冻融过程中重塑土水盐迁移试验研究

为探究盐渍土地基冻融过程中的水盐迁移规律,以内蒙古东部典型盐渍土为研究对象,通过改变土样冷端温度,初始含水率,干密度和含盐量等因素,进行室内重塑土单向冻结,双向融化试验。结果表明：试样温度的改变存在滞后性,离冷端越近,温度变化越敏感；在冻结过程中,土样初始含水率、干密度或者含盐量的增大,将造成冻结锋面的移动速度减小。试件水分迁移量随着初始含水率的增大而增大；当初始含水率较低时,冷端温度的变化对水分迁移影响较小,只有当初始含水率足够大时,迁移量才随着冷端温度的降低而增大；土溶液冻结和电导率突变存在关联性；含盐量的增加,会抑制水分迁移。试件整体盐分迁移量随着冷端温度的降低而增大；只有当冷端温度足够低时,盐分迁移量才会随着初始含水率的增大而增大；增大干密度会减少盐分迁移；含盐量的增多,使盐分往试件暖端方向汇聚。

Experimental study on migration and salinity of remolded soil during freezing and thawing

In order to explore the law of water and salt migration during the freezing and thawing process of saline soil, the typical saline soil in eastern Inner Mongolia was studied by changing the temperature, initial moisture content, dry density and salt content of remolded soil with one - way freezing and two - way melting test . The results show that the change of the temperature in the soil column is hysteresis, the closer to the cold end, the more sensitive the temperature changes. In the freezing process, increasing the initial moisture content, dry density or salt content, will reduce the frozen frontal movement speed. The water migration of the specimen increases with the increase of the initial water content. When the initial moisture content is low, the temperature of the cold end has little effect on the water migration of the specimen, only when the initial moisture content is large enough, the migration will increase with the cold end temperature decreases; There is a correlation between the freezing of soil solution and the abrupt change of conductivity; salt content increases, will inhibit the water migration. The total salt shift of the specimen increases with the decrease of the cold end temperature. Only when the cold end temperature is sufficiently low, the salt migration will increase with the increase of the initial water content. Increasing the dry density will reduce the salt migration; the increase in salt content causes the salt to converge in the warm end of the specimen.