水保所知识产出(1956---)知识库

近 20 年来，我国大力推进交通、水利等基础设施项目建设，由此引起大量弃
土弃渣堆置形成数量巨大的工程堆积体，成为新增水土流失的重要组成部分。由于
建设项目施工工艺和运行方式多样，致使工程堆积体下垫面条件复杂，表面土壤结
构缺失、土质松散、植物根系缺乏，土壤抗冲性极差，极易产生水土流失。为揭示
工程堆积体坡面细沟形态指标动态变化规律以及细沟形态指标与侵蚀产沙量之间
的关系，本文运用标准试验小区进行径流冲刷试验，探讨其在 2 个坡长、3 个坡度、
4 个放水流量条件下堆积体坡面细沟侵蚀过程。得到以下主要研究结论：
（1）工程堆积体坡面细沟产流率随时间的持续呈现波动变化趋势，产沙率随
产流时间的延续呈―多峰多谷‖的变化趋势，坡面产沙率的变化过程主要受坡面细沟
沟壁坍塌的影响，随着坡长的增大，产沙率的波动频率变小，振幅变大。累积产流
量与冲刷时间呈线性关系，累积产沙量随冲刷时间呈二次函数关系，累积产沙量存
在最大值，随着坡长的增加，累积产沙量增大。
（2）工程堆积体坡面细沟径流含沙量随着产流时间的延续逐渐减小，坡度和
流量对含沙量的影响不显著，含沙量随坡长的增大而增大。流量、坡度和坡长均对
坡面产流产沙过程产生重要的影响，流量对坡面产流产沙的影响作用大于坡度和坡
长，流量对坡面产流产沙表现为正效应，坡度和坡长对坡面产流产沙表现为负效应。
（3）细沟沟宽和沟深均随冲刷历时的延续总体上呈增大趋势，沟宽和沟深在
前 9 min 内快速发育，后 36 min 内平稳发育，沟宽和沟深与放水时间之间存在良好
的对数函数关系，沟宽和沟深的发育过程主要受放水流量的影响，均随放水流量的
增大而增大，但随坡度和坡长的增大细沟发育却减弱。
（4）细沟宽深比在 0~27 min 内为变化剧烈阶段，细沟下切侵蚀速率减弱，在
27 min之后为保持稳定阶段。在10m坡长条件下，细沟宽深比最终稳定在0.81~1.48，
在 15m 坡长条件下，细沟宽深比最终稳定在 0.88~2.05，细沟的断面形态最终大致
呈现为―矩形‖形状。随着坡长的增大，细沟的宽深比增大；细沟断面积随冲刷历时
的延续呈现持续增大趋势，与放水时间之间存在良好的线性函数关系。
（5）在 10m 坡长条件下，坡面细沟发育速度较慢，坡长为 15m 的坡面，细沟的发育在 15min 内就达到稳定形态。雷诺数在侵蚀过程中逐渐由小变大，雷诺数的
变化受径流量的影响比较大。在产流0~15 min之间坡面流呈现急流状态，产流15~45
min 之间坡面流呈现缓流状态。在 10m 坡长条件下，阻力系数总体介于 0.01~0.69
之间，在 15m 坡长条件下，阻力系数总体介于 0.01~1.08 之间。流速、雷诺数、佛
汝德数和阻力系数与放水时间之间均存在良好的幂函数关系。水流剪切应力和径流
功率随产流时间的变化分为两个变化阶段，在产流开始 20min 之间，水流剪切应力
随产流时间增加，产流 20min 以后，水流剪切应力随产流时间的延续呈现波动变化
趋势。
（6）细沟的形态指标-沟宽和沟深与产流率、产沙率、累积产流量和累积产沙
量之间存在良好的函数关系，径流含沙量显著影响坡面产沙量，随着含沙量的增大，
坡面侵蚀产沙量也相应增大。
（7）工程堆积体坡面细沟侵蚀产流率、产沙率与水动力学参数流速、雷诺数
和阻力系数之间存在良好的函数关系，工程堆积坡面细沟侵蚀的土壤可蚀性参数为
1.6×10 -3 s/m，侵蚀性细沟开始剥离土壤颗粒产生侵蚀的临界水流剪切力为 0.38 Pa。
关键词： 黄土; 工程堆积体; 细沟形态; 发育过程; 侵蚀产沙

Over the past 20 years, infrastructure construction like water and transport projects
have been rapidly developed in China, which produced a large amount of engineering
accumulation formed by tons of deposits, creating more soil and water loss. Because of
different construction modes, the underlying surface condition of engineering
accumulation is complex. Broken topsoil structure, loose soil property, lack of plant roots
and low soil anti-scourability can easily cause soil and water loss. In order to analysis the
process of rill erosion and explore the changing characteristics of runoff and sediment
yield on slopes of engineering accumulation, the article used water-scouring experiment
to simulate runoff scouring process under different rainfall intensities in different
gradients and slope length, get the following main research conclusion:
（1）Rill runoff yield rate shows fluctuation trends over the time continuing in the
slope of engineering accumulation, sediment yield rate shows multimodal multi valley
trends over the time continuing, rill sediment yield rate is significantly influenced by rill
wall collapse, with the increase of the slope length, sediment yield rate fluctuation
frequency becoming smaller and magnitude becoming larger. The cumulative runoff and
scouring time have a linear relationship, the cumulative sediment and scouring time have
the quadratic function relationship, which means that cumulative sediment have a
maximum value, cumulative sediment yield increased with the slope length increasing.
（2） Rill sediment concentration shows the gradually reducing trends over the time
continuing in the slope of engineering accumulation, the slope and flow have faintness
