Derivation of soil-specific streaming potential electrical parameters from hydrodynamic characteristics of partially saturated soils

Détails

ID Serval
serval:BIB_0E7898C2D1E7
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Derivation of soil-specific streaming potential electrical parameters from hydrodynamic characteristics of partially saturated soils
Périodique
Vadose Zone Journal
Auteur(s)
Jougnot D., Linde N., Revil A., Doussan C.
ISSN-L
1539-1663
Statut éditorial
Publié
Date de publication
2012
Peer-reviewed
Oui
Volume
11
Pages
15
Langue
anglais
Résumé
Water movement in unsaturated soils gives rise to measurable electrical potential differences that are related to the flow direction and volumetric fluxes, as well as to the soil properties themselves. Laboratory and field data suggest that these so-called streaming potentials may be several orders of magnitudes larger than theoretical predictions that only consider the influence of the relative permeability and electrical conductivity on the self potential (SP) data. Recent work has improved predictions somewhat by considering how the volumetric excess charge in the pore space scales with the inverse of water saturation. We present a new theoretical approach that uses the flux-averaged excess charge, not the volumetric excess charge, to predict streaming potentials. We present relationships for how this effective excess charge varies with water saturation for typical soil properties using either the water retention or the relative permeability function. We find large differences between soil types and the predictions based on the relative permeability function display the best agreement with field data. The new relationships better explain laboratory data than previous work and allow us to predict the recorded magnitudes of the streaming potentials following a rainfall event in sandy loam, whereas previous models predict values that are three orders of magnitude too small. We suggest that the strong signals in unsaturated media can be used to gain information about fluxes (including very small ones related to film flow), but also to constrain the relative permeability function, the water retention curve, and the relative electrical conductivity function.
Création de la notice
30/03/2012 16:10
Dernière modification de la notice
20/08/2019 12:35
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