【作者】 王媛；

【导师】 李怀恩； 福原辉幸；

【作者基本信息】 西安理工大学 ， 环境工程， 2010， 硕士

【摘要】 在参阅国内外文献资料的基础上发现,已有不少研究者参与到揭示土壤盐渍化规律的研究中,并通过机理研究及模拟研究的手段不断深入展开探讨,并在土壤内水盐运动规律方面取得了不少成果；而在土壤表层水盐变化规律这方面,仍存在研究空间。本论文以滨海地区普遍存在的潮土土质为研究对象,在总结分析了国内外研究的基础上,通过大量的室内模拟实验,提出并利用“吸水纸法”、“直接测定法”、“土样测定法”等测量方法,对饱和潮土表面结晶化机理进行了深入的试验研究和理论探讨。通过模拟土柱实验,本论文从以下方面研究了伴随饱和潮土表面结晶化的水盐变化规律,具体内容及获得成果如下：1.首次从微观及宏观两方面,利用显微镜拍摄方法,对饱和潮土表面结晶盐的生长情况做了细致而全面的观察,并总结出两阶段变化过程：“水平生长”及“垂直生长”；“水平生长”阶段中,结晶盐出现并覆盖于整个土壤表面之上；随后进入“垂直生长”阶段,结晶盐随时间不断积累并在垂直于表面的方向呈“树枝”状竖直生长。2.从不同角度测量分析了伴随潮土表面结晶化过程,一系列变化因子的变化规律。利用“吸水纸法”测定了土壤表面盐浓度随时间的变化,认为表面盐分是在盐浓度达到饱和时,析出并不断积累的；利用“直接测定法”测定了土壤表面结晶盐在不同时刻的质量,随着时间的延长,质量不断增加,这以测量结果与试验现象吻合；并运用“土样测定法”准确测定了土壤盐浓度在上层0.01米土层间的详细垂直分布情况,并得出接近表面的土壤盐浓度均达到饱和盐浓度。3.基于Terasaki(2009)的研究成果,通过大量试验,总结提出了“吸水纸法”,在测量土壤表面盐浓度过程中,显示出其准确性和有效性,并得到许多研究者的一致认同。4.总结实验结果与现象,阐述了潮土表面结晶化与蒸发的关系,它们是相互联系、相互影响及相互制约的。土壤蒸发可以促进土壤表面结晶化的进行；相反,表面结晶盐的析出也会影响蒸发过程,通过降低土壤表面蒸汽压抑制蒸发速率。更多还原

【Abstract】 On the basis of referring to a lot of liytrature search of both domestic and abroad, it is found that there are many researchers have studied the mechanism of crystallization, and through the theoretical analysis and experiment research, they have made quite a number of achievements in the field of the principle of water and salt movement in the soil. However, there exists an amount of space on the study of soil surface variation. Based on the past researches, a series of experiments were conducted with Chao soil which distributs widely in Jiangsu Province Coastal region, analyzed and summarized the mechanism of crystallization on saturated Chao soil surface deeply by using these measuring methods, "water absorption paper method", "direct method" and "sampling method".Through the simulation column experiments, the main contents and findings of this dissertation are listed as follows.1. From the view of microcosmic and macroscopic, using the visualization method by microscope, the whole process of surface crystallization was observed, and divided into two phases, named horizontal growth and vertical growth. In the first phase, crystallized salt would occur and cover the entire soil surface; nevertheless the crystallized salt in the second one will accumulate and grow vertically in the form of branching.2. Considering all of the varies factors, the rule of crystallization on saturated Chao soil surface was analyzed out. The surface salt concentration was measured by the water absorption paper method, and the results showed:while the condition that the surface salt concentration reached to saturate was satisfied, crystallized salt would appear and accumulate on the soil surface. Using the direct method, the crystallized salt mass at different time was obtained, with the longer elapsed time; we got the higher value, which is in line with the experimental phenomenon. In addition, the vertical profile of salt concentration in the top 0.01m-soil layer was gained in details through the sampling method, comparing three sets of results, it is indicated that the salt concentration near the surface attained saturated.3. Based upon the research of Terasaki (2009), through a great deal of experiments, it is proposed a new technique to measure the surface salt concentration-water absorption paper method, and the measurement value showed a good agreement with the phenomenon, which confirmed the measurement accuracy, was satisfactory. This method has already been adopted by others.4. Comparing all of the results and phenomenon, it was included that, there existed a close connection between evaporation and surface crystallization; both of them were interrelate, interdependent and mutual-constraining. Evaporation can accelerate the accumulation of salts; conversely, through reducing the surface vapor pressure, accumulated salts on the soil surface also can affect the evaporation rate.更多还原