Structural anisotropy by static compaction

Induced anisotropy can be applied to soils in different ways, in natural or in laboratory conditions. The aim of this work was to study the effect of load compaction in a specific remoulded residual soil from granite, especially in terms of its effect on the critical state behaviour and isotropic compression. For that purpose, isotropic compression tests and triaxial compression tests were performed up to high pressures in specimens compacted in two different ways: by moist tamping or by multi-layer heavy static compaction imposed by a load frame. The results indicated that isotropic consolidation to high pressures can minimize the effect of compaction, although the anisotropic behaviour still remains expressed by different normal compression lines for each type of compaction despite the lack of particle crushing. The same was observed when the critical state lines were obtained from triaxial compression tests taken to high strains. Analysis of radial and axial strains as well as velocities of shear waves transmitted and polarised under distinct paths and directions were also clear in showing a distinct pattern of stress–strain behaviour.