The theory of finite strains of a granular material

The flow of a granular material is modelled using the rheological method supplemented by a new element, viz., a rigid contact, which serves to take into account the different resistances of the material to extension and compression. The elastic properties characteristic of the compact medium are taken into account on a phenomenological level. The Cauchy stress tensor and Hencky's logarithmic strain tensor are used to describe the stress-strain state in Euler variables. It is shown that such a choice of tensors ensures thermodynamic correctness of the constitutive relations and leads to a faithful description of the effect of dilatancy for an arbitrary magnitude of the shear.