Model Test Study On The Shield Tunnel Lining Of Subway Affected By Xi'an Ground Fissure

With the rapid development of Xi'an, traffic problems have become increasingly prominent. The Metro project has been put up. However, due to natural and man-made factors, ground fissures have been developing constantly and 14 pieces of ground fissures have appeared from north to south in the area of Xi'an since the late 1970s. These ground fissures have caused great damages and economic losses to the city's building. The Metro project in Xi'an which is under constrction is unable to avert these ground fissures. This is the first time to build metro through ground fissures at home and abroad. It is urgent to be solved that making sure how the ground fissures affect the metro structure, the deformation failure mechanism of the metro tunnel affected by the ground fissures, what structural measures should be adopted to avoid damage by the ground fissures.In the large-scale (1:5) model test about the metro shield tunnel through a ground fissure, this paper educes the stress-strain characteristic of shield tunnel lining crossing the ground fissure, the stress situation of soil around the lining and the settling characteristic of soil in the stratums ,and researches how the ground fissures affect the shield tunnel lining in the typical depth of the layers 20.0m scope of Xi'an, including the deformation and damage of the lining, the stress and deformation of the soil near the structure, and makes sure the damage mode of the shield tunnel lining and provides scientific bases for metro structures.Based on the model test, the author established the numerical model about the ground fissures and the metro tunnel by MARC finite element software. By numerical calculation, the author analyzed the stress and deformation of the lining under the influence of the ground fissures, the deformation of the soil near the lining and so on. What's more, the author compared the results of the numerical analysis and the model test in order to supply scientific basis for the structure design of the No.2 metro that is built by shield-driven tunnel when passing through the ground fissures. At last, the author made propose for the structural measures of the shield-driven tunneling subway when passing through the ground fissures.The study of this paper is subsidized by the key project of National Natural Science Foundation of China (40534021).