Simulation Analysis On Influence Of Shield Tunnel Excavation To Neighboring Foundation Pit Support

Shield tunneling has been widely used in metro tunnel construction because of it’sadvantages, shield tunnel technology is constantly improved and perfected in practice. But,due to the influence of different geological conditions and construction craft, the effectswhich induced by the underground space exploitation on the surrounding clay andstructures are inevitable. Shield tunneling will influence the behaviors of adjacentfoundation pit fencing structures, even case engineering accidents. The study on thisproblem becomes more and more instant.For considering the construction of shield tunnel adjacent to an existing deepexcavation, this paper demonstrates the analysis of the soil mass deformation by means ofsimilar model test under laboratory condition and3D FEM computation. Through thecomparing experimental results with the numerical simulation results, the feasibility andreliability of the simulation was verified. In order to investigate the influence of shieldtunneling on the ground settlement, soil displacements and pit supporting structure, thethree dimension-al finite element method was be used, which considering the interaction ofthe shield tunnel, soil and existing excavation. The main works of this paper are listed asfollows:1. In this paper, the feature of ground settlement distribution were studied bycombination of model test and numerical calculation, it also analysis the surface settlementabove tunnel at different construction stages.2. With the numerical calculation results, the distributions of soil displacement aroundthe tunnel associated with the shield tunneling are analyzed in detail, the soil performancesand its behavior mechanism induced by shield tunneling is also explained.3. This paper analysis the displacement and deformation of underground continuouswall, the analyses provide not only the global displacement of the wall, but also thedeformation feature and displacement regularity.4. This dissertation analyses and studies on the shield tunnel construction of adjacentdeep excavation based on the three-dimensional FEM, the impact on different retainingstructures are studied, and the results are compared with each other. Meanwhile, somehelpful suggestions on soil displacements and deep excavation safety control of shieldtunneling approaching are offered.