Security research and analysis of subway shield tunnel in different buried depth

The basic research method for this paper is the stratigraphic structure method, carrying out finite element analysis for the stress, strain and deformation of the subway shield tunnel lining segment, the segment joint and segment layup rubber cushion layer, based on considering three basic factors of subway shield tunnel buried depth, segment layup rubber material and ground heap load. The finite element analysis of this paper uses the three−dimensional entity finite element model(Koyama Y., Konishi S., Arai Y. and Okano N. (1997)), which includes lining segment, segment layup rubber layer and the surrounding soil. The research combines with the geological conditions of the Beijing subway, and takes into account of the tunnel lining design, rubber layer of material anticipates, the tunnel buried depth and many other factors. The results of the study show that the stress, strain and deformation of the whole subway shield tunnel lining segment and rubber layer is relatively homogeneous; the segment joints appear discontinuous displacement, which increases along with the tunnel buried depth increases ,with rubber layer elastic model decreases; the segment joints exist obvious tension stress concentration phenomenon, when tunnel buried depth exceeds 75 meters, the concentrated tensile stress is beyond the limit of reinforced concrete segments tensile stress. The study has a certain theoretical and practical value on the subway shield tunnel lining segment design.