Stoked by their debut success with the timely completion of Kajang Line’s underground section, Gamuda Engineering found themselves pitted once more against the unique challenges of tunnelling in Kuala Lumpur’s notorious karstic limestone, abrasive granite regions, and complex geological interfaces.
Fresh from delivering Malaysia’s first metro with great success, tunnelling contractor MMC Gamuda KVMRT (T) (MGKT - a joint venture between MMC and Gamuda Berhad in which Gamuda Engineering is its subsidiary) has recently celebrated the completion of its tunnels on Putrajaya line; it is the second extension to the Klang Valley Mass Rapid Transit. The scope of work includes 13.5-km of twin bored tunnel (internal diameter of 5.8-m), 11 underground stations, and other ancillary structures. A total of 12 tunnel boring machines (TBMs) were deployed, out of which 8 were variable density TBMs, and 4 were Earth Pressure Balance TBMs.
At first glance, there are many striking facts about the project. The alignment falls within some of the capital city’s most prime locations, crossing high density neighbourhoods, high-rise buildings, and public infrastructures. What’s more, the geological profile of the region is heterogeneous, further complicating the mining and deep excavation works required for the shafts. The geology includes Kenny Hill formation and Kuala Lumpur limestone—similar to that of the previous job—plus a particularly abrasive granite region, new to the tunnellers this time around.