Abstract: With the continuous advancement of urbanization, there are more and more cases of shielded tunnel excavations passing through roads, hospitals, schools and other municipal facilities. This paper presents a shielded tunnel in East China to underpass an existing express highway. The relative position between the existing highway and the proposed under passing tunnel. The engineering geological conditions, site soil and rock stratigraphy and properties, hydrological and geological structures were thoroughly investigated. Based on the site-specific information, Peck formula was used to predict the ground response to the tunnel excavation. The analytical results are also compared with the numerical results by MIDAS. The results demonstrate the deformation pattern of the surrounding rock mass as well as the highway and retaining walls after the tunnel excavation. Based on the above analysis results, it is believed that the impact of shielded tunnel construction on the existing expressways is acceptable. 

Key words: tunnels, shield, underpass highway, stability, MIDAS software