In Singapore the Land Transport Authority used for the first time a rectangular tunnel-boring machine, which excavates rectangular instead of circular tunnels, and this tunnel-boring machine could be used for speedier, cleaner and significantly less disruptive works.
Using a set of six cutter heads, the machine has completed about 20 per cent of the 150 m underground pedestrian walkway. This new type of tunnel-boring machine is more expensive than the original method, but the machine, supplied by China Railway Engineering Equipment Group, saves time, manpower and is far less disruptive, and moreover the underpass will be completed in “six to eight monthsâ€, instead of “three to four years†with the cut-and-cover method.