Rate Dependent Elasto Plastic Deformation Of Shear Bands In Sensitive Clays

 

Vikas Thakur

ICG and Geotechnical Division, NTNU, Trondheim, Norway

Vikas.thakur@ntnu.no

Steinar Nordal

Professor, ICG and Geotechnical Division, NTNU, Trondheim, Norway

ABSTRACT

Failure in sensitive clays (with a post-peak strain softening behavior) is often associated with the development of shear bands, i.e. narrow zones of localized deformation, and the failure loads depend on the thickness of these shear bands. This feature is both a conceptual and numerical challenge and the real physical thickness of the shear band becomes an important issue. Contracting behavior of sensitive clay is responsible for generating excess pore pressure within shear band, while a high hydraulic gradient between elastically unloaded body and shear band will cause dissipation of pore water pressure. Consequently, a reduced rate of strain softening will act as a counterbalancing mechanism and may contribute to the thickness of shear band.

In this paper, rate dependent one dimensional finite element model is simulated and coupled pore water strain localization phenomenon is studied.

Keywords: sensitive clays, shear band, strain softening, finite element

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