Effect of Freeze-Thaw Cycles on Mechanical Behavior of Compacted Fine-Grained Soil

A large amount of work has been conducted to study the effect of freeze-thaw cycles on the geotechnical properties of various soils. But less laboratory work has been focused on the effect of number of freeze-thaw cycles and on quantitative relationship between mechanical behavior and freeze-thaw cycles. This study undertook a series of tests including freeze-thaw (FT) (after 0, 2, 5, 11, 21, and 31 freeze-thaw cycles respectively), unconfined compression (UC) and unconsolidated-undrained triaxial compression (UUTC) tests. These tests aim to assess the influence of freeze-thaw cycles on the mechanical behavior of compacted fine-grained soil, to establish correlation between the mechanical behavior and freeze-thaw cycles, and to facilitate the prediction of changes in geotechnical properties of soil. Freeze-thaw cycles notably influence the stress-strain curve reducing the UC strength by 11%, elastic modulus by 32%, and cohesion by 84% after 31 freeze-thaw cycles in comparison with those soils unexposed to freeze-thaw. The angle of internal friction is slightly increased by 1 to 2°. The weakening and deteriorating effects of freeze-thaw on the compacted fine-grained soil are confirmed. They can provide a scientific basis for design consideration of cold-region infrastructures, and for countermeasures against frost heave and thaw settlement.