弯曲河道成因及演化机制研究进展

Research progress on genesis and evolution mechanism of curved channel

在总结前人研究成果的基础上,对弯曲河道成因、水沙运动规律、河道演化机制3个方面的研究进展进行了概述。在弯曲河道成因研究中,概述了水沙变化、河床比降等对弯曲河道形成发育过程的影响;在弯曲河道水沙运动规律中,概述了水面横比降、横向环流和流速分布以及泥沙的输移问题等对水沙运动规律的影响;在弯曲河道演化机制中,概述了弯曲河道演化过程中出现的撇弯切滩现象。通过对以往研究的系统梳理发现,弯曲河道在形成过程中受水沙及边界条件的影响较大,目前对大尺度弯曲河道形成机制的影响因素的作用强度及水沙条件变化后弯曲河道非典型演变特性的研究成果较少,为进一步阐释弯曲河道的形成及演变机制等方面的问题,对弯曲河道的成因及演变机制研究进行了展望。

On the basis of previous studies,the research progress of curved channel was reviewed in three aspects:the genesis,the law of flow and sediment movement,and the mechanism of channel evolution. In the study of the genesis of curved channel,we summarized the influence of changes in flow,sediment and riverbed gradient on the formation and development of curved channel. In the study of the law of flow and sediment movement in curved channel,we laid out the transversal slope of water surface,lateral circulation,velocity distribution and the sediment transport. In the study of evolution mechanism of curved channel,we outlined the phenomenon of bend bypassing and shoal cutting during the evolution of curved channel. It is revealed that flow and sediment conditions and boundary conditions exert greater impacts on the formation of curved channels. However,there are few researches on the intensity of the factors affecting the formation mechanism of large-scale meandering channel and the atypical evolution characteristics of meandering channel after the change of flow and sediment conditions. In order to better explain the formation and evolution mechanism of curved channels,the prospect of the study on the genesis and evolution mechanism of curved channel is provided.