The research presents the experimental investigations on the strength of frozen sand by conducting the triaxial compressive tests under confining pressures varying from 0.0 to 18.0 MPa at a temperature of −4 °C. The results demonstrated that the strength of frozen sand increases with increasing in confining pressure at first,and then decreases with a further increasing in confining pressure for pressure melting and crushing phenomena. A strength criterion is presented to describe the failure mechanism of frozen sand under general stress state by the combination of strength function F1(p) in p–q plane and F2(q,θσ) in π plane. In this study,the strength function F1(p) was well fitted by cubic polynomial equation, considering the pressure melting and crushing phenomena of frozen sand under high confining pressures. The strength function F2(q,θσ) derived from the extended Matsuoka–Nakai model, considering the influence of hydrostatic pressure, was used. All the parameters of this failure criterion can be easily determined using the conventional triaxial compression tests.

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