Failure of Partially Saturated Frozen Soils: A Micromechanical Analysis

ABSTRACT: A micromechanically based failure criterion is developed for shear strength of partially saturated frozen soil. Following a multiscale framework, a relation between the macroscopic stresses and the interparticle forces is formulated, which eventually leads to a failure criterion at the macroscopic level in terms of parameters such as ice strength, matric suction, void ratio, average particle size, and contact fabric. The strength predictions are compared to three different experimental datasets where the model demonstrates good accuracy without resorting to any retrospective calibration. Crucially, the failure model establishes a connection between strength of soil at frozen and unfrozen states, which can be used in estimating the strength degradation in frozen soils upon thawing.