Study on the Water-Salt Migration Pattern of Ili Salinized Loess under Freeze-Thaw Conditions

In order to study the influence of different water content and salt content on the water-salt migration mechanism of Ili salinized loess. The water-salt migration test of saline loess under the action of the freeze-thaw cycle was carried out, and the temperature, moisture, and salt fields and their cohesion change rules were analyzed. The study shows that under the action of freezing and thawing, the temperature field, moisture field and salt field of saline loess show cyclic changes. With the increase of the number of freezing and thawing cycles, the water content of the soil column as a whole is increased, showing a pattern of high water content at the two ends and low water content in the middle. The change of salts in the soil layer under freezing and thawing is consistent with the overall change of moisture, and the salts in each soil layer show a homogeneous distribution before the unfreezing and thawing. Under the effect of temperature potential, the water carries the salts to migrate upward, resulting in higher salinity in the middle and upper part of the soil column. The increase of water content and salinity has a promoting effect on the migration of water and salts. In addition, the increase in water content will have a lubricating effect between the soil particles, resulting in the cohesion of the sample with low water content being greater than that of the sample with high water content. With the increase of salt content, the agglomerates formed by the salt crystals wrapped around the soil particles play the role of skeleton, which makes the cohesion of the specimen with high salt content larger than that of the specimen with low salt content, the value of internal friction angle of salinized loess after freeze-thawing shows a wave distribution.