Research On Mutual Influence Of Metro Shield Tunnel Construction And Adjacent Pile Foundation

It’s often occur that in the subway construction the subway tunnels have the existing pile foundation, the adjacent pile will interaction with the tunnel which is under construction, it will bring a potential threat for security and safety of the tunnel construction, so studying the interaction between the tunnel and the neighboring foundation pile has important project value.This papers according to the background of the north tower bridge project in the shenyang Subway Line 10 Project (Dingxiang Park-Zhang Shabu), using the numerical simulation software FLAC3D to study the interplay between the adjacent shield tunneling and pile foundation mutual. Study location factors, by controlling the two parameters which include the level of the pile to the centerline axis of the tunnel distance e, and the pile at the bottom of the vertical to the tunnel centerline distance h, and by doing simulation calculations, comparative analysis of the results obtained with different positions of pile foundation influence of tunnel segments; studying the pile load factor, load values suffered by changing the basis of simulation piles, comparative analysis of the results obtained under different loads influence of pile foundation and between tunnel segments.Research shows that shield construction to adjacent had the greatest influence on the vertical deformation of the pile foundation, the existence of pile foundation will cause the tunnel segment displacement and stress change. Pile foundation at the top of the tunnel (e≤ 0.5D, D is the outer diameter of the tunnel), affected more than other cases, and the impact will increase with the decreasing h; Deformation of tunnel segments significantly increased, dome suffered tensile stress and compressive stress on both sides of the tunnel changed significantly. When pile foundation located on both sides of the tunnel (0.5D <e), pile foundation impact decreases with the increase of e, and with the reduction h decreases; In the different load cases, get the variation of the deformation of pile foundation settlement tunnel segments and stress and fitting expression formula. For the calculation of the specific project, get a different order of tunneling and pipe sheet pile foundation deformation little effect; Grouting measures taken within the shield zone, the impact will be between the size of the pile foundation and tunnel segments effective control, the effect is significant.