广西红黏土的孔径分布特征及其对溶质运移的影响

发布时间：2018-04-16 17:04

本文选题：红黏土溶质运移 + 土-水特征曲线　；参考：《广西大学》2017年硕士论文

【摘要】：土壤中溶质运移规律的研究是当今环境岩土工程中的热点,但目前以红黏土为对象的相关研究开展较少。本文对桂林、柳州两地红黏土开展了全吸力土-水特征曲线试验、压汞试验、饱和渗透试验、一维土柱上渗试验和一维土柱蒸发试验研究,对广西红黏土溶质运移机理进行探讨,取得了以下成果:(1)使用压力板法、滤纸法和饱和盐溶液法测定了全吸力范围内的桂林、柳州两地红黏土的土-水特征曲线,结果表明,在同一含水率下桂林红黏土的基质吸力大于柳州红黏土,前者具有更强的持水能力,此现象主要与土壤的矿物成分、物性指标和孔隙结构有关。(2)结合压汞试验获得的孔径分布的数据,用毛管束模型预测桂林、柳州红黏土的渗透系数,发现理论值与试验值相差较大,主要是公式中渗透系数取决于孔隙的平均半径r50,通过对不同等效半径的渗透系数理论值比较,发现,当桂林、柳州红黏土的等效半径分别取r20和r30进行预测时,模型预测结果与实测值较吻合。(3)分别通过一维土柱上渗、蒸发试验研究了水分和溶质在桂林和柳州红黏土中的运移规律:上渗过程中,相同条件下桂林红黏土水分运动和溶质运移速度比柳州红黏土快,相应的入渗体积也比柳州红黏土多,且溶质运移是滞后于水分运动的;蒸发过程中,柳州红黏土脱湿速度比桂林红黏土快。
[Abstract]:The study of solute migration in soil is a hot topic in environmental geotechnical engineering nowadays, but there are few researches on red clay.In this paper, the full-suction soil-water characteristic curve test, mercury injection test, saturated permeation test, one-dimensional soil column infiltration test and one-dimensional soil column evaporation test were carried out on red clay in Guilin and Liuzhou.The mechanism of solute transport of red clay in Guangxi was discussed. The following results were obtained: 1) the soil-water characteristic curves of red clay in Guilin and Liuzhou were measured by pressure plate method, filter paper method and saturated salt solution method.At the same water content, the matrix suction of red clay in Guilin is greater than that in Liuzhou red clay, and the former has stronger water holding capacity, which is mainly related to the mineral composition of soil.The permeability coefficient of Guilin and Liuzhou red clay was predicted by capillary bundle model, and the difference between theoretical value and experimental value was found.The permeability coefficient mainly depends on the average radius of pore r50. By comparing the theoretical values of permeability coefficient of different equivalent radii, it is found that when the equivalent radii of Guilin and Liuzhou red clay are predicted by R20 and R30, respectively,The model prediction results are in good agreement with the measured values.) the evaporation experiments were conducted to study the migration of water and solute in the red clay of Guilin and Liuzhou by means of one-dimensional soil column infiltration.Under the same conditions, the water movement and solute migration of Guilin red clay are faster than that of Liuzhou red clay, and the corresponding infiltration volume is larger than that of Liuzhou red clay, and the solute migration lags behind the water movement.The dehumidification speed of Liuzhou red clay is faster than that of Guilin red clay.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU446

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