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Skuk S.,Brenner Basistunnel BBT SE | Wegscheider D.,OSTU Stettin Hoch und Tiefbau GmbH
Geomechanik und Tunnelbau | Year: 2015

The Brenner Base Tunnel, with two main bores and an investigation tunnel running parallel in the middle, crosses the main ridge of the Alps beneath the Brenner Pass and the border of Austria and Italy. The first construction contract was a 10.5 km long investigation tunnel bored by a double shield machine in granite. Numerous investigation measures, laboratory tests and geological face surveys were carried out, and the TBM data was recorded on a 10-second cycle. Due to the large amount of data and the very well known homogeneous geology, it seemed appropriate to develop correlations between the data of the rock mass, the rock and the TBM. Statistically reliable statements could be derived. The unconfined compression strength of the rock, discontinuity parameters and index parameters such as the RMR (Rock Mass Rating), GSI (Geological Strength Index) and RQD (Rock Quality Designation) were compared with the penetration behaviour. GSI values between 30 and 40 showed four times the penetration rate compared to GSI values between 90 and 100. This applies similarly for the RQD, RMR and discontinuity spacing values. The objective was to precisely localize rock mass zones with a high degree of fracturing or faults for the main bores. This is only possible to a limited extent from the face surveys since the sides of the tunnel are not visible between the individual face surveys and the delivered information is not complete. By matching the geological face information with the TBM data, the faulted rock mass zones in the investigation tunnel could be defined well. In addition, experience from the investigation programme and its geotechnical monitoring is described. The constant presence of geologists on the TBM, the installation of measurement segments and continuous probe drilling can be seen as particularly positive. © 2015 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

Reichard N.,Ostu Stettin Hoch und Tiefbau GmbH | Voringer J.,G. Hinteregger and Sohne Baugesellschaft m.b.H | Rappold M.,Steiermarkische Landesregierung Fachabteilung
Geomechanik und Tunnelbau | Year: 2011

The enormous traffic congestion on the B73 road has significantly worsened the original quality of living in the residential area of Hausmannstätten in the Austrian state of Styria. The bypass currently under construction ought lead to a considerable improvement. The route of the Hausmannstätten bypass starts in the west at the connection to the existing state road B73 and runs 2,320 m to the east. In the central section, the route passes under the Himmelreich mountain ridge through the approximately 1,045 m long Himmelreich Tunnel and then connects again to the existing B73. Starting from the west portal, an investigation heading altogether 740 m long that also serves as a drainage heading was constructed in 2005 and 2006. Since 2010, the consortium ÖSTU-STETTIN-HINTEREGGER has been working on the full construction Himmelreich Tunnel under a contract awarded by the office of the Styrian state government. © 2011 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co.

Schwab P.,OSTU STETTIN Hoch und Tiefbau GmbH | Neumayer J.,OSTU STETTIN Hoch und Tiefbau GmbH
Geomechanik und Tunnelbau | Year: 2010

The term tunnel refurbishment is mostly understood to mean the upgrading or improvement of underground cavity structures like rail or road tunnels and also structures for hydropower stations and underground operations. Before starting refurbishment measures, it is absolutely necessary to survey the exact condition of the existing structure. This survey of the actual condition cannot be based on the assumption that the available design documents correspond to the facts on site. It is therefore sensible, or even essential, to call on engineers, whose experience goes back to the time the relevant construction methods were in use and who can visualise the ideas of the former state of technology. This basic knowledge is necessary in order to plan adequate and correct investigations so that certain results can be obtained for the design of the refurbishment works. Experience shows that false assumptions about the existing structure have resulted in extensive design changes during the construction phase and severe delays with considerable cost effects. The examples in this article show that different refurbishment measures have to be approached differently and that in the future, the consequences of tolerances should be planned and clearly specified according to the specific nature of the task. © 2010 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

Sachs M.,Ostu Stettin Hoch und Tiefbau GmbH
Geomechanik und Tunnelbau | Year: 2010

