A 6.53 m-diameter, 200 m-long, 600 t Double Shield Robbins TBM named Magliadrun (meaning Glutton) is gearing up for the Gemeinschafts Kraftwerk Inn GmbH (GKI) project in Tirol, Austria. The name was selected as part of a TBM naming contest. The winners, students from the Ramosch Elementary School, were recognized at a naming ceremony on 03.08.2015. The joint-venture GKI is composed of Verbund, Tiwag-Tiroler Wasserkraft AG and Engadiner Kraftwerke AG. The JV power generating plant GKI in the Upper Inn region at the Swiss-Austrian border represents a unique cross-border hydroelectric power plant project. The largest part of the power plant will be underground, stretching from the Martina district of the Swiss municipality of Valsot across seven municipalities in the Tyrolean region of Oberes Gericht.
The project consists of three main elements: a backwater area and weir system, a pressure tunnel and a powerhouse. In the border region, between Martina district of the Swiss municipality of Valsot and Nauders, a weir system with a 15 m-high weir for water collection will be constructed. From the dammed water, up to 75 cu m/s will be conveyed along a long pressure tunnel. This tunnel ends in the pressure shaft, which leads to the turbines in the powerhouse in Prutz/Ried.
Full construction began on the three construction sites in Ovella, Maria Stein and Prutz in the summer of 2014. In accordance with the timetable, all elements of the power plant should be completed by the middle of 2018 and ready for test operation.
Hochtief Infrastructure Austria is constructing for the GKI the 23.2 km-long Mariastein pressure tunnel on the orographic right side of the valley at a depth of approximately 130 m to 1,200 m. The 600 m access tunnel at Maria Stein has been built using drill/blast techniques.
The first hard rock double shield TBM, brought into position in August, will drive from the south about 13 km towards Ovella, extracting 560,000 cu m of rock; the second TBM, named Zauberbohrer, will begin in October in the direction of Prutz to drill 9 km from the north.
To reduce the construction traffic to a minimum, the tunnel spoil is being stored close to the site. All excavated material which is suitable for the manufacture of concrete will be used directly on-site in the segment production facility in Maria Stein. Excess material will be transported on conveyor belts to the nearby storage area. The underground power house in Prutz will generate electricity for more than 100,000 households. Visit http://www.gemeinschaftskraftwerk-inn.com/, http://www.hochtief-construction.at/ and http://www.therobbinscompany.com/. 34/15.
