Impact of nearby excavation on stability of existing urban tunnel

The rapid expansion of underground construction in urban areas has intensified interactions between new and existing subterranean structures, such as tunnels and foundations. Construction activities near existing tunnels require careful monitoring to assess expected displacements and stresses, ensuring structural safety. Excavations alter ground stresses, affecting tunnel behaviour and potentially compromising their service life if mishandled. This study presents a numerical analysis using PLAXIS, a finite element software to investigate the effects of excavation depth and other parameters on tunnel stability. Input data included soil properties, tunnel geometry, and tunnel material characteristics. Displacements and stresses were evaluated, with results validated against available data, showing that tunnel displacement from nearby excavation decreases with increased tunnel depth. The analysis considered tunnel crown, spring line, and invert levels. These findings enhance understanding of excavation-tunnel interactions and provide a foundation for safer urban underground development.