In order to investigate the bonding performance of bonded anchorage systems in deep-buried tunnels and ensure the safety during the excavation of deep tunnels, this study takes the high-stress conditions of the No. 2 diversion deep-buried tunnel at Jinping Second Hydropower Station as a research background. The bonding performance during tunnel excavation and anchor pull-out processes was studied by combining numerical simulation, experiment and monitoring. The study analyzed the variation patterns of stress states in surrounding rock at different depths. Based on the stress conditions obtained, a physical model of the anchorage system was constructed to analyze the load-displacement evolution characteristics at the interface between the anchor rod and grouting body during the pull-out process. The research results show that after excavation, the stress of the surrounding rock is redistributed, with the confining pressure generally increasing with depth, and the inhomogeneity and local instability of the surrounding rock stress occurring. As the resistance of surrounding rock increases, the peak shear stress of the bonded anchors rises. After reaching the peak value, the shear stress decreases more rapidly. The force process of the anchor can be categorized into three phases: the elastic phase, the plastic softening phase, and the complete sliding phase, culminating in complete failure. When the diameter difference between the anchor rod and grouting body is about 6~9 mm, the bonding performance is optimal. The model precision was confirmed through the integration of lab testing and on-site monitoring data. This study can provide a reference for the application of bonded anchors in deep-buried tunnels and other underground engineering projects.
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