Chemico-Osmotic Effects in Fine-Grained Soils

A theory to describe the simultaneous coupled diffusional flow of salt and water in soils is summarized. Examination of the coupling effects indicated by the theory and a computer analysis of consolidation caused by chemico-osmotic coupling shows that the effects of coupling should increase as soil void ratio decreases and soil compressibility and salt concentration differences increase. Test results have shown that chemico-osmotic effects do not exist, and the rates of solution flow are in reasonable accord with theoretical predictions. Chemico-osmotic consolidation is likely to be small for most soils, except for very fine-grained active clays like bentonite. However, these and other studies have shown that chemico-osmotic coupling is capable of moving soil pore water and dissolved salts and that chemico-osmotic soil stabilization might be feasible in certain cases.