SINGAPORE: The Land Transport Authority (LTA) has suspended tunnelling works for the Cross Island Line’s Ang Mo Kio station after discovering extensive underground ground anchors that caused repeated damage to the Tunnel Boring Machine (TBM) and required 100 cutterhead interventions between May and July 2026, extracting approximately 800kg of wire ropes from the machine.
To facilitate recovery works, Ang Mo Kio Avenue 3 will be temporarily reconfigured from November 14, 2026 until May 2028, which equates to an 18-month disruption that will affect traffic, pedestrian access, and the AMK Hub pick-up and drop-off point.
What happened underground
LTA first detected signs of underground obstructions in May 2026 when foreign materials were unexpectedly discharged from the TBM. A cutterhead inspection revealed wire ropes entangled around the machine. After the ropes were removed and cutters replaced, tunnelling resumed, but between May and July 2026, a further 100 cutterhead interventions were required to clear additional obstructions, with 22 damaged cutters replaced in the process.
Further investigations identified the obstructions as ground anchors, which included steel structures drilled into the ground as temporary support for retaining walls or structures, located beneath Ang Mo Kio Avenue 3. Ground anchors can damage TBM cutter tools, disrupt tunnelling operations, and pose significant safety risks to underground works and the roads above.
LTA said investigations are ongoing to determine the full extent of the obstruction and its origin. Recovery measures will include ground improvement works to strengthen and stabilise the ground along the tunnel alignment before tunnelling resumes safely. The obstructions will be progressively removed from within the TBM as tunnelling proceeds in a controlled manner.
Traffic and pedestrian changes from Nov 14
The temporary traffic reconfiguration includes the conversion of the eastbound carriageway between the AMK Hub pick-up/drop-off point and the Ang Mo Kio Avenue 8 junction to a bus-only lane, and a reduction of the westbound carriageway from three lanes to two.
Changes will also be made to ingress and egress arrangements for the AMK Hub pick-up and drop-off point, and the existing pedestrian crossing will be relocated. The ground-level access to the overhead bridge across Ang Mo Kio Avenue 3 will be closed, with alternative access available through Level 2 of AMK Hub during mall operating hours.
Access to the AMK Hub basement car park and the HDB car park serving Blocks 322 and 343 will remain available.
Motorists should expect queue lengths to increase during peak periods, with an additional travel time of approximately 10 to 15 minutes entering AMK Hub. Variable Message Signages, OBU notifications, directional signage, and traffic wardens will be deployed. Bus stops along Ang Mo Kio Avenue 3 will remain accessible, and temporary covered linkways will be provided along diverted pedestrian routes where possible.
LTA said public safety remains the foremost priority throughout the recovery works and will continue to monitor ground conditions around AMK Hub and the surrounding area.