An Analytical Model for Fully Grouted Rockbolts with Consideration of the Pre- and Post-yielding Behavior

Abstract

For rockbolts subjected to tensile loads, there exists a unique local slip–strain relationship as well as a unique bond–slip relationship between rockbolts and rock mass. An analytical model is presented in this study for fully grouted rockbolts under tension, based on the slip–strain relationship of rockbolts. This analytical model takes into account the trilinear bond–slip relationship and the pre- and post-yielding characteristics of the rockbolt material. The reliability and accuracy of the proposed analytical model are verified by experimental pullout tests. Verification studies show that the proposed model is capable of representing the strain and stress distributions of the rockbolts, and the overall load–displacement relationships of rockbolts before and after yielding. Additionally, the model has successfully captured the decoupling mechanism at the bolt–rock interface.