南方酸雨物理特征及入渗特性的模拟试验研究

发布时间：2018-10-26 08:29

【摘要】：近些年来由于含硫矿物的燃烧,空气中含硫氧化物逐渐增多,致使我国南方酸雨出现的频率逐年升高,而红壤在我国南方的覆盖面积较广,受酸雨破坏较为严重。酸雨不但会酸化土壤,而且会改变土壤的物理结构和化学特性,从而改变土壤的水文状况及水土流失特征。因此,研究酸雨对雨滴物理特征及土壤水分入渗的影响有助于深入理解南方红壤地区酸雨条件下的土壤水分循环机理,为酸雨地区的水土资源合理利用和生态环境建设提供理论依据。本研究以南方酸雨主要成分为特征,采用硫酸溶液调配模拟不同浓度酸雨试验方法,以红壤为研究对象,从酸雨雨滴特征、酸雨入渗的水力参数和长期酸化后土壤的物理特性及入渗特性等方面较为系统地探讨了酸雨对红壤入渗特性的影响。主要研究结果如下：(1)雨水的雨滴直径和体积随着雨水酸化程度的增强逐渐变大。随着雨水酸化程度的增加,单个雨滴具有的雨滴动能呈明显变大趋势。但考虑到降雨强度,酸化雨水的雨滴能量流随着酸化程度的增加呈明显降低趋势。(2)利用室内一维土柱水平入渗和渗透筒垂直入渗试验研究了酸性溶液对红壤水分入渗特征的影响,试验结果显示：红壤入渗速率、水分扩散度和饱和导水率的大小均为(pH=3) (pH=5)蒸馏水(pH=2)(pH=1)；利用RETC软件拟合扩散度与实测值吻合度较高,其剩余标准差均接近零；RETC软件拟合的土壤水分特征曲线表明：pH=1溶液使土壤保水能力增强,而pH=5、pH=3、pH=2溶液使土壤保水能力减弱。(3)不同酸性溶液多次积水入渗试验显示,蒸馏水和pH=5的硫酸溶液各次的入渗时间基本保持稳定,且pH=5的硫酸溶液入渗速度比蒸馏水快。而pH=3硫酸溶液前期积水入渗的入渗速度大于蒸馏水和pH=5的硫酸溶液,但随着积水入渗次数的增多,入渗速度呈显著下降趋势。pH=2的硫酸溶液入渗速度最慢且随着入渗次数的增加,土壤入渗速度急剧下降。(4)对酸化后土壤物理特性和入渗特性测定显示,蒸馏水处理组的土壤,其渗透筒上部容重变小,下部容重增大;pH=2、pH=3、pH=5的硫酸溶液处理组的土壤,渗透筒上部和下部的容重都明显增大；其对容重改变大小的关系为：pH=2pH=3pH=5。不同酸化程度的土壤入渗速率、水分扩散度的大小关系为：pH=5蒸馏水PH=3pH=2。
[Abstract]:In recent years, due to the combustion of sulfur-bearing minerals, the sulfur oxides in the air gradually increased, which caused the frequency of acid rain in southern China to increase year by year, while the red soil covers a wide area in the south of China and is seriously damaged by acid rain. Acid rain will not only acidify the soil, but also change the physical structure and chemical characteristics of the soil, thus changing the hydrological status and soil erosion characteristics of the soil. Therefore, the study of the effect of acid rain on the physical characteristics of raindrops and infiltration of soil water is helpful to understand the mechanism of soil water circulation in the red soil region of southern China. It provides theoretical basis for rational utilization of soil and water resources and construction of ecological environment in acid rain area. In this study, the main components of acid rain in southern China were used to simulate the acid rain of different concentrations by using sulfuric acid solution. The red soil was used as the research object, and the characteristics of acid rain raindrops were analyzed. The effects of acid rain on the infiltration characteristics of red soil were systematically discussed in terms of the hydraulic parameters of acid rain infiltration and the physical characteristics and infiltration characteristics of soil after long-term acidification. The main results are as follows: (1) the diameter and volume of Rain Water raindrops gradually increase with the increase of acidification degree of Rain Water. With the increase of acidification degree of Rain Water, the kinetic energy of single raindrop increases obviously. But given the intensity of the rainfall, The raindrop energy flow of acidified Rain Water decreased obviously with the increase of acidizing degree. (2) the effects of acid solution on the water infiltration characteristics of red soil were studied by using horizontal infiltration of one-dimensional soil column and vertical infiltration in permeable cylinder. The results showed that the infiltration rate, water diffusivity and saturated conductivity of red soil were (pH=3) (pH=5), distilled water (pH=2) (pH=1); The fitting diffusivity by RETC software is in good agreement with the measured values, and the residual standard deviations are close to zero. The characteristic curves of soil moisture fitted by RETC software showed that pH=1 solution enhanced soil water retention capacity, while pH=5,pH=3,pH=2 solution made soil water retention capacity weakened. (3) repeated water retention experiments of different acid solutions showed that the soil water retention capacity was enhanced by pH=1 solution, while the soil water retention capacity was decreased by pH=5,pH=3,pH=2 solution. The infiltration time of distilled water and pH=5 sulphuric acid solution is stable, and the infiltration rate of pH=5 sulphuric acid solution is faster than that of distilled water. However, the infiltration rate of pH=3 sulphuric acid solution was higher than that of distilled water and pH=5 sulfuric acid solution in the early stage, but with the increase of water infiltration times, The infiltration rate of pH=2 sulphuric acid solution was the slowest and the infiltration rate decreased sharply with the increase of infiltration times. (4) the physical and infiltration characteristics of soil after acidification were measured. In the soil of distilled water treatment group, the bulk density in the upper part of the osmotic tube becomes smaller and the bulk density in the lower part increases. The bulk density of the soil treated with sulfuric acid solution of pH=2,pH=3,pH=5 increased obviously in the upper and lower part of the osmotic tube. Its relation to the change of bulk density is as follows: pH=2pH=3pH=5. The relationship between soil infiltration rate and water diffusivity of different acidification levels is as follows: pH=5 distilled water PH=3pH=2.
【学位授予单位】：湖南农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X517;S152.7

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