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Earthquake-induced rock shear through a deposition hole: Laboratory tests on bentonite-material models and modelling of three scale tests

Published online by Cambridge University Press:  22 June 2018

Lennart Börgesson ,
Ann Dueck  and
Jan Hernelind
Lennart Börgesson
Affiliation:
Clay Technology AB, IDEON Science Park, SE-223 70 Lund, Sweden
Ann Dueck*
Affiliation:
Clay Technology AB, IDEON Science Park, SE-223 70 Lund, Sweden
Jan Hernelind
Affiliation:
5T Engineering AB, Fornforskargatan 86, SE-723 53 Västerås, Sweden
*
*E-mail address of corresponding author: ad@claytech.se
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Abstract

Earthquake-induced rock shear through a bentonite-filled deposition hole in a repository for spent nuclear fuel is an important scenario for the safety analysis because it may cause substantial damage to the canister hosting the spent fuel. Appropriate tools to investigate the effects on the buffer and the canister are required.

The study described here explored the laboratory tests conducted to develop a material model of the bentonite buffer to be used in the simulations, the material models that these tests have provided and finite element (FE) simulations of three scale tests of a rock shear for comparison between modelled and measured results. The results were used for validation of the material models and the calculation technique that was used for modelling different rock-shear cases.

The laboratory study consisted of swelling-pressure tests and tests to determine shear strength and stress-strain properties. The material model is elastic-plastic with a nonlinear stress-strain relation which depends on the density of the bentonite buffer and is a function of the strain rate. The three scale tests were modelled using the Abaqus finite element code. Good agreement between modelled and measured results was observed, in spite of the complexity of the models and the difficulties associated with measuring stresses and strains under the very fast shear.

The modelling results thus validate the modelling of the SR-Site. The modelling technique, the element mesh and the material models used in these analyses are well fitted and useful for this type of modelling.

Keywords

stressstrainshearAbaqus finite element codefinite element modellingnuclear fuel disposal
Type
Article
Information
Clay Minerals , Volume 53 , Issue 2 , June 2018 , pp. 213 - 235
Copyright
Copyright © Mineralogical Society of Great Britain and Ireland 2018 

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Footnotes

Associate Editor: S. Kaufhold

This paper was presented during the session: ‘ES-04: Clay barriers performance in the long-term isolation of waste’ of the International Clay Conference, 2017.

References

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