Abstract
Different methods are available for determining the swell pressure of expansive soils. Selecting the appropriate method depends on the prevailing boundary condition in situ. Two boundary conditions (constant stress and constant volume) applied during wetting were investigated in this paper. The influence of examined boundary condition on volume change characteristics is presented in this research. The evaluated volume change characteristics include axial and mean swell pressures as well as compression and swelling indices. Three methods for evaluation of swell pressures were utilized in current research, namely; swell under load, swell-load and constant volume methods. Findings show that the boundary condition applied during wetting has a considerable effect on swell pressures estimated and to some extent affect the estimated compression index while it has no impact on the predicted swell index.