When clay soils are subjected to salt concentration gradients, Various interrelated processes come into play. It is known that chemical osmosis induces a water flow and that a membrane potential difference develops that counteracts diffusive flow of solutes and osmotic flow of water. fit this paper, we present the result of experiments oil file influence of membrane potential oil chemical osmotic flow and diffusion of solutes and we show how we are able to derive the membrane potential value from theory. Moreover, the simultaneous development of water pressure, salt concentration and membrane potential difference are simulated using a model for combined chemico-electroosmosis in clays. A flew method for short-circuiting the day sample is employed to assess the influence of electrical effects oil How of water and transport of solutes. (c) 2005 Elsevier Inc. All rights reserved.