HR: 0830h
AN: H31D-0493    [PDF]
TI: Analytical modelling of chemical and electro-osmosis in clayey soils
AU: * Bader, S
EM: s.bader@citg.tudelft.nl
AF: Department of Hydrology, TU Delft, Stevinweg 1, PO Box 5048, Delft, 2600GA Netherlands
AU: Schotting, R
EM: r.j.schotting@citg.tudelft.nl
AF: Department of Hydrology, TU Delft, Stevinweg 1, PO Box 5048, Delft, 2600GA Netherlands
AB: \noindent{Groundwater flow and solute transport are} generally well described by the linear Darcy and Fick equations. In clayey environments however, these equations may not suffice to describe evolution of salinity and hydraulic head. Because of the semipermeability of clay, various other driving forces come into play. For example, water flux can be induced by a concentration gradient (chemical osmosis) or by an electrical potential difference (electro-osmosis). Understanding the role of osmosis in groundwater systems may, for instance, facilitate assessment of contaminant leakage from waste disposal sites screened by clay liners.\\ \\* In this study, various coupled processes in clay soils were investigated. Analytical methods were employed to model experiments from literature. For example, closed form solutions have been found for differential equations describing chemical osmosis across a clay sample. Also, an experiment on streaming potential was modelled: the buildup of potential, related to the pressure evolution, was reproduced in numerical simulations. The counterpart of streaming potential is electro-osmosis; the aforementioned modelling of chemical osmosis was extended with the influence of an electric potential gradient.\\ During a chemical osmosis experiment on clay, the sample will swell due to the uptake of water. This phenomenon was investigated using material coordinates and solutions were obtained for one-dimensional swelling and consecutive shrinking of clay.
UR: http://www.hydrology.citg.tudelft.nl/work/staff/sbader.html
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: 2003 Fall Meeting