부산대학교 도서관

With the rapid development of underground space and the metro system in an urban area, the interaction between superstructures, foundations, and excavations with existing tunnels has been increasing. Hence, to ensure the safety of the tunnel, it is necessary to predict the displacement and stresses in tunnel induced by construction activity in its vicinity. The objective of the present study is to analyse the effect of superstructure construction on the stability of underground metro tunnels. A 2D numerical model has been developed using finite element software OptumG2 to replicate the Delhi Metro Phase 3 tunnel project. An elastoplastic model of the tunnel at a standard depth of 18 m has been analysed. The behaviour of the tunnel at the crown, invert, and springer (spring line) has been reported. The shear force and bending moment developed in tunnel lining has also been observed. The study investigates the stresses and displacement in the surrounding soil. Two parametric studies based on tunnel depth and load position have been studied. The study found that the displacement in tunnel points decreases but the lining forces increase with an increase in tunnel depth. The tunnel became stable with an increase in load eccentricity. It is also found that the maximum displacement of soil is not affected significantly either with the depth of tunnel or with load position. However, the stability of soil around the tunnel increases with an increase in depth of the tunnel and superstructure load eccentricity.