Laboratory investigation on strength and deformation characteristics of ice-saturated frozen sandy soil

To investigate the properties of ice-saturated frozen sandy soil, a series of triaxial compression tests on frozen sandy soil with a volumetric ice content of about 50% were carried out at a temperature of − 2.0 °C. The effect of confining pressure on strength and deformation features is analyzed according to the experimental results. The results show that the strength changes with increasing confining pressure in three distinct phases. According to the effective stress principle, the mechanism of strength is explained. A strength criterion is proposed to describe the strength characteristic. The equivalent stress versus axial strain curve shows strain-softening under each confining pressure, and the extent of strain-softening decreases with the increase in confining pressure, until it behaves the so-called perfect elasto-plastic feature when the confining pressure is large enough. The improved Duncan–Chang hyperbolic model is taken to simulate the stress–strain behaviors. The simulation shows that the model can well describe the strain-softening. The dependency of the volumetric deformation on the confining pressure is also discussed. ► Triaxial compression tests on an ice-saturated frozen sandy soil were carried out. ► The strength changing with confining pressure can be divided into three phases. ► A new strength criterion was proposed; the mechanism of strength was explained. ► An improved D-C model was applied to describe the stress-strain relationship. ► The reason why the model can describe strain-softening is explained.