Analytical model for the mechanical behaviour of bolted rock joints subjected to shearing

This study proposes a new analytical model for the prediction of the contribution of bolts to the shear strength of a rock joint. The main characteristics of this model are the accounts for the interaction of the axial and the shear forces mobilised in the bolt, as well as the large plastic displacements of the bolt occurring during the loading process. The complete curve of the bolt contribution as a function of the displacement along the joint can be computed, and the maximum bolt contribution is obtained by dissociating the bolt cohesion and the confinement effects. The comparison of the performances of this analytical model with test results shows its capacity to describe the observed phenomena. The effects of the most important parameters such as bolt inclination, mechanical properties of bolt material, rock strength and joint friction angle are clearly established and discussed.