非饱和带土壤水分特征曲线的测定与预测
发布时间：2018-09-06 06:17
【摘要】：非饱和带又称包气带,是连接地表水、土壤水和地下水的纽带,存在着气体、液体等流体的流动以及多种物质与成分之间的迁移转化过程,该带内的水分运动对整个水循环活动起着至关重要的作用。土壤水分特征曲线是研究非饱和带水分运动的基本参数,反映了土壤水能量和数量的关系,在研究非饱和带土壤水分流动、溶质运移以及土壤污染质迁移转化过程中有着非常重要的作用。土壤水分特征曲线是一个高度非线性函数,它们之间的关系复杂,难以从理论上推导出确切的关系式,因此对土水特征曲线进行解析与预测意义重大。本文在“西北大型盆地典型流域水文地质参数调查”项目的支持下,针对目前国内外研究现状、研究中所存在的问题,对土壤水分特征曲线的解析及预测进行了较为深入的研究,研究的主要内容有:1.利用Ku-pF非饱和带土壤参数测定仪测定了六种标准砂样的土水特征曲线,并对比分析了不同粒径下土水特征曲线的变化规律。试验结果表明粒径对土水特征曲线的影响是通过对土体孔隙状况的影响来反映的,土壤粒径越小,其孔隙结构越密实,中、小空隙增多且连通性变差,土壤具有较高的进气值和良好的持水性能。2.利用五种经验模型对实测土水特征曲线进行拟合,对不同粒径土壤水分特征曲线拟合结果的差异性进行研究,并结合拟合参数的物理背景,对不同的模型做出评价。结果表明Van Genuchten模型对六种土壤拟合结果的确定性系数都达到了0.95以上,同时拟合出来的各参数值也符合其实际的物理背景,是描述土壤水分特征曲线的一个最优模型。3.以土壤基本物理性质为基础,利用两种物理-经验方法(Arya-Paris模型及非相似性介质模型)间接预测土壤水分特征曲线,综合评价了两种方法的预测精度,结果表明Arya-Paris模型要优于非相似性介质模型,且更适合用来预测粉砂、粉土这种中等质地的土壤。当利用Arya-Paris模型预测土水特征曲线时,建议对Arya-Paris模型中的经验参数?进行讨论。当对?进行非线性拟合时,预测值与实测值相比具有最大的确定性系数以及最小的均方根误差,预测结果最为精确;而当?单纯的取常数时,预测结果最差。
[Abstract]:Unsaturated zone, also called aeration zone, is the connection between surface water, soil water and groundwater. There exists fluid flow, such as gas and liquid, as well as the process of migration and transformation between a variety of substances and components. The water movement in the zone plays an important role in the whole water cycle. The characteristic curve of soil moisture is the basic parameter to study the water movement in unsaturated zone, which reflects the relationship between the energy and quantity of soil water. Solute migration and soil pollution transport play an important role in the process. Soil water characteristic curve is a highly nonlinear function, the relationship between them is complex, it is difficult to deduce the exact relationship from the theory, so it is very important to analyze and predict the soil water characteristic curve. With the support of the project "Survey of hydrogeological parameters in typical basins in Northwest China", this paper aims at the current research situation at home and abroad and the existing problems in the research. The analysis and prediction of soil moisture characteristic curve were deeply studied, and the main content of the study was: 1. 1. The soil water characteristic curves of six kinds of standard sand samples were measured by Ku-pF unsaturated zone soil parameter analyzer, and the variation rules of soil water characteristic curves under different particle sizes were compared and analyzed. The results show that the influence of particle size on soil water characteristic curve is reflected by the influence of soil pore size. The smaller the soil particle size is, the more dense the pore structure is. The soil has high air intake value and good water holding capacity. Five kinds of empirical models were used to fit the measured soil water characteristic curves. The difference of fitting results of soil water characteristic curves with different particle sizes was studied. The physical background of fitting parameters was used to evaluate the different models. The results showed that the deterministic coefficients of the Van Genuchten model for the six soil fitting results were above 0.95, and the fitted parameters were in line with its actual physical background, which was the best model to describe the soil moisture characteristic curve. Based on the basic physical properties of soil, two kinds of physical-empirical methods (Arya-Paris model and dissimilar medium model) were used to predict soil water characteristic curves indirectly, and the prediction accuracy of the two methods was evaluated synthetically. The results show that the Arya-Paris model is superior to the dissimilar medium model and is more suitable for predicting silt and silt. When the characteristic curves of soil and water are predicted by Arya-Paris model, the empirical parameters in Arya-Paris model are suggested. Have a discussion. Right? When nonlinear fitting is carried out, the predicted value has the largest deterministic coefficient and the smallest root mean square error compared with the measured value, and the prediction result is the most accurate. The prediction results are the worst when the constants are taken simply.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S152.7
本文编号：2225507
[Abstract]:Unsaturated zone, also called aeration zone, is the connection between surface water, soil water and groundwater. There exists fluid flow, such as gas and liquid, as well as the process of migration and transformation between a variety of substances and components. The water movement in the zone plays an important role in the whole water cycle. The characteristic curve of soil moisture is the basic parameter to study the water movement in unsaturated zone, which reflects the relationship between the energy and quantity of soil water. Solute migration and soil pollution transport play an important role in the process. Soil water characteristic curve is a highly nonlinear function, the relationship between them is complex, it is difficult to deduce the exact relationship from the theory, so it is very important to analyze and predict the soil water characteristic curve. With the support of the project "Survey of hydrogeological parameters in typical basins in Northwest China", this paper aims at the current research situation at home and abroad and the existing problems in the research. The analysis and prediction of soil moisture characteristic curve were deeply studied, and the main content of the study was: 1. 1. The soil water characteristic curves of six kinds of standard sand samples were measured by Ku-pF unsaturated zone soil parameter analyzer, and the variation rules of soil water characteristic curves under different particle sizes were compared and analyzed. The results show that the influence of particle size on soil water characteristic curve is reflected by the influence of soil pore size. The smaller the soil particle size is, the more dense the pore structure is. The soil has high air intake value and good water holding capacity. Five kinds of empirical models were used to fit the measured soil water characteristic curves. The difference of fitting results of soil water characteristic curves with different particle sizes was studied. The physical background of fitting parameters was used to evaluate the different models. The results showed that the deterministic coefficients of the Van Genuchten model for the six soil fitting results were above 0.95, and the fitted parameters were in line with its actual physical background, which was the best model to describe the soil moisture characteristic curve. Based on the basic physical properties of soil, two kinds of physical-empirical methods (Arya-Paris model and dissimilar medium model) were used to predict soil water characteristic curves indirectly, and the prediction accuracy of the two methods was evaluated synthetically. The results show that the Arya-Paris model is superior to the dissimilar medium model and is more suitable for predicting silt and silt. When the characteristic curves of soil and water are predicted by Arya-Paris model, the empirical parameters in Arya-Paris model are suggested. Have a discussion. Right? When nonlinear fitting is carried out, the predicted value has the largest deterministic coefficient and the smallest root mean square error compared with the measured value, and the prediction result is the most accurate. The prediction results are the worst when the constants are taken simply.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S152.7
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