【摘要】：非飽和帶又稱包氣帶,是連接地表水、土壤水和地下水的紐帶,存在著氣體、液體等流體的流動(dòng)以及多種物質(zhì)與成分之間的遷移轉(zhuǎn)化過程,該帶內(nèi)的水分運(yùn)動(dòng)對(duì)整個(gè)水循環(huán)活動(dòng)起著至關(guān)重要的作用。土壤水分特征曲線是研究非飽和帶水分運(yùn)動(dòng)的基本參數(shù),反映了土壤水能量和數(shù)量的關(guān)系,在研究非飽和帶土壤水分流動(dòng)、溶質(zhì)運(yùn)移以及土壤污染質(zhì)遷移轉(zhuǎn)化過程中有著非常重要的作用。土壤水分特征曲線是一個(gè)高度非線性函數(shù),它們之間的關(guān)系復(fù)雜,難以從理論上推導(dǎo)出確切的關(guān)系式,因此對(duì)土水特征曲線進(jìn)行解析與預(yù)測(cè)意義重大。本文在“西北大型盆地典型流域水文地質(zhì)參數(shù)調(diào)查”項(xiàng)目的支持下,針對(duì)目前國(guó)內(nèi)外研究現(xiàn)狀、研究中所存在的問題,對(duì)土壤水分特征曲線的解析及預(yù)測(cè)進(jìn)行了較為深入的研究,研究的主要內(nèi)容有:1.利用Ku-pF非飽和帶土壤參數(shù)測(cè)定儀測(cè)定了六種標(biāo)準(zhǔn)砂樣的土水特征曲線,并對(duì)比分析了不同粒徑下土水特征曲線的變化規(guī)律。試驗(yàn)結(jié)果表明粒徑對(duì)土水特征曲線的影響是通過對(duì)土體孔隙狀況的影響來反映的,土壤粒徑越小,其孔隙結(jié)構(gòu)越密實(shí),中、小空隙增多且連通性變差,土壤具有較高的進(jìn)氣值和良好的持水性能。2.利用五種經(jīng)驗(yàn)?zāi)Ｐ蛯?duì)實(shí)測(cè)土水特征曲線進(jìn)行擬合,對(duì)不同粒徑土壤水分特征曲線擬合結(jié)果的差異性進(jìn)行研究,并結(jié)合擬合參數(shù)的物理背景,對(duì)不同的模型做出評(píng)價(jià)。結(jié)果表明Van Genuchten模型對(duì)六種土壤擬合結(jié)果的確定性系數(shù)都達(dá)到了0.95以上,同時(shí)擬合出來的各參數(shù)值也符合其實(shí)際的物理背景,是描述土壤水分特征曲線的一個(gè)最優(yōu)模型。3.以土壤基本物理性質(zhì)為基礎(chǔ),利用兩種物理-經(jīng)驗(yàn)方法(Arya-Paris模型及非相似性介質(zhì)模型)間接預(yù)測(cè)土壤水分特征曲線,綜合評(píng)價(jià)了兩種方法的預(yù)測(cè)精度,結(jié)果表明Arya-Paris模型要優(yōu)于非相似性介質(zhì)模型,且更適合用來預(yù)測(cè)粉砂、粉土這種中等質(zhì)地的土壤。當(dāng)利用Arya-Paris模型預(yù)測(cè)土水特征曲線時(shí),建議對(duì)Arya-Paris模型中的經(jīng)驗(yàn)參數(shù)?進(jìn)行討論。當(dāng)對(duì)?進(jìn)行非線性擬合時(shí),預(yù)測(cè)值與實(shí)測(cè)值相比具有最大的確定性系數(shù)以及最小的均方根誤差,預(yù)測(cè)結(jié)果最為精確;而當(dāng)?單純的取常數(shù)時(shí),預(yù)測(cè)結(jié)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.
【學(xué)位授予單位】：長(zhǎng)安大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：S152.7

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本文編號(hào)：2225507