Developing three-dimensional rheological model for clay from K0 oedometer test

Abstract The rheological deformation of soil can pose significant threats to the economy and public safety, making accurate prediction of soil rheological deformation crucial. In this paper, one-dimensional compression rheological tests were operated for over-consolidated clay by a novel K0 oedometer. The test results show that the coefficient of earth stress at rest K0 remains constant over time under constant load. The strain-time relationship during reloading can be described by a hyperbolic function, while the stress-strain relationship can be represented by a power function. Based on the relationship of strain-stress-time and the equal timeline theory, a one-dimensional viscoplastic equation was proposed to describe the axial strain rate. By introducing K0, a viscoplastic volumetric strain rate equation is derived, leading to the development of a three-dimensional elastic viscoplastic model under general stress conditions. Verification shows that the predictions of the proposed model agrees well with the test data of triaxial rheological. The model, based on K0 oedometer tests data, offers a simplified alternative to complex triaxial rheological tests and extends the modeling approach of rheological models.