ABSTRACT
This study focuses on the seismic safety of tunnel-shaft joints in urban underground roads. Using a shield tunnel project as an example, a numerical model was created in ABAQUS to analyze how the relative elastic modulus ratio and connection stiffness affect the joint opening and the end wall effect.
The findings show: (a) The elastic modulus ratio significantly affects the joint opening but has an upper limit. Flexible materials reduce the range of the end wall effect but may increase joint deformation. (b) Different contact conditions lead to noticeable result differences. The study used multi-point constraints and connector elements to calculate connection stiffness, which was verified by theory and offered supplemental insight into seismic calculations. Based on the research findings, a new joint type is proposed, which combines rigid-spring connections to reduce axial protrusion and joint impact. Detailed construction steps and methods are included in other patent results of this study.
