Study On Mechenical Characteristics Of Segment Ring Of Shield Tunnel Under High Water Pressure

With the economic development, the submerged tunnel appears more and more, and itsload condition of high water pressure becomes more apparent with the buried depth. At pre-sent, metro shield tunnel under low water pressure and shallow covering has been studied alot, and its stress mechanism is well studied. However, load system of shield tunnel underhigh water pressure changes frequently due to the environmental changes. So the lining stressmechanism of shield tunnel under high water pressure is different from that of commonshield tunnel. Therefore, the design of the shield tunnel under high water pressure is quitedifferent from that of common shield tunnel. Therefore, the design of the shield tunnel underhigh water pressure is quite different from that of common shield tunnel. The research ondouble water seal and inclined bolt in transverse and longitudinal of segment joint are rare.Therefore, it is necessary to conduct deeper research on mechanical properties of shield tun-nel under high pressure and its design details of segment joint.In this paper uses the finite element analysis software MIDAS/GTS for geotechniqueand tunnel is used. Based on the Zhanjiang Bay Shield Tunnel Project, the elaborated3DFEM solid model of the segment ring lining is established without considering the longitudi-nal effect. This paper simulates the features of joint according to the mechanical characteris-tics of different materials of the joint, and studies the deformation and stress features of thewhole segment ring lining structure subject to different factors that can influence the struc-ture’s stress. This study is supposed to give some guidance to the tunnel design and construc-tion, and provide a valuable idea for stress analysis of shield tunnel lining.The main works of this paper are as follows:(1)In this paper, the cases of shield tunnel under high water pressure in China are re-searched. The research and design progress of shield tunnel under high water pressure aresummed up. This paper takes the Zhanjiang Bay Shield Tunnel Project as the background,and conducts deep analysis on its design material. Based on this, on one hand, the design in-tent is discussed through some details and features of the segment; on the other hand, thisanalysis affords relatively accurate judgments for following choice of computational parame-ters and conditions. (2)In this paper, the segment detail features such as double seal, inclined bolt joint, posi-tioning bar, load cushion, handhole are considered based on the Zhanjiang Bay Shield TunnelProject. The research status of interface and peripheral spring foundation model are also in-troduced. Based on these, the elaborate3D solid FEM model of the segment ring is estab-lished. Besides, the separate calculation of water and soil pressure is selected in aspects ofloading. In this case, soil pressure is calculated by Terzaqhi soil pressure formula and waterpressure is according to static water pressure.(3) The factors that affect the stress of the shield tunnel lining are discussed. Accordingto the elaborate3D solid FEM model of the segment ring and factors such as different geo-logical conditions, underwater conditions, grouting pressure, and different space positions ofthe key segment, this paper obtains the segment ring lining’s main deformation features andthe relation curves of the deformation, stress, stress concentration level with those factors bynumerical simulation method.