Development of crack and damage in shield tunnel lining under seismic loading: Refined 3D finite element modeling and analyses

Abstract

This paper investigates the development of crack and damage in shield tunnel lining under seismic loading. Based on a recently constructed undersea-shield tunnel, i.e. the Shantou Bay Tunnel, a series of refined 3D Finite Element (FE) models are created and validated. In order to consider the stratum–structure interaction, a preliminary FE model is generated with a simplified lining tube. Thereafter, a refined lining model is created with the loading condition obtained by the aforementioned preliminary model. The refined lining model is employed for exploring the seismic response of the tunnel lining, considering the details of the lining components. Finally, two types of partial segment models are used for examining the cracking process during the seismic loading within the framework of quasi-static analysis. XFEM, as well as the CDP (Concrete Damage Plasticity) constitutive assumption, is adopted in the partial segment models. The simulation results show that: (i) the damage tends to occur at the crown and bottom of the tunnel lining; (ii) the segment assembling type has significant influence on the damage development; (iii) the direction of the bending-moment induced by the earthquake has little influence on the ultimate moment of the segment at failure, and the cracks tend to emerge at the middle of the segment first instead of the joint; (iv) some of the cracks in the standard segments is probable to initiate inside of the concrete instead of the outer rim of the segment; and (v) longitudinal cracks are dominant in the standard segment with the cracking area within the range of 1.4–1.6 m on both sides of the maximum bending-moment point of the segment.