黄河宁夏段特大洪水中河相变化特征研究

李颖曼 王乐 宋天华 王彦君 马良

摘 要：黄河宁夏段受上游来水来沙变化等因素的影响，河道断面会发生变化，最终会影响河道的过流能力。基于水文站实测数据分析黄河宁夏段主要断面近几十年来的过流面积变化特征，借助河相关系参数阐释河槽过流能力的变化趋势。在此基础上，进一步研究黄河宁夏段典型断面的水流弗劳德数变化规律。结果表明，石嘴山断面形态及河相关系的变化相比于下河沿及青铜峡断面更为显著;代表断面形态的河相关系参数与水流弗劳德数紧密相关，具体表现为下河沿、青铜峡断面的流量与弗劳德数对应关系良好，整体优于宽浅型的石嘴山断面。

关键词：河相关系参数;弗劳德数;黄河宁夏段

中图分类号：TV62;TV882.1

文献标志码：A

doi：10.3969/j.issn.1000-1379.2021.12.012

引用格式：李颖曼，王乐，宋天华，等.黄河宁夏段特大洪水中河相变化特征研究[J].人民黄河，2021，43（12）：57-62.

Abstract： It could be anticipated that the cross sections within Ningxia reach of the Yellow River followed a natural law by self-adjusting channel geometry to accommodate the associated changes of flow and sediment from upstream， which in turn could alter the channel capacity to delivering flow and sediment. The present study therefore aimed to analyze the spatial-temporal variability of main cross-sectional geometry within Ningxia reach of the Yellow River through using river gage records. Also， the channel capacity for discharging bank-full flow was analyzed with the aid of channel geometric parameter. Further， the variations associated with Froude number for flow passing through main cross sections was investigated in detail. The findings from the present study show that the changes of section morphology and river facies relationship in Shizuishan are more significant than that of Xiaheyan and Qingtongxia. The parameters of river facies relationship representing the section shape are closely related to the Froude number of flow， specifically， there is a good corresponding relationship between the discharge of Qingtongxia section and Froude number and it is better than the wide and shallow Shizuishan section as a whole.

Key words： channel geometric parameter; Froude number; Ningxia reach of the Yellow River

河相關系是河道经过一段时间调整后，河道断面形态与其所在河段的流量、泥沙、河床变化等形成的某种定量关系。Kennedy[1]最先开始河相关系的研究并确定了稳定河床水力因子与流量之间的指数函数关系。随后，Leopold等[2]基于美国平原河流数据，将稳定河床的河相关系扩展到了粒径范围较广的天然冲积河流，并建立了河流形态参数及水力变量的平均值与流量之间的幂函数关系。Richards[3]认为当漫滩流量出现时可能会存在河相关系的非连续性，而且漫滩流量以下的河相关系参数与流量之间存在非线性的响应关系，基于此提出了二次对数关系式。……