The influence of pile group loading on existing neighboring tunnels is assessed by using the finite element method with the aim of furthering the understanding of the interaction problems. Firstly

some parametric studies including foundation layout and clear distance between piles and existing tunnels are carried out using the 2-D plane strain approach. Then a case study of Pacific Square Ⅱ of which minimum distance between pile foundations from Metro No.1 in Shanghai is only 15m

is analyzed by using this approach. According to the results

this approach can satisfy the pile rows loading problems. The loading of piles causes global downward movement and squatting of the tunnel lining. And the horizontal displacement of tunnel lining is much smaller than vertical displacement. The tunnel diametrical distortions are occurred in this case. It is very disadvantageous because of the differential movement of the two rails of the subway tunnel. The bending moment distribution behaves clockwise rotation due to pile loading. The crown settlement of tunnel lining and maximum bending moment change reduce with the increasing of pile space and clear space between pile and tunnel.