Mathematical descriptions for the behaviour of ice-rich frozen soils at temperatures close to 0 °C

With the use of creep and constant strain rate (CSR) tests, mathematical formulations were found that describe the thermomechanical behaviour of ice-rich frozen soils. A Glen-type relationship was chosen for the formulation of minimum creep strain rates at temperatures between –4 °C and –1 °C. The shear strength of the material could be described by a Mohr–Coulomb failure criterion. Furthermore, it was possible to compare the creep behaviour with the strength of similar soils under constant strain rates. The minimum creep strain rate increases proportionally as the temperature approaches the melting point of the ice, which can be attributed to the increasing amount of unfrozen water, which strongly influences the mechanical response. Even though only a few tests could be used for the determination of the angle of friction and the apparent cohesion, the trend showed that the volumetric ice content influences both parameters, but only the latter seems to be influenced by the temperature and the applied compression strain rate.Key words: permafrost, frozen soil, creep, strength.