Study on the Force Transfer Process of Bolt–Slurry Interface of Full-Length Bonding Anchor System at Earthen Sites

The debonding and sliding of the bolt–slurry interface is the main failure form of the full-length bonding anchor system (FLBAS) of earthen sites, so it is urgent to carry out a quantitative study of the force transfer process of the anchorage interface. Based on field test results and existing research results, it was found that the bilinear bond–slip model is in line with the description of the constitutive relationship of the bolt–slurry interface. The whole process of debonding slip is discussed accordingly; the expressions for the slip, the axial strain of the bolt, and the load displacement at the bolt–slurry interface corresponding to the different loading stages are deduced; and the calculations of the ultimate load-carrying capacity and the effective anchorage length are given at the same time. On this basis, the bond–slip model parameters were calibrated by identifying the characteristic points of the bond–slip curve; a multi-parameter cross-comparison validation of the reasonableness of the theoretical analytical model was carried out on the basis of in situ pull-out tests; and the law of the influence of anchor bond length and axial stiffness on the anchorage performance was analyzed. The analytical model proposed in this study is widely applicable to the analysis of force transfer processes at the bolt–slurry interface in the presence of complete debonding phenomena and provides a useful reference for optimizing the design of anchors while minimizing interventions.