Contents lists available at ScienceDirect Tunnelling and Underground Space Technology journal homepage: www.elsevier.com/locate/tust 3D response analysis of a shield tunnel segmental lining during construction and a parametric study using the ground-spring model Pattanasak Chaipanna, Pornkasem Jongpradist ⁎ Department of Civil Engineering, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, Thung Khru, Bangkok, Thailand ARTICLE INFO Keywords: Ground-spring model Shield tunneling Soil-tunnel interaction 3D FEM Lining ABSTRACT In this research, an analysis method aiming as a tool to investigate the behavior of a tunnel lining during construction is developed based on a nonlinear ground-spring model in conjunction with a finite element method. A nonlinear ground-spring model that considers yield pressures is proposed and implemented into the numerical analysis. All relevant components of the shield tunnel construction process including the TBM, jack thrust force, shield tail wire brush, segmental lining, key-segment and ring and segment joints and proper in- teractions are considered in the analysis model. The reliability of the developed method is verified by comparing the analysis results with the full-scale test and field measurements of a previous study. The developed analysis method could reasonably reproduce the responses of a segmental lining at various stages with special attention during construction. A series of parametric analyses are conducted to highlight the robustness of the developed method to capture the effect of the key factors on the structural behavior of the segmental lining during con- struction. The effects of the tunnel depth, forces from eccentric jack thrust together with shield tail wire brush and position of key segment on the induced lining stresses can be well captured. 1. Introduction Shield tunnel construction, a rapidly developed construction tech- nique, has been increasingly employed in urban development due to several merits such as low impact on the surrounding structure, good applicability in a wide range, allowing for a long boring route and any tunnel depth (Guglielmetti et al., 2007; Koyama, 2003). A segmental lining is a vital component of the shield tunnel, which supports against various kinds of loads during construction as well as the surrounding soil pressure, water pressure and a localized load from any future ac- tivities throughout the service stage. Generally, the segments are stag- geringly assembled within the Tunnel Boring Machine (TBM) and connected together by tightened curve bolts to making up the tunnel ring. Normally, a tunnel ring consists of several standard segments, two special segments and one key-segment (standard + special + key). The reinforced concrete adopted in casting the tunnel segment is generally designed according to the standard load cases of demoulding, storage, embedded ground condition and grouting processes (DAUB, 2013). During the tunnel construction, various loads act on the tunnel lining, including the jack thrust force, shield tail wire brush pressure, grouting pressure and ground pressure. The hydraulic jack pushes against the lining edge to drive the TBM. The already congested underground space has obligated the excavation of the tunnel at greater depths and unfavorable conditions, leading to higher load levels. In this context, there has been an increase in the seriousness and the frequency of lining damage during the construction stage, as reported in previous studies (e.g., Han et al., 2017; Sugimoto, 2006; Yang et al., 2017), particularly during driving along a curve alignment (Sugimoto, 2006). Segment cracking usually takes place at the key and adjacent segments (Yang et al., 2017). In addition to the contact deficiency during the installation of the segments (Blom et al., 1999; Burguers et al., 2007; Waal, 1999; Mo and Chen, 2008), the great jack thrust force is also a reason for vast segment damage and cracks, which appear between jack pads and under jack pads in the tunnel axis direction (Blom, 2002; Conforti et al., 2017; Liao et al., 2015; Sugimoto, 2006). The jack thrust also forces key-segment squeezing through the gap between adjacent segments, which causes chips in the edge or spalls at the corner (Blom et al., 1999; Cavalaro and Aguado, 2012; Fuente et al., 2017). Fur- thermore, during TBM driving along the curve alignment, not only the hydraulic jack but also shield tail wire brush will press on the lining. The pressing of the wire brush induces segment dislocation and damage (Mo and Chen, 2008; Yang et al., 2017). Various load scenarios are suggested to be considered in the current design guidelines (BTS and ICE, 2004; ITA-WG2, 2000; JSCE, 2007). These also include the jack https://doi.org/10.1016/j.tust.2019.05.015 Received 13 September 2018; Received in revised form 18 April 2019; Accepted 18 May 2019 ⁎ Corresponding author at: Department of Civil Engineering, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, 126 Pracha Uthit, Bang Mod, Thung Khru, Bangkok 10140, Thailand. E-mail address: pornkasem.jon@kmutt.ac.th (P. Jongpradist). Tunnelling and Underground Space Technology 90 (2019) 369–382 0886-7798/ © 2019 Elsevier Ltd. All rights reserved. T