Effect of Tunnel Construction on the Settlement of Existing Pile-Supported Superstructure

The need for subway transportation systems has been increased in many important cities. The most tunnels are constructed in congested city areas hence the risk of damage to surrounding infrastructure is very high. Any subsurface construction will generate ground vibrations that resulting in ground settlements and lateral movements, which have the potential to cause damage to the existing surface and underground structures. The subway development in computing technology has led to the use of the finite element method (FEM) in the analysis of the surface subsidence has been increased in recent years. In the current study, a 2D analysis of the varying depth of tunnel and effect of existing pile-supported structure on the settlement of ground surface is carried out by using PLAXIS finite element software. The result of the varying depth of the tunnel, existing pile-supported structure above the tunnel and the used of grout anchor on the ground surface settlement shown in terms of the Gaussian distribution curve. Results show that when pile lengths are sufficient to bear superstructure load then stresses are less on tunnel lining so it resulting in a low ground settlement and vice versa.