【摘要】 硫酸盐渍土广泛存在于中国西北地区，在季节交替过程中，水分和盐分会产生相变从而引起盐渍土基质吸力发生改变。以硫酸钠黄土作为研究对象，设计了不同含盐量和压实度的冻融试验。结果表明：硫酸钠的含量和干密度的变化对土体温度与未冻水含量的曲线形态影响有限；在温度降低过程中，含盐量相同的情况下，基质吸力的初始值随干密度的提高而提高；在干密度相同时，基质吸力的初始值随含盐量的提高而提高；在土体发生冻结前，土样的基质吸力随温度降低而线性增加；土体会因硫酸钠的存在而产生相变，初次相变只明显存在于12℃左右时含盐量为4%土样当中，此时土样的基质吸力产生了约100 kPa的突变；二次相变出现在负温时的所有试验土样当中，且含盐量越高的土体在二次相变过程中基质吸力的增量反而越小。本文的研究可以为硫酸钠盐渍土水盐相变与水分迁移动力研究提供参考。更多还原

【Abstract】 Sulfate saline soils widely exist in Northwest China. During the alternation of seasons, water and salinity will produce phase changes, which will cause changes in the matric suction of saline soils. Therefore, taking sodium sulfate loess as the research object, freeze-thaw experiments with different salinity and compaction degrees were designed. The results show that the change of sodium sulfate content and dry density has limited influence on the curve shape of soil temperature and unfrozen water content; The frozen water content decreased significantly with the decrease of temperature, and there was a hysteresis effect of the unfrozen water content in the process of alternate freezing and thawing. In the process of temperature decrease, under the same salt content, the initial value of matric suction increases with the increase of dry density; when the dry density is the same, the initial value of matric suction increases with the increase of salt content; in soil Before freezing, the matric suction of soil samples increases linearly with decreasing temperature. The soil will undergo a phase transition due to the presence of sodium sulfate. The primary phase transition only obviously exists in the soil sample with a salt content of 4% at about 12 ℃. At this time, the matric suction of the soil sample has a sudden change of about 100 kPa; the secondary phase transition The transformation occurred in all the test soil samples at negative temperature, and the soil with higher salinity had a smaller increment of matric suction during the secondary phase transformation process. The research in this paper can provide an important reference for the study of water-salt phase transition and water migration dynamics of sodium sulfate saline soil.更多还原