Nonlinear analysis on load transfer mechanism of wholly grouted anchor rod along anchoring section

A novel nonlinear shear-slipping model of anchor rod according to load-displacement curve in the pullout test was established. Based on this model, the nonlinear differential equation of load transfer was established and the analytical solutions of axial force and shear stress were developed. The features of this model as well as the axial force and shear stress distributions along the anchor rod were analyzed. Results indicate that this model gives a peak value in its curve. With the slip increases, the shear stress initially goes up to the peak value then decreases, that is, this model characterizes the softening behaviors of anchorage interface reasonably. Under the pulling load, the anchorage interface undergoes three stages including elastic bonding stage, elastic-plastic deformation stage and rapidly softening stage. With the increase of pulling load, the shear stress distribution evolves from a monotone decay curve into a single peak curve and the influencing zone of the shear stress expands into far end gradually. Under the ultimate limited state, the whole anchorage interface softens rapidly into failure. The developed solutions are suitable for analyzing axial force and shear stress along anchor rod undergoing various stages, which provides theoretical reference for researches on the load transfer mechanism of wholly grouted anchor rod.