中文摘要：

不连续宽级配床沙在天然河道中广泛存在,作为非均匀沙的特殊类型,其床面水流特性与一般意义上的非均匀床面相比具有不同的特性.以不连续宽级配床沙为例对其床面垂线流速结构进行了试验研究,结果表明不连续宽级配近底床面垂线水流结构出现S型转折,S型位置与水流强度和床面形态有关.并提出了基于近底S型的水流垂线流速分段表示的流速公式及垂线流速S型平均转捩位置的计算公式.

英文摘要：

Discontinuous wide-grading sediment widely exists in natural rivers as a specific type of non-uniform sediment.It has different flow characteristics while comparing with traditional non-uniform sediment.The vertical velocity structures of the discontinuous wide-grading sediment bed are studied in a series of flume experiments.The experimental results show that S-type vertical velocity exists near the bed surface,and the S-shaped position is related to flow intensity and bed form.The vertical velocity formula expressed by section and based on the S-type is put forward and the S position of a vertical velocity profile is derived.The study provides a basis for the research of the flow structure of the discontinuous wide-grading sediment.