Linear elastic constitutive relation for multiphase porous media using microstructure superposition: Freeze–thaw soils

The constitutive relation derived in our previous work based on the microstructure superposition technique is implemented here for three-phase microstructure configuration to study the mechanical behavior of freeze–thaw soils. Three scenarios were considered for the frozen soils: frozen soil consisting of only two solids, soil skeleton and ice; frozen soil with soil skeleton, ice, and void; and frozen soil consisting soil skeleton, ice and pores saturated with fluid. The frozen soil studied is Alaska frozen soil mainly consisting of clay and silt particles at temperature about −10 °C. The effective elastic constants were calculated for the media under each scenario using two sets of elastic constants of soil skeleton (clay mineral). The modeled results were compared with Hashin–Shtrikman's upper bound solution and the experimentally measured data. In addition to be able to model the mechanical behavior of freeze–thaw soils, the derived constitutive relation, as indicated in the results of this study, could also be used as a tool in determining the microstructure of freeze–thaw soils by measuring the elastic constants of soil skeleton, the elastic properties and unfrozen water content of the media.