ABSTRACT
The growth of population leads to innovative transportation modes like tunnels which improves traffic congestion, travel duration and connectivity. The current numerical study focuses on the performance of single and twin circular tunnels of varying diameters constructed using TBM method in sand under static and earthquake loading conditions in terms of vertical displacements at ground surface and crown levels of the tunnels. With increasing diameter, the ground surface displacement showed least value while the tunnel lining at crown level underwent larger displacement for single tunnel. However, the influence of twin tunnels on ground settlement was substantial (> 50%) rather than crown level movement (around 20%) as compared to that single tunnel with same diameter under static conditions. The study was extended to the dynamic analysis of twin circular tunnels showing a significant increment in surface and crown level settlements of 102.80 mm and 176.81mm, respectively, for twin tunnels of 12 m diameter.
