本文選題：鹽漬土　切入點(diǎn)：水分遷移　出處：《長(zhǎng)春工程學(xué)院》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：吉林省西部地區(qū)地處我國(guó)松嫩平原西南部,是我國(guó)土地鹽堿化較為嚴(yán)重的地區(qū)之一,屬于東北典型的季節(jié)性凍土區(qū)。季節(jié)性凍土是一種由土顆粒、液態(tài)水、冰、氣態(tài)水組成的四相地質(zhì)體。土壤發(fā)生凍結(jié)時(shí),土壤中的水分和鹽分均發(fā)生運(yùn)移,會(huì)在農(nóng)牧業(yè)、環(huán)境、水資源、基礎(chǔ)工程等方面引發(fā)不同程度的病害,鹽脹、凍脹及翻漿等會(huì)導(dǎo)致路基開(kāi)裂、隆起、膨脹,從而降低了路基的穩(wěn)定性和強(qiáng)度。土壤中水鹽的運(yùn)移是導(dǎo)致該地區(qū)鹽漬化加劇的重要原因,水鹽運(yùn)移的研究越來(lái)越受到人們的關(guān)注,該研究不僅有助于促進(jìn)非飽和土體水分遷移理論研究的進(jìn)展,而且為冬季出現(xiàn)的不同程度的凍脹破壞現(xiàn)象以及道路病害治理提供理論依據(jù)和技術(shù)支持,對(duì)治理土地鹽堿化、防止農(nóng)業(yè)生態(tài)系統(tǒng)退化等具有重要理論價(jià)值。本文以吉林省農(nóng)安縣鹽漬土為試驗(yàn)研究對(duì)象,對(duì)研究區(qū)土樣的物質(zhì)組成和基本理化性質(zhì)進(jìn)行試驗(yàn)分析,然后進(jìn)行室內(nèi)直接法和溫度梯度凍結(jié)法水分遷移試驗(yàn)。結(jié)合水、熱、鹽運(yùn)移之間的相互聯(lián)系,參考以往研究取得的理論成果并結(jié)合能量守恒方程、質(zhì)量守恒方程等建立凍結(jié)條件下鹽漬土水、熱、鹽運(yùn)移耦合數(shù)學(xué)模型。采用有限元法對(duì)模型進(jìn)行求解,將求解結(jié)果與室內(nèi)試驗(yàn)結(jié)果相對(duì)比,以此驗(yàn)證模型的有效性。主要研究成果有:1.土壤中的粒度成分以粉粒和粘粒為主,礦物成分有大量原生礦物和少量次生礦物,各深度土體的天然密度基本維持在1.91g/cm3左右,易溶鹽總量隨深度的增加而減小,其中表層易溶鹽總量含量最高為1.69%,土壤中的鹽分組成以Na2CO3和NaHCO3為主,土體為弱碳酸鹽漬土。2.直接法毛細(xì)水上升試驗(yàn)結(jié)果表明在室溫狀態(tài)下毛細(xì)水上升的高度是很小的,并且土體壓實(shí)度越大毛細(xì)水上升高度越低。溫度梯度凍結(jié)法水分遷移試驗(yàn)結(jié)果表明在凍結(jié)狀態(tài)下土體中水分和鹽分均發(fā)生了運(yùn)移,溫度梯度致使土體中結(jié)合水發(fā)生運(yùn)移而并非毛細(xì)水,鹽分的運(yùn)移以水分為載體,受溫度勢(shì)、溶質(zhì)勢(shì)等多種因素影響,并且土體壓實(shí)度越大水分和鹽分的運(yùn)移量越少。3.凍結(jié)條件下,鹽漬土系統(tǒng)中任意一點(diǎn)的水分、熱量、溶質(zhì)的運(yùn)移都是相互聯(lián)系、相互影響、相互作用的,形成了一個(gè)復(fù)雜的水、熱、鹽運(yùn)移耦合系統(tǒng)。所建模型求解結(jié)果與試驗(yàn)結(jié)果吻合度較好,說(shuō)明模型能較好的模擬實(shí)際情況。4.依托工程實(shí)例,根據(jù)處理原理,結(jié)合鹽漬土水鹽遷移規(guī)律及地下水文條件,就路基提出了相關(guān)處理措施,預(yù)防鹽漬土地區(qū)公路路基病害的發(fā)生。
[Abstract]:The western region of Jilin Province is located in the southwest of Songnen Plain in China. It is one of the most serious salinization areas in China and belongs to the typical seasonal frozen soil region in Northeast China. Seasonal frozen soil is a kind of soil particle, liquid water and ice. A four-phase geological body composed of gaseous water. When the soil freezes, both the water and salt in the soil migrate, which will lead to different degrees of disease and salt swelling in agriculture, animal husbandry, environment, water resources, basic engineering, etc. Frost heaving and mudding will lead to the cracking, uplift and expansion of the roadbed, thus reducing the stability and strength of the roadbed. The migration of water and salt in the soil is an important reason for the increase of salinization in this area. More and more attention has been paid to the study of water and salt migration, which is not only helpful to promote the research progress of unsaturated soil water migration theory. It also provides theoretical basis and technical support for different degrees of frost heaving and road disease treatment in winter, and it can control the salinization of land. It is of great theoretical value to prevent the degradation of agricultural ecosystem. In this paper, the material composition and basic physical and