中文摘要：

为了探索硫酸钠盐渍土的盐胀与冻胀机理，对硫酸钠溶液分别在环境温度-20℃和变环境温度-5℃～-10℃下进行降温试验；并对硫酸钠盐渍土在环境温度-20℃下进行降温试验，通过试验研究了硫酸钠溶液和硫酸钠盐渍土中芒硝的析出规律及各自的冻结温度。试验表明：在相同外界环境温度下，浓度大的溶液，芒硝更容易析出；具备一定浓度的溶液，在环境温度变化缓慢条件下更容易析出但溶液的冻结温度的趋势一致：相同浓度硫酸钠盐渍土的冻结温度均低于硫酸钠溶液的冻结温度，随着含盐量增加，其冻结温度降低；在相同外界环境温度下，盐晶在土体中更容易析出。

英文摘要：

In order to study the mechanism of salt heave and frost heave of sodium sulphate saline soil, the cooling experiments are designed for the sodium sulfate solution at -20℃ environment temperature and in changing temperature ranging from -5 ℃to -10℃ and for the sodium sulphate saline soil at -20℃ temperature. It is tried to find the laws of precipitation of mirabilite in the sodium sulfate solution and the sodium sulphate saline soil and their freezing points. The experiments show that at the same environment temperature, a higher concentration of solution leads to an easier precipitation of mirabilite. In the same concentration of solution, a relatively slow environment temperature variation changes precipitation of mirabilite more easily, and the rules of freezing points of the solutions are the same. Compared with that of the sodium sulfate solution, the freezing point of the sodium sulphate saline soil is lower, and at the same environment temperature, salt crystals are more likely to precipitate in the soil.