Construction of large cross-section double-tier Metropolitan Inter-city Highway (Ken-O-Do) Ome Tunnel by NATM

Ome Tunnel is a double-tier highway tunnel with large cross-section of 220-260 m2 excavated at a shallow depth in unconsolidated ground. The tunnel was excavated by NATM. Since the tunnel passes under a road in dense residential area, surface settlement due to tunneling was restricted. Therefore, various auxiliary construction method such as long span steel pipe fore-piling with injection was adopted based on monitoring and analyzing ground behavior during construction. A total of 1060 m of tunneling work was successfully completed without major interruption of work excessive damage on surface residents and other facilities.