chemical properties of soil samples in Nong'an County of Jilin Province are studied. Then the indoor direct method and the temperature gradient freezing method were used to test the water migration. Considering the interrelation of water, heat and salt migration, and referring to the theoretical results obtained from previous studies and the energy conservation equation, The coupled mathematical model of water, heat and salt migration in saline soil under freezing condition was established by mass conservation equation. The finite element method was used to solve the model, and the results were compared with the results of laboratory tests. The main results of this study are as follows: 1. The particle size components in the soil are mainly silt and clay, and the mineral composition has a large number of primary minerals and a small amount of secondary minerals, and the natural density of each depth of soil is maintained at about 1.91 g / cm ~ 3, and the natural density of the soil is about 1.91 g / cm ~ 3. The total content of soluble salt decreased with the increase of depth. The content of soluble salt in surface layer was the highest, and the salt composition in soil was mainly Na2CO3 and NaHCO3. The results of direct capillary water rising test show that the height of capillary water rise is very small at room temperature. The higher the compaction degree of soil is, the lower the rising height of capillary water is. The results of water migration test by temperature gradient freezing method show that both moisture and salt in soil are transported under freezing condition. The temperature gradient results in the migration of combined water instead of capillary water in soil, and the migration of salt is divided into water as carrier, which is affected by temperature potential, solute potential and other factors, such as temperature potential, solute potential and so on. And the larger the compactness of soil is, the less the amount of water and salt migration is. 3. Under freezing conditions, the movement of water, heat, solute at any point in the saline soil system is interrelated, interacted, interacted, and formed a complex water. Coupled system of thermal and salt transport. The results of the model are in good agreement with the experimental results, which shows that the model can simulate the actual situation well. 4. Based on engineering examples, according to the principle of treatment, combined with the law of water and salt migration in saline soil and the conditions of groundwater text, In order to prevent highway roadbed disease from occurring in saline soil area, the related treatment measures are put forward in this paper.
【學(xué)位授予單位】：長(zhǎng)春工程學(xué)院
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：U416.16

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 高玉佳;王清;陳慧娥;宋晶;;溫度對(duì)季節(jié)性凍土水分遷移的影響研究[J];工程地質(zhì)學(xué)報(bào);2010年05期

2 張少民;屈立軍;褚新穎;;標(biāo)準(zhǔn)受火條件下考慮水分遷移混凝土板溫度場(chǎng)數(shù)值計(jì)算[J];火災(zāi)科學(xué);2006年04期

3 徐e呑，

本文編號(hào)：1566294