Effect of shield tunneling on adjacent pile foundations in water-rich strata

Abstract

Shield tunneling in urban environments inevitably intersects with adjacent pile foundations, adversely affecting their internal forces and deformations. In this study, a series of model tests and numerical simulations were conducted to examine shield tunneling across pile foundations. The disturbance caused by shield tunnel excavation on the ground surface and pile foundations under different groundwater conditions was analyzed in detail. The results indicate that, compared to dry strata, shield tunneling in water-rich strata increases the maximum surface settlement by approximately 22 %, while also raising the axial force of pile foundations by 16 %–23 % and the lateral displacement of pile bodies at various depths by 15 %–28 %. Furthermore, as the pile foundation diameter increases, the absolute bending moment rises significantly. It is suggested that the pile-tunnel distance should be greater than 2 D_t in engineering design to greatly reduce the response of pile foundation.