Abstract: Building a large-span multi-arch tunnel by single-tunnel method under complex urban shallow-buried conditions is a challenging engineering problem. Without the middle wall supporting, it is very important to choose a suitable construction method and scheme, which is used to control the deformation of the surrounding rock, and reduce the adverse effect of construction process. By finite element method, the excavation effects of two construction methods, the bench method and the center cross diaphragm (CRD) method, were compared based on the displacements of surrounding rock and lining. The result shows that the CRD method has advantages in coupling the surrounding rock. For the CRD method, it is better to excavate the outer than the inner regions.

Key words: multi-arch tunnel, shallow-buried, single-tunnel method, schemes optimal, deformation control