- Microstructure and anisotropic swelling behaviour of compacted bentonite/sand mixture
- S. Saba ; J.D. Barnichon ; Y.J. Cui ; A.M. Tang ; P. Delage
- Book Title / Journal: Journal of Rock Mechanics and Geotechnical Engineering
- Year: 2014 , Volume: 6
- Soil Mechanics
- Description
- Pre-compacted elements (disks, torus) of bentonite/sand mixture are candidate materials for sealing plugs of radioactive waste disposal. Choice of this material is mainly based on its swelling capacity allowing all gaps in the system to be sealed, and on its low permeability. When emplaced in the gallery, these elements will start to absorb water from the host rock and swell. Thereby, a swelling pressure will develop in the radial direction against the host rock and in the axial direction against the support structure. In this work, the swelling pressure of a small scale compacted disk of bentonite and sand was experimentally studied in both radial and axial directions. Different swelling kinetics were identified for different dry densities and along different directions. As a rule, the swelling pressure starts increasing quickly, reaches a peak value, decreases a little and finally stabilises. For some dry densities, higher peaks were observed in the radial direction than in the axial direction. The presence of peaks is related to the microstructure change and to the collapse of macro-pores. In parallel to the mechanical tests, microstructure investigation at the sample scale was conducted using microfocus X-ray computed tomography (μCT). Image observation showed a denser structure in the centre and a looser one in the border, which was also confirmed by image analysis. This structure heterogeneity in the radial direction and the occurrence of macro-pores close to the radial boundary of the sample can explain the large peaks observed in the radial swelling pressure evolution. Another interesting result is the higher anisotropy found at lower bentonite dry densities, which was also analysed by means of μCT observation of a sample at low bentonite dry density after the end of test. It was found that the macro-pores, especially those between sand grains, were not filled by swelled bentonite, which preserved the anisotropic microstructure caused by uniaxial compression due to the absence of microstructure collapse.
PDF |
- Thermal pressurization in Boom clay
- A.M. Tang ; M. Mohajerani ; J. Sulem ; P. Delage ; M. Monfared
- Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris, September 2-6 2013
- Year: 2013
PDF |
- Technical session 1e: Analysis
- R. Nova ; A. Murakami ; M. Rouainia ; P. Delage ; A. Gens ; J. Pestana ; D.V. Griffiths ; R. Uzuoka
- 16th International Conference on Soil Mechanics and Geotechnical Engineering (Osaka)
- Year: 2005
PDF |
- Sur la susceptibilité à l'effondrement des loess du Nord de la France
- Y.J. Cui ; P. Delage ; D. Marcial ; J.-M. Terpereau ; G. Marchadier
- 16th International Conference on Soil Mechanics and Geotechnical Engineering (Osaka)
- Year: 2005
PDF |
- Thermal pressurization in Boom clay
- M. Monfared ; P. Delage ; J. Sulem ; M. Mohajerani ; A.M. Tang
- International Conference on Soil Mechanics and Geotechnical Engineering - 18th International Conference on Soil Mechanics and Geotechnical Engineering (Paris)
-
PDF |
- Macroscopic effects of the hydration mechanisms in smectites; applications to engineered and geological barriers for radioactive waste disposal
- P. Delage
- TC106 Conferences in Unsaturated Soils - 7th International Conference on Unsaturated Soils 2018 (Hong Kong)
-
PDF |
- Effondrement d’un matériau de remblai compacté trop sec
- P. Delage
- International Conference on Soil Mechanics and Geotechnical Engineering - 12th International Conference on Soil Mechanics and Foundation Engineering (Rio De Janeiro)
-
PDF |
- Technical session 1e: Analysis
- R. Nova ; A. Murakami ; M. Rouainia ; P. Delage ; A. Gens ; J. Pestana ; D.V. Griffiths ; R. Uzuoka
- International Conference on Soil Mechanics and Geotechnical Engineering - 16th International Conference on Soil Mechanics and Geotechnical Engineering (Osaka)
-
PDF |
- Experimental characterizations of the hydro-mechanical behavior of a pellet/powder bentonite mixture
- A. MolineroGuerra ; N. Mokni ; Y.-J. Cui ; A.M. Tang ; P. Delage ; P. Aimedieu ; F. Bernier ; M. Bornert
- TC106 Conferences in Unsaturated Soils - 7th International Conference on Unsaturated Soils 2018 (Hong Kong)
-
PDF |
- Récents développements de la technique osmotique de contrôle de succion
- P. Delage ; Y.J. Cui ; E.De Laure
- International Conference on Soil Mechanics and Geotechnical Engineering - 15th International Conference on Soil Mechanics and Foundation Engineering (Istanbul)
-
PDF |
- INFLUENCE DE LA SUCCION SUR LA COMPRESSIBILITE D’UN LIMON NON SATURE
- P. Delage ; G.P.R. DeSilva
- International Conference on Soil Mechanics and Geotechnical Engineering - 13th International Conference on Soil Mechanics and Foundation Engineering (New Delhi)
-
PDF |
- Sur la susceptibilité à l'effondrement des loess du Nord de la France
- Y.J. Cui ; P. Delage ; D. Marcial ; J.-M. Terpereau ; G. Marchadier
- International Conference on Soil Mechanics and Geotechnical Engineering - 16th International Conference on Soil Mechanics and Geotechnical Engineering (Osaka)
-
- Soil Mechanics ; Laboratory Testing
PDF |
- Influence des mécanismes de rétention des polluants sur la résistance au cisaillement d’un sol compacté
- Y.J. Cui ; P. Alzoghbi ; L. Lei ; P. Delage
- International Conference on Soil Mechanics and Geotechnical Engineering - 15th International Conference on Soil Mechanics and Foundation Engineering (Istanbul)
-
PDF |
