Investigating soil-structure interaction through the tunnel excavation with focus on structure height and width; Case Study: Isfahan Metro Tunnel

In the construction of urban underground infrastructures, the passage of tunnels below the surface structures is inevitable. Prediction and control of deformations resulting from excavating, especially the ground's surface subsidence, should always be considered before drilling. For this purpose, the present study deals with the numerical analysis of the interaction between the tunnel and its adjacent buildings. In this paper, the Isfahan Metro Tunnel in the range of Azadi Square to Sheikh Koleini Station is considered and FLAC2D software is used for modeling. The characteristics of the buildings in the limited area have been considered and the effect of the width and height of the structures around the tunnel on the rate of ground subsidence caused by the tunnel excavation has been investigated. In order to validate the results, data of the subsidence instrumentation were utilized. Finally, based on the performed analysis, it was concluded that the permissible range of constructing structures around the tunnel area depends on the geometry of the structure and as the size of the structure increases, reliable limits for the construction of structures around the tunnel drilling area are reduced. As a practical result, a diagram was provided to determine the permissible range of construction around the twin tunnel based on different values of the width and height of the structure.