper Yangtze River are lack of reliable data of sediment yield, unclear defined division between suspended and bed load, and non\|quantified percentage of sediment yield from slopes and gravitational sediment yield in the total. For solving the afore\|said problems, the author has done some theoretical analysis on the sediment delivery ratio in river channels and gullies and qualitative analysis on some landform indices that reflect sediment delivery ratio. The research results are that the sediment delivery ratio in the high and medium high mountain areas is close to 1 (excluding areas suffering gravitational soil erosion and debris\|flow), but smaller in the hill and wide valley areas in the upper Yangtze River.