Influence of Matric Suction on the Volume Change Behaviour of a Compacted Clayey Soil

Estimation of volume changes in compacted soils is an important aspect for the analysis, design and performance of geotechnical works. It has been observed that several stability problems, involving those materials, are due to water content changes and therefore to matric suction changes that occur periodically in nature. This paper shows the results of an experimental programme carried out to study the volume change behaviour due to wetting processes on compacted kaolin samples. The influence of the dry density, compaction water content and the stress conditions prior to wetting, on the collapsible and expansive behaviour, is discussed paying special attention to the influence of suction. The experimental programme used conventional oedometer and suction controlled oedometer testing. Different wetting stress paths were followed verifying the applicability of an elastoplastic constitutive model for the volume change behaviour of compacted soil.