Eurailmag - #15 - March 2007 - (Page 104)

Tunnels Geology The emergency stop stations provide a place for trains to halt in an emergency, where passengers can escape and be evacuated. To reach the other railway tunnel, passengers do not have to cross railway tracks, climb steps, or use lifts. Should an incident occur, smoke is sucked out of the affected tunnel and fresh air blown into the emergency stop station through the side tunnels and connecting galleries. A slight overpressure is enough to prevent smoke entering the escape route to the unaffected tunnel. From the emergency stop station, an evacuation train transports passengers out of the tunnel. If a train stops before it reaches an emergency stop station, passengers can use the connecting galleries to escape to the other railway tunnel. granite. Wedged in between are younger sedimentary rocks, some of which are massively fractured. Because of this, when constructing the Gotthard Base Tunnel, highly diverse rock strata must be traversed. This ranges from the tough Gotthard granites, through the highly-stressed pennine gneisses of the Leventina, to the butter-soft rocks of the Tavetsch intermediate massif. The Piora syncline played a key role in the geology factor because its structure and extent were initially unclear. However, four inclined test bores down to tunnel level indicated that conditions at this depth are solid rock with no water pressure or circulation. Subsequent testing of bore samples, as well as temperature measurements and seismic tests, confirmed these positive findings for construction of the tunnel. Squeezing rock conditions in parts of the Tavetsch intermediate massif, on the other hand, call for special construction methods. Intermediate headings providing additional access to the tunnel from above (shafts), or from the sides (adits), shorten the construction time of long tunnels. The intermediate headings at Amsteg, Sedrun and Faido halve the construction time of the Gotthard Base Tunnel and divide it © AlpTransit Ltd Choosing the route Above ground, the choice of route is affected by the concerns of local residents as well as political decisions. Geographical aspects, such as the location of towns and villages, as well as hydro-electric reservoirs and access routes to the construction sites, must also be taken into account. Another important factor influencing the optimal route for the Gotthard Base Tunnel was geology. The Aare and Gotthard massifs form the backbone of the Swiss Alps. Both are mostly made up of gneisses and Drilling and blasting at Faido into five sections: Erstfeld (with the north portal), Amsteg, Sedrun, Faido and Bodio (with the south portal). Construction work began on the Piora test bore system in 1993, and in 1998 it delivered clear results on the geology of the Piora syncline. Starting in 1996, all necessary adits and shafts were constructed. Now, the railway tunnels themselves, the cross-passages between them, and the multifunction stations are being built. In 2016, the world's longest railway tunnel will enter into operation. GBT overview Issue 15 EURAILmag Business & Technology

Table of Contents for the Digital Edition of Eurailmag - #15 - March 2007

SOMMAIRE
NOTICE BOARD
COATINGS
NEWS
SERVICES
INFRASTRUCTURE
HIGH-SPEED LINES
TUNNELS
PEOPLE
ROLLING STOCK
WEBSITE DIRECTORY

Eurailmag - #15 - March 2007

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