Study On Interaction Berween Subway Shield Interval And Building Structures In Soft Soil Area

Subway line is mostly planned in the prosperous area of city center, which could not avoid the construction with some adverse effects to the surroundings. East China (such as Shanghai, Nanjing, Ningbo, etc) is in soft soil area. Shield construction method is mostly used in this area, whose construction risk is less than mining and open-cut construction method. In soft soil area, mostly comprised of sandy soil and muddy clay, soil quality is worse than Northern China and the strength of soil will be dramatically reduced after disturbed. Some soil layers contain the bearing water. Therefore, if the construction effects to the surroundings not controlled, shield construction method can easily make the ground structure produce excessive uneven settlement leading to risk.This paper use FLAC3D finite element sofeware to simulate and analyze the project case concerning shield across below the YONG-JIN large overpass and the effect of foundation pit excavation to the adjacent built shield.In this paper, shield across soil of YONG-JIN overpass is simulated numerically by FLAC finite element software. Firstly, establish FLAC3D strata structure model, considering three different calculation working conditions (not grouting, partial grouting reinforcement ground, all grouting reinforcement ground).Then simulate the bridge pile foundation settlement and the uneven settlement along the bridge and cross the bridge for the YONG-JIN overpass AC(WEST)、BD(EAST) ramp bridge and ring road bridge mainline, resulting from the process of double line shield tunnel driving. Finally, create Midas civil load-structure model and check the additional internal force and deformation for the upper structure of bridge under the worst working conditions of uneven settlement.