THE first tunnel drive for the MRT Sungai Buloh-Serdang-Putrajaya (SSP) Line was successfully completed despite difficult geological conditions, marking a significant milestone in construction.
The 1.9km tunnel between Bandar Malaysia North MRT Station and Chan Sow Lin MRT Station which took 11 months, was excavated with the same Tunnel Boring Machine (TBM) used for the first successful tunnel drive in the MRT Sungai Buloh-Kajang Line in January 2014.
SSP Line underground works contractor, MMC Gamuda KVMRT (T) Sdn Bhd construction director Datuk Ubull Din Om said the arrival of the TBM on the other side was an achievement because the ground condition was unfavourable compared to Line 1.
“Karstic limestone is known for its unpredictable ground conditions, making it risky for TBM operations.”
Ubull said the experience gained in tunnelling Line 1 enabled them to take precautionary measures to ensure a smoother process this time.
He said they were very careful while going through two of the most sensitive areas which was the busy 13-lane Jalan Sungai Besi and under the live tracks near the Chan Sow Lin LRT station.
Ubull noted numerous sinkholes formed in the same area during work on the Smart Tunnel in 2003, leading to disruption in traffic and human activities above ground.
Ubull said several steps were taken to ensure safe tunnelling and timely completion.
“We enhanced our TBM from Line 1 and learned how to predict a sinkhole based on past experience, conducted very good soil investigation, used experienced tunnel crew and installed instruments to detect any movement.
“It was an integrated effort using technology and humans.
“We had two teams walking ahead of the TBM to detect any ground movement,” he said.
There are 16 tunnel drives that need to be bored with a cumulative length of 13.5km in the underground section of the SSP Line.
MRT Corp Sdn Bhd strategic communications and stakeholder relations director Datuk Najmuddin Abdullah said the overall construction was on track with a 41% completion rate as of December 2018.
“We are confident of delivering the project as scheduled.
“We have 12 TBMs, five are in operation and seven more will be launched by the end of the year. Some TBMs will be handling two tunnel drives.
“The TBM that has arrived will be pulled across the Chan Sow Lin Station box and then restarted to excavate the second tunnel drive between the Chan Sow Lin Station box and the Tun Razak Exchange MRT Station.
“Once it reaches the Tun Razak Exchange MRT Station, it will be disassembled and retrieved in parts,” he said.
The SSP Line is scheduled for completion by the middle of 2022.