An Investigation on Tunnel-Structure Interaction on Settlement of Surface Buildings with Numerical Method

The construction of underground tunnel plays a more and more important role in the development of big cities. One of the most important problems caused by the construction of the tunnel is that underground excavation will cause large settlement of the ground and buildings. Previous studied showed the difference between numerical and experimental results. In this study the case study of Niyayesh-Sadr tunnel is selected and the conditions of this project were applied. This tunnel is located at north of Tehran with a span of 14 meters which constructing with the multi drift method. During construction، this tunnel should pass near some buildings near Mahyar Street then the settlement of surface should be considered. Numerical methods in this study was performed with the finite element code with PLAXIS 2D and the effect of tunnel-adjacent interaction is investigated. In addition the effect of foundation stiffness and weight of the structure is considered in these analyses and the results are compared to the emphasis on tunnel surface structure interaction. Results show that the settlements of foundation are increased 15% due to interaction analysis respect to green field one. Varieties of structures along the tunnel in surface، different overburden depth of the tunnel and also location of building respect to the axis of the tunnel need several numerical models in one project. In this study، one simple approach is suggested to control structures against settlement and prevent using several models.