EXPERIMENTAL STUDY ON MOISTURE MIGRATION OF UNSATURATED LOESS UNDER FREEZING EFFECT

This paper carries the moisture migration tests of unsaturated loess with the large size sample under freezing effect. It examines the influence of density, water content, freezing temperatures and freezing way on moisture migration of unsaturated loess. Results show that the soil sample temperature change under freezing process is divided into three stages: rapid cooling stage, the slow cooling stage, and stable stage. For higher dry density, the increase of water content at the frozen front is greater, but the increase of water migration of moving to the frozen part is lower. For a certain dry density, if the initial water content is higher, the amount of moisture migration is greater. And the increase of water content of the frozen front is also the greater. From the cold end to the warm end in the unfrozen area, water content increases at first, then decreases. And, this phenomenon is the more evident with lower initial water content. This phenomenon is the combined effect of the freezing interface suction force, temperature gradient and the matric suction gradient. The water content distribution and the total amount of moisture migration in frozen area are affected directly by the freezing way.