Study on Damage Evolution and Safety Assessment of Bridge Pile Foundation Structure under Repeated Blasting Vibrations from Canal Excavation

In the blasting excavation project of the Pinglu Canal channel, the adjacent bridge pile foundation is in a repeated blasting vibration environment for a long time, and its structural damage accumulation effect directly affects the safety performance of the whole life cycle of the bridge. Clarifying the damage evolution mechanism of pile foundations under repeated blasting vibration is a key scientific premise for ensuring the coordinated development of efficient canal channel excavation and the safe operation of adjacent bridges. Based on the channel blasting project for the Luyang New Village Bridge in Pinglu Canal, combined with a finite element numerical model that considers the cumulative damage of the concrete structure, the influence of on-site blasting construction on the pile foundation during construction is simulated and analyzed. Based on the reliability analysis of the model, the cumulative damage variation law of pile foundation under different blasting times is simulated and analyzed. The damage variable prediction model based on the peak vibration velocity of pile foundation is established, and the cumulative blasting times of pile foundation safety under the given blasting center distance are obtained. The results show that the maximum damage variable value of the pile foundation appears on the horizontal side of the explosion source. When the explosion center distance is less than 20 m, the damage to the pile top area is significantly aggravated. The safe blasting times for pile foundations are 2~3 times longer when the blasting center distance is 20 m.