Since the start of the worldwide success of the new Austrian tunnelling method in the middle 1960s, not only our society but also tunnelling have experienced fundamental change in many areas. The increasing influence of law and bureaucracy have led to the situation where today's tunnelling contracts have become extensive, intricate and disputed compared to former times. Collaboration as among colleagues has been replaced by the collective shedding of responsibility. The creation of tender documents, processing of the tenders and the construction of the works are all subject to the principle of lowest price, which is forced on the clients by law. Tender documents often contain errors and the tenders are not seldom speculative and under-priced. This inevitably leads to disputes during the construction phase. The NATM is, however, a construction method, which needs flexible contract arrangements between partners, competent professionals, slender structures and short decision routes on the tunnel site in order to fulfil its entire potential. In contrast to this, tunnel sites today are often characterised by senseless administrative work and irrelevant reciprocal controls. The rapid development and increasing automation of machines and the development of construction materials still offer great chances for the NATM in the future. The future of the tendering and award arrangements, however, should be reconsidered and the training of managers capable of making decisions should be encouraged, in order to recreate the old team spirit of tunnellers on the site.© 2010 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

Pittino G.,University of Leoben | Galler R.,University of Leoben | Mosslacher A.,OSTU STETTIN Hoch und Tiefbau GmbH | Schwab P.,OSTU STETTIN Hoch und Tiefbau GmbH
Geomechanik und Tunnelbau | Year: 2011

The Conrad Observatory in the state of Lower Austria is a geophysical research and development facility of the Central Institute for Meteorology and Geodynamics (ZAMG). The isolation of the tunnel system fulfils the optimal requirements for high-precision measurements. The client specified shotcrete class EV700 for the plastic fibre-reinforced shotcrete, i.e. the test bodies have to show an energy absorption capacity of at least 700 J in the slab test. The quality verification for the suitability of a fibre-reinforced shotcrete is performed according to the ÖVBB guideline ''Sprayed Concrete'' with a slab test as defined in the Austrian standard ÖNORM EN 14488-5, which can determine the energy absorption capacity and assign the shotcrete to an energy absorption class. The test rig used at the Chair of Subsurface Engineering is described, together with test results from different plastic fibre shotcretes from various testing institutes. © 2011 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

Sellner P.J.,3G Gruppe Geotechnik Graz | Sonnleitner H.,OSTU STETTIN Hoch und Tiefbau GmbH
Geomechanik und Tunnelbau | Year: 2016

In 2013 Asfinag published the tender for the construction of the second tube of the Gleinalm Tunnel. The tunnel is situated in hard rocks (gneiss) and the tender design contained excavation works realized by “drill and blast” in a top heading, bench and invert sequence. Additionally to this tender design, technical alternatives were allowed. One of the tenderers, the later contractor, offered both, a concept according to the tender and an alternative excavation concept including full face excavation by drill and blast. This alternative was based on considerations and experience the tenderer had gained from the construction works of the first tube in the early 1970s presuming optimal full face excavation conditions over wide areas of the tunnel and thus reducing time and costs. Due to these economic advantages and the low cost risk the owner finally commissioned the alternative. Minimizing the blasting vibration of the full face excavation on the nearby running tube, which was operated without any disturbance, was only one of the challenges of the project. In terms of logistics the supply of the excavation works with air and support materials as well as the huge mucking volume to be transported were identified as limiting factors. Das im Jahr 2013 ausgeschriebene Vortriebskonzept für die zweite Röhre des Gleinalmtunnels hat den Ausbruch grundsätzlich als Sprengvortrieb in den Teilquerschnitten Kalotte, Strosse und Sohle vorgesehen, jedoch auch technische Alternativen zugelassen. Durch die später beauftragte Bietergemeinschaft wurde neben dem Hauptangebot auch eine Alternative eingereicht, die über weite Bereiche des Tunnels den Sprengvortrieb im Vollausbruch beinhaltet, und auf geologischen und geotechnischen Überlegungen beruht. Aufgrund der Wirtschaftlichkeit und Kostensicherheit wurde die Alternative beauftragt. Die Minimierung von Sprengerschütterungen im Zuge des Vollausbruchs im Zusammenhang mit der parallel verlaufenden und in Betrieb befindlichen Bestandsröhre stellt nur eine Herausforderung dar, die es zu bewältigen galt. Logistisch gesehen befand sich die Versorgung der Vortriebe im Grenzbereich des Machbaren. © 2016 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin

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