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黄土区工程堆积体水蚀特征及测算模型 坡长因子试验研究
邓利强
Subtype硕士
Thesis Advisor王文龙
2014-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Keyword生产建设项目 工程堆积体 产流产沙 坡长因子 水动力学参数
Abstract

随着我国基础设施建设项目投资力度的不断加大,各类生产建设项目增加迅猛,全
国到处是新开的建设工地,建设中大量的植被遭破坏,地表和地下土体被扰动、剥离、
运移和松散堆置,造成了严重的人为水土流失。施工过程形成的大量弃土弃渣体,亦即
工程堆积体,因无任何防护措施,成为水土流失最为严重的地方,同时也成为人为新增
水土流失最主要的泥沙策源地,造成了局部生态环境的进一步恶化。全国各类生产建设
项目的水土保持方案编制中,关于水土流失测算,仍采用类比法等,缺乏实验依据与模
型的理论支撑,精度不高。要建立我国生产建设项目水土流失测算模型,需要借用美国
通用流失方程 ULSE 的基本思想,对其可蚀性、坡度坡长、降雨侵蚀力诸因子进行修订。
在工程堆积体方面的此类研究尚属空白。因此,本文以黄土区生产建设工程堆积体坡长
因子为主要研究对象,采用室内人工模拟降雨的方法,对工程堆积体的产流、产沙和水
动力学特征研究,探讨其侵蚀机理和水土流失规律,确定工程堆积体水蚀测算模型坡长
因子 L 值的关系表达式和定值方法。为最终建立生产建设项目工程堆积体水土流失测算
模型提供科学依据,其结果可为水行政主管部门监督执法提供工具,具有重要的科学意
义和实际应用价值。主要得出以下结论:
(1)在陡坡 25º,不同坡长条件下,径流率随时间的变化绝大部分表现为先增大后
在一定范围内围绕某一均值呈现平稳的波动过程。土壤剥蚀率随时间的变化表现为(约
5 min 前)先急剧下降后呈现出不同程度的波动变化趋势,随着土体石砾含量的增大,
坡面出现细沟侵蚀的几率在减小。
(2)不同石砾含量条件下,径流率和土壤剥蚀率均随降雨量的增大而增大;当降
雨量一定时,径流率随石砾含量的变化并不明显;石砾含量增大时,土壤剥蚀率有减小
的趋势;可知石砾含量的增加有减小侵蚀的作用。径流率与降雨量和石砾含量呈线性函
数关系,土壤剥蚀率与降雨量呈指数函数关系。
(3)不同坡长条件下,径流率和土壤剥蚀率波动程度会有差别,随着坡长的增加,细沟数量明显增多,波动程度亦增大。径流率随坡长增加,会显著增大,但土壤剥蚀率
随坡长增加规律有所不同。坡长 λ≤5m 时,土壤剥蚀率随坡长增加呈极其缓慢的增加趋
势;坡长 λ≥6.5m 时,土壤剥蚀率随坡长增加的变化趋势亦趋于缓和;5≤λ≤6.5m 时,土
壤剥蚀率随坡长的增加会有一个急剧增加的过程。细沟侵蚀存在一个临界坡长,超过临
界坡长时,会有明显的细沟发育,可能位于 5~6.5m 之间,此结论对于生产实践有着重
要的指导意义。
(4)坡长一定时,各石砾含量条件下,径流剪切力、雷诺数、佛罗德数和水流功率
均随降雨量的增大呈明显递增关系,随石砾含量的增加规律有所不同。径流剪切力除在
坡长 5m 时随石砾含量增加递减外,其他坡长条件下均无明显变化规律。当坡长≤5m 时,
雷诺数随石砾含量增加呈减小的趋势,坡长≥6.5m 时,无明显变化规律。坡长≤6.5m 时,
雷诺数 Re≤500,坡面流属于层流。佛罗德数在坡长较短(≤6.5m),雨强较小时坡面流
为缓流,雨强较大时表现为急流,大坡长(λ=12m)时,均表现为急流。
(5)径流剪切力、雷诺数、佛罗德数和水流功率均随着坡长的增加而增大,并建
立了各水动力参数与坡长、石砾含量的经验方程式。各水动力参数与降雨量呈显著的线
性关系。对各坡长条件下的土壤剥蚀率及其影响因子作灰色关联分析,表明,水流功率
对土壤剥蚀率影响最大,雷诺数次之。建立了各个坡长条件下,土壤剥蚀率与水流功率
的线性关系式,相关性都比较高。
(6)在参阅 USLE/RUSLE 中对标准小区和坡长因子定义的基础上,结合工程堆积
体的特点,提出了我国关于各类工程堆积体水蚀测算模型标准小区和坡长因子的明确定
义。
(7)以土石混合体类型为基准,建立了不同石砾含量条件下,坡长因子 L 值与坡
长的幂函数方程式。结果表明,陡坡坡长因子 L 值与坡长近为 0.65 次方的关系,此试
验结果高于国内现有采用值,与美国 RUSLE 模型中陡坡地采用值相近。
(8)建立了土石混合体类型的地形坡长因子 L i 与纯土体的坡长因子 L 0 和石质含量

