ABSTRACT
Singapore is currently expanding its underground Mass Rapid Transit System with the construction of 22 kilometers of twin bored tunnels and 16 No. stations. It will be a state of the art, driverless rail transport system serving the North-East sector of Singapore from the World Trade Center to Punggol. Contract 704 of the North-East Line is complex as it involves not only the construction of two cut and cover stations and 2.5 km of twin bored tunnels but also the construction of a viaduct and two road underpasses. This paper focuses primarily on the tunnelling aspects of the contract where two 6.5m outer diameter EPB machines were employed. Some challenging and difficult ground conditions were encountered particularly when tunnelling through the interfaces between the weathered and fresh Bukit Timah granite.
