Lausanne Puts the Final Touches to Garbage TunnelAnother major project in Lausanne is TRIDEL, which stands for Traitement et Incinération des Déchets de Lausanne (treatment and incineration of the garbage in Lausanne). This project has been divided into three main contracts: the incineration plant in La Sallaz in the upper part of the city, a 3.8 km-long 44 sq m single-track railway tunnel to ferry the compacted garbage from Sebeillon station and a 800 m-long tunnel between the TRIDEL plant and a heating plant in Pierre-de-Plan. CHF300 million has been budgeted for the garbage plant and CHF70 million for the tunnel. Read E-News Weekly 46/2003.The plant will treat some 138,000 tonnes of rubbish every year, produced by 144 municipalities in the Vaud canton. 90,000 tonnes of these will transit through the underground railway tunnel. Built at a depth ranging from 30 to 50 m, the tunnel alignment forms an S and the gradient does not exceed 5% so that any train of the Swiss federal railways will be capable of travelling on the track. In La Sallaz, the tunnel widens to form a vast cavern with two tracks, 7.5 m high, built using drilling and blasting.After 20 months of hard work, the last centimetres of tunnel have been holed through on 7th October, 2005 by consortium ATT (Frutiger, Wayss & Freytag and Atra), at 50 metres below ground. The tunnel has been built in top heading and bench sequence using roadheaders. Three Eickhoff machines have been operated until end of June 2005 on three different drives (one from Sebeillon, one uphill drive to La Sallaz and one downhill drive to Sebeillon from La Borde intermediate shaft), then two machines on two drives (from Sebeillon and downhill from La Borde). No geological surprise has been reported. The subsoil was composed of molasse and 15% of swelling marls. Visit www.eickhoff-bochum.deTrack laying is programmed for summer 2006, so that the first trains will circulate from the end of the year. In the future, the trains will carry 60% of the rubbish produced in the Vaud canton, the equivalent of 6,000 trucks of the through traffic in Lausanne.The 800 m-long 2.2 m-wide technical tunnel forms a horse shoe and fulfils a triple objective: save and utilize the energy produced by the combustion of the garbage for distance heating, supply electric energy to the new plant and deviate a high-tension overhead line. A big pipe will convey the heat produced and distribute it through the urban network. The tunnel has been driven in molasse and required little support. A Voest Alpine AM50 roadheader has been operated from a 18 m-deep 8 m x 8 m shaft. The internal lining consists of shotcrete reinforced with fibres. Tunnelling of this service tunnel ended in April 2004. The contractor is Prader Losinger. Visit www.vab.sandvik.com and www.tridel.ch 12/06.