A new double hardening constitutive model for frozen mixed soils

In this paper, a new double hardening constitutive model for frozen mixed soils is proposed, in which a new yield function is formulated based on the strength data of frozen soils. The associated flow rule is adopted, and the position, shape and size of the plastic potential surface are determined by four hardening parameters, two of which are considered to be functions of plastic volumetric strain and plastic shear strain, respectively. By this method, the plastic potential surface can change in shape during the process of loading. Furthermore, the constitutive model can be used to simulate both strain hardening-softening and volume contraction-dilatancy. In addition, the suggested range of constitutive parameters and the sensitivity analysis of the parameters are also provided. Finally, by verifying the experimental data of frozen mixed soils under different confining pressures, temperatures and mass ratios, it is found that the constitutive model proposed here can accurately predict the mechanical properties of frozen mixed soils well.