Design of repair measures of a damaged shield driven tunnel

摘要

As part of an extension of the existing blue metro line in Lisbon Portugal a shield driven segmental tunnel lining was constructed connecting the existing Baixa/Chiado station and the new Santa Apolonia station. The new stretch of tunnel is partly situated beneath the river Tagus. During grouting activities through the existing tunnel structure leakage occurred and as a measure to prevent ground loss the complete 1800 m long tunnel stretch between the Baixa/Chiado station and the Santa Apolonia station was flooded. After treatment of the leakage zone the water tunnel was pumped out and a strongly deformed and cracked tunnel section of approximately 400 m was found. Given the damaged state of the tunnel structure it had to be determined whether remedial measures were necessary in order to guarantee the service life of the tunnel.