São Paulo Metro - developments in shield tunnelling

The Metro Network in São Paulo has five lines in service with a total length of 107 km in one of the most booming cities in South America with a population of over 11 million inhabitants. The network can still be considered to be in its early stages; the first line was only constructed in 1968 and is now being extended. Whilst the settlement-prone Tertiary soils under São Paulo and also the crystalline basement, with its different grades of weathering and fracturing and high abrasiveness, pose challenges for shield tunnelling, they actually represent optimum conditions for high performance shield tunnelling. The paper deals with the experience gained by operator Companhia do Metropolitano de São Paulo- Metrô, contractor Construtora Norberto Odebrecht and consultant Maidl Tunnelconsultants in the construction of the metro lines with mechanised shield tunnelling technology.