An experimental study of vaporous water migration in unsaturated lime-treated expansive clay

To ensure safety of lime treatment for expansive clay foundation, investigation of vaporous water migration features is of great significance since moisture migration leads to changes in engineering behaviors of the lime-treated expansive clay. Herein, a novel model was described to perform the vaporous water migration tests of unsaturated lime-treated expansive clays. And effects of initial water content, lime dosage, curing time, migration period, and transfer distance on vaporous moisture migration were discussed. The soil–water characteristic curves (SWCCs) and textures of expansive clay and the corresponding improved soil treated with 7 % lime were determined to further investigate changes in hydraulic characteristics by means of the geotechnical digital system (GDS) and scanning electron microscopy (SEM) tests. The results indicated vaporous water migration between two soil columns of different initial water contents increased as migration time went by, and moisture content variation mostly occurred in the first 30 days. For the cases of same 24 % initial water content in the left soil column, variation of moisture content in the case of 0 % initial water content in the right soil column after 90 days migration was about 3 times and 78 times, respectively, bigger than that for the cases of 6 and 12 % initial water content in the right soil column. Besides, as migration distance increased, it took longer time to reach the water migration balance. Moreover, the left and right soil columns behaved different migration characteristics, and transfer speeds of mixing water within the soil columns and vaporous water between columns were different.