Different salt types have different effects on the liquid water content of saline soil, resulting in differences in the physico-mechanical properties and water/salt migration process of saline soil. In order to investigate the phase transition process and the change of the liquid water content in composite saline soil, saline soils with the same total salt content and different ratios of sodium chloride and sodium sulfate were taken as the objects. The results indicated that two phase transitions occur in the saline soil with single salt type, while three phase transitions can be found in the composite saline soil with two salt types. Mirabilite crystallization contributes to the 1st phase transition, mirabilite and ice precipitate together in the 2nd phase transition process, and mirabilite, ice, and hydrohalite precipitate simultaneously in the 3rd phase transition process. The liquid water is reduced in the phase transition process during cooling, and the pore characteristic has been changed significantly. The change of the liquid water content reflects the processes of salt crystallization and ice formation in saline soil, then the amounts of ice and hydrated salt were calculated at different temperatures, and the mechanism of inhibiting the deformation of sulfate saline soil was examined by adding sodium chloride. The results have reference value for those seeking understanding of the deformation in natural composite saline soil, and these findings can provide theoretical basis for the phase transition mechanism of saline soil in cold regions.

中文翻译：

---

含氯离子和硫酸根离子复合盐渍土液态水含量的调查

不同盐类对盐渍土液态水含量的影响不同，导致盐渍土的物理力学性质和水/盐运移过程存在差异。为了研究复合盐渍土中的相变过程和液态水含量的变化，以总盐含量相同、氯化钠和硫酸钠比例不同的盐渍土为对象。结果表明，单一盐类盐土发生两次相变，而两种盐类复合盐土则发生三次相变。芒硝结晶有助于第一相变，在第二相变过程中芒硝和冰一起沉淀，在第三相变过程中芒硝、冰和水卤石同时沉淀。冷却过程中相变过程中液态水减少，孔隙特性发生显着变化。液态水含量的变化反映了盐渍土中盐结晶和冰形成的过程，进而计算了不同温度下的冰和水合盐的量，并探讨了添加钠抑制硫酸盐盐渍土变形的机理。氯化物。研究结果对于了解天然复合盐渍土的变形具有参考价值，可为寒区盐渍土的相变机制提供理论依据。