The conclusions of risk analysis as a basis for deciding between variants through the example of Contract H8 / Ein Fazit zur Risikoanalyse als Grundlage für eine Variantenentscheidung am Beispiel Los H8

Abstract

The Brenner Eisenbahn GmbH (BEG) was appointed in 1995 to design and construct the new railway line in the Lower Inn Valley between the national border near Kufstein and Innsbruck. In the densely populated Inn Valley, large parts of the line with a planned speed of 250 km/h had to be run through tunnels. Near Jenbach, a semi‐quantitative process was used as part of a risk analysis for the decision between the variants of a shallow, mined special construction and a deep mechanically driven tunnel. Die Brenner Eisenbahn GmbH (BEG) wurde im Jahr 1995 mit der Planung und Errichtung der Neubaustrecke im Unterinntal zwischen der Staatsgrenze bei Kufstein und Innsbruck beauftragt. Im dicht bebauten Inntal mussten große Teile der mit einer Spitzengeschwindigkeit von 250 km/h geplanten Strecke in Tunnellage errichtet werden. Im Bereich Jenbach wurde ein semi‐quantitatives Verfahren im Rahmen der Risikoanalyse zur Variantenentscheidung zwischen einer seicht liegenden, bergmännischen Sonderbauweise und einem tiefliegende Maschinenvortrieb angewandt.

Some examples for the selection of tunnelling methods / Wahl der Vortriebsmethode anhand von Beispielen

“…On neighbouring contracts, such a method was used and conclusions derived from that experience can confirm the results of the risk analysis carried out for contract H4 [10].…”

“…Originally, the aim had been to offer two variants for market competition and allow the market price to decide which variant to construct. Due to the complexity of the process and the fact that different vertical alignments were required for the selection of process, and as only one variant had been handed in for railway approval, there would have been difficulties tendering one variant, which had not been approved, and one variant, which had been approved [10]. Die terminlichen Randbedingungen der Asfinag gaben eine Bauzeit für die Vortriebs-und Innenschalenarbeiten vor, die unabhängig davon, welche Variante für die Erkundungs-und gebirgsverbessernden Maßnahmen gewählt wird, bei konservativer Einschätzung schon aufgrund der langen Bestellzeit der TVM in keinem Fall erfüllt werden konnten.…”

“…As described in detail in [10], the variant for construction had to be decided under time pressure before tendering between either a combination of deep excavations with mined special construction (BSBW) and a Hydroshield drive in contract H4 (later renamed to H8) ( Figure 4). …”

“…Originally, the aim had been to offer two variants for market competition and allow the market price to decide which variant to construct. Due to the complexity of the process and the fact that different vertical alignments were required for the selection of process, and as only one variant had been handed in for railway approval, there would have been difficulties tendering one variant, which had not been approved, and one variant, which had been approved [10]. Zum Zeitpunkt der Beitragserstellung befand sich der Nordvortrieb in der Mitte der GA4d bei Abschlagslängen von 1,1 bis 1,3 m -bis dato ohne größere Schwierigkeiten.…”

“…Zum Zeitpunkt der Beitragserstellung befand sich der Nordvortrieb in der Mitte der GA4d bei Abschlagslängen von 1,1 bis 1,3 m -bis dato ohne größere Schwierigkeiten. As described in detail in [10], the variant for construction had to be decided under time pressure before tendering between either a combination of deep excavations with mined special construction (BSBW) and a Hydroshield drive in contract H4 (later renamed to H8) ( Figure 4).…”