Investigation of the structural effect induced by stagger joints in segmental tunnel linings: Numerical explanation via macro-level structural modeling

Abstract

It is known that the local joint behavior has a significant influence on the overall performance of the lining structure. In the previous study, the authors designed and conducted a series of full-scale experiments to obtain the structural bearing capacity and failure mode of single rings and stagger-jointed triple rings. The stagger effect, which is caused by the stagger-joint assembly method, was discussed. However, due to the high cost of full-scale tests, the sample size was still limited for the authors to reach a general quantitative conclusion regarding the optimization strategy of the stagger effect. To solve the problem, the authors developed a macro-level numerical model to simulate the nonlinear behavior of stagger-joint segmental tunnel linings. The results of full-scale ring tests are employed to validate the model. Based on the model, the interaction between rings is described as inter-ring shear forces, which were divided into radial and tangential directions. The distribution and structural effect of the inter-ring shear forces are revealed. The present paper also contains a report on a comprehensive parametric study of the influence of several design parameters, such as the bolt ratio, bolt location, thickness-diameter ratio, shear capacity of the circumferential joint, and distribution of longitudinal joint. The influence of the various parameters on the initial structural stiffness, reserve strength, bending transmission factor, and ductility coefficient of segmental tunnel linings are discussed. Based on this analysis, several design strategies are suggested to ensure the safety, reliability, and economy of design of segmental tunnel linings.