Binary-medium-based constitutive model of frozen soils subjected to triaxial loading

摘要

To model the elastoplastic behaviors of frozen soils, a binary-medium-based constitutive model is developed and validated by a series of cryotriaxial compressive tests. In the framework of the proposed model, frozen soils are conceptualized to consist of structural blocks and weakened bands. Herein, the structural blocks are idealized as bonded elements with elastic-brittle deformational behaviors. Moreover, the weakened bands are conceptualized as frictional elements whose deformational characteristics are described by a nonlinear Duncan–Chang hyperbolic model. The bonded elements are found to gradually break up and transfer into frictional elements, which collectively contribute to the resistance capability against external loading. From the micro perspective and in the representative volume element (RVE) of the soil specimen, nonuniform strain distributions and particle slippage mechanisms are considered in the strain concentration coefficient and breakage ratio to formulate a constitutive model. Predictions are calibrated with available laboratory results, demonstrating that the proposed model can reasonably account for a breakage mechanism and can quantitatively simulate the nonlinear elastoplastic behavior of frozen soils.