宁夏黄河干流床沙组成与河势变化的相关性研究

Influences of river bed composition on the river regime of the Ningxia Yellow River

根据宁夏黄河干流床沙取样资料分析,卫宁段及青铜峡至仁存渡分汊型河段为卵砾石河床,粒径d〉20.0 mm的卵石或碎石占全沙的百分数为80.9%~27.9%,呈沿程递减的趋势;仁存渡至石嘴山上段为过渡型河段,下段为游荡型河段,由粒径d〈1.0 mm的砂壤土及黏土组成,其中粒径为0.005 mm〈d〈1.0 mm范围的泥沙占全沙的百分数为72.0%~92.6%,呈沿程增加的趋势。研究了床沙组成与河势变化的相关性,提出河势变化除与来水来沙条件、河道比降、河道工程、天然节点等因素有关外,还与床沙组成密切相关。

Based on analysis on bed material sampling data in the Ningxia Yellow River,the braid river reaches in Wei-Ning and Qingtongxia-Rencundu are classified as gravel bed,with the particle size greater than20. 0 mm,and account for 80. 9% ~ 27. 9% of the total sand. The particle sizes are decay along the flow way.The upper and lower sub-reaches are transitional and meandering respectively,which is consist of sand and clay with particle size less than 1. 0 mm. Among them,sandy loam and clay with particle size between 0. 005 mm and 1. 0 mm account for the percentage 72. 0% ~ 92. 6% of the total sand with an increasing trend along the way. Based on the study of the effect of bed material composition on river regime variation,the conclusion shows that the river regime change is related synthetically to flow and sediment conditions,river slopes,river engineering,natural node and bed material composition.