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Application of Elasto-Plastic Model to Mechanical and Hydraulic Behavior of Buffer Material Under Water Uptake in a Repository

Published online by Cambridge University Press:  28 February 2011

T. Fujita ,
K. Hara ,
Y. Yusa  and
N. Sasaki
T. Fujita
Affiliation:
Power Reactor and Nuclear Fuel Development Corporation, Tokai-mura, Ibaraki, JAPAN
K. Hara
Affiliation:
Power Reactor and Nuclear Fuel Development Corporation, Tokai-mura, Ibaraki, JAPAN
Y. Yusa
Affiliation:
Power Reactor and Nuclear Fuel Development Corporation, Tokai-mura, Ibaraki, JAPAN
N. Sasaki
Affiliation:
Power Reactor and Nuclear Fuel Development Corporation, Tokai-mura, Ibaraki, JAPAN
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Abstract

Mechanical and hydraulic behavior of buffer material during water uptake in a repository is a major issue from the viewpoint of mechanical stability of engineered barriers and near-field conditions for performance assessment. This paper presents the results of hydraulic-mechanical modeling of buffer material and the simulations carried out on an engineered barrier system under water uptake.

Hydraulic behavior of compacted bentonite of buffer material was modeled as moisture diffusion. An elasto-plastic model was applied to the deformation behavior of compacted bentonite, of which swelling pressure was described by swelling coefficient under restraint condition. The hydraulic diffusivity and swelling coefficient were given based on the result of swelling tests of KUNIGEL-V1 bentonite which contains about 50 % montmorillonite. Being used this model, simulations on re-saturation behavior of an engineered barrier system were carried out for the cases of water uptake from the whole surface of both crystalline and sedimentary rock and from partial surface of opening. The results are : (1) The hydraulic and mechanical behavior of compacted bentonite can be described by a swelling-elasto-plastic model. (2) The distribution of the water content depends on the water uptake conditions. (3) The deformation of compacted bentonite and the displacement of the overpack under water uptake are negligibly small.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 212: Symposium P – Scientific Basis for Nuclear Waste Management XIV , 1990 , 459
Copyright
Copyright © Materials Research Society 1991

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References

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