Bauer Expertise for the Longest
Switzerland is becoming smaller... On June 1st, the Gotthard Base Tunnel was ceremonially opened in the presence of state guests from across Europe. Over 1,100 guests took part in the official maiden journey through the tunnel, which is 57 km long and runs up to 2,300 m below the Alps. It is the longest and deepest railway tunnel in the world. The Swiss subsidiary of BAUER Spezialtiefbau GmbH and BAUER Umwelt GmbH were also involved in the construction project of the century. The twin-tube Gotthard Base Tunnel links Erstfeld and Bodio. Construction work started in 1999: the tunnel was excavated from 5 different starting points simultaneously. The northernmost starting point is in Erstfeld, from this point the tunnel was extended towards the south. In 2005, BAUER Spezialtiefbau Schweiz AG carried out the specialist foundation engineering works here for the ARGE VGE Lot 1. The main works consisted of bored piles with diameters of 1,200 and 1,500 mm, which were drilled to 33.5 m under extremely difficult conditions – in boulder-like landslide material. A BAUER BG 40 rotary drilling rig was used for this. BAUER Spezialtiefbau Schweiz AG installed permanent anchors up to 70 m long in the pile wall. For this, bore holes were drilled through the boulder-like unconsolidated rock through to the solid rock. As a first step, the excavation pit served as a starting pit for the tunnel boring machine. After completion of the drilling works, the tunnel was constructed in this area using the open-cut tunnelling method, then the excavation pit was refilled. From January 2011 to August 2013, BAUER Spezialtiefbau Schweiz AG also constructed foundation piles for a 1,060 m long viaduct between Lugano and Bellinzona. For the static basis of the structural design, test piles were constructed beforehand and static pile load tests were carried out. A total of 313 cast-in-place concrete piles with a diameter of 1,200 mm and lengths of up to 29 m were drilled and concreted. BAUER Umwelt GmbH was also involved in the construction of the tunnel. The company was commissioned – partly as a joint venture – with the construction and operation of 2 water treatment plants: the first in Amsteg, where the resulting mountain water had to be treated before its introduction into the river; and the second in Faido, where Bauer installed a nitrite treatment plant due to the high nitrite concentration resulting from the explosives used in the tunnel driving. The breakthrough in the east tunnel took place on October 15, 2010, and in the west tunnel on March 23, 2011. Test operation began in October 2015. At the start of June, this year, AlpTransit Gotthard AG handed over the operation of the tunnel to Swiss Federal Railway (SBB). After further testing, the tunnel will be put into operation as the heart of the new AlpTransit on schedule on December 11, 2016. Traveling by train on the north-south line will soon be much more attractive for people as well as goods from the whole of Europe.
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