Influence of freeze–thaw on the stored free energy in soils

In K0 consolidation, i.e. laterally confined compression, the axial pressure creates some plastic work on the soil samples. Part of this plastic work is dissipated by friction between soil grains. The other part is stored as free energy (SFE) in the soil. When the soil micro-structure is disturbed, SFE is either accumulated or released. In this paper, formula for SFE is deduced under K0 conditions. Lanzhou loess and Qinghai–Tibet silty clay were used as study objects. After freeze–thaw, changes in mechanical properties of the two soils lead to the changes in SFE. It is found that freeze–thaw has different effects on the soil density, and thus on SFE. They are increased for the soils with low original dry unit weight, and decreased for the soils with high original dry unit weight.