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Accumulated Vertical Strain Without Confining Pressure for Compacted Bentonite Due to Hydration Effort

  • Tomoyoshi Nishimura
  • Junichi Koseki
Conference paper
Part of the Environmental Science and Engineering book series (ESE)

Abstract

To use high dense compacted bentonite or bentonite-sand mixture material are accepted as engineered barriers for high level nuclear waste disposal waste. The bentonite as engineered barrier is initially in unsaturated condition before pore water coming from natural host rock. The bentonite subjected to thermo-hydro-mechanical actions by natural geological situation and the canisters of high-level radioactive disposal waste. This study conducted out the creep test for compacted bentonite, and the developed relative humidity circulation triaxial apparatus. Two different initial water contents were prepared to make the specimens at constant dry density. As parameter for this creep test, the stress ratio was defined using specified unconfined compressive strength. All specimens were applied without confining pressure. The vapor transfers due to changing of relative humidity induced some hydration efforts that were controlled using vapor pressure technique. Performing the creep test in this study is of couple hydro-mechanical and is applied to identification for two efforts (i.e. strain due to hydration and stain by deviator compression stress). Investigation of creep behavior that accumulated strains associated to couple thermo-mechanical actions are measured at constant deviator compression stress.

Keywords

Bentonite Creep test Suction 

References

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Copyright information

© Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  1. 1.Ashikaga UniversityAshikagaJapan
  2. 2.The University of TokyoTokyoJapan

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