A constitutive elasto-viscoplastic model is presented which combines the properties of the jointed rock mass and the rock bolt system. Different mechanisms of single joint-bolt systems are analyzed. Mechanisms like axial straining, tension-stiffening (due to bonding between grouted bolts and rock) and dowel action are included in the model. Stiffness properties are derived from pull-out tests on single bolts. The various stiffnesses and compliances from multi-directional joint sets and bolt sets are superimposed with intact rock properties in a model of the rock mass.