THREE-DIMENSIONAL NUMERICAL ANALYSIS OF EFFECT OF TUNNEL CONSTRUCTION ON ADJACENT PILE FOUNDATION

Three-dimensional numerical analysis is used to simulate the influence of tunnel construction on adjacent pile foundation;and its comparison with two-stage method is carried out.Results show that this numerical program is able to simulate effectively the interaction effects between tunnel and piles.Based on these,a 3D elastoplastic model is established to study the whole interaction among pile,soil and tunnel in the cohesive foundation with actual tunnel construction steps.The outcome of numerical simulations shows that tunnel construction imposes a significant effect on adjacent pile foundation.The deformation and stress states of piles are closely dependent on not only the tunneling step,but also the position,length and quantity of piles.The presence of piles not only improves the stress state of the neighboring soil greatly but also aggravates the soil deformation.The pile bending moment along the tunnel axis is fairly large in value and complicated in distribution,especially for the long pile.The pile group is able to increase the stress performance of piles due to tunnel construction obviously.