Abstract: Three dimensional finite element modeling and insitu monitoring were used to study the impact of transverse gallery construction on the main tunnel lining for a project in Qinghai Province.  The stress and deformation of the main tunnel lining increased sharply at the beginning of transverse gallery construction, and began to stabilize with the increase of excavation depth.  The largest deformation of the main tunnel lining is the settlement at the vault.  Largest change in the principal stress also occurred at the vault of main tunnel lining, while the smallest change in principal stress occurred at the interior wall.  The construction of transverse gallery introduced asymmetrical deformation and stress distribution in the main tunnel lining.  The settlement at the interior wall is much larger than the exterior wall.   The principal stress at the exterior wall is much larger than the interior wall.  The insitu monitoring also confirmed that the location with the maximum amount of cracking coincided with location with largest predicted change in stress and deformation.

Key words: Transverse Gallery, Crack, Tunnel Lining, Three Dimensional Finite Element Method