influences to sediment concentration, sediment concentration increased with the slope
length, the slope, slope length and flow have significant influence to the slope runoff and
sediment process, the flow have the majority effect to the slope runoff and sediment  process compared with the slope and slope length, the flow have the positive affections
with slope runoff and sediment process, the slope and slope length have the negative
affections with slope runoff and sediment process.
（3）With the scouring time continuing the rill width and depth both shows
increasing trend, the rill width and depth both raided development with the first 9 min,
the rill width and depth both steady development with the next 36 min, rill width and
depth have a logarithmic function with discharge time, rill width and depth both have a
positive correlation with flow, the rill width and depth enlarged with the flow increasing,
but slope and slope length have a negative affection with the development of rill width
and depth.
（4）Wide depth ratio rapid decreased in the 0 ~ 27 min, rill erosion rate cut more
slowly, after the 27 min wide depth ratio keep it steady, the wide depth ratio final
stabilization with 0.81~1.48 under the 10 m slope length, the wide depth ratio final
stabilization with 0.88~2.05 under the 15 m slope length, the rill sectional area shows a
rectangular shape. With the slope length increases, the width depth ratio increased. Rill
cross-sectional area continuing increased with the discharge time, there is a good linear
correlation between cross-sectional area and discharge time.
（5）The rill development shows slower under the 10 m slope length condition, rill
development in a short time of 15min reaching a stable form under the 15 m slope length
condition, Reynolds number gradually increased with discharge time, runoff have the
significant effect with the Reynolds number, Froude number decreased with 0~15 min
that shows the flow was the rapids state, Froude number maintain steady at the time of
15~45 min that shows the flow was the flow state. Darcy-weisbach between 0.01~0.69
under the 10 m slope length, Darcy-weisbach between 0.01~1.08 under the 15 m slope
length, The velocity of flow, Reynolds number, Froude number and resistance coefficient
all have the good power function with the discharge time. Water runoff shear stress and
power in runoff time is divided into two stages changing, there were increased in the
runoff started 20 min and fluctuations changing with runoff after 20 min.
（6）Rill morphological indexes ditch rill width and depth have well functional
relationship with runoff yield rate, sediment yield rate, cumulative runoff and cumulative
sediment.Rill sediment concentration have the significant effect with sediment yield,  slope erosion increased with the sediment concentration bigger.
（7）Rill erosion runoff yield rate and sediment yield rate have well functional
relationship with velocity of flow, Reynolds number and resistance coefficient with
engineering accumulation slope, the rill erodibility of engineering accumulation was
calculated to be 1.6×10 -3 s/m ,the critical flow shear stress for rill erosion occurring was
0.38 Pa.
Key words： loess，engineering accumulation，rill morphology，the development process，
erosion and sediment yield