Study on vertical bearing characteristics of pile group foundation considering damage

Aiming at the change of mechanical properties of bridge pile group foundation under corrosion, Abaqus finite element software was used to establish a bridge pile foundation model for analysis. Based on the improved Najar damage theory, the theoretical derivation of the damage evolution parameters in the code is derived. The damage factor is derived. The corrosion of the pile foundation is simulated by the method of reducing the elastic modulus. The spalling thickness represents the corrosion degree of the pile foundation. The displacement and bearing capacity of the pile under load, as well as the axial force and friction resistance of the corner pile, side pile and center pile are studied. The results show that under the working load condition, the load sharing ratio of the corner pile is the highest, followed by the side pile, and the sharing ratio of the middle pile is the lowest. However, as the peeling thickness increases, the difference between the three gradually decreases. The vertical ultimate bearing capacity of pile foundation decreases with the increase of peeling thickness, while the vertical displacement of pile foundation increases with the increase of peeling thickness. Under the action of load, the corner pile first shows signs of damage. In the process of increasing load, the damage range of the central pile gradually expands and deepens due to the increase of the load borne by the central pile. Therefore, enough attention should be paid to the reinforcement of damaged pile group foundation caused by pile foundation corrosion.