A. Ghorbani - Department of Mining and Metallurgical Engineering, Yazd University, Yazd, Iran.
Ph Cosenza - UMR ۷۶۱۹ Sisyphe, Université Paris ۶, Paris, France
A. Revil - Colorado School of Mines, Dept. of Geophysics, Golden, CO, ۸۰۴۰۱, USA-CNRS-ANDRA / GDR FORPRO ۰۷۸۸, Nîmes, France-CNRS, LGIT (UMR ۵۵۵۹), Université de Savoie, ۷۳۳۷۶ Le Bourget-du-lac, France
M. Zamora - Institut de Physique du Globe de Paris, CNRS et Université Paris ۷ Denis Diderot, France

The characterization of flow and transport properties of clay soils and clay rocks is a challenging task, particularly in unsaturated states, due to the lack of suitable in situ and laboratory measurement techniques. Laboratory measurements can provide valuable information on the soil characteristics at sampling locations. Geophysical exploration techniques have been increasingly used to infer the monitoring of the properties of the saturated and the unsaturated zones. Seven well-characterized clay-rocks have been taken from three test sites, located in France, to perform spectral induced polarization (SIP) measurements during desiccation of these samples. To dry these samples, we first desaturate them at ambient temperature. This first phase was followed by a second (heating) phase during which the same samples were heated at four temperature levels from 65ْ C up to 105ْ C. Measurements of the SIP spectra show that the quadrature conductivity, at very low frequency, is sensitive to the loss of free water from the macropores and to the loss of water in the micropores associated with textural changes. The non-clayey (calcite and quartz) grain size distributions have a significant effect on the low-frequency spectral signature.

Spectral induced polarization, Complex resistivity, Clay-rock