Bangkok Orange Line TBM delivered

Contractor Italian-Thai Development (ITD) will carry out one of three contracts to complete 11.38km of twin single-track tunnel, and 9km of elevated track. Contract E3 was awarded to ITD in May 2017 and equates to 6km of the tunnels, and three underground stations.

The alignment runs through the variable soft ground geology of the city, which ranges from soft and medium to stiff and very stiff clays, with lenses of dense sand and the potential for high pressure groundwater inflows.

A spokesperson for the manufacturer said, “In order to handle these challenging conditions, the TBM’s soft ground cutterhead features a spoke style design with a 43% opening ratio and the addition of back-loading knife bits to assist break-in and break-out of the concrete station shaft eyes. In addition, the machine is fitted with an active bentonite face support injection system and double gated screw, to ensure face stability and mitigate ground settlement during excavation within areas of flowing sands and high groundwater pressure.”

The lining will be formed of 1,200mm-wide precast universal concrete segments in a 5+key arrangement, for an internal diameter of 5.7m. These are being produced by ITD at the same factory used for segment manufacture during its MRT Blue Line underground works contract five years ago.

ITD Project Manager, Sanya Thirakajornwong added, “The TBM will arrive on site at the end of July, with tunnel excavation due to begin in December.”

Bangkok’s new Orange Line will eventually total about 35.4km with 26.2km aligned underground with 23 underground stations and another 9km and seven stations on elevated structures. The route starts underground at Taling Chan railway station, west of the city, passes under the Chao Phraya River near Somdet Phra Pin Klao Bridge, and connects to the depot of the Mass Rapid Transit Authority of Thailand (MRTA), which is located at the current MRTA Office Building. It then continues along the Rama IX road, turns left into Ram Khamhaeng Road, passes beneath the Lam Sari intersection and transitions to the elevated section from the Khlong Ban Ma Station, terminating at Suwinthawong Station near the Ram Khamhaeng-Suwinthawong junction.

When complete, in 2023, the Orange Line will provide a vital transportation link from Bangkok’s city centre to districts in the east, reducing traffic congestion and paving the way for improved accessibility, economic growth and new residential and commercial opportunities along the alignment.