MRT underground stations: Not an easy task but we did it

KUALA LUMPUR: The construction of seven underground stations of the Mass Rapid Transit (MRT) Sungai Buloh-Kajang (SBK) Line phase two has proven that local talents including architects, designers and engineers are capable of undertaking a very challenging world class project.

These 261 local skilled workers can say: "Not an easy task but we did it."

One of the youngest engineers involved in this project, Izyan Syahirah Hasanuddin, 26, said various factors have to be taken into account in planning and building the underground stations and among them were the geological settings underneath the city.

She said the underground alignment for the MRT SBK Line navigated past two distinctly different geological settings which were the Kenny Hill Formation (sedimentary rock and sand formation) and Kuala Lumpur Karstic Limestone Formation.

"Fifty percent of the underground alignment was in the form of extreme karstic limestone and in order to dig the tunnel, we had to maintain the equilibrium of the sub-surface geological system containing underground reservoirs and water-filled cavities.

"It is very challenging as any disturbances from underground activities could cause karstic sinkholes and ground subsidence. To overcome that, 10 Tunnel Boring Machines (TBM) were used to dig in the ground as the TBM is the most efficient machine in clearing ground - be it all rock, all soft soil, or all sand," Izyan told Bernama when met at the Cochrane underground station recently.

Extreme karstic is a geological formation consisting of weakly soluble bedrock such as limestone eroded by mildly acidic water over millions of years, leaving behind an elaborate labyrinth of unstable caverns, cliffs and pinnacles in the depth of Kuala Lumpur city.

She said the most physically and mentally taxing moment was during the intervention process which required her to temporarily stop the TBM to look at the underground cavity being dug.

"You cannot imagine how I felt when I faced temperatures of 38°C, the nauseating smell of dirt and the darkness with limited movement in the tunnel," said Izyan who holds a Bachelors Degree in Civil Engineering from Universiti Teknologi Malaysia (UTM)

Izyan said that she was thankful for the opportunities given to her in undertaking the task although it was a very specialised field, usually dominated by men and more often by foreigners.

Another engineer, Ismail Bukhari Wan Ibrahim, 27, who joined the MRT project when he was 23, right after graduation, said: "It was almost impossible for fresh graduates to land such a post abroad, so when MMC-Gamuda Sdn Bhd made the offer, I could not refuse,".

"For me, it offered a unique learning platform and each day it gave me a new experience, knowledge and problems to solve in a more critical and analytical manner," said the Construction Management graduate from Universiti Teknologi MARA (UiTM), Shah Alam.

The underground stations for the 9-5-km underground SBK Line which cost of RM8.23 billion are Muzium Negara, Pasar Seni, Merdeka, Bukit Bintang, Tun Razak Exchange (TRX), Cochrane and Maluri.

Meanwhile, MMC Gamuda KVMRT Architectural Manager, Tricia Low Yi Ching said among those seven underground stations, TRX was the deepest station for the MRT SBK line with a depth of 45m, equivalent to a 13-storey building.

"There are seven levels at the TRX station while the Cochrane, Bukit Bintang, and Merdeka station have four levels, Pasar Seni three, and Muzium Negara two.

"The general concept for these underground stations was inspired by the Klang Gates Quartz Ridge, a pure quartz dyke found in the Klang Valley, which the multi-faceted characteristic of the quartz and its kaleidoscopic reflections symbolise Malaysia's multiracial and multicultural society," said Tricia.

Apart from that, the stations are also strategically located in areas which are currently being developed and would be developed for example at the Merdeka station, the new tower KL118 would be built nearby.

She said designing the underground stations' interiors was also another challenge as they needed to design proper layout for ventilation and emergency exit routes.

"In order to allow perfect ventilation in and out of the stations, we need to create a sustainable layout at entrances, said Tricia who has 12 years working experience.

Tricia said the design for all underground stations have taken into account the flash flood factor in the city so that its operation would not be affected should the problem arise.

"Historically, flooding does occur at the station areas. Hence, we have installed flood boards below the floor in order to prevent the water from entering the stations," said Tricia.

Prime Minister Datuk Seri Najib Abdul Razak is scheduled to launch the second phase of the SBK line on July 17, allowing the train to run the entire 51km alignment from Sungai Buloh to Kajang. — Bernama