Constitutive model for rate-independent behavior of saturated frozen soils

Abstract

The mechanical behavior of frozen soils is strongly affected by the amount of ice. The amount of ice depends on the temperature and the applied mechanical stresses. The influence of ice content and temperature on the mechanical behavior and the coupling effects on the reverse direction can be mentioned as the main difference between frozen and unfrozen soils. In the light of this difference, an elastoplastic constitutive model for describing the stress-strain behavior of saturated frozen soils is proposed. By dividing the total stress into fluid pressure and solid phase stress, in addition to consideration of the cryogenic suction, the model is formulated within the framework of two-stress state variables. The proposed model is able to represent many of fundamental features of the behavior of frozen soils such as ice segregation phenomenon and strength weakening due to pressure melting. In unfrozen state the model becomes a conventional critical state model. Typical predictions of the model for simulating the characteristic trends of the frozen soil behavior is described qualitatively. Model predictions are also compared with the available test results and reasonable agreement is achieved.

An elastic-viscoplastic model for saturated frozen soils

“…Following the discussion presented in Ghoreishian Amiri et al (2016), the solid phase stress and the cryogenic suction are considered as the relevant stress variables:…”

“…the ratio of the unfrozen water volume on the volume of frozen and unfrozen water), I denotes the unit tensor, S is the cryogenic suction, p w and p i denote the pressure of water and ice phases, respectively, ρ i indicates the density of ice, l is the specific latent heat of fusion, T stands for temperature on the thermodynamic scale and T 0 is the freezing/thawing temperature of water/ice at a given pressure. Similar to the reference elastic-plastic model (Ghoreishian Amiri et al, 2016), any strain increment is decomposed into two major parts due to variations of solid phase stress and suction. In this model, elastic-viscoplastic behaviour is considered for the deformation due to variation of solid phase stress, while elastic-plastic behaviour is assumed for the suction-induced deformation.…”

“…Ghoreishian Amiri, Grimstad, Kadivar, and Nordal (2016) proposed another two stress variables model by introducing the solid phase stress and the cryogenic suction as the relevant stress variables. The solid phase stress is defined as the combined stress in the soil grains and ice.…”

“…In this study, the above-mentioned elastic-plastic model (Ghoreishian Amiri et al, 2016) is extended to an elastic-viscoplastic version. The model is developed based on the overstress framework which is originally proposed by Perzyna (1966) and followed by many researchers in the field of geotechnical engineering [e.g.…”

Constitutive Model for Long-Term Behavior of Saturated Frozen Soil

“…The interfacial mechanism is the result of disjoining pressure and tends to widen the gap by sucking in more water.This mechanism has not been taken into account in the model proposed by Nishimura et al (2009). Ghoreishian Amiri et al (2016A)proposed another two stress variables model by introducing the solid phase stress and the cryogenic suction as the relevant stress variables. The solid phase stress is defined as the combined stress in the soil grains and ice.…”