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SUMMARY:A thermo-hydro-mechanical stress-strain framework for modelling th
 e performance of clay barriers in deep geological repositories for radioac
 tive waste - Prof. Lyesse Laloui\, Swiss Federal Institute of Technology -
  EPFL
DTSTART:20091106T163000Z
DTEND:20091106T173000Z
UID:TALK20020@talks.cam.ac.uk
CONTACT:Zelda Stuck
DESCRIPTION:Assessing the performance of deep geological repositories for 
 heat-generating radioactive waste requires reliable predictions of the the
 rmo-hydro-mechanical (THM) behaviour of the clay barriers (the buffer mate
 rial as well as the host rock/clay). This represents an important element 
 of the waste isolation system. In order to provide reasonable assurance th
 at clay barriers will ensure nuclear waste isolation\, it is essential to 
 understand their behaviour under a variety of environmental conditions. Th
 e phenomena involved are complex\, and adequately understanding the consti
 tutive behaviour of clays and modelling their evolution is challenging. Th
 e stress-strain material behaviours that need to be understood and modelle
 d include drying and wetting in non-isothermal conditions and heating-cool
 ing in non-saturated conditions. Other aspects should be considered\, such
  as drying induced cracks and the role of the material structure and its m
 ulti-porosity. The difficulty of some of these tasks is increased by the f
 act that some effects are coupled. \nThe fundamental behaviours of clayey 
 materials under the considered THM conditions are first identified and hig
 hlighted for deep repository experiments. We then propose a mechanical str
 ess-strain constitutive framework to model the behaviour of clay barriers.
  This includes aspects such as the thermo-plastic behaviour of saturated a
 nd unsaturated materials. In the third part\, we show that the proposed fr
 amework allows us to experimentally explain observed behaviours and to pre
 dict the THM behaviour of clay barriers.\n\n
LOCATION:Engineering Department - LR6
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