Mechanical behaviour of heavily compacted bentonite under high suction changes

A. Lloret, M. Villar, M. Sanchez, A. Gens, X. Pintado, E. Alonso

Research output: Contribution to journalArticle

294 Citations (Scopus)

Abstract

The paper reports the results of an experimental study carried out on a bentonite compacted to a dry density of up to 1·7 Mg/m3, a high value for this type of soil. The soil fabric has been studied using a variety of techniques, revealing a clear bimodal pore distribution that corresponds to two distinct structural levels: a microstructural one and a macrostructural one. The main testing programme has been performed using oedometers especially designed to apply a very large range of suctions. By applying the axis-translation technique (using nitrogen as the gas fluid), it has been possible to reach suctions up to 15 MPa. The higher suction range has been achieved by applying a controlled atmosphere where the relative humidity has been fixed by a solution of sulphuric acid or salts. In this way suctions up to 550 MPa could be reached. The maximum vertical stress that could be applied in the apparatus was 10 MPa. Two types of test have been carried out: (a) tests in which a combination of loading paths at constant suction and drying/wetting paths at constant load were applied; (b) swelling tests under constant-volume conditions in order to determine the swelling pressure and the stress path followed during wetting. The results of the experimental programme are examined, taking into account the role of the soil fabric in controlling observed mechanical behaviour. In addition, the results of the laboratory tests are reproduced and interpreted using a generalised plasticity model that considers explicitly the interaction between macrostructure and microstructure. In this way, it is possible to achieve a more complete understanding of the mechanisms that underlie observed behaviour, and in particular the interplay between the two structural levels.
LanguageEnglish
Pages27-40
Number of pages13
JournalGeotechnique
Volume53
Issue number1
DOIs
Publication statusPublished - 2003

Fingerprint

Bentonite
bentonite
suction
Soils
Swelling
Wetting
wetting
swelling
Plasticity
Atmospheric humidity
Drying
soil
Protective atmospheres
Salts
dry density
Nitrogen
Microstructure
Fluids
Acids
sulfuric acid

Keywords

  • constitutive relations
  • soils
  • laboratory tests
  • radioactive waste disposal
  • suction
  • bentonite
  • mechanical engineering

Cite this

Lloret, A., Villar, M., Sanchez, M., Gens, A., Pintado, X., & Alonso, E. (2003). Mechanical behaviour of heavily compacted bentonite under high suction changes. Geotechnique, 53(1), 27-40. https://doi.org/10.1680/geot.53.1.27.37258
Lloret, A. ; Villar, M. ; Sanchez, M. ; Gens, A. ; Pintado, X. ; Alonso, E. / Mechanical behaviour of heavily compacted bentonite under high suction changes. In: Geotechnique. 2003 ; Vol. 53, No. 1. pp. 27-40.
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Lloret, A, Villar, M, Sanchez, M, Gens, A, Pintado, X & Alonso, E 2003, 'Mechanical behaviour of heavily compacted bentonite under high suction changes' Geotechnique, vol. 53, no. 1, pp. 27-40. https://doi.org/10.1680/geot.53.1.27.37258

Mechanical behaviour of heavily compacted bentonite under high suction changes. / Lloret, A.; Villar, M.; Sanchez, M.; Gens, A.; Pintado, X.; Alonso, E.

In: Geotechnique, Vol. 53, No. 1, 2003, p. 27-40.

Research output: Contribution to journalArticle

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AU - Lloret, A.

AU - Villar, M.

AU - Sanchez, M.

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AU - Alonso, E.

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