砂土冻融特性试验研究

An Experimental Study on Freeze-thaw Properties of Sand Soil

为探究外界条件对砂土在冻融过程中的温度及水分迁移的影响,分别控制水分补给状态、冷端温度以及土体的初始含水率进行单因素研究。以顶端单向冻结的方式,对冻融过程中土体不同高度处的温度及含水率进行监测。试验结果表明:随着冻结锋面的下移,温度影响范围内各高度处的温度均有所降低,含水率也呈现出不同程度的减少;高冷端温度冻结下,不同系统状态土样各高度的温度及含水率变化基本一致,水分补给对砂土的水分重分布影响不大;温度对土体的冻深及水分迁移量有显著影响,温度低冻深大,相同高度处的含水率存在差异,温度低水分迁移量大;不同初始含水率冻融后土体温度变化趋势相同,初始含水率本身对土体的水分迁移量不存在影响,但从客观上减缓冻结锋面的推进速度,增大了水分迁移量。

In order to explore the influence of external conditions on temperature and water migration of sand soil during freezing and thawing process,this experiment separately controlled the water supply state,the temperature and the initial moisture content of the soil for carrying out the single factor study. The experiment was carried out by means of unidirectional freezing at the top of the soil,the temperature and moisture content of the soil were monitored during the freezing and thawing process. The results showed that with the downward movement of the frozen front,the temperature at each height within the temperature influence was reduced,and the moisture content was also reduced depending on the varying degree. At high temperature freezing,the change of temperature and moisture content at each height of the soil samples of different system states were basically the same,the water supply state had little effect on the water redistribution of the sand soli. The temperature had a significant effect on the freezing depth and water migration of the soil. The lower the temperature is,the height of frozen front lower. The moisture content at the same height was different. These indicated that the water migration was larger with a lower temperature. The temperature of different initial water content soil changed in a similar trend,the initial water content itself had no effect on the water migration of the soil,however,it objectively slowed the promotion of the frozen front and increased the amount of moisture migration.