Greece’s Deputy Minister of Infrastructure and Transport, Nikos Taxiaos, struck a reassuring yet measured tone regarding the cracks and ground subsidence reported in buildings across the Kypseli neighborhood of Athens, caused by ongoing Metro construction works. Speaking in a radio interview on Parapolitika 90.1’s “On Air” program with journalist Niki Lyberaki, Minister Taxiaos addressed the situation in detail.
“I fully understand why residents are upset — no one wants to suddenly see a crack appear in their home. We are talking about millimeter-level shifts, not figures that should cause alarm. It is the visual impact that is distressing for those experiencing it firsthand,” he stated.
Taxiaos on Kypseli: “The tunnel boring machine doesn’t pass through without continuous monitoring”
“Instrument-based measurements are taken continuously — there are monitoring stations that constantly track the passage of the tunnel boring machine and any ground movements, subsidence, and so on, both in the soil and in the buildings above. This happens without interruption. The tunnel boring machine never passes through without these readings being recorded. These readings have predefined alert thresholds and alarm thresholds. In this case, the alarm thresholds were exceeded, which was confirmed by the damage observed in the buildings,” he continued.
Why construction works were halted
When asked whether there was a problem that prompted the suspension of works, Minister Taxiaos stated: “There is certainly an issue, in the sense that the soil profile encountered by the tunnel boring machine operators during excavation was very different from what was anticipated. When the project was designed, all underground areas were surveyed, building permits were obtained from urban planning authorities, a complete picture of the above-ground structures was compiled, and a geotechnical study of the soil was carried out. However, what they found on the ground was different from what had previously been recorded.”
The need for independent inspections
When asked whether he believed independent expert inspections should be conducted, Minister Taxiaos said: “There is absolutely no objection to having qualified specialists review the data. Not just any engineer can handle this information — you need people with specific expertise. I have no objection, and I believe Athens Metro has no objection either. The directive we have given them is to have no hesitation in sharing the recorded data with anyone capable of reading and interpreting it.”
The role of the Technical Chamber of Greece
“Expert assessment is a process regulated in Greece through the Technical Chamber of Greece. No one objects to having certified expert assessors appointed by the Technical Chamber access the data available to Athens Metro — not to the contractor. Athens Metro operates under strict regulations; you simply cannot pass beneath a structure without following established protocols. Any engineer who handles this data must be officially appointed as an expert assessor by the Technical Chamber,” he added.
“Athens Metro intervened from the very first moment. They have conducted on-site inspections of the buildings, documented all affected structures, and instructed the contractor — who has complied — to carry out repair works in all cases where residents allowed access, at the contractor’s own expense and liability. The contractor has also undertaken to cover all repair costs for residents who chose to arrange their own restoration works. Meanwhile, the tunnel itself has already been constructed underground,” Minister Taxiaos continued.
“When the tunnel boring machine passes through, there is no void left behind”
“When the tunnel boring machine passes through, it does not leave a void beneath the surface — the tunnel is constructed simultaneously. At the point where the machine is currently stopped, there is a continuous injection of grout that counterbalances the pressure — maintaining equilibrium with the load of the buildings above. There is no ongoing issue at this moment, and this is not a developing or escalating phenomenon,” he said.
When the journalist pointed out that this contradicts residents’ accounts of cracks changing daily, Minister Taxiaos responded: “Because we have carried out macroscopic inspections — and I have personally seen this myself — some of the cracks appearing in the photographs were clearly pre-existing, as can also be verified through Google Earth imagery.”
“We are completely open to any discussion”
“I am not saying residents are lying. What I am saying is that people often suddenly recognize as a new problem something that was already part of their everyday reality. We are completely open to any discussion — there is no objection whatsoever to further dialogue. However, these conversations must always involve people with the right expertise, and very few engineers in Greece truly understand how to handle the geotechnical complexities of tunnel construction,” Minister Taxiaos continued.
“We are here to provide further explanations”
When asked whether he would feel comfortable sleeping in a home that had experienced subsidence and cracks, Minister Taxiaos replied: “There is no way a tunnel boring machine can pass beneath a structure without some degree of ground movement being recorded. There are movements that fall within acceptable limits, and movements that trigger the alarm. That alarm was triggered in this case. But when it goes off, it does not mean there is a risk of building collapse or any dramatic structural failure. Yes, I would sleep there — though I would certainly expect someone to come and explain exactly what is happening. Inspections and visits have been carried out at all affected buildings by representatives of both the contractor and Athens Metro. If some residents are skeptical of what they have been told, or feel unsatisfied with the answers they have received, we are here to provide further explanations.”
“There is no chance Athens Metro would proceed with tunneling if it saw any danger to a building”
Finally, when asked whether any initiative would be taken with the Technical Chamber of Greece to arrange additional independent expert reviews, Minister Taxiaos stated emphatically: “No objection whatsoever. I will say again what I firmly believe: there are no engineers in Greece who know these issues better than the engineers at Athens Metro. These are specialist engineers who travel to places like Tel Aviv, for example, to assist with tunnel boring operations there — the very same engineers who work on international projects. There are no better-qualified professionals available. There is absolutely no chance that Athens Metro would observe any danger to any building and proceed with tunnel excavation while ignoring the issue.”
