ABSTRACT
Contract 705 (C705) of the MRT North East Line Project (NELP) includes the construction of two stations and twin-bored tunnels 1.7km in length. The Contract for the construction of C705 was awarded to Kumagai-SembCorp-Mitsui Joint Venture (KSM JV) in July 1997. A section of the new Deep Tunnel Sewerage System (DTSS) passes beneath the NELP tunnels near the junction of Upper Serangoon Road and Pan Island Expressway (PIE). A Contract was awarded to KSM JV to construct an Advance Tunnel ahead of the NELP bored tunnels and ahead of the DTSS Tunnel. This Advance Tunnel was designed and constructed using Sprayed Concrete Linings (SCL) and had an internal diameter of 8m was 40m in length. It was constructed wholly in Old Alluvium with 25m cover to surface. This Paper will describe the construction of the Advance Tunnel and the associated access works. The construction sequence, monitoring, programme, progress rates and problems encountered during construction will also be discussed. These works were one of the first major uses of SCL in Singapore and it is hoped that the experiences presented in this Paper can be built upon in future SCL works in Singapore.
