中文摘要：

针对硫酸盐渍土盐胀过程中较为欠缺的四场耦合理论,在已有的冻土三场耦合模型的基础上,建立了盐渍土水-盐-热-力四场耦合动力学模型。首先,基于水动力学模型和质量守恒定律,在水分场方程和盐分场方程中分别引入等效含水量和等效含盐量的概念,以此为耦合因子简化了水-盐-热耦合模型,不仅考虑了溶质扩散及水动力弥散的作用,还考虑了结晶盐-盐溶液相变（化学反应）对盐分迁移,以及结晶盐相变潜热对温度场的影响。其次,根据能量守恒定律,增加结晶盐的相变潜热,使温度场方程更符合工程实际情况。同时,在建立应力场方程时,盐胀部分由溶质的摩尔质量差进行计算,冻胀部分由原土中的部分水加上迁移来的水减去硫酸钠结晶所需要的水进行计算,从而推导出了应力与水分迁移、盐分迁移以及温度的关系,完善了盐渍土四场耦合理论。最后运用该理论模型,计算分析了新疆某公路盐渍土路基的盐冻胀变形过程。结果表明：计算所得地温规律、盐分迁移规律和盐冻胀规律与实测结果基本一致,计算与实测结果均表明,从秋末至来年春季,硫酸盐渍土路基经历了降温到升温的温度剧烈变化阶段,此阶段路基的变形过程可分为平稳区、缓慢盐冻胀区、剧烈盐冻胀区、盐冻胀变形滞后区、缓慢沉降区、剧烈沉降区6个部分。

英文摘要：

For the lack of four-field coupling theory of sulfate salty soil during salt heaving process,a coupling dynamic model of moisture-salt-heat-stress field was established on the basis of three-field coupling model of frozen soil.First,based on hydrodynamic model and the law of conservation of mass,the two concepts,equivalent moisture content and equivalent salt content were introduced into the equations of moisture field and salt field respectively as the coupling factors,so moisture-salt-heat coupling model was simplified.Not only the effect of solute diffusion and hydrodynamic dispersion,but also the effect of phase transformation of crystal saltsalt solution（chemical reaction）on salt transfer,and the effect of phase transformation latent heat crystal salt on the temperature field were considered in the modified theory.Second,according to the law of conservation of energy,the equation of temperature field was more consistent with the actual engineering by the increase of phase transformation latent heat of crystal salt.At the same time,the salt heaving was calculated through the molar mass difference of the solute,and the frost heaving was calculated through the water margin between the original water content of the soil together with the migrated water and the water needed by sodium sulfate crystallization.Then the relationships between stress and water migration,salt migration and the temperature were deduced,and four-field coupling theory of salty soil was refined as well.At last,the theory model was used to calculate and analyze the progress of the salt heaving and the frost heaving of a sulfate salty soil at a road in Xinjiang,China.The results show that the calculated rules of the temperature,the migration of the salt,the salt heaving and the frost heaving are in accordance with the simulated results.The deformation progress of the salty soil subgrade can be divided into six stages as steady,slow salt heaving and frost heaving,severe salt heaving and frost heaving,lagging transformation salt heaving and