Centrifuge Modeling of Soil Loss Effects on Adjacent Pile Foundations Induced by Tunnel Excavation

In the context of rapid urbanization and infrastructure development, tunnel excavation has become increasingly popular in urban areas. However, the effect of tunneling on adjacent foundation piles is one of the most serious issues, especially in cohesionless soils. This study was performed by centrifuge modeling at 100 g acceleration to investigate the effects of tunnel‐induced soil loss on the performance of adjacent pile foundations. The results revealed significant redistribution of soil stress, with a reduction near the tunnel and an increase beyond one to two tunnel diameters away from its centerline. Axial force and bending moment distributions in piles were substantially dependent on tunnel depth, soil properties, soil loss levels, pile length, and relative pile position. Furthermore, piles located within 0.5–1.0 tunnel diameter from the tunnel centerline exhibited significant negative skin friction, significantly reducing their load‐bearing capacity. Additionally, the study also proposed an improved method to evaluate pile‐tip bearing capacity, explicitly accounting for tunneling‐induced stress changes. These findings offer practical guidance to decrease tunneling‐related foundation settlements, improve foundation designs, and provide a solid experimental basis for subsequent numerical analysis and field validations.