Multishear bounding surface modelling of anisotropic sands accounting for fabric and its evolution

This paper presents a multishear bounding surface model for sands that considers evolving fabric anisotropy. The model is formulated by decomposing the overall response into a macro volumetric response and a set of spatially distributed micro shear responses. The micro stress–strain and stress–dilatancy relationships are defined for each direction of the micro shear structure. The evolving fabric tensor and anisotropic state parameter are used to characterize changes in the anisotropic structure and to satisfy the anisotropic critical state theory. The model performance is validated by the test data under different confining pressures, densities, loading modes, and loading directions.