Singapore’s Land Transit Authority (LTA) has said that the rectangular tunnel boring machine (RTBM) driving a pedestrian underpass at Stevens Station is on programme to complete the bore in January 2018.
The RTBM is being used to drive a 60m long pedestrian underpass below a road, viaduct piers and a canal as part of the Thomson-East Coast Line metro work.
The RTBM features a rectangular shield box jacking technique which makes use of the principles of an Earth Pressure Balance Machine during excavation.
The RTBM was first used to drive a tunnel below Havelock Station last year and the LTA said that the technique resulted in a shorter construction duration compared to the conventional cut and cover approach.
According to the LTA, the trenchless method with an RTBM brings about an estimated 30% increased productivity and higher quality workmanship.
The underpass at Stevens Station is due to open to the public in 2020.