温度对硫酸钠盐渍土盐胀影响的试验研究

Experimental Study on Influence of Temperature on Salt Expansion of Sodium Sulfate Saline Soil

为了探究温度对硫酸盐渍土盐胀的影响规律,保障我国盐渍土地区道路工程安全运营,通过室内试验,测试了不同温度环境下硫酸钠盐渍土的盐胀率。从样品降温前后体积变化、未相变含水量随温度变化、以及CT扫描图像分析了不同温度下盐胀对土体各组分的影响。研究结果表明:随着温度不断降低,盐胀不断加剧并趋于稳定;盐胀主要温度区间为0℃至盐晶体初始析出温度,在负温下盐晶体析出很少,引发的盐胀十分微小;在正温下含水率随着温度降低而减小,其递减趋势不断减小并在0℃附近趋于稳定;随着温度不断降低,土体结构的损伤也不断增大;空气所占孔隙率的变化主要取决于含水率的变化,当含水率剧烈变化时,其也会剧烈变化,二者呈现反比关系。

In order to find the rule of effect of different temperature conditions on salt expansion of sodium sulfate saline soil, and ensure the safty operation of road engineering in area of saline soil, the salt expansion ratio of sodium sulfate saline soil in different temperature environments are measured by laboratory test. By analyzing the variation of soil samples before and after cooling, the water contents without phase change at different temperature, and CT scan images, the influence of salt expansion on the soil components at different temperatures is obtained. The research result shows that （ 1 ） salt expansion intensifies and tends towards stability as the temperature decreases ; （2） the main temperature range of salt expansion is from 0 ℃ to the initial precipitation temperature of salt crystals, its precipitation is very little at negative temperature, so the induced salt expansion is very small; （3） moisture content decreases as temperature decreases at positive temperature, the diminishing trend is decreasing and gradually stabilizing at 0 ℃ ; （4） the damage of soil structure increases as the temperature decreases; （5） the change of porosity occupied by air is mainly decided by the change of water content, and it changes acutely as the water content changes acutely, in addition, they show a inverse relationship.