ABSTRACT
In contrast to Proctor’s theory, the mechanical approach to soil compaction allows analysis of the density and evolution of soil variables at each point of the space subjected to compaction. From a mechanical point of view, compaction of soils is similar to strain hardening of metals. Nevertheless, soil compaction does differ significantly from hardening of metals. Metal hardening occurs at the crystalline level by rearranging structural defects, but soil compaction happens in a distinct material by changing the geometry of the arrangement of particles which can occur together with some modification of particle’s sizes, shapes and surface roughness due to attrition or crushing. In contrast, the right side of a compaction curve is controlled by possibility of air leaving the void space of the soil which means that it depends on air conductivity. Once the vertical stress exceeds the over-consolidation stress, soil undergoes plastic volumetric strains which increase the unit weight of the soil and produce irreversible strains, i.e. compaction.
