Deterioration mechanisms of cantilever anti-slip pile rusting and swelling under acid rain erosion environment

This study utilized a self-developed “thrust load-acid rain erosion-dry-wet cycle” coupled experimental system. It analyzed the crack distribution patterns of pile bodies and clarified the distribution characteristics of steel reinforcement corrosion. Microscopic testing methods, such as XRD and SEM, were used to reveal the deterioration mechanism of cantilever anti-slide piles under acid rain erosion. A time-dependent model for the bearing performance of anti-slide piles was subsequently established. The results indicate that the horizontal thrust is positively correlated with the initial crack parameters (distribution width and quantity) of cantilever anti-slide piles, with crack spatial differentiation significantly concentrated on the tensile side. Moreover, an increase in load stress levels accelerates the process of concrete corrosion-induced cracking. The corrosion of steel reinforcement in cantilever anti-slide piles exhibits a longitudinal gradient distribution, intensifying from the pile top to the pile bottom, and shows a nonlinear positive correlation with load stress levels. The corrosion rate of stirrups (short limbs > long limbs) is significantly higher than that of longitudinal tensile reinforcement, while high loads reduce the critical corrosion rate at the onset of initial corrosion cracking. By establishing a quantitative relationship model between steel reinforcement corrosion rate and corrosion-induced crack width, it was found that crack width is approximately linearly correlated with the corrosion rate. Acid rain erosion, through chemical dissolution, expansion-induced cracking, and stress synergy, accelerates the failure of the concrete protective layer and the corrosion of steel reinforcement in cantilever anti-slide piles. The findings provide a theoretical basis for evaluating the durability of pile foundations in acid rain environments.