Researches On 3D Finite Element Simulation And Measured Datum Analysis Of Excavation Of A Subway Deep Foundation Ditch In Changchun West Railway Station

With the further expansion of city size, the existing system is difficult to bring traffic to meet the travel needs of the densely populated, more and more choice for the construction and planning of urban subway lines to ease traffic pressure, corresponding also brings a lot of metro station Deep pit excavation engineering problems.While expanding the size of the pit, increasing the depth of change in cross-section, it gave the existing underground structure construction design brings new challenges.Deep excavation of the difficulty and high risk, the need to protect the safety of the construction process and the environment.Each step by the finite element numerical simulation of excavation stages, can be a good analysis of the stress state and deformation behavior pit structure to determine whether its design and excavation reasonably safe.For the cross-section of a large deep pit has changed, its structure itself and the space where the action has been brought by the site can not be ignored, the two-dimensional finite element analysis is very confined, so consider joint action structure and soil is very three-dimensional numerical simulation necessary.Then accurate numerical simulations can not replace the real-time monitoring of the scene, conduct actual research projects in Metro, deformation and internal force of supporting structure to monitor various conditions of the construction phase, can provide protection for the safety of the construction phase, to avoid pit major accidents during the construction phase; also can provide the theoretical analysis and design methods to improve the basis for engineering test data, comparative analysis and numerical simulation can also be further validated the theory and design reliability. Therefore, the study found the deep excavation site of great significance.In summary, the subway station deep excavation for three-dimensional simulation of the measured value and the scene is very significant.Taking a major subway deep excavation in Changchun West Railway Station for the project basis, summed up the past excavation experience, strength and deformation of that study during excavation, concrete impact on the steel support facilities for excavation analysis to verify the support necessity structure specifically as follows:1.From the support structure deformation and mechanical performance pit start, on the mechanical characteristics during excavation were analyzed.2.Based on the actual situation of deep excavation of a metro station in Changchun, discusses the calculation model and parameter value, using Midas GTS NX software to support the excavation pit and there were no supporting excavation of two dimensional numerical excavation simulation, by contrast structural deformation during excavation work to study each exert specific effects on pit steel support, the support structure is applied to verify the necessity of excavation time.3.Excavation deformation and internal force-site monitoring, the excavation measured data and numerical simulation of Midas value of each stage of the comparative analysis, combined with the actual situation of the construction to discuss the reliability of calculation and analysis, the theory and practice of combining engineering for similar projects accumulated relevant experience.