An investigation on the constitutive response of frozen saline coarse sandy soil based on particle breakage and plastic shear mechanisms

Abstract

The particle breakage has significant influence on the mechanical properties of geomaterials during loading process. Considerable particle breakage commonly occurs for frozen sandy soils under relatively high pressure and large shear strain. A constitutive model for frozen saline coarse sandy soils was developed based on the breakage and plastic shear mechanisms. The particle breakage mechanism is derived from the breakage mechanics theory, which is based on thermodynamics principles. The plastic shear mechanism considers both strain hardening and softening properties. A non-associated flow rule is adopted to calculate the increments of relative breakage and plastic strains. The established model can reflect the influence of salt content on the constitutive response of frozen sandy soils. Parametric studies were further conducted to investigate the effects of model parameters on relative breakage and deformation behaviors. On the other hand, a series of triaxial tests under different stress paths were performed on frozen coarse sandy samples with different salt contents to calibrate the model parameters and to examine the performance of the proposed model. Comparisons between the calculated data and experimental results indicate that the established model can describe the particle breakage and deformation characteristics for frozen coarse sandy soils with various salt contents. The strain hardening/softening, high dilation and pressure melting features can be well captured.