关键词: 盾构法, 桩-隧道相互作用, 隧道埋深, 平行双隧道, 垂直双隧道, 开挖顺序

Abstract: Metro is an effective way to solve the traffic problem in downtown around the world. It happens occasionally that metro tunnel is constructed near building foundation such as pile foundation. It is a difficult job to evaluate the effect of tunneling on piles nearby. Finite element method is adopted to fully understand the effect. Pressures and shearing forces are enforced on the soils in the finite element models to simulate the real reactions between shield driven machine and the soil surrounded during tunneling. Results from the model adopted here in the finite element method show fine agreement with those measured in the Tianjin metro line project No.1. Researches on the effects of shield driven tunneling on the adjacent single pile are carried out considering the buried depth, number of tunnels and the sequence of tunnel construction. When the horizontal distance between pile and tunnel is kept unchanged, there is a critical depth of tunnel; when the tunnel is located at this critical depth, the settlement at pile top and the deformation of pile reach the maximum value. When the depth of tunnel is small, pile may move upwards during tunneling. The smaller the buried depth of tunnel, the greater the increment of settlement at pile top when the lateral horizontal distance between pile and tunnel is reduced by the same amount. Settlements at pile top caused by twin tunnels are always greater than those caused by single tunnel. Settlement and deformation of pile arisen from twin tunnels driven together are greater than those when the two tunnels are driven separately. Whether the twin tunnels are driven together or not, settlements at pile top caused by twin vertical-tunnels are smaller than those caused by twin parallel-tunnels.

Key words: shield driven, pile-tunnel interaction, buried depth of tunnel, twin parallel tunnels, twin vertical tunnels, sequence of tunneling