Study of Longitudinal Long-term Stability of Shield Tunnel in Soft Clayed Soil

According to the similitude relations for the centrifuge rmdd test, the consolidation time of centrifugal model is 1/n² of the prototype, which could simulating the soft soil foundation long——term settlement in a relatively short time. The method was used to study the longitudinal long term settlement and stability of the paralld shield tunnel of the subway line 4 in Shanghai. Form the results, the longitudinal settlement of the intact, repaired and connected tunnel could be predicted. The conclusion was that the differential settlement of connected tunnel is the largest, and the connection with the repair section of the tunnel should be rigid, which should be used to improve the ability adapting to the defon'nation the tunnel.