To investigate the impact on the mechanical effects and deformation of existing pile foundations due to subway tunnel excavation,a combined approach of theoretical analysis and model test was adopted.The study analyzed tunnel excavation-induced soil disturbances,stress characteristics of existing pile foundations,and the interaction between tunnels and piles.The results reveal that:(1)The disturbance deformation region caused by tunnel excava-tion is primarily concentrated within four times the tunnel diameter on both sides of the tunnel axis.The disturbance degree of the surrounding soil increases as excavation progresses,and the additional bending moment of the pile foundation exhibits an"S"shape at different excavation stages.(2)The closer the distance between the tunnel and the pile foundation,the greater the disturbance to the pile foundation.As the tunnel depth increases,strain distur-bances in the pile foundation decrease while deformation disturbances increase.(3)Based on the single pile distur-bance degree theory,the excavation influence range between the tunnel and pile foundation was classified,and cor-responding reinforcement measures were proposed for different influence zones.
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