Moisture Migration Tests on Unsaturated Expansive Clays in Hefei

Expansive clay in semiarid area behaves features of typical unsaturated soil, which is sensitive to climate and moisture, appears multi-fissures, deterioration of mechanical performances with the change of moisture. Consequently, to ensure the rational design of foundation treatment, and safe operation, research on moisture migration mechanism of expansive clays is of great significance. Herein, test models of mixed water migration and vaporous water migration were presented to investigate the mechanism. Series of tests, in which the moisture content in left soil column was same as 24%, and in right soil column was 0%, 6%, 12% and 18% respectively, were conducted under constant temperature. It is concluded that the moisture content changed with increase of migration time in both migration models, and the migration behaves nonlinear when the initial water content increase up to 6% for mixed water migration model and 12% for vaporous water migration model. But the migration characteristic of mixed water and vaporous water were different. The initial 30 days the change of moisture water was larger in mixed migration model, however in vaporous water migration model within 60 to 90 days was larger. These results will provide a basis for reveal evolution mechanism of engineering behaviors of unsaturated expansive clays.