Experimental investigation into temperature effect on hydro-mechanical behaviours of bentonite
Visualitza/Obre
10.3724/SP.J.1235.2010.00071
Inclou dades d'ús des de 2022
Cita com:
hdl:2117/15238
Tipus de documentArticle
Data publicació2010
EditorScience Press
Condicions d'accésAccés obert
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Abstract
The bentonite barrier of underground repositories for high-level radioactive waste will be hydrated by the groundwater while it is subjected to high temperatures due to the radioactive decay of the wastes. These changes of temperature affect the hydraulic and mechanical responses of bentonite, which has important effects on design and performance of repositories. The temperature influence on the hydro-mechanical behaviour of bentonite was studied in this paper by experiments, which were carried out with the Spanish FEBEX bentonite compacted at dry densities expected in the repository (from 1.5 to 1.8 Mg/m3). The dependence of the swelling strains of bentonite on the temperature has been measured from 30 °C to 90 °C. At high temperatures the swelling capacity of clay slightly decreases. Also, a clear decrease of swelling pressure as a function of temperature was observed for the same dry densities. Nevertheless, the deformation of bentonite is more dependent on the stress than the temperature. An increase in the permeability of water saturated bentonite with temperature has also been detected. The water retention curves of bentonite compacted at different dry densities were determined under isochoric conditions and in the range of temperatures from 20 °C to 120 °C. For a given density and water content, the suction decreases as the temperature increases at a rate, which is larger than the one predicted on the basis of water surface tension changing with temperature. Mechanisms related to the physico-chemical interactions that take place at microscopic level, in particular the transfer of interlayer water to the macropores triggered by temperature, seem to explain qualitatively the experimental observations.
CitacióVillar, M.V.; Gómez-Espina, R.; Lloret, A. Experimental investigation into temperature effect on hydro-mechanical behaviours of bentonite. "Journal of rock mechanics and geotechnical engineering", 2010, vol. 2, núm. 1, p. 71-78.
ISSN1674-7755
Versió de l'editorhttp://www.rockgeotech.org/qikan/manage/wenzhang/2010-01-07.pdf
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