A numerical study of interaction between rock bolt and rock mass

In order to improve the design of rock bolts, it is necessary to have a good understanding of the behavior of rock bolts in rock masses. Several analytical models of describing the interaction among of the rock bolts, the grout medium and the rock mass have been proposed in literatures. In this paper, a numerical simulation procedure was developed for a rock bolt subjected to a concentrated load in pullout tests. The study was concentrated on the failure at the interface between the bolt and the grout. The commercial code FLAC3D was used to analyze the coupling and decoupling phenomenon at the bolt-grout interface. The interface provided by FLAC3D which is characterized by Coulomb sliding and/or tensile separation is proved the premise for simulating the problem. On the basis of a numerical parametric study, the effects of dilation angle and confining pressure on the behavior of the inter-face were clarified and the failure mechanism on the interface was identified.