The Interaction Between an Urban Tunnel and an Excavation Soil Nailed Wall
The current research is aimed to investigate the mutual effects of a metro tunnel and an adjacent excavation which supports with nailing method. To achieve this, numerous numerical analyses are performed. It was shown that the horizontal movement of tunnel is toward the excavation for all cases because of horizontal unloading induced by excavating process. In addition, it was observed that there would be a critical zone around the excavation in which, soil excavation has considerable effect on adjacent existing tunnel, both in terms of horizontal and vertical displacements as well as internal loads on the tunnel lining. For vertical displacement, however, soil excavation leads to upward deflection of tunnel due to unloading effect. The numerical analyses were clearly showed that the tunnels existed in high depths have larger upward deflection due to soil excavation than tunnels in less depths. Further, the results were showed that both vertical and horizontal displacement on top of the wall increases as the distance of tunnel from excavation increases. Finally, it was observed that increasing the distance of tunnel from the excavation significantly reduces the relative bending moment, shear force and axial force on the lining.
Index Terms: Tunnel, Soil excavation, Soil nailing, Interaction, Supported wall