This thesis is dedicated to the modelling and to the mechanical analysis of a rockfall protection barrier under dynamic impact. The considered rockfall dam is built with an assembly of parallelepiped cells. Cells are wire netting cages filled with granular material. A multi-scale approach is proposed to study the behaviour of the structure. In order to model the rockfall protection dam and its components, the distinct element method is used. The double twisted hexagonal mesh of the cells is described by a discretization of the wire netting sheet. The elasto-plastic behaviour of the wire mesh is considered until the failure. After the coupling of the wire mesh with the granular material under the same computing environment, the mechanical behaviour of a single cell is explored under different loading paths in quasi-static and dynamic conditions. Form these tests, a constitutive model representative of the macroscopic behaviour of the cell is proposed in order to model the structure. Discrete elements are used to model the structure. The interactions between these elements are described by the constitutive model of the cell. The study of the structure behaviour submitted to a dynamic loading is carried out to show the influence of structural parameters and the influence of impact conditions.
