STUDY ON THE INTERACTION OF SHALLOW URBAN TUNNELS AND ADJACENT OPEN CUT FOR LARGE BULDIGS - A CASE STUDY ON THE EXTENSION OF LINE ONE OF TEHRAN METRO

The interaction of the tunneling at a variety of depth and open excavation for large structures, is studied in this research. Stability during the construction and operation phases, deformation and displacement that have occurred on the ground surface are investigated for part of the extension of line One of the Tehran Metro, where the tunnel underpasses the surface structures. Very limited study has been conducted on this subject. In 1369, on line Two of the Tehran Metro, an investigation using site monitoring
was done. No research had been conducted on the subject of the interaction of tunnel excavation and an adjacent open excavation in Iran. In this research, finite element modeling was used. Construction stages of the tunnel and open cut were modeled. The stages involved excavation and installing the supporting system both in the tunnel and the open cut. Thorough sensitivity analyses on the effect of different parameters have been done. The parameters include the dimension (width and depth) of the open cut, the distance between the tunnel and open cut, type of supporting system and the timing of the construction of the tunnel and open cut, with respect to each other. The results of the sensitivity analyses helped to determine the
most sensitive parameters and their effect and optimized the most appropriate construction sequence of tunnel and open cut.