Abstract <p>To assess frozen clay behavior under complex loading, a custom-built true triaxial apparatus for frozen soils was adopted to investigate how salinity and the intermediate principal stress ratio affect its strength and deformation properties. The experimental results indicate that the deviatoric stress-major principal strain curves under different test conditions show strain hardening characteristics. When the intermediate principal stress ratio ranges from 0 to 0.67, the failure strength increases with an increase in intermediate principal stress ratio. However, when the intermediate principal stress ratio increases from 0.67 to 1, the failure strength decreases. The strength decreases linearly with an increase in salinity. As the intermediate principal stress ratio increases, the intermediate principal strain changes from a dilative to a contractive behavior, while the minor principal strain remains in a dilative state throughout the loading process. Shear contraction is observed first in the volumetric strain, followed by dilation. With increasing salinity, the slopes of the curves relating the intermediate, minor and volumetric strains to the major principal strain gradually increase. As the intermediate principal stress ratio increases, the deformation modulus first increases and then decreases, while it decreases with an increase in salinity. Based on the experimental results, an improved Duncan-Chang model was established by regressing the Duncan-Chang parameters, incorporating the influences of salinity and the intermediate principal stress ratio. The proposed model demonstrates a good capability in reproducing the stress-strain behavior of frozen clay under complex stress paths with different intermediate principal stress ratio and salinity levels.</p>