VISCOUS BEHAVIOR OF SOIL UNDER OEDOMETRIC CONDITIONS

The viscoplastic constitutive theory of Perzyna, and Olszak and Perzyn a has been modified and used to model one-dimensional compression of c ohesive, normally consolidated soils. Predictions of the model have be en compared with the results of a few nonstandard oedometric tests. Th e model simplifies the one-dimensional creep theory of Yin and Graham by eliminating the traditional concept of plastic strain. Both stress- and strain-controlled tests are discussed. The reference time t(0) us ed in the literature for the description of creep subsequent to a load step has been shown to be a function of the overconsolidation ratio.