Analysis of Soil Structures and the Mechanisms under the Action of Freezing and Thawing Cycles

A series of indoor tests were conducted to study the changes of soil particles and pores under freezing and thawing cycles. Testing results showed that grain breakages of coarse particles occurred during freezing and thawing cycles, resulting in an increase of the Atterberg limits and specific surface area of the soil samples. Meanwhile, the pore size distribution, tested by the mercury intrusion method, was also changed during the cycles; macro pores increased, mini pores reduced, and micro pores remained roughly unchanged. The interaction of soil particles (solid phase), soil pores (gas phase), and soil water (liquid phase), namely soil’s three phase components, is discussed to explore the change mechanisms of soil structures under freezing and thawing cycles.