Abstract: To analyze the coupling action of rock block, bonding layer and rockbolt, a three-dimensional refined numerical model of jointed rock mass anchorage system under constant normal stress was established considering the elastic-plastic behavior of rock block, the deterioration of tensile and compressive stiffness of bonding layer and the necking characteristics of anchor bolt. The joint surface morphology was established based on Barton's joint surface roughness. The reliability of the model was demonstrated by comparing with the experimental results first. Then, the effects of anchorage angle and joint surface morphology on the shear performance and the progressive damage behavior of each element were further analyzed. The results are summarized as follows: the deformation of rockbolt exhibits three stages: linear elasticity, plastic strengthening and ductile damage softening. The anchor angle has a great influence on the stress distribution, and the breaking displacement of rockbolt decreases with the increase of anchor angle. The horizontal displacement of rock block shows three stages: no obvious increase, slow increase and rapid increase. The roughness of joint surface greatly affects the morphology of plastic zone of rock block. The stiffness reduction trend of bonding layer exhibits a three-stage linear variation law. The bonding layer is prone to debonding due to extrusion, resulting in uncoordinated deformation of anchoring system. The conclusions are of great significance to the disaster prevention of anchorage engineering.

Key words: jointed rock mass, anchorage, coupling effect, progressive damage, 3D simulation