高原宽谷河段河床粒径与辫状形态特征研究  

Grain-size and geometry characteristics of braidedriversin a wide plateau valley

作　　者：韩凯 孙健[1] 李治 林斌良[1] 杨英 黄哲 HAN Kai;SUN Jian;LI Zhi;LIN Binliang;YANG Ying;HUANG Zhe(State Key Laboratory of Hydroscience and Engineering,Tsinghua University,Beijing 100084;State Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin 300072)

机构地区：[1]清华大学水沙科学与水利水电工程国家重点实验室,北京100084 [2]天津大学水利工程仿真与安全国家重点实验室,天津300072

出　　处：《水力发电学报》2021年第12期1-11,共11页Journal of Hydroelectric Engineering

基　　金：国家自然科学基金(5177090430)。

摘　　要：我国西南高原地区的河流在地质作用和河流动力过程等因素的塑造下,河谷形成宽窄相间的藕节状,其中宽谷河段呈现独特的辫状河流地貌,洲滩林立与汊道纵横的不规则形态特征十分显著。本文对其典型宽谷河段的泥沙粒径与河流地貌进行了现场观测,并根据卫星遥感影像资料解译了河道几何参数与洲滩几何参数等辫状地貌特征指标。泥沙柱状样和表层样的对比结果表明,目标河段内泥沙粒径沿程先增大后减小,表层河床组分以中、细砂为主,泥沙粒径垂向分布较均匀;遥感影像解译结果表明研究河段地貌特征在洪、枯季存在的显著差异,可通过基于汊道和洲滩参数的地貌参数进行描述。研究成果可为高原典型宽谷河段的河流形态和泥沙运动研究建立一定的基础。Riversin the southwestplateau of Chinaare affected by the geologicalandfluvial dynamic processes,and present alternating wide and narrow valleys shaped like lotus root joints.The wide valleys are featured with braided fluvial landscapes-irregular shapes of incessant sand bars interspersed in reticular channels.In this study,field observations have been carried out on sediment particle sizes and river landscapes in a typical reachof wide valleys,and the morphological features of its braided streams are interpreted through analysis of remote sensing data,including river geometric parameters and bar geometric parameters.Comparison between column and surface sediment samples shows that in this reach,the sediment diameter increases first and then decreases as the channel width changes,and its riverbed is covered with a surface layer featuring mostly medium and fine sands while the vertical profile of grain sizes is relatively uniform.Remote sensing images show that significant geomorphic differences exist between flood and dry seasons and this can be demonstrated using certain geomorphic parameters.The results lay a basis for further studies of the river morphology and sediment movement in plateau rivers.

关 键 词：辫状河流 高原河流 泥沙粒径 洲滩 汊道 

分 类 号：TV147.1[水利工程—水力学及河流动力学]