Influence of compaction procedure on the mechanical behaviour of an unsaturated compacted clay - Part 1: Wetting and isotropic compression

The influence of compaction pressure, compaction water content and type of compaction (static or dynamic) on subsequent soil behaviour during wetting and isotropic loading has been investigated by conducting controlled-suctio n tests on samples of unsaturated compacted speswhite kaolin. The results a re interpreted within the context of an elastoplastic framework for unsatur ated soils, to examine which compaction-induced effects can be explained si mply by variation in the initial state of the soil and which require that s oils produced by different compaction procedures are modelled as fundamenta lly different materials. The compaction pressure influences initial state, by affecting the initial position of the yield surface, but it also influen ces, to a limited degree, the positions of the normal compression lines for different values of suction. The compaction water content influences the i nitial suction, but also has a significant influence (greater than does com paction pressure) on the positions of the normal compression lines. A chang e from static to dynamic compaction has no significant effect on subsequent behaviour.