清水冲刷下顺直河道交错边滩演变过程试验研究  

Experimental Study on Evolution of Alternate Bar in Straight Channelunder Clear Water Scouring

作　　者：王茜[1] 卢金友[1] 周银军[1] 柴朝晖[1] 黄莉[1] WANG Xi;LU Jin-you;ZHOU Yin-jun;CHAI Zhao-hui;HUANG Li(Key Laboratory of River Regulation and Flood Control in Middle and Lower Reaches of Yangtze River of Ministry of Water Resources,Changjiang River Scientific Research Institute,Wuhan 430010,China)

机构地区：[1]长江科学院水利部长江中下游河湖治理与防洪重点实验室,武汉430010

出　　处：《长江科学院院报》2024年第2期21-26,共6页Journal of Changjiang River Scientific Research Institute

基　　金：国家自然科学基金长江水科学联合基金项目(U2240206);中央级公益性科研院所基本科研业务费项目(CKSF2021530/HL)。

摘　　要：为进一步认识清水冲刷下顺直河道交错边滩的演变过程,基于长江中游典型边滩形态参数,采用概化水槽试验对不同流量条件下的交错边滩纵向、横向和平面冲淤变化进行了研究。结果表明:试验工况下,纵向上,沿程呈冲刷态势,流量越大,冲深越大(流量为215 L/s的深泓平均冲深约是流量为46.71 L/s的2.1倍),且大流量下深泓纵向比降变缓;横向上,边滩侧以冲刷为主,冲刷最大的位置在滩边附近,其它部位则呈冲刷—淤积—冲刷的变化规律(如流量为215 L/s时,2#断面边滩以外部分(0,2]h平均冲深约3.5 cm、(2,12]h平均淤高约0.5 cm、(12,21]h平均冲深约0.7 cm);平面上,边滩整体下移,变得细长,淤积主要发生在边滩下游1m范围内。此外,上游异岸边滩的存在初期会促使下游边滩淤积,而后加深下游边滩的冲刷,且对边滩坡脚影响最大。A generalized flume experiment was conducted based on typical morphological parameters of alternative bars in midstream Yangtze River to investigate the longitudinal,transverse,and horizontal changes in scouring and silting of the bars under varying conditions.The aim was to comprehensively understand the evolution of alternate bars in straight channel under clear water scouring.The findings indicate that the bed experiences extensive erosion over a long distance in the longitudinal direction,with a greater discharge resulting in increased scouring depth.To be specific,the average thalweg scouring depth at a flow rate of 215 L/s is approximately 2.1 times that at a flow rate of 46.71 L/s.Additionally,the longitudinal gradient of the thalweg attenuates under larger discharge.In the transverse direction,the alternative bars primarily undergo scouring,with maximum scouring typically occurring at the edge.Other sections demonstrate fluctuating patterns of scouring,silting,and then scouring(e.g.,at a discharge of 215 L/s,the average scouring depth outside section 2#ranges around 3.5 cm in(0,2]hours,followed by an average silting height of approximately 0.5 cm in(2,12]hours,and finally an average scouring depth of about 0.7 cm in(12,21]hours).Regarding the planar movement,the bar shifts downstream as a unified entity and becomes elongated,with deposition mainly concentrated within 1 m downstream of the bar.Furthermore,the presence of an upstream bar initially promotes sedimentation of the downstream bar,subsequently intensifying scouring of the downstream bar,particularly affecting the toe of the bar.

关 键 词：清水冲刷 交错边滩 冲淤变化 水槽试验 顺直河道 

分 类 号：TV85[水利工程—水利水电工程]