Long-term On-site Measurement of Railroad Shield Tunnel in Diluvial Deposits

Abstract

The achievement of the goals of rational design and safety in a shield tunnel project requires on-site measurement performed to collect information on loads acting on the shield tunnel and stresses and to investigate the mechanism of deformation. There have been few projects, however, for the construction of a shield tunnel in diluvial deposits in which loads acting on the shield tunnel and stresses in the segmental lining were measured over a long period of time. For about 10 years, therefore, on-site measurement has been continued at a railroad tunnel site in the Hongo work area of the subway Nanboku Line in the Tokyo area. This paper reports the results obtained from the 10 years, on-site measurement. The overburden depth at the measurement location is 17.5 m, and the outside diameter of the tunnel is 9.8 m. The lining segments used are made of ductile cast iron and are 1.0 m wide and 350 mm thick. The secondary lining is 150 mm thick.