AECOM has been appointed by Ch. Karnchang Public Company Limited (CK), one of the largest civil contractors in Thailand, to be its design consultant for the underground civil infrastructure works of the Bangkok Mass Rapid Transit Blue Line Extension: Contract 2 – Sanam Chai to Tha Phra Section, Underground Civil Works and Contract 5 – Hua Lamphong to Lak Song & Tao Pun to Tha Phra Sections, Trackwork System. The extension will add 4km underground and 23km twin-track elevated railway, including a further 19 new stations.The design elements of the Blue Line Extension Contract 2 include two 30m deep underground stations, a 40m deep intervention shaft, twin bored tunnels 2km in length and a section of cut and cover tunnel. This is the first tunnel project in Bangkok to pass through the historic area of Rattanakosin Island and beneath the famous Chao Phraya River, with shallow ground cover above the tunnels passing under the river bed. Another major challenge arises because one of the proposed stations is located beneath an area with buried artifacts of great archeological importance; thus there are stringent requirements for “no open excavation”. AECOM developed innovative excavation methods to construct much of the station in soft clay and sandy materials under the water table, without open excavation of the ground above.
This is the second project win for the Blue Line Extension, after securing Contract 5 in which AECOM was also commissioned by CK to carry out the definitive design and construction support for the trackwork system for the entire 27km long Blue Line Extension and Depot.