Instability of gradient dependent viscoplastic model for clay saturated with water and FEM analysis

Document Type


Publication Date



For the last two decade, several constitutive models have been proposed for geomaterials and applied to practical problems. There remains, however, still some outstanding issues to be resolved. One of them is the formation of shear band before and after failure. This problem is strongly connected to the strain localization phenomenon. Recently, the importance of simulation of post localization regime has been pointed out. For this problem an interesting approach has been proposed by Aifantis and co-workers based on the introduction of higher order strain gradients into constitutive equation. The purpose of this paper is to propose a strain gradient dependent elastoviscoplastic model for clay and study the instability condition of the constitutive theory. The model is then implemented into FEM code to simulate the clay behavior under plane strain condition by considering the transport of pore water based on Biot’s theory of solid-fluid mixture. © 1992 American Society of Mechanical Engineers.

Publication Title

Applied Mechanics Reviews