Description of induced anisotropy in microstructure of granular soils

The primary focus in this work is on developing a methodology for specification of an evolution law which correlates the changes in the fabric of granular soil with the continuing deformation. The fabric descriptors are based on lineal intercept measurements and include the areal pore size and the mean intercept length distribution. The approach involves performing a series of Discrete Element simulations for a granular assembly under evolving directions of the principal stress/strain and defining a correlation with the evolution of material axes. It is demonstrated that granular materials with spherical particles may become anisotropic as a result of a continuing deformation process. For dense assemblies characterized by a high macroscopic friction angle (e.g., dense sand), the evolution law governing this induced anisotropy may be defined by assuming coaxiality between the microstructure and the total strain tensors.