长江大通站床沙粒径变化及其对流域工程建设的响应分析  

The analysis on the grain size variation of bed materials at Datong Hydrological Station and its response to the project constructions along the Yangtze River

作　　者：何坚[1] 潘少明[1] 沙红良 陈望琴 

机构地区：[1]南京大学地理与海洋科学学院海岸与海岛开发教育部重点实验室,南京210093 [2]长江水利委员会水文下游局大通水文站,安徽池州247126

出　　处：《南京大学学报（自然科学版）》2010年第3期349-357,共9页Journal of Nanjing University（Natural Science）

基　　金：国家基础科学人才培养基金(J0630535);国家重点基础研究发展规划项目(2002CB412401)

摘　　要：根据长江大通水文站1977-2006年的水文监测资料,研究分析出大通站床沙物质组成主要为砂(94.48%)和粉砂(3.78%),粘土(0.77%)和砾石(0.95%)的含量较少.利用肯德尔秩相关检验和有序聚类分析等方法,着重对床沙中值粒径时间序列进行了统计分析,结果表明大通站床沙粒径在1977-2006年间呈现出整体变粗的趋势.并且,1980年和1994年为阶梯上升的跳跃点,跳跃幅度分别为11.4%和2.3%,2003年为阶梯下降的跳跃点,跳跃幅度为-4.3%.研究表明,1977-2003年通过大通站水文断面的水流含沙量下降是导致大通站河床粗化的主要原因,水流含沙量下降导致水流挟沙力增大,对河床侵蚀能力增加.而含沙量的下降主要是受葛洲坝等水利工程建设及长江上游"长治长防工程"影响所致.2003年以来,大通站床沙粒径有所减小,可能是受到三峡水库的影响.According to the hydrological data（1977-2006） from Datong Hydrological Station,it was found that the majority of the bed materials were sands（94.48%） and silt（3.78%）.Probability statistics and time series method such as Kendall method and sequential cluster method were used to analyze the grain size variation of bed materials at Datong Hydrological Station.The median diameter of bed materials has tended to increase gradually during 1977-2006.The grain size variation of bed materials is mainly in the form of jumping during 1977 to 2006,with 1980 and 1994 as its hopping sites of step on,and 2003 as its hopping site of step down.The jumping ranges are 11.4%,2.3% and-4.3% respectively.The change point analysis shows that the decline of suspended sediment concentration is the main reason for the coarsening of bed during 1977 to 2003,which is caused by water conservation projects（such as Gezhou Dam） as well as Soil and Water conservation focal harness project in the upper and middle reaches of Yangtze River and Protection Forest Project in the Yangtze River.Sediment carrying capacity of river flow increases with the decline of suspended sediment concentration,as well as the riverbed erosiveness,which can promote the exchange between suspended sediments and bed materials.Since 2003,the grain size of bed materials has tended to decrease,which is possibly influenced by the Three Gorges Reservoir.

关 键 词：床沙 粒径 粗化 含沙量 大通水文站 长江 

分 类 号：P339[天文地球—水文科学]