Construction of Athens Metro Line 4 in the Kypseli neighborhood remains suspended pending an independent safety assessment, after tunneling work was linked to ground subsidence and damage to 20 buildings.
The Ministry of Infrastructure and Transport, state-owned metro operator Elliniko Metro and construction contractor AVAX have said work by the tunnel-boring machine, which stopped on May 8, will resume only if an independent evaluation committee determines that the necessary safety measures are sufficient.
At a news conference attended by representatives of the ministry, Elliniko Metro, AVAX and the Technical Chamber of Greece, officials outlined the damage and the next steps for repairs and the possible restart of construction.
Of the 87 buildings in the affected area, 35 have been inspected, and damage was recorded in 20, according to the authorities.
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Ground subsidence halted tunneling in May
Infrastructure and Transport Minister Christos Dimas said the monitoring system recorded ground subsidence as the tunnel-boring machine excavated the section between Kypseli and Dikastiria, part of the new Line 4 route.
The machine was halted on May 8, after which damage was recorded separately for each affected building.
Dimas said alarm thresholds were exceeded in some buildings but stressed that there was no question of residents being required to abandon their homes.
No new damage has been recorded since tunneling stopped, he added.
The Technical Chamber of Greece, the country’s technical and engineering body, is conducting expert assessments of the affected properties. According to the minister, the alarm thresholds were initially exceeded in 14 buildings, with six more subsequently added to the list.
Repairs to begin immediately
The ministry said the Technical Chamber has delivered the first interim expert reports, allowing repair work to begin immediately.
The AVAX-led construction consortium will undertake the repairs and cover their costs.
However, the precise timetable for completing the restoration work remains uncertain. Dimas said the authorities are awaiting the Technical Chamber’s final reports, which are expected by the end of the year.
Metro construction will resume only after safety review
No date has been set for the tunnel-boring machine to resume work in Kypseli.
Dimas said construction would restart only once the required safety conditions had been met and sufficient measures had been adopted to ensure that work could proceed safely.
The decision will depend on an independent committee that will include a British expert. The committee is expected to assess the measures needed before tunneling can resume.
Ministry and contractor cite geological conditions
Both the ministry’s leadership and AVAX CEO Konstantinos Mitzalis said they were not seeking to identify a specific “mistake” behind the incident.
They attributed the subsidence to the area’s geological characteristics and maintained that the necessary precautions had been taken during tunneling.
According to their account, the tunnel-boring machine had stopped work at least four times since February when subsidence was detected.
The immediate priorities are now to repair the damaged buildings, complete the technical assessments and determine whether the proposed safety measures are sufficient for construction to resume.