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Schruns, Austria

As result of the two-year route selection process, the southernmost variant Pfaffensattel was chosen in April 2008 as the best variant for the New Semmering Base Tunnel, which run from Gloggnitz to the Mürzzuschlag-Langenwang area, and the route has since been optimised for design through a detailed programme of investigations. As a result of this, the final route of the tunnel was fixed in autumn 2009. All design work for the partially concentrated approvals process are now based on this route. This article is concerned with the essential technical tunnel construction aspects of the design to be handed in for approval, above all the construction concept and the procedure for geotechnical design to be used as a basis. At the time of writing this article, the final evaluation of the geomechanical and hydrogeological investigations and the geotechnical design are still underway. © 2010 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. Source

Strappler G.,OBB Infrastruktur AG | Vigl A.,Viglconsult ZT | Scheutz R.,OBB Infrastruktur AG
Geomechanik und Tunnelbau | Year: 2012

In the last 15 years, a number of transport tunnels for Austrian Railways ÖBB have been tendered for mechanised tunnelling by TBM and some have already been completed. The question whether to use one or two layers of lining was considered on practically all these projects. This either led to a decision which system to tender, or else the two alternatives were held to be equally suitable and the decision was left to market forces. These fundamental considerations about the lining system normally involved a systematic comparison and evaluation of the features of each system regarding the structural system (actions and resistance), serviceability (waterproofing, durability), the properties during and after a fire and operational and maintenance considerations. The article explains: -the essential system requirements concerning actions and resistance, serviceability and fire safety, with examples, - the basic requirements for the operation and maintenance of ÖBB tunnels, including discussion of previous experience with maintenance, - the basic features of single- or two-layer construction for continuously advanced tunnels, which are presented and briefly described, - the system matrix used to make system decisions and the evaluation procedure, - the economic considerations, mentioning the contrasting conditions in neighbouring European countries, including construction price and time considerations. The system decisions or recommendations are analysed and argued through the example of rail tunnels in Germany and Switzerland as well as ÖBB tunnel projects. This overall treatment is intended to clarify how system decisions or recommendations were reached on ÖBB projects and what assistance can be derived for future projects, also considering foreseeable technical developments. © 2012 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin. Source

Pressure shafts, due to their complexity and length, are one of the most challenging parts of the headrace system of a high head hydropower plant. Pressure shafts offer great potential for optimisation and this has to be reflected in their design and construction. The article first describes most common system concepts for headrace systems. Then it introduces the graphical-analytical design method from Seeber in its main features and uses this as a basis for understanding the mode of action of common lining systems. Finally, the common mechanised heading methods are briefly discussed in terms of their areas of application depending on the expected ground behaviour with a qualitative risk assessment of their feasibility. © 2015 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin. Source

Barwart C.,Viglconsult ZT | Romualdi P.,L.E.S.S. | Barioffi A.,L.E.S.S.
Geomechanik und Tunnelbau | Year: 2013

The 3.3 km long headrace tunnel (Lot 2) of El Alto hydropower project in Panama has been tendered as drill and blast excavation. Lot 2 has been arwaded to SELI, Rome /Italy. By using an EPB TBM for tunnel excavation general alignment of tunnel has to be redesigned completely. General and detailed design has been done by viglconsult ZT/Schruns. Internal pressure conditions does allow to use segmetnal ining as final lining most of the tunnel length. Only the last 300m of tunnel does have the requirement of inner lining made of steel. Traditional bar reinforcement has been substitued with steel fibre reinforcement with ductile post crack behaviour. A three-step grouting programm is foreseen to gain segment stability and is responsible for sealing of the headrace tunnel. © 2013 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin. Source

Gehwolf P.,University of Leoben | Walter A.,Viglconsult ZT | Galler R.,University of Leoben | Wagner H.,OBB Infrastruktur Bau AG
Geomechanik und Tunnelbau | Year: 2016

For the driving of cross passages in mechanized tunnelling, different systems can be used for load transfer at the cross passage opening. With thin segmental linings, achieving high load-bearing capacity of the precast lining and the load transfer elements used pose a great challenge. For the selection of a system, not only the required support measures but also practical construction aspects such as the integration of the load transfer elements into the precast element and the installation of the elements play an important role. The use of shear dowels as a connection and load transfer element between segment rings in the cross passageoffers new possibilities in mechanized tunnelling. Particularly in connection with thin segmental linings, flexible systems of plastic with integrated steel core make it possible to resist loads with large deformations, both in the radial and longitudinal directions. In order to investigate the system behaviour of the overall system of segmental lining with thin construction and plastic shear dowels, shear tests were performed at the Chair for Subsurface Engineering of the Montanuniversität Leoben with a dowel system as the connecting element between segments. The objective of the research project initiated by the ÖBB-Infrastruktur AG is to determine the effects of different reinforcement concepts on the load-bearing capacity of the connection system. Ways of determining the failure of the construction element based on crack detection are also described. Für das Anfahren von Querschlägen im maschinellen Tunnelbau kommen unterschiedliche Systeme für die Lastabtragung im Bereich der Querschlagsöffnung zum Einsatz. Bei schlanken Tübbingauskleidungen stellt das Erzielen einer hohen Lastkapazität der Fertigteilauskleidung sowie der eingesetzten Lastabtragungselemente eine hohe Herausforderung dar. Bei der Auswahl der Systeme spielen neben den erforderlichen Sicherungsmaßnahmen die baupraktischen Aspekte wie das Integrieren der Lastabtragungselemente in das Fertigteilsegment und die Installation der Elemente eine wesentliche Rolle. Durch Verwendung von Scherdübeln als Verbindung- und Lastübertragungselement zwischen Tübbingringen im Querschlagsbereich ergeben sich neue Möglichkeiten im maschinellen Tunnelvortrieb. Insbesondere im Zusammenhang mit schlanken Tübbingauskleidungen bieten flexible Systeme aus Kunststoff mit integriertem Stahlkern die Möglichkeit, Lasten mit großen Verformungen sowohl in Radial- als auch in Längsrichtung zu übertragen. Um das Systemverhalten des Gesamtsystems zwischen Tübbingauskleidung mit schlanker Bauteildicke und Kunststoffscherdübel zu untersuchen, wurden am Lehrstuhl für Subsurface Engineering der Montanuniversität Leoben Scherversuche mit einem Dübelsystem als Verbindungselement von Tübbingen durchgeführt. Ziel des von der ÖBB-Infrastruktur AG initiierten Forschungsprojekts ist es, die Auswirkungen unterschiedlicher Bewehrungskonzepte auf die Tragfähigkeit des Verbindungssystems zu bestimmen. Ergänzend werden Möglichkeiten zur Bestimmung des Bauteilversagens auf Basis der Risserkennung aufgezeigt. © 2016 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin Source

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