Structural Response of a Single-Span Reinforced Concrete Tunnel under Combined Vertical and Lateral Loading

The structural stability of single-span reinforced concrete tunnels is significantly influenced by the interaction of diverse loading conditions throughout their service life. While vertical loads often represent standard service conditions, the inclusion of lateral loading—resulting from surrounding soil pressure or seismic activity—can drastically alter the stress state and deformation profile of the tunnel lining. This study presents a numerical investigation into the structural response of a single-span reinforced concrete tunnel (۸m span, ۴m height, ۳۰cm thickness) under the simultaneous action of vertical and lateral loads. Using the ABAQUS finite element environment, a three-dimensional model was developed to analyze the stress distribution and displacement patterns under combined loading scenarios. The study focuses on evaluating the critical zones of the lining by examining von Mises stress (S, Mises) and displacement components (U۱ and U۲). The results demonstrate that the interaction between vertical and lateral loads shifts the critical stress concentrations, revealing a more complex structural demand compared to isolated vertical loading. This comparative analysis provides essential insights into the structural efficiency and safety margins of tunnel linings, establishing a necessary foundation for evaluating performance under more severe, time-dependent, and accidental loading conditions. The findings underscore the importance of integrating lateral effects in the design process to ensure the long-term integrity of underground infrastructure.

کلیدواژه ها:

Single-span tunnel ، Concrete lining ، Finite element analysis (FEA)