An independent assessor from the Imperial College in London has arrived in Dublin to examine damage to homes in the Marino area.
Residents expressed concern last week after tiles broke and cracks appeared on the walls of their homes, as the Dublin Port Tunnel boring machine was in operation.
Following negotiations with the residents, the city council agreed to bring Dr Michael de Freitas from London to examine the situation. Dr de Freitas has previously advised the Marino Consultative Group - a committee of public representatives and concerned citizens - and is seen by both residents and the city council as an independent expert.
The number of hours the tunnelling machine operates has also been restricted. The machine has tunnelled under Griffith Avenue, The Cloisters, Gracepark Terrace and is currently working under Annedale in Marino.
Noise and vibration were perceptible in the area last week.
Annedale is an estate of single and two-storey homes, many of them local authority houses built between the 1930s and 1950s. A condition survey was carried out on the homes before work began and another is planned for when tunnelling is complete.
However, an interim survey will form a central part of the investigation conducted by Dr de Freitas.
A certain amount of noise was expected from the outset of the tunnelling operation and it is understood that harder-than- expected rock was encountered. While this could cause more vibration, it would lessen the possibility of subsidence.
Of concern to the residents will be whether the cracks are superficial or of sufficient depth to damage extensions, some of which have been in place since before the Planning Act of 1963. The residents also want to be assured that the mass concrete walls dating from the original houses are safe.
A spokesman for the city council, project manager Mr Tim Brick, said the restriction on tunnelling hours - which now end at 8 p.m. instead of previously at 11 p.m - "would have an effect on the duration of the tunnelling programme".
Work on the Port Tunnel, which is due for completion in 2005, is currently about four months behind schedule but according to Mr Brick there is sufficient scope to make up that time.
Dr de Freitas was last night studying reports of the damage. He is expected to address the consultative committee today and his report is expected to be available within a few days.
