Numerical and analytical solutions for describing the mechanical response of segment joints for tunnels

Abstract

In literature there are several analytical models for describing the mechanical behavior of non-bolted segment joints (longitudinal joints) of shield driven tunnels. These joints modify the structural response of the segmental lining and therefore they affect the global response of this kind of tunnels. The rotational stiffness of these joints is divided into linear and multi-linear models being two typical moment-rotation constitutive equations those exposed by Janssen and Gladwell. The first one considers a linear stress distribution in the longitudinal joint. However, this is not correct according to elasticity theory due to at the edge of the contact area stresses reach infinite values and non-linear stress distributions are produced at the joint. The second typical moment-rotation equation is based on elasticity theory. The analytical results obtained from these moment-rotation equations were compared to numerical results of a 3D model based on Finite Element Method (FEM) using isoparametric solid elements for modeling the concrete segments, whilst for simulating the joint were incorporated contact elements; achieving to confirm that the constitutive equation proposed by Gladwell provides results more precise of the mechanical response of these joints achieving a difference of 0.07% in the maximum capacity of bending moment between the analytical model proposed by Gladwell and 3D numerical model carried out in this study.