长江中游动床阻力计算及其近期变化特点研究  

Calculation of dynamic bed resistance in middle reachesof Changjiang River and its recent changes

作　　者：刘鑫 夏军强[1] 周美蓉[1] 邓珊珊[1] LIU Xin;XIA Junqiang;ZHOU Meirong;DENG Shanshan(State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 430072,China)

机构地区：[1]武汉大学水资源与水电工程国家重点实验室,湖北武汉430072

出　　处：《人民长江》2020年第11期34-40,152,共8页Yangtze River

基　　金：国家重点研发计划项目(2016YFC0402303);国家自然科学基金项目(51725902,51579186)。

摘　　要：冲积河流的动床阻力复杂多变。分析长江动床阻力变化特点对研究长江中游洪水演进及河床冲淤变形过程具有重要意义。利用长江中游枝城、螺山、监利、沙市及汉口等5个水文站的7019组实测流量资料和二次曲线拟合的水面纵比降数据,计算了各流量级下的糙率系数,定量分析了2001~2017年长江中游河段动床阻力的变化特点。结果表明:①三峡工程运行后,荆江河段典型断面各流量级下的动床阻力均明显增大,城汉河段典型断面各流量级下的糙率在2013年前变化较小,2013年后明显增大,枝城站和汉口站2017年各流量级下的糙率与2001年相比分别增大约60%和20%,阻力增大的主要原因是床沙粗化和水流强度减小;②各流量级下的阻力整体上均沿程减小,即枝城河段>沙市河段>监利河段、螺山河段>汉口河段;③荆江及城汉河段洪、中、枯流量对应的阻力均呈增大趋势,与2001~2002年相比,2017年各水文站洪水流量对应的糙率均增大了20%以上,除枝城站外,其余各水文站枯水流量对应糙率的变化幅度均小于10%。The dynamic bed resistance of alluvial rivers is complex and changeable.It is of great significance to study the flood evolution and river bed erosion and siltation in the middle reaches of the Changjiang River.Based on the measured flow data of 7019 groups from 5 hydrological stations of Zhicheng,Luoshan,Jianli,Shashi and Hankou and the longitudinal ratio drop data fitted by the quadratic curve,the roughness coefficients under each flow level were calculated.The results showed that:(1)after the operation of the Three Gorges Project,the dynamic bed resistance of the typical section of Jingjiang River reach increased obviously.The roughness of the typical section of Chenglingji-Hankou reach changed little before 2013,but increased obviously after 2013.The roughness at Zhicheng Station and Hankou Station increased by 60%and 20%respectively from 2001 to 2017 under each discharge level.The main reason for the resistance increase is the bed sand coarsening and flow strength decreasing.(2)The resistance of dynamic bed under each flow stage decreases along the course.(3)Compared with that in 2001-2010,the bed roughness in flood season discharge of each hydrological station increased by more than 20%in 2017,and the variation ranges of roughness in dry season discharge were less than 10%,except Zhicheng station.

关 键 词：动床阻力 水沙条件 床沙粗化 河床下切 长江中游 

分 类 号：TV143[水利工程—水力学及河流动力学]