Finite element investigations of granular material behaviour during cyclic wall shearing under a constant normal stiffness condition

Abstract

The behaviour of dry and cohesionless sand during quasi-static cyclic wall shearing under a constant normal stiffness (CNS) condition was studied. Numerical calculations were carried out using a finite element method based on a hypoplastic constitutive model extended by micropolar quantities: rotations, curvatures, and couple stresses. The mean grain diameter was used as the characteristic length of the microstructure. The constitutive model takes into account the effects of pressure, void ratio, and direction of deformation rate on the material’s behaviour. Calculations were performed for several shear cycles in a direct wall shear tester. The initial void ratio, mean grain diameter of sand, and vertical normal stiffness were varied. The numerical results with medium density sand were compared with corresponding laboratory tests.