Response of shield tunnel linings under seismic loading

A series of 1/50 scale dynamic centrifuge model tests was conducted to investigate response of two types of shield tunnel linings under seismic loading, one with a conventional internal concrete lining without reinforcing steel bars and the other with a newly developed internal lining that consists of thin FRPM pipes and air-mortar. The linings were modeled as pipes on the basis of results from full scale loading tests on actual linings with 2 m external diameter. The model tests showed that: (1) the linings with the conventional internal concrete linings can get damaged easily during strong earthquakes, as was observed in the 1995 Hyogoken-Nambu Earthquake, and (2) the new internal lining is significantly effective in reducing earthquake damage to shield tunnel linings.