Kuala Lumpar’s Klang Valley MRT Project has celebrated another major achievement with the breakthrough today (9th January) of the world’s first Variable Density TBM, used for the MRT Sungai Buloh-Kajang Line. The TBM was launched from the Cochrane Launch Shaft in Cheras on 22 July 2013 and has excavated a distance of around 1km through limestone to complete the tunnel at the Pasar Rakyat Station. The breakthrough marks the completion of the first section of twin tunnels for the 9.5km MRT Sungai Buloh-Kajang Line underground alignment.
The Variable Density TBM is the first of its kind, designed and jointly developed by the MRT Project’s underground works contractor, MMC Gamuda KVMRT (T) Sdn Bhd and Herrenknecht AG specifically for tunnelling beneath Kuala Lumpur.
Tunnelling in Kuala Lumpur is extremely challenging as the city is built above two different geological formations. In the west of the city lies the Kenny Hill Formation which is more consistent and suitable for tunnelling. In the eastern part however lies the Kuala Lumpur Limestone geological formation, consisting of hard rock with soft overlaying, as well as void chambers and cavities which cannot be easily identified.
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The Variable Density TBM is specially designed to handle excavation through the transition between the two geological formations, as well as to overcome the challenges posed by tunnelling through the karstic nature of the Kuala Lumpur Limestone Formation.
Mass Rapid Transit Corporation Sdn Bhd Acting Chief Executive Officer Encik Haris Fadzilah Hasan said the breakthrough was a significant achievement for the construction of the MRT Sungai Buloh-Kajang Line.
“Within seven months of Prime Minister Dato’ Sri Mohd Najib Tun Abdul Razak launching the first TBM, we have completed the first section of tunnels. I am confident that we will be able to complete constructing the entire length of tunnels by mid-2015 according to the programme,” Encik Haris said.
Encik Haris said following the programme strictly was critical to ensure that the MRT Sungai Buloh-Kajang Line becomes operational by 31 December 2016 for Phase I (between Sungai Buloh and Semantan) and by 31 July 2017 for the rest of the line.
MMC Gamuda KVMRT (T) Sdn Bhd Deputy Project Manager III (Construction) Encik Ubull Din Om said there had not been any incidences of sinkholes since the start of tunnelling works.
The breakthrough follows an earlier one which took place at the KL Sentral MRT Station worksite on 24 December 2013. That machine, Semantan 1, was a conventional EPBM and will be re-launched to excavate through to Pasar Seni MRT Station.
A total of ten TBMs will be used for the construction of tunnels for the 9.5km underground portion of the MRT Sungai Buloh-Kajang Line. Four EPBMs and six Variable Density TBMs will be used. Six TBMs are currently in operation at various stages of tunnelling for the Project.