COMPUTATIONAL ANALYSIS OF CREEP IN ICE AND FROZEN SOIL BASED ON FISH UNIFIED MODEL

The ability of the creep model of Fish to simulate the observed behaviour of ice and frozen soils in multiaxial stress-strain fields is investigated. The generalization of the original uniaxial creep model is made through the use of several assumptions and the multiaxial model is implemented in an iterative, time-incrementing finite element code. Sample creep parameters for the model are evaluated using previously reported uniaxial creep tests on ice and frozen silt. The finite element code is used to demonstrate the ability of the model to predict different stages of creep deformation in frozen media, by re-simulating some uniaxial creep tests on ice. Pressuremeter tests, plate load tests, and laterally loaded rigid cores (piles considered in cross section) in frozen media are simulated to demonstrate the similarity between the global response of ice and frozen soils predicted by the model and the reported experimental findings. Redistribution of stress predicted by the model is also investigated. The model is seen to possess validity in situations of attenuating as well as accelerating creep of ice and frozen soils.