Effects of Drying on the Low-Frequency Electrical Properties of Tournemire Argillites |
| |
| Authors: | Philippe Cosenza Ahmad Ghorbani Nicolas Florsch André Revil |
| |
| Institution: | (1) Université Pierre et Marie Curie, UMR Sisyphe, Case 105 - Tour 46/56- 3ème étage 4, place Jussieu, 75252 Paris Cedex 05, France;(2) UMR 6635, CNRS-CEREGE, Université d'Aix-Marseille III, Aix-en-Provence, France |
| |
| Abstract: | Nearly water-saturated argillite samples (initial water content near 3.4 wt%) were cored from an undisturbed area of an underground
facility of the French Institute for Radioprotection and Nuclear Safety (IRSN), located at Tournemire (Aveyron, France). These
samples were subjected to the following desiccation path: (a) A desaturation phase during which the samples were dried at
ambient temperature conditions, relative humidity equal to 43% in average and (b) a heating phase during which the same samples
were heated at four temperature levels from 70°C up to 105°C. During both phases, the low-frequency complex resistivity (0.18Hz–12
kHz) was recorded by a four-electrode device. The amplitude of the complex resistivity was extremely sensitive to water content
change. At the end of the isotherm desaturation phase, it was multiplied by a factor of 3 to 5. During the heating phase,
the resistivity increased by more than two orders of magnitude compared to the initial state. The percentage of Frequency
Effect shows a low sensitivity to water content changes during the desaturation stage while it increased by two orders of
magnitude during the heating phase. This result confirms that low-frequency spectral signature is extremely sensitive to textural
changes (i.e., thermal-induced microcracking in this case) that occurred during heating. Moreover, the complex resistivity
of the samples shows a strong anisotropy (a ratio of 10 between both amplitudes measured in the perpendicular directions).
The classical Cole-Cole model cannot be used to fit the experimental data obtained in the heating phase. A generalized formulation
of this model is required and was successfully applied to represent the complex resistivity data. |
| |
| Keywords: | Spectral-induced polarization complex resistivity argillite drying microcracks |
| 本文献已被 SpringerLink 等数据库收录！ |
|
