As far as the working mechanism of a rock nail is concerned, the strains of the rock induce a stress state in the nail composed of shear and traction stress, due to the roughness of the joints, to their opening and to the direction of the nail, generally non-orthogonal to the joint itself.
The functioning principle of a rock nail is based on the fact that the strains within the rock cause a stress state in the nail, comprising shear and frictional stresses, due to the irregularities of the joints, their opening, and the direction of the nail, which is generally not parallel to the joint.