ONE OF EUROPE'S biggest tunnelling projects has caused extensive settlement damage to a Swiss Alpine village after excavations lowered local groundwater.
Lötschberg 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 near the tunnel alignment.
When completed in 2007 the 34. 6km Lötschberg tunnel will carry rail passengers and freight through the Alps between Frutigen and Raron. The project is an attempt to relieve pressure on the region's roads and tunnels from increasing traffic volumes.
UK contractor Balfour Beatty is a member of one of several international tunnelling consortia building the twin-bore tunnel (GE February 2001).
Now at the halfway stage, the tunnel is being excavated below ground water level, providing a drainage route. As the ground water level has dropped it has caused 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 March to between 2mm and 8mm a month.
A BLS spokesman said vibration and monitoring equipment had been installed in the village.
A working party comprising representatives of BLS, residents and the local council had been established.
A general planner from a local architect is assessing the damage and the client is discussing with residents how best to repair it.
Most of the affected buildings have only suffered cosmetic cracks but four will require structural repairs.
BLS said it hoped to have completed repairs to all the buildings by the end of the year.