Professor Tadatsugu Tanaka
Professor Tadatsugu Tanaka

Video of the 2023 Biot Lecture is now available online.

Title: Plastic Behaviors of Geomaterials and Their Application to Static and Dynamic Problems

Presenter: Professor Tadatsugu Tanaka, Professor Emeritus, University of Tokyo

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Biot developed a theory for fluid saturated porous media. Applying Biot theory, elasto-plastic analyses for both static and dynamic problems of geomaterials are carried out via finite element methods. For static problems, dynamic relaxation methods are applied. Special considerations are given to element types, with antihourglass scheme, to avoid both shear and dilatancy lockings. Constitutive models developed for geomaterials contain non-associated strain hardening-softening elasto-plasticity. A strain softening material model is used with the features of post-peak strain-localization into a shear band with a specific width. Visco-plastic (new Iso-tach model and TESRA, temporary effect of strain rate and acceleration) models are also developed. The consolidation analyses of sequential excavation and setting-up of struts for sheet piles in soft ground are carried out. Dynamic progressive failure analysis of small embankment dams of dry sand on shaking table is carried out. The computations of existing fill-type dams are also carried out by total stress elasto-plastic constitutive model and effective stress constitutive model by taking into account the pore water pressure build-up. The developed models are successfully validated with the field measured response. 

Full Abstract