With the increasing complexity of the three-dimensional cross-distribution system of pile foundations and tunnels in the urban underground space

the stability of the pile foundation caused by tunnel seepage erosion becomes more and more prominent. However

the current research mainly focuses on the mechanism of erosion induced by defective tunnels

and little on its interaction with the adjacent pile foundation. Thereby

based on the seepage erosion mechanism revealed by the physical model test

the erosion-induced stratum form is quantitatively characterized by establishing the critical fine particle content expression. Subsequently

a multi-zone eroded strata model is simulated by the random and quantitative removal of fine particles in the DEM domain

and then the erosion response characteristics of the foundation under different positions

loads

sinking methods and types are analyzed. The results show that the pile foundation has different degrees of subsidence under different erosion conditions

and tilts to the eroded area under the drive of unbalance force on its eroded position. After the erosion-induced reduction

the pile-tip resistance increases gradually with the subsidence

but the loss of lateral frictional resistance is basically unrecoverable. In addition

the changing mode of displacement and resistance of the pile is basically the same under different sinking methods and loads

only different in the changed amount. Compared with the single pile

pile group foundation has a better erosion resistance.