坡度对黑土坡面产流产沙影响效应的实验室模拟研究

发布时间：2018-04-01 21:19

  本文选题：人工模拟降雨　切入点：黑土坡面　出处：《东北师范大学》2015年硕士论文

【摘要】：黑土是一种性状好、肥力高,非常适合植物生长的土壤[1]。但是近几十年来,由于自然因素和人们不合理的生产经营活动,黑土侵蚀退化严重,主要是以水蚀和风蚀为主,造成土壤肥力下降。而黑土区作为我国重要的商品粮基地,土壤肥力下降,对该地区的土地生产力、粮食生产和区域社会经济发展都造成严重的影响。因此,本文以中国东北地区的黑土坡耕地为研究对象,利用人工模拟降雨机进行室内模拟降雨试验,在雨强为60 mm/h的条件下,利用变坡土槽研究坡面坡度分别为1°、3°、5°、7°和9°时,产流时间、流速、平均入渗率、径流量、累计径流量等产流特征以及侵蚀泥沙量、累计泥沙量、径流含沙率等产沙特征,探讨黑土坡面产流产沙规律。研究得出以下结论:(1)在降雨强度一定的情况下,随着黑土坡面坡度增加,干、湿运行下,产流时间变化趋势不同;干运行下,坡度越大,产流时间越短;湿运行下,随着坡度的增大产流时间变化趋势不明显。(2)干、湿两种运行状态下,均随着黑土坡面坡度增加,坡面平均入渗率减小;同一个坡度下,干、湿两种运行状态下,坡面平均入渗率变化不大,且坡面平均入渗率随着降雨历时的增加而减少。(3)干、湿两种运行状态下,随着黑土坡面坡度的增加,径流流速加快,而在坡度一定的情况下,随着降雨时间的增加,干、湿运行状态下流速均呈增快趋势,但干运行状态下流速比湿运行下流速增加得快。发现干运行状态下3°、5°、7°时流速与降雨历时呈现幂函数关系,9°时流速与降雨历时呈线性关系。湿运行状态下1°、7°、9°下,流速与降雨历时呈指数关系,3°、5°下径流流速与降雨历时呈指函数关系。(4)在降雨历时一定的情况下,黑土坡面坡度越大,累计产流量越大。坡度一定时,随着降雨时间的增加,累计产流量在增加。干运行下,累计产流量与降雨历时呈现线性关系;湿运行下,累计产流量与降雨历时呈幂函数关系。(5)在降雨强度一定的情况下,干、湿两种运行状态下,坡度越大,侵蚀含沙量越大;干运行状态下,当坡度为3°、5°时,随着降雨历时的增加而增加,7°、9°时先增加,达到一定值后,基本保持恒定;湿运行状态下时,坡度为1°、3°、5°、7°时,侵蚀含沙量先增加,后保持恒定,9°时一直在增加。(6)在降雨强度一定的情况下,干、湿两种运行状态下,坡度越大,累计含沙量越大。而当坡度一定时,累计含沙量在两种状态下均随着降雨时间的增加而增加。(7)在降雨强度一定的情况下,干、湿两种运行状态下,坡度越大,侵蚀含沙率越大,且侵蚀含沙率与降雨时间符合二次项关系。(8)黑土坡面随着径流所携带的泥沙的颗粒以小粒径的粘粒和粉粒为主。并且土壤机械组成与坡面产沙关系明显。砂砾与侵蚀泥沙的关系最显著,粒径2 mm的石砾与侵蚀泥沙量、累计含沙量、含沙率均存在不同程度的正相关;坡面侵蚀泥沙量、累计泥沙量、径流含沙率增加的过程中,粒径在0.05~0.002 mm之间的粉粒和0.002 mm的粘粒所占的比重在减少。(9)人工模拟降雨下,黑土坡面产沙特征与产流特征关系显著,尤其是流速与累计含沙量。分析发现,流速与累计含沙量在5个坡度即1°、3°、5°、7°、9°下,均存在极强的相关性。流速越大时,累计含沙量越大。
[Abstract]:Black soil is a kind of good character, very suitable for soil fertility, [1]. plant growth but in recent decades, due to natural factors and people's unreasonable production activities, soil erosion serious degradation is mainly by wind and water erosion, resulting in the decrease of soil fertility. The black soil zone as an important commodity grain base in China and the decline in soil fertility, the area of land productivity and seriously affect grain production and regional social and economic development. Therefore, based on the slope farmland in the black soil in Northeast China Chinese as the research object, simulated rainfall experiments were carried out using artificial rainfall simulation machine, rainfall intensity of 60 mm/h under the condition of using the variable slope study on the soil trough slope gradient was 1 degrees, 3 degrees, 5 degrees, 7 degrees and 9 degrees, the time of runoff, flow rate, average infiltration rate, cumulative runoff, runoff and runoff characteristics and erosion sediment amount, the cumulative amount of sediment runoff. The rate of sediment and sediment, on black soil slope runoff and sediment production. The research draws the following conclusions: (1) in the case of certain rainfall intensity, slope gradient increased with soil, dry, wet operation, runoff time varied; dry run, the greater the slope runoff, the shorter the time; wet operation, with the increase of slope runoff change trend is not obvious. (2) dry, wet two kinds of operating conditions, with the increase of black soil slope gradient, slope average infiltration rate decreases; with a slope under dry, wet two kinds of operating conditions, the slope average infiltration rate changes is small, and the slope average infiltration rate decreased with the increase of rainfall duration. (3) dry, wet two kinds of operating conditions, with the increase of soil slope, runoff flow speed, and in the slope under certain conditions, with the increase of rainfall time, dry, wet condition showed a faster speed down but the trend. 骞茶繍琛岀姸鎬佷笅娴侀，

本文编号：1697342