A New Strength Criterion for Frozen Clay Considering Temperature Effect

To study the strength property of frozen soil under complex stress states, a series of directional shear tests on remoulded frozen clay were conducted under four mean principal stresses (p = 1, 3, 4.5 and 10 MPa) and four coefficients of intermediate principal stress (b = 0, 0.25, 0.5, and 0.75) at three temperatures (−6, −10, and −15 °C) using the hollow cylinder apparatus (HCA). The experimental results indicated that stress-strain curves of frozen clay all performs as strain hardening under directional shearing. In the p-q plane, the strength of frozen clay increases with increasing mean principal stress at first, and then decreases with a further increase of p. An elliptic strength criterion is proposed to describe this variation law. The test results also showed that the strength of frozen clay increases with decrease of temperature significantly. Then, temperature parameters are introduced into the elliptic function to consider the temperature effect.