Behavior analysis of existing underground structures as a result of excavation in its vicinity

The development of transnational commuting lines is one of the most necessities in urban areas. As a result, the usage of underground areas is increasing daily. In most situations, new tunnels are built near existing tunnels and existing underground structures in developed areas. The proximity of the excavations causes substantial interactions in the construction of structures and ground surface subsidence. As a result, predicting induced stresses in tunnels and existing structures is critical. The effect of excavating an access gallery to the S۷ station from the seventh line of the Tehran metro on inductive stresses on the final supporting system of the Towhid tunnel crown and its under piles was analyzed using PLAXIS ۳D software. The modeling results show that with the completion of the access gallery excavation, the bending moment in the western and eastern crowns has increased by ۵.۶۳ and ۵.۵۹ percent. Also, the axial force on both crowns of the Towhid tunnel has increased. The output values have shown that in the eastern side piles, a decrease of ۳.۶۲ percent, and in the western side piles, ۴ percent increase in shear force has occurred. Also, the bending moment distribution on the east and west side piles has increased by ۳.۴۱ percent and decreased by ۵.۱۷ percent, respectively.