A MODEL FOR ATTENUATING CREEP OF FROZEN SAND

The paper presents a constitutive model for attenuating creep of a frozen sand. The model treats the frozen sand as an elastic medium, the deformation parameters of which vary with creep. The sand is treated as an elastic medium over an infinitesimal interval of stress and time. Thus the elastic constants, K and G, were replaced by creep functions, K(c) and G(c), which were determined experimentally. The K(c) function, determined by isotropic compression triaxial creep tests, increased exponentially with increasing mean normal stress, and decreased exponentially with time. The G(c) function, determined by constant mean normal triaxial compression tests, increased exponentially with an increase in the resultant of the deviatoric components of stress; and decreased exponentially with time. The two creep functions determined by separate tests, were then coupled to provide a general stress state, constitutive model. The predictive reliability of the model was tested by performing a triaxial compression test involving simultaneous changes in the two functions, and comparing the observed axial strains with those predicted by the model. The comparison was generally good.