Abstract: In an attempt to determine the stress condition of anchor in drawing process, two softening constitutive models for anchoring interface in consideration of residual strength are introduced, and the physical meanings of the parameters are analyzed. According to field data of load-displacement relation, parameter inversion of interface constitutive model was conducted by particle swarm optimization algorithm in two engineering examples. With the parameters of the interface model obtained by inversion, by solving the loading transfer differential equation, the axial force and the interfacial shear stress distribution of anchor under different drawing loads are predicted. The predicted results are in good agreement with the experimental data, which proves the rationality of the introduced models and the feasibility of the inversion method. Moreover, the stress variation process of anchor was analyzed. Results reveal that during the drawing process, the shear stress distribution evolves from a monotone decaying curve with the maximum value at the pull end into a single peak curve, with the peak extending to the far end. The research results of this paper provide a basis for the design and construction of anchor bolts.

Key words: anchor bolt, interface constitutive model, parameter inversion, particle swarm optimization, load transfer