ABSTRACT
Recently two-arch tunnel has been commonly constructed because it has many advantages such as the minimization of tunnel section, less loading on the environment and easy connection to adjacent roads. But the behavior of two-arch tunnel and ground around it have not been fully clarified because of its complex construction sequences and relaxation history. Effects of the existing discontinuities in the ground and the construction sequences on the behavior of two-arch tunnel, especially loads on the center pillar, are not well known yet.
