ISWC OpenIR  > 水保所知识产出(1956-2013)
沙层厚度和粒径组成对覆沙黄土坡面产流产沙的影响*
谢林妤
2017
Source Publication土壤学报
Volume54Issue:1Pages:60-72
Abstract

片沙覆盖黄土区是水蚀风蚀交错带内土壤侵蚀最为强烈的区域,研究该区内土壤侵蚀
特征可对水蚀风蚀交错带水土流失的预报及防治提供理论依据。采用室内模拟降雨,研究黄土坡面不
同覆沙厚度(2 cm、5 cm和10 cm)和沙层粒径组成(100%<0.25 mm、75%<0.25 mm +25%>0.25
mm、50%<0.25 mm +50%>0.25 mm、未处理原沙和100%>0.25 mm)对坡面产流产沙的影响。结果
表明,覆沙黄土坡面较黄土坡面的初始产流时间明显延长,产流速率和产流量减小,产沙速率和产沙
量增大,降雨过程中产流产沙波动性增大,且这些变化随覆沙厚度增加而明显加强;沙层粒径组成在
不同覆沙厚度下对坡面产流产沙的影响不同,2 cm覆沙厚度坡面在降雨前期随粒径变粗产流产沙呈增
大趋势,降雨后期无明显变化;5 cm覆沙厚度坡面随沙层粒径变粗产流速率呈增加趋势,降雨前期上
覆粗粒径沙层坡面的侵蚀速率高于细粒径沙层坡面,降雨后期恰好相反;10 cm覆沙厚度的坡面产流产
沙随沙层粒径组成变化不明显。典型覆沙黄土坡面的产流过程为雨水垂直入渗―沙土界面潜流―沙层
边缘渗流―地表径流,产沙过程为沙层边缘渗流侵蚀―沙层坍塌重力侵蚀―地表径流输移,明显不同
于无覆沙黄土坡面的超渗产流方式及溅蚀―片蚀―细沟侵蚀的侵蚀发展过程。

Other Abstract

【Objective】The region of loess slopes covered with sporadic aeolian sand is the most
serious erosion-stricken area in the aeolian-water erosion interlaced zone of the Loess Plateau. This project
is oriented to study characteristics of the soil erosion in this region in an attempt to provide some principal
theory for prediction and control of soil erosion in the aeolian-water erosion interlaced zone. Observations in
this special region found that aeolian sand-covered loess slopes were different in runoff production pattern and
erosion process from ordinary loess slopes. So far,a little has been reported about studies on soil erosion on
this special type of slopes. 【Method】An indoor experiment with simulated rainfalls on soil erosion on
sand-covered loess slopes was carried out. The experiment was design ed to have only one rainfall intensity
(90 mm h-1),one slope gradient(15°),three levels of thickness for overlying aeolian sand(2 cm,
5 cm and 10 cm)and five patterns of particle size composition(100%<0.25 mm,75%<0.25 mm + 25%
>0.25 mm,50%<0.25 mm + 50%>0.25 mm,original aeolian sand and 100%>0.25 mm). 【Result】
Results show that overlying aeolian sand layers delayed the initiation of runoff and reduced the generation rate
and volume of runoff,but increased the yielding rate and volume of sediment on loess slopes. The initiation
of runoff on slopes covered with 2 cm,5 cm and 10 cm thick of aeolian sand was 6~10 times,12~20 times
and 16~26 times later than that on the ordinary loess slope,respectively. Thickness of the aeolian sand
layer is the main factor affecting delayed runoff and sediment yield. The thicker the overlying sand layer,
the later the initiation of runoff,the lower the runoff rate and runoff volume and the higher the yielding rate
and volume of sediment yield. During the rainfall process,runoff and sediment fluctuated sharply in rate
and volume and the fluctuation intensified with the aeolian sand layer increasing in thickness. The effect of
particle size composition of the sand layer on runoff and sediment yield varied with thickness of the sand layer.
On slopes covered with a sand layer 2 cm in thickness,runoff and sediment yield tended to increase with the
sand layer increasing in particle size during the initial period of rainfall,but no such a tendency was observedduring the late period of rainfall. On slopes covered with a sand layer 5 cm in thickness,runoff increased in
rate with the sand layer increasing particle size. The slopes covered with coarse sand was higher in erosion
rate than the slopes covered with find sand during the initial period of rainfall,and it went reversely in the
late period of rainfall. On slopes covered with a sand layer 10 cm in thickness,runoff and sediment yield did
not vary much with particle size composition of the sand layer. There might be a reasonable range of aeolian
sand thickness in which the influence of particle size composition of the sand layer on runoff and sediment
yield existed. In short,thickness,particle size composition and their interaction significantly(p<0.05)
influence the initiation of runoff,60 min runoff volume and 60-min sediment yield. 【Conclusion】 The
runoff production process on aeolian sand-covered loess slopes goes as vertical infiltration of rainwater-flow
at the interface between sand layer and loess layer-seepage at the toe of the sand layer-overland runoff,
while the erosion process goes as seepage erosion at the toe of the sand layer-retrogressive collapse caused by
gravity and flow-surface runoff transport,which are completely different from the pattern of runoff yield under
excessive infiltration and the erosion development process of splash erosion-sheet erosion-rill erosion on bare
loess slopes.

Keyword覆沙黄土坡面
Indexed By中文核心期刊要目总览
Language中文
Document Type期刊论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/8454
Collection水保所知识产出(1956-2013)
Affiliation西北农林科技大学水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室
Recommended Citation
GB/T 7714
谢林妤. 沙层厚度和粒径组成对覆沙黄土坡面产流产沙的影响*[J]. 土壤学报,2017,54(1):60-72.
APA 谢林妤.(2017).沙层厚度和粒径组成对覆沙黄土坡面产流产沙的影响*.土壤学报,54(1),60-72.
MLA 谢林妤."沙层厚度和粒径组成对覆沙黄土坡面产流产沙的影响*".土壤学报 54.1(2017):60-72.
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