Simulation And Analysis Of Shield Tunneling Method Construction For Subway

In the 21st century, the world's economy has accelerated the rapid development of urbanization. With the improvement of urban density and increasing of high-rise buildings, Less and less ground space is available, And a variety of pipelines bestrew the underground. So how to use effectively and create underground space has become an important issue for the current urban modernization, It is a best choice for us to use shield tunneling method to exploit underground space.To ease the traffic pressure of Nanchang's urban roads and improve the traffic environment, the 1st line of subway in Nanchang currently is in full construction. For a city with just started construction of the subway, it needs a certain simulated analytical data to do some predictions. Moreover, with the development and innovation of software technology, now FEM simulation technology has been widely applied to the subway construction. It not only acquaints construction personnel with the construction craft and circumstance, but also more conducive to conduct the design and construction.This paper regard shield tunneling method construction in subway as the research's object, through the finite element software ANSYS to simulate and analysis it, and obtained some useful conclusions, for that the study content of this paper are as follows:(1) Use current knowledge and theory to come up with modeling implementation methods of subway tunnel, then by the data from Zhengzhou subway construction, achieve three improvements and their implementation methods in ANSYS direct at the inadequacies existing in current simulating method1) According to the actual construction conditions, use a non-uniform distribution grouting to replace the previous uniform distribution grouting in simulating way of grouting pressure;2) When the soil ahead excavation face suffer from the jacking pressure of shield machine, its rigidity decrease due to be disturbed, and because of the effects of the excavation face's unloading, jacking pressure change correspondingly, at this point consider improvement of the solving way when properties of soil material change.3) Simulating improvement for the change of grouting layer's rigidity:according to the actual value of grouting layer's rigidity based on time, establish dynamic model more reasonably and accurately.(2) According to the subway tunnel construction in Nanchang which will be started with, establish model and calculate it on section tunnel project from FengHe station to QiuShui Square station of 1st line, the analysis content are as follows:1) The duration curve of earth's surface subsidence under this project condition;2) The change of lining segment's stress under this project condition;3) The variation of influencing factors on the earth's surface subsidence;4) The earth's surface subsidence on every influencing factor's value of sensitive degree.Provide some suggestive measures on the basis of analysis and summary for Nanchang subway construction, and provide reference for the design, conduct construction with informatization, and play a role for predictions.