A bounding surface constitutive model for simulating repeated freeze–thaw cycles of saturated soil

Repeated cycles of frost and thawing actions of soil can cause serviceability issues in soil structures. Many theoretical models have been developed to account for soil deformation resulting solely from either freezing or thawing processes. They fail to adequately capture the plastic strain accumulated through repeated cycles of pore water/ice phase transitions. A new bounding surface constitutive model is developed using two stress state variables (Bishop’s effective stress and cryogenic suction), enabling simulation of soil stress state under repeated cycles of freezing and thawing processes. A new freeze–thaw state parameter is introduced to consider the effects of soil’s stress history on a soil’s residual state after infinite freeze–thaw cycles. By incorporating this new parameter and bounding surface plasticity, the model is capable of predicting plastic deformation during hardening and softening induced by freeze–thaw cycles, even when the stress state of soil remains within the yield surface. It is shown that the model can capture the accumulated volumetric response due to freeze–thaw cycles. Moreover, by implementing the freeze–thaw state parameter into the hardening law, the newly developed model can also capture the effects of OCR on freeze–thaw-induced volume changes, particularly the irreversible heave observed in heavily over-consolidated soils.