The Numerical Analysis On The Deep Foundation Pit Excavation By Steps Of Subway Station

At present, subways construction is in full swing in mangy large cities of China. As a result, a large number of excavation engineering occurs automatically. And the size and depth of the foundations are increasing continuously. People pay more and more attention to the security problems and the influence on surrounding environment because of excavation engineering.The excavation engineering incorporates many subjects such as the geotechnical and structural engineering into an organic integrity, which is highly comprehensive and influenced by many factors. In the excavating process, not only the stability of excavation should be ensured in order to construct all kinds of engineering both inside and outside excavation safely, but also the safety of facilities such as adjacent buildings and underground pipe-lines should be ensured. So doing research about the displacement after excavation and the stability of soil and supporting structure is an essential problem.This paper mainly introduces the following content:the features, deformation and deformation mechanism of excavation engineering; the status of earth pressure theories on excavation engineering; the influence factors of deformation; the application on excavation engineering by Finite Difference Software FLAC3D; the control measures on deformation and so on.The deformation must happen in foundation pits in the process of excavation, which includes horizontal displacement of underground diaphragm walls, ground surface settlement and bottom heave. This paper simulated the process of excavation by Numerical Analysis Software FLAC3D, taking Xi Xiang Station of Shenzhen Metro for example. In the process of numerical analysis, this paper simulated the properties of soil by Mohr-Coulomb Plasticity Model, underground diaphragm walls and steel timbering by elastic materials, the contact between walls and soil, then simulated the process of excavation in steps and multi-timbering structure construction. At last, this paper obtained the changing situation of displacement during the process of excavation in steps and multi-timbering structure construction. In the mean time, the control methods of deformation of foundation pit are summarized. This paper's conclusion provides reliable reference to design, informational construction and construction monitoring of deep foundation pit.