多沙河流治导线流路方程研究

为确定多沙河流河道整治治导线的形态特征,本文试图建立治导线流路方程,以便定量描述自然状态下主流线变化规律。通过整理黄河模型试验资料,发现诸断面最大单宽流量连线所给出的水流动力轴线与河道合理整治后的流路均呈曲率半径逐渐变化的圆滑曲线形式,因此可以正弦派生曲线作为描述自然冲积河流治导线流路变化的方程框架。通过理论探讨、天然河流与室内模型资料分析,建立了治导线流路特征参数同河流水力因子之间的定量关系式。其中弯曲系数及弯道幅度计算式采用61组取自黄河、长江、淮河干支流以及模型试验典型河段的资料进行拟合;流路起始角计算式考虑了实际作用流量与整治流量差异的影响,引入造床流量下流速与河床启冲流速来反映河床的相对稳定性;弯道跨度计算式考虑了弯道环流强度的作用,从而所建立的治导线流路方程不仅适用于砂质河床、卵石河床及砂卵石河床的稳定流路变化,还能描述实际作用流量变化时河道主流线"小水上提、大水下挫"的变化规律。此外,利用黄河上下游游荡型典型河段及寻峪河卵石河段资料对本文方法进行了验证与应用。

Study on the regulation line flow path equation of the sandy river

The design of the regulation line is an important content of river regulation.In this paper,a governing equation of the regulation line is established to describe the variation of the flow path in the natural state quantitatively.Based on the data of the Yellow River Model Test,it is found that the flow dynamic axis given by the maximum single width flow line of the cross section is in the form of a smooth curve with the change of curvature radius,so the sine generated curve was used to describe the flow path of the treatment planning.Through theoretical analysis,field and model data analysis,the mathematical expressions of parameters of the flow path have been established associating with the hydraulic factors of the river.The bending coefficient and bend amplitude are based on 61groups of nature and experimental data; The starting angle considering the influence of the difference between the practical discharge and the regulation discharge;The bend span considering the changes of bend strength of circulation.The regulation line flow path equation is not only suite to describe the stable form of the sandy and gravel bed rivers,but also can describe the special phenomena caused by the change of discharge in the river evolution.In addition,the method is validated by the typical braided reaches of the upper and lower reaches of the Yellow River and is applied to plan regulation line of the Inner Mongolia section of the Yellow River.