Abstract:

Groundwater in seasonal frozen ground migrates towards the freezing front by capillary action when frozen. Several freeze-thaw cycles maybe experienced in a very short time during the frozen process in regions of high-altitude or large temperature difference between day and night. In view of this, a unilateral freezing triaxial apparatus for freeze-thaw cycle was developed. Unidirectional freezing test under the condition of filling water and triaxial shear strength test of freezing and thawing cycle can be conducted in the apparatus. Unidirectional freezing test on silty clay was conducted and the results show that CT numbers of the cross sections of samples decrease during the frozen process. The freezing front moves from the cross section of lower temperature to the cross section of higher temperature. The test result reflects the migration process of the freezing front during unilateral freezing.

Key words: seasonally frozen soil, unilateral freezing, freeze-thaw cycle, triaxial apparatus, computerized tomography scan