Abstract:

 It is important to consider the effect of shield tunneling on adjacent pile foundation during the construction of urban tunnels.This paper discusses the methods of three-dimension numerical simulation of shield tunneling,and then analyzes the effect of tunneling on the adjacent single-pile foundation and the corresponding affecting rules in terms of different relative position between the tunnel and the adjacent pile.The analytical results are finally compared with those from field monitoring and laboratory model testing.It is indicated that（1） both the end bearing force and the side friction of the pile highly relate to the tunnel position;（2） when the tunneling is just below the pile toe,the end bearing force continuously decreases and even disappears at a small ground loss,while the side friction gradually increases;（3） when the tunneling is at the side of the pile（about half tunnel diameter away from the pile）,the end bearing fore continuously increases,while the side friction decreases even to a negative value;（3） when the tunnel is at the mid-depth position of the pile side,large bending moment of the pile may occur;and（4） the impact of tunneling significantly decreases with the increase in horizontal distance between the tunnel and the pile.

Key words: tunneling, pile, three dimensional numerical analysis, end bearing force, shaft friction, negative friction