i
P 之间的简化关系式。运用得到的坡长因子简化关系式,建立了坡长因子 L 值的查算
表。
关键词:生产建设项目;工程堆积体;产流产沙;坡长因子;水动力学参数

Other Abstract

Various production and construction projects are increasingly implemented along with
increased investment in China's infrastructure construction projects.In the process of
construction, plenty of vegetation is destroyed as well as surface and underground soils are
disturbed,detached,removed and loosely packed, which has caused serious man-made water
and soil loss.Owing to be short of protective measures,massive waste soils and residues
forming in the process of construction namely engineering accumulations became the most
serious places subject to water and soil loss and the main sediment origins for the
newly-added soil and water loss by human,which severely deteriorates local eco-environment.
The calculation of water and soil loss still adopt analogy in our country’s program of water
and soil conservation,which lack of experimental basis and model support.It is essential to
refer to the basical ideas involved in the Universal Soil Loss Equation (USLE) and revise
such factors as soil erodibility, slope steepness, slope length and rainfall erosivity to construct
a water and soil loss calculation model suitable for production and construction projects in
China.At present, research on these fields still has many works to do in China.In this study,
by taking the slope length factor of engineering accumulation of production and construction
projects in the loess area as the research object, runoff yield, sediment yield and
hydrodynamics on indoor simulated engineering accumulation were focused through an
artificially simulated rainfall experiment. Specific objectives were to understand the
mechanisms of soil erosion and the processes of soil and water loss and find the relational
expression and the method to define fixed value for slope length factor (L) incorporated in the  soil and water loss calculation model. Our study may provide a scientific basis for the
calculation model and the supervision and law enforcement by governmental departments in
charge. The study is of important significance in science and practical values in application.
The main conclusions are as follow:
(1)In the condition of slope steepness 25º,runoff rate first increases with the time then
maintain fluctuate around a average value with the range of slope length from 3m to 12m.Soil
detachment rate decreases rapidly with the time,then fluctuate in different level of
tendency.The probability of rill ersion on slope is decrease with the enlargement of gravel
content.
(2)For the different gravel content,runoff rate and soil detachment rate increase with
increasing rainfall amount.On the same rainfall amount,runoff rate varies gravel content
unconspicuously.With the gravel content increase,soil detachment rate has a tendency of
decrease,which indicates the increase of rock can reduce soil erosion.The runoff rate has a
linear relation with rainfall amount and rock content.The relationship between soil
detachment rate and rainfall amount can be described using exponential function.
(3)The level of fluctuation range between runoff rate and soil detachment rate under the
condition of different slope length.The groove has a evident increase with the slope length
increase,meanwhile the fluctuation increase.The runoff rate has a significant increase with the
slope length increase,but this law for soil detachment rate is different.Slope length λ≤5m or
λ≥6.5m,increase of soil detachment rate is not significant with slope length;Slope length
5≤λ≤6.5m,the soil detachment has a rapid increase with the slope length increase.Rill erosion
has a critical slope length,rill erosion will emerge exceeding this value,the value maybe
between 5~6.5m.The conclusion will play an important function in practice.
(4)For the same slope length,the runoff shear stress、Reynolds number(Re)、Froud
number(Fr) and runoff power increase with increased rainfall amount,which has different law
with increased rock content.Runoff shear stress decrease with increased rock content for the
slope length of 5m,which has no significant law in other slope length.Slope length
≤5m,Reynolds number(Re) decrease with increased rock content;Slope length ≥6.5m,this law
is not evident.Slope length ≤6.5m,Reynolds number(Re)Re≤500,runoff of slope belong to
layer flow.Slope length ≤6.5m,Froud number(Fr) belong to slow flow in the condition of little
precipitation but display as rapid flow in the condition of strong rainfall.For the slope length
of 12m,the runoff of slope all belong to rapid flow.
(5)Runoff shear stress、Reynolds number(Re)、Froude number(Fr) and runoff power
increase with increased slope length,and build the experienced equation between parameter of   water motive power and slope length and rock content.The relationship between parameter of
water motive power and rainfall amount can be described as linear equation.By means of grey
related analyse between soil detachment rate and such factors under different slope
length,prove that runoff power has the most effection on soil detachment rate,while the
Reynolds(Re) ranks second.Buildidng the linear relationship between soil detachment rate
and runoff power,the relation is significant.
(6)The standard plot and slope length factor used in the water erosion calculation model
are defined in combination with the characteristics of the engineering accumulation under the
basis of refer to USLE/RUSLE.
(7)A power function between slope length factor(L) and slope length is established
under the condition of different gravel content in the basis of soil-gravel Mixture.Result
indicate that slope length factor(L) is 0.65 exponentional relation of slope length,the value is
higher than our country’s and similar with the value of RUSLE.
(8)A simple relationship between slope length factor( L i ) of Soil-gravel Mixture and
slope length factor( L 0 ) as well as gravel content(
i
P ) is established. A check spreadsheet of the L
values for the slope length of 3m to 20m is established using the simple relationship of
slope length factor.
Key words:production and contribution project, engineering accumulation, runoff and
sediment, slope length factor, hydrodynamic parameters

Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/9001
Collection水保所知识产出(1956---)
Recommended Citation
GB/T 7714
邓利强. 黄土区工程堆积体水蚀特征及测算模型 坡长因子试验研究[D]. 北京. 中国科学院研究生院,2014.
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