Creep characteristics and poromechanics-based viscoelastic-plastic constitutive model of warm and ice-rich frozen sand

Motivated by the pronounced rheological behavior of warm and ice-rich frozen soils, we developed a specimen preparation method tailored to ice-rich materials. We conducted a series of triaxial creep tests on saturated frozen sand with 20% ice content and on ice-rich frozen sand with 67% ice content; comparative analyses revealed distinct differences in their creep responses. Building on poromechanics and a binary-medium framework, we propose a viscoelastic-plastic constitutive model for warm frozen soils that accounts for interactions among the soil skeleton, ice, and unfrozen water, as well as the progressive breakage of ice-cement bonds. Validation against experimental data demonstrates that the model accurately captures the creep behavior of warm frozen soils across a range of ice contents and stress levels.