Influence of stress-volume path on swelling behavior of an expansive clay

Abstract

This study deals with the influence of stress-volume paths on the swelling behavior of an expansive soil. Swelling potential is usually characterized by means of free swell tests, swelling tests under constant load or constant volume tests (to infer the swelling pressure). However, in "real life" engineering applications, the boundary conditions and resulting stress paths are more complex. A weathered claystone comprising about 27% in mass of smectite and coming from the Hunter Expressway site, near the University of Newcastle, has been used for this study. The material was tested under different stress-volume paths and initial conditions (void ratio and water content). Mercury intrusion porosimetry was combined to freeze-drying technique in order to investigate the correlation between swelling and microstructure. The final swollen equilibrium state was defined at both the macro scale (values of swelling pressure and/or swelling strain) and micro scale (pore size distribution). The results suggest, at least for the soil tested, that the stress-volume path does not influence the final swollen state in a large extent