Abstract: The inability of the Cable model in FLAC3D to simulate anchor failure poses challenges in analyzing the stability of the surrounding rock under complex geological conditions. To address this limitation, the author enhances the Cable model using numerical methods and proposes a failure criterion for anchors. The constitutive relationship between the normal of the Cable model and the axis of anchorage is modified using the FISH language and the algorithm is embedded in the calculation program. Additionally, a multimechanical characteristics(MMC) model for anchors based on the link model is constructed. Furthermore, this model is validated through anchor tension tests and simulations. Finally, a case study is conducted on the Yuezhishan tunnel to analyze the applicability of the Cable and MMC models in project simulations. The results demonstrate the following: (1) The modified constitutive model encompasses the damage and failure stages, aligning the actual mechanical behavior of the anchors. (2) The anchor tension test simulation results closely match the real test results, with a maximum error of 2.9%, indicating the feasibility of the MMC model in simulating the anchor force and failure characteristics. (3) The MMC model can visually depict the location of anchor fracture and failure in engineering simulations and simulate anchor system failure. In contrast, the Cable model continues to support the surrounding rock after anchor failure and exhibits substantial errors. (4) The MMC model expands the application range and improves FLAC3D and simulation capability, thereby enhancing the applicability of the Cable model. 

Key words: tunnel, high geostress, anchor, multimechanical characteristics anchor model, Cable model, anchor failure criteria