Feasibility Study of New Shallow Tunneling Method for Subway Station Construction in Tehran Alluvial Condition

In the present study, the feasibility of implementing the shallow tunneling method (STM) for the Abshenasan (Z6) subway station construction in geological conditions of Tehran's alluvium was conducted numerically based on the evaluation of deformation and subsidence of the ground surface. The numerical modeling process was performed in three-dimensional method using Plaxis finite element software. The results obtained from numerical modeling using the STM method show a significant reduction in the deformation and surface subsidence compared to the traditional pile and rib method. So that the maximum subsidence estimated at ground level is about 6.09 mm and is related to the front of the face excavation. This amount of deformation and displacement behind the face excavation was recorded at a distance of approximately one times the width of the station at about 3.52 mm. In fact, with the implementation of the STM method for the Z6 station, the deformation and displacement of the ground occurred at a lower rate than the pile and rib method, resulting in a reduction of maximum subsidence in the ground surface.