硫酸盐渍土降温过程中的盐胀与冻胀特性

为研究降温过程中硫酸盐渍土盐胀与冻胀的内在联系,以冻结温度作为土体盐胀与冻胀的分界点,通过改变降温过程中盐渍土的水盐含量,控制盐胀与冻胀变形相对大小,开展了一系列盐渍土冻结变形试验,分析了水盐变化过程中,土体盐胀与冻胀的变化规律。结果表明降温过程中的盐胀与冻胀存在叠加效应,即总变形与总结晶体积之间不满足正相关关系,总变形受盐胀与冻胀强弱关系的影响,满足盐胀与冻胀的均势规律,即在盐胀变形与冻胀变形相等时,盐、冻胀总变形最小,总变形与盐胀比之间满足“M”形变化规律。研究结果对深入理解盐、冻胀变形的机理,建立盐、冻胀变形计算模型,以及开展盐、冻胀变形病害防治具有积极意义。

Salt Expansion and Frost Heave in Cooling Sulfate Saline Soil

The aim of this study is to explore the connection between salt expansion and frost heave in cooling sulfate saline soil. Freezing deformation tests are conducted on sulfate saline soil samples to examine the variations of salt expansion and frost heave of soil under varying water and salt content. The salt expansion and frost heave are controlled by changing the water content and salt content in the freezing process. Freezing temperature is set as the demarcation point identifying between salt expansion and frost heave. Results reveal a duplicate effect between salt expansion and frost heave in the freezing process, i.e. there is no positive correlation between total deformation of samples and crystalline volume. Total deformation obeys the law of the balance of power between salt expansion and frost heave, which means that total deformation reaches the minimum when salt expansion deformation equals frost heave deformation. The curve between total deformation and ratio of salt expansion displays an M-shape. The research findings are of active significance for further understanding the mechanism, building models, and hazard prevention of salt expansion and frost heave.