ABSTRACT: Isotache models are being used increasingly to describe the time-dependent compression of soft soils. Parameters are usually obtained from incremental loading compression tests and, in the case of 2D isotache models, triaxial tests as well. It is possible to determine all necessary parameters, including strength parameters, from a constant rate of strain oedometer which also measures lateral stress. This is described in the paper. Some effects of unloading on the form of the isotaches are also presented, and it is shown that to be completely effective, adaptations of existing isotache formulations are necessary.

Key words:  compression, constant rate of strain, creep, isotache, K_o oedometer, organic clay, peat, pre-loading, relaxation (IGC: E2)