Numerical modeling of the dynamic behaviour of tunnel lining in shield tunneling

This paper studies the impact of metro train operation on the shield tunnel lining and its soft foundation. A complex elasto-plastic 3D dynamic finite difference model is used by fully considering the joints to show the dynamic response of the shield tunnel buried in soft soil under the vibrating load. The simulation result for joint was compared with the result when the joint was not considered. Through the formulation of computationally efficient numerical models, this paper examines the dynamic behaviour of these two particular types of lining structure. The differential Eq.s governing the vibration of a curved beam is discretized by the FLAC^3D code. Numerical results demonstrate that an operating metro train induces significant dynamic response in the structure of the lining of the shield tunnel and its soft foundation. Of two horizontally symmetric the one near the joint is more severe in its dynamic response than that of the one far from the joint; the nearer the zone of the foundation soil to the lower half of the segment-ring, the more severe the dynamic response. The dynamic response influenced by joints is more severe than the response not influenced by joints, showing that the non-joint assumption is somewhat impractical.