An Investigation of Swell-Shrink Behavior of an Expansive Soil



Expansive soils show swelling and shrinkage behavior when subjected to cyclic wetting and drying. The variation in water content influence the volume change in this kind of soil. These volume changes can cause ground movement which may result in damage to the buildings and structures. To study the behavior, a number of successive wetting-drying cycles were conducted on a statically compacted expansive soil in a modified oedometer apparatus. Axial deformations and changes of void ratio as well as the degree of saturation of soil during the drying-wetting cycles were determined according to variation in its water content. Results show that cyclic wetting-drying reduces the susceptibility of soil to swelling. Also variations of water content and void ratio demonstrate that water content-void ratio swell-shrink paths are S-shape curves, while shrinkage of soil occuring in three different phases, happening in specific water content and degrees of saturation.