Experimental study on the creep behavior of frozen clay with thermal gradient

Thermal gradient is one of the main features in frozen engineering, especially in artificial frozen wall (AFW) in deep alluvium. This paper investigated the creep behaviors of frozen soil with thermal gradient. A series of uniaxial creep tests were carried out on frozen saturated clay under various thermal gradients and creep stresses by GFC (freezing with non-uniform temperature without experiencing K-0 consolidation) method. Two stages were observed during the whole creep process, i.e., instantaneous elastic deformation and decaying creep deformation. Radial creep deformation of epsilon(3) almost increases linearly with an increase in axial creep deformation of epsilon(1) and the slope of epsilon(3)-epsilon(1) curve increases as the thermal gradient (or creep stress) increased. Long-term strength decreases as the thermal gradient (or the creep time) increased. Considering the correction equation on thermal gradient, the generalized Kelvin model consisting of one Hooke element and two Kelvin elements has been developed to describe the axial creep deformation. The validity of the model is verified by comparing its calculated results with the results of creep tests under both low and high thermal gradient. It is found that the axial creep deformation behavior of frozen saturated clay can be represented by generalized Kelvin model, and the proposed model reflects thermal gradient effects to the creep deformation well. (C) 2012 Elsevier B.V. All rights reserved.