Abstract
This study reports a series of triaxial compression tests on frozen clay. The tests were performed on reconstituted Kasaoka Clay frozen at -2, -5 and -10 oC from isotropic normal consolidation of 400kPa. The specimens were sheared at constant or varying strain rates and temperatures, and their observed strength and its dependence on these factors are discussed. The results show that, within the investigated range of conditions, the shear strength increases log-linearly with an increase in the strain rate. The shear strength normalized by that at a given temperature, or by that at a given strain rate formed unique relationships against the strain rate or the temperature, respectively. The stress in a temperature-varying condition can generally be predicted for a given strain if constant-temperature stress-strain curves are considered as backbone relationships. The same observation is probably true for the strain-rate, as described by the isotache rule. These effects are similar on the deviator stress for strains larger than 5% as on the strength. At these strain levels, the stress-strain curves suggest that the frozen specimens were at a sufficiently plastic stage. The above features of temperature and strain rate effects are relatively simple to formulate and will be useful in developing a general rate-dependent thermo-mechanical model for frozen clays.
