The effects of longitudinal joint assembly imperfections on the internal forces in segmental linings

Abstract During the assembly of concrete segments into a tunnel lining, small geometric imperfections are unavoidable. In the longitudinal joints, they lead to contact deficiencies, which affect the eccentricities of the forces transferred through them. This influences the development of internal forces along the lining's circumference. However, it is often not realistically considered in structural calculations. In this paper, the effects of longitudinal joints assembly imperfections on the lining's internal forces were investigated by employing finite element models for various lining configurations. The results show that assembly imperfections have an unfavorable effect on the internal forces in most cases. Depending on the loading situation, this can lead to more required reinforcement and higher utilization ratios in the segments field and joints compared to perfectly assembled linings. Stiffer and less deformable configurations are at higher risk of experiencing more severe effects. In systems at risk, an individual assessment is recommendable. Therefore, a simplified method is introduced that requires a significantly reduced modeling effort and calculation time and lower software capabilities.