ONE OF Europe's biggest tunnelling projects has caused extensive settlement damage to a Swiss Alpine village after excavations lowered local ground water.
Lotschberg tunnel client BLS Alptransit has accepted responsibility for the damage to buildings in the Swiss village of St German. As designer of the £1.2bn project, it has agreed to repair buildings close to the tunnel alignment.
The Lotschberg tunnel will carry passengers and freight through the Alps, between Frutigen and Raron in an attempt to reduce the increasing volumes of traffic on the region's roads and tunnels.
British contractor Balfour Beatty is a member of one of several international tunnelling consortia which are building the 34.6km tunnel (NCE 6 December 2000).
The twin bore tunnel is 49% complete and due to be finished in 2007.
The tunnel is being excavated below ground water level and has consequently provided ground water in the area with a drainage route. As a result, the ground water level has dropped causing dessication and shrinkage in the silty clay immediately below St German.
Total maximum settlement in the village has been recorded at 183mm with 100mm recorded in November and December.
Settlement began to stabilise at the end of last month to between 2mm and 8mm a month.
A BLS spokesman said that vibration and monitoring equipment had been installed in the village and a working party comprising BLS, residents and the local council, had been established.
A general planner from a local architect has been appointed to assess the damage caused by the settlement and the client is in talks with residents as to how best to repair the damage.
Most of the affected buildings have only suffered cosmetic damage in the form of cracks but four will require structural repairs.
BLS said it hoped to have repairs to all the buildings completed by the end of the year.