摘要
对汉江上游现代大洪水高水位滞流沉积物(SWD)系统地采样测试分析,结果表明:汉江上游现代大洪水SWD沉积物性质是沙质粘土或粘土质沙、沙质粉沙或粉沙质沙。其分布特征大致分为两大类:安康段以上基本是以粉沙质沙或沙质粉沙为主,安康段以下基本是沙质粘土或粘土质沙。粒度成分和粒度参数都反映现代洪水SWD经过充分的分选,但是受多种因素影响,其粒径组成具有明显的空间变化。水库或大坝对大洪水SWD的粒度自然分布频率单峰曲线尖窄的形状没有明显的影响,而更多与其沉积的微地貌环境和水动力条件有关。
Modem large flood events were marked clearly by grayish slackwater deposits of silty fine sand on the channel side. The most recent large floods in the upper Hanjiang River occurred on 19 July, 2010 with a peak discharge 21 400 m^3/s and 19 September, 2011 with a peak discharge 21 000 m^3/s as measured in the Bai- he gauge station in the upper Hanjiang River basin. Modem flood slackwater deposits （SWD） were systemati- cally investigated and sampled from upstream to downstream along the upper Hanjiang River in 2010-2012. These results showed that modem flood SWD is sandy clay, clay sand, sandy silt and silty sand in the upper Hanjiang River. There are two parts for the distribution of modem flood SWD. Sediment properties of modem flood SWD in the upstream of Ankang section are sandy silt and silty sand, but they are sandy clay and clayey sand in the downstream of Ankang section. The average clay （〈2 μm） content （5.9%） in the upper stream of Ankang section （LSC site） is higher than that in the down stream （clay content 2.1%）. The average fine silt （2-16 μm） content （24.7%） in the upper stream of Ankang section （LSC site） is higher than that （17.0%） in the down stream. The average coarse silt （16-63 μm） content of modem flood SWD is 36.4% in the upper Hanji- ang River. Clay and fine silt present high values in the upstream of LSC site and low values in the down stream of LSC site. On the contrary, sand （〉63 μm） content shows that the low values （33.3%） in the upper stream of LSC site, whereas high values （44.2%） present in the down stream of LSC site. Mean size and medium size of modem flood SWD in the upstream of Ankang section are finer than that in the downstream. Mean size is larg- er than medium size of modem flood SWD along the upper Hanjiang River. Both sorting and skewness gradu- ally decrease, but kurtosis gradually increases along the upper Hanjiang River. These results reflect that mod- em flood SWD are suspend deposits during highly energetic fl
出处
《地理科学》
CSCD
北大核心
2014年第11期1369-1376,共8页
Scientia Geographica Sinica
基金
国家自然科学基金重点项目(41030637
41271108
41371029)
陕西师范大学研究生培养创新基金项目(2013CXS012)资助
关键词
现代大洪水
滞流沉积物
粒度
空间分布
汉江上游
modem flood
slackwater deposits
grain size
spatial variation
the upper Hanjiang River
