Influence of the Anisotropy of Confining Stress on the Sand/Steel Interface Behaviour in a Cylinder Shear Apparatus

According to the type of works and to the consolidation of the ground, soil-structure interfaces are orientated in various ways with respect to the stress tensor in the soil. For instance, before shearing, the normal stress applied to the interface could be the major stress in the soil or the minor one or some intermediate value. This paper shows how the anisotropy of confining stresses can influence the behaviour of sand/steel interface. To this end, a series of tests was conducted with the cylinder shear apparatus. The cylinder shear apparatus is dedicated to the study of the shear behaviour of ground/structure interfaces. This device controls the radial confining stress and an average axial confining stress. One is particularly interested in estimating the influence of anisotropy of confining stresses and to look for empirical laws clarifying this influence on the peak shear, the post-peak shear, the displacement needed for full mobilization. The influences of the roughness of the interface, of the density of the sample and of the level of confining stresses are also studied.