Mechanical behaviour of semi-rigid connections coupling two concrete segmental linings

This paper describes the use of segment joints in shield-driven tunnel linings. The opening of segment joints due to the application of a bending moment under different levels of axial stress is studied. The main focus is the mechanical behaviour of the joints, which are considered to be semi-rigid, and the moment-rotation behaviour of the joint. A physically based mathematical model is proposed based on the joint dimensions and material properties. Considering joints connected by two long curved bolts as an example, the model parameters are evaluated, and the moment-rotation curves for the joint are presented. The model distinguishes joint behaviour before and after opening, and agrees well with the real mechanical behaviour of the joints. A comparison with previous experiments on segment joints and with Janssen's and Gladwell's models is provided, and the proposed model is found to be accurate and universal.