Abstract: During the tunnel excavation using Tunnel Boring Machine (TBM), the initial geostress field will be changed. This change of geo-stress results in the rock mass disturbance and deforming at the face of excavation and then induces the ground subsidence. This paper presents the a threedimensional elasto-plastic numerical simulation of the TBM excavated tunnel for No.1 Line of Qingdao Metro that skewed undercrossing the urban viaduct at Renmin Road of Shibei District. The process of tunnel excavation on the urban municipal bridge above is simulated with the focus on the deformations at top of tunnel and the pile supported foundation of the viaduct structure. Further, the breakage and deformation surrounding rock mass at the TBM excavation face was also simulated and the rock stress changes as well as the development of plastic zone were also compared so that the broken zone of the rock mass can be predicted.

Key words: Tunnel Boring Machine, Tunnel Engineering, Undercrossing a Viaduct, Elastoplastic Analysis