Abstract: With the increasing of hydropower infrastructure projects in China and the gradual transferring the construction projects to mountainous areas, the mechanized construction has become the mainstream direction. The TBM tunneling technology has become one of the important methods of diversion tunnel construction. Often water diversion tunnel project is at the relatively remote area, mostly without sensitivity surrounding the building structures, and emphatically introduced in this paper under the water diversion tunnel engineering in an existing highway tunnel, the removal of soil and rock will induce the process of TBM construction original stress release, causing additional stress in the existing highway tunnel. The analysis under different working conditions is very important to the impact of the highway tunnel structure. In this paper, the commercial software, Midas GTS, is used to simulate the disturbance of the TBM construction to the strata, and a 3D model of the TBM tunneling through the existing highway tunnel is established. TBM construction parameters are carefully simulated, and the influence of various working conditions on the stress increment and deformation of the existing highway tunnel are analyzed. Through analytical results show that under the oblique in TBM tunnel construction, the above the highway tunnel will result in the surface of the large differential settlement, at the same time the uneven lateral highway tunnel lining structure, oblique position near the existing highway tunnel structure under the lateral appeared different degree of tensile stress and deformation, the deformation and meet the requirements to ensure the normal operation of the existing road tunnel.

Key words: Up and Down Crossing, TBM Excavation Construction, Existing Highway Tunnel, Finite Element Analysis, Deformation