M odelTest ofConstructing Shield Tunnel under Large Underground Structure

A 3D model testwas carried out to investigate the interference when a metro tunnel is excavatedwith the shield method under an existing underground structure, the Xuanwuhu tunnel in NanjingCity. The experimental results show thatthe construction of the shield tunnelhas a slighteffect on theXuanwuhu tunnel is and large deformation to lead to the“excursion”of the Xuanwuhu tunnel does not occur. Under the conditions of setting uplife piles and reinforcing the ground below the Xuanwuhu tunne,l the additional deformations and internal forces are obviously reduced. In addition, the settlementof ground is smal,l so pavement structures can not be destroyed. Finally, to compare with the experimental resultFEM (finite elementmethod) was used. The numerical simulation result shows that both the Xuanwuhu tunnel and the shield tunnel are safe during the construction of the shield tunne,l and specialmeasures are needed.