黄土丘陵区小流域淤地坝泥沙沉积特征  

Characteristics of sediment deposition in check dam in small watershed in Loess Hilly Area

作　　者：李勉[1] 杨二[1] 李平[2] 鲍宏喆[1] 李莉[1] 申震洲[1] 焦鹏[1] 

机构地区：[1]黄河水利科学研究院水利部黄土高原水土流失过程与控制重点实验室,郑州450003 [2]黄河水利委员会绥德水土保持科学试验站,绥德718000

出　　处：《农业工程学报》2017年第3期161-167,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金(41371284)

摘　　要：了解淤地坝泥沙沉积特征是坝地泥沙输移过程及规律研究的基础和前提。该文通过对黄土丘陵区小流域淤地坝不同位置泥沙沉积剖面中各沉积旋回层厚度及粒径组成变化的分析,研究了淤地坝次洪水沉积过程中泥沙的再分布特征。结果表明:坝地内次洪水泥沙沉积过程为非均匀分布,各沉积旋回层厚度在纵剖面和横剖面都存在一定差异,早期沉积层厚度的起伏变化要大于后期的起伏变化。坝地泥沙粒径组成以粉粒为主,黏粒、粉粒和沙粒的平均含量分别为4.66%、58.78%和36.56%。坝地泥沙沉积过程中,各旋回层中黏粒、粉粒和沙粒的平均含量变化较小,但在坝地不同位置,土壤粒径组成发生了一定程度的分选。从坝尾到坝前,土壤质地粗化度显著下降,土壤粒径组成呈逐步细化的趋势。As one of engineering measures for conserving soil and water, many check dams have been constructed on theLoess Plateau and played important roles in holding back eroded soil just like sediment ponds. Meanwhile, a lot of informationon the erosion and sediment yield is recorded and preserved in the check dams. Understanding the sedimentary characteristicsis an essential prerequisite for studying the sediment transport processes and laws for a watershed with check dams. A typicalcheck dam without spillway located in the top of a branch gully in the Wangmaogou watershed in the Loess Hilly Area wasselected for this study. In the check dam, 8 open test pits with a depth of 1.5-2.0 m were dug in the longitudinal section andcross section. The boundaries between sedimentation cycles were obvious, and the thickness of each sedimentary cycle andplough layer was measured. A total of 108 soil samples were collected from the 8 open test pits in the check dam. The ploughlayer was divided into upper （0-20 cm） and lower layers （below the depth of 20 cm）. The soil samples were analyzed with thelaser diffraction technique using a Mastersizer 2000 laser particle size analyzer, and the soil particle size fractions weredetermined. Based on the investigation on the sedimentary cycle thickness and particle size composition changes in differentdeposition profiles in the check dam in the study watershed, the redistribution characteristics of sediment deposition of eachflood in the dam were studied. The results showed that the sediment deposition process in the dam had non-uniformdistribution, and the differences of the sedimentary cycle thickness in both the longitudinal section and the cross section wereobvious, and the fluctuation of early sedimentary cycle thickness was larger than that in the late years. When the rainstorm andsediment yield were large, the sediment thickness was larger and the difference was also large. On the contrary, the sedimentthickness and the difference were relatively small. Thus, there was no relatio

关 键 词：土壤 泥沙 淤地坝 沉积旋回 土壤质地 黄土丘陵区 

分 类 号：S157.2[农业科学—土壤学]