Constitutive model for swelling properties of unsaturated bentonite buffer materials during saturation
Bentonite-based materials are candidate buffer materials for the geological disposal of radioactive waste in many countries. Once the disposal facility is closed and the groundwater level recovers, the buffer will gradually become saturated by the infiltration of groundwater. The swelling properties...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2022-08-01
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| Series: | Soils and Foundations |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0038080622000695 |
| _version_ | 1828231406129512448 |
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| author | Shinji Ito Shinya Tachibana Tomohide Takeyama Atsushi Iizuka |
| author_facet | Shinji Ito Shinya Tachibana Tomohide Takeyama Atsushi Iizuka |
| author_sort | Shinji Ito |
| collection | DOAJ |
| description | Bentonite-based materials are candidate buffer materials for the geological disposal of radioactive waste in many countries. Once the disposal facility is closed and the groundwater level recovers, the buffer will gradually become saturated by the infiltration of groundwater. The swelling properties of saturated bentonite affect the distribution of dry density and the stress state within the buffer. Therefore, to evaluate the long-term safety of the buffer, a model must be developed that can continuously express the mechanical behavior of bentonite from the construction and operation of the repository for disposal (the unsaturated state) to the resaturation phase (saturated state). In this study, the existing elastoplastic constitutive model for saturated expansive soils was extended to predict the mechanical response in the unsaturated state. In formulating this model, the effective degree of saturation and the plastic volumetric strain were employed as the hardening parameters to express the changes in stiffness and swelling properties due to desaturation or saturation. In addition, a method was proposed for estimating the material parameters added to the expanded constitutive model. This study demonstrated the validity of the proposed constitutive model and the parameter estimation method by comparing the results of simulations with those of laboratory tests. |
| first_indexed | 2024-04-12T19:05:09Z |
| format | Article |
| id | doaj.art-2f5cd96aa8ad4d529c0c7415a3f26b00 |
| institution | Directory Open Access Journal |
| issn | 2524-1788 |
| language | English |
| last_indexed | 2024-04-12T19:05:09Z |
| publishDate | 2022-08-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Soils and Foundations |
| spelling | doaj.art-2f5cd96aa8ad4d529c0c7415a3f26b002022-12-22T03:20:03ZengElsevierSoils and Foundations2524-17882022-08-01624101161Constitutive model for swelling properties of unsaturated bentonite buffer materials during saturationShinji Ito0Shinya Tachibana1Tomohide Takeyama2Atsushi Iizuka3Civil Engineering Design Division, Kajima Corporation, JapanResearch Center for Urban Safety and Security, Kobe University, Japan; Corresponding author.Department of Civil Engineering, Graduate School of Engineering, Kobe University, JapanResearch Center for Urban Safety and Security, Kobe University, JapanBentonite-based materials are candidate buffer materials for the geological disposal of radioactive waste in many countries. Once the disposal facility is closed and the groundwater level recovers, the buffer will gradually become saturated by the infiltration of groundwater. The swelling properties of saturated bentonite affect the distribution of dry density and the stress state within the buffer. Therefore, to evaluate the long-term safety of the buffer, a model must be developed that can continuously express the mechanical behavior of bentonite from the construction and operation of the repository for disposal (the unsaturated state) to the resaturation phase (saturated state). In this study, the existing elastoplastic constitutive model for saturated expansive soils was extended to predict the mechanical response in the unsaturated state. In formulating this model, the effective degree of saturation and the plastic volumetric strain were employed as the hardening parameters to express the changes in stiffness and swelling properties due to desaturation or saturation. In addition, a method was proposed for estimating the material parameters added to the expanded constitutive model. This study demonstrated the validity of the proposed constitutive model and the parameter estimation method by comparing the results of simulations with those of laboratory tests.http://www.sciencedirect.com/science/article/pii/S0038080622000695Elastoplastic constitutive equationExpansive soilsBentoniteSwellingUnsaturated soils |
| spellingShingle | Shinji Ito Shinya Tachibana Tomohide Takeyama Atsushi Iizuka Constitutive model for swelling properties of unsaturated bentonite buffer materials during saturation Soils and Foundations Elastoplastic constitutive equation Expansive soils Bentonite Swelling Unsaturated soils |
| title | Constitutive model for swelling properties of unsaturated bentonite buffer materials during saturation |
| title_full | Constitutive model for swelling properties of unsaturated bentonite buffer materials during saturation |
| title_fullStr | Constitutive model for swelling properties of unsaturated bentonite buffer materials during saturation |
| title_full_unstemmed | Constitutive model for swelling properties of unsaturated bentonite buffer materials during saturation |
| title_short | Constitutive model for swelling properties of unsaturated bentonite buffer materials during saturation |
| title_sort | constitutive model for swelling properties of unsaturated bentonite buffer materials during saturation |
| topic | Elastoplastic constitutive equation Expansive soils Bentonite Swelling Unsaturated soils |
| url | http://www.sciencedirect.com/science/article/pii/S0038080622000695 |
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