Loew S.,ETH Zurich |
Lutzenkirchen V.,Dr. von Moos AG |
Hansmann J.,ETH Zurich |
Ryf A.,AlpTransit Gotthard AG |
Guntli P.,Sieber CassinaHandke AG
International Journal of Rock Mechanics and Mining Sciences | Year: 2015
The Gotthard Base Tunnel (GBT) is a 57. km long and up to 2500 m deep railway tunnel constructed between 2000 and 2011 in the Central Alps of Switzerland. As drainage of fractured rocks by deep tunnels accompanied by significant decrease in groundwater pressure causes large-scale deformations even in hard crystalline rocks, a comprehensive surface deformation and tunnel inflow monitoring system has been established and operated for more than ten years. This paper presents the results from this monitoring system and explains the observed hydro-mechanically coupled and transient rock mass behavior based on detailed assessments of geological, geomechanical and hydrogeological conditions and conceptual continuum models. The collected data show that significant tunnel-drainage induced surface deformations also develop in rock masses with moderate hydraulic conductivity (2E-9 m/s) and small cumulative tunnel inflows (a few liters per second per kilometer). In this case deformations are caused by pore pressure reductions and rock mass deformations around the draining tunnel at depth, and not by groundwater table elevation changes. The pattern of surface settlements observed along the tunnel axis is very irregular (up to 11. cm in 2013) and strongly influenced by hectometer scale hydro-mechanical heterogeneities of steeply dipping geological units striking at large angle to the tunnel axes. At the depth of the studied tunnel section (1500-2500 m) about 50% of the surface settlements can be recorded. The surface settlements are connected to horizontal displacements and strains directed towards the tunnel axes or advancing tunnel face. The resulting horizontal displacement at the Nalps dam has reached about 65 mm in 2013. Compressive strains in the order of 20-50 microstrain are typically observed within a corridor of about 1 to 1.5 km width. Outside the reversal point of the settlement trough, extensile strains of similar magnitude develop. © 2015 Elsevier Ltd.
Ehrbar H.,AlpTransit Gotthard AG |
Otto B.,Axpo AG
Geomechanik und Tunnelbau | Year: 2010
The determination of the alignment of the Gotthard Base Tunnel made sure not to tunnel directly under the dams of the Vorderrhein AG power stations. The Gotthard Base Tunnel will, however, have to be driven through the zone, which could affect the three arch dams at Nalps, Santa Maria and Curnera. The Zeuzier dam in Wallis (Valais) suffered severe damage in 1978 as the result of drainage of the rock mass for an investigation tunnel being driven in the vicinity. The cracks in the dam led to years of operational limitations and required extensive repair works. A whole range of measures was undertaken for the Gotthard Base Tunnel in order to avoid a repetition. The construction of the tunnel near the dam was the subject of years of preparatory work. Since the end of 2005, the southward drive from Sedrun has been near the Nalps dam and since the middle of 2009, that from Faido has been within the zone influencing the anta Maria dam. Long-term safe operation of both dams has to be ensured despite the near approach of the tunnelling works. Although the task is the same for both dams, completely different solutions were chosen. © 2010 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.
Ehrbar H.,Heinz Ehrbar Partners GmbH |
Wildbolz A.,AlpTransit Gotthard AG |
Priller A.,AlpTransit Gotthard AG |
Seiler A.,AlpTransit Gotthard AG
Geomechanik und Tunnelbau | Year: 2013
In long, deep tunnels, it is not possible to completely investigate the ground conditions along the future alignment in advance. Unexpected ground conditions and fault zones thus have to be accepted as residual risks and overcome by suitable measures. This is also the situation at the Gotthard Base Tunnel (GBT), which is 57 km long with overburden depths of up to 2.350 m. The main contracts included items for systematic advance probing from the tunnel and provided a catalogue of suitable additional measures. These measures were intended to detect and overcome unforeseen ground conditions. © 2013 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.
Ehrbar H.,AlpTransit Gotthard AG |
Sala A.,Amberg Engineering AG |
Wick R.,Gahler und Partner AG
Geomechanik und Tunnelbau | Year: 2011
For the construction of the longest rail tunnel in the world, the selection of the optimal method of tunnelling was of considerable importance. Not only the ground properties were decisive for the decision but also other constraints, like for example the environmental requirements or the access to intermediate starting points. In two of the five sections, the employer had essential grounds for the specification of tunnelling method, but in three of the five sections, there were no essential grounds in the view of the employer. The selection of tunnelling method was therefore decided by economic criteria as the result of competition between the international bidders in the tendering phase. In the end, TBMs were used in all three sections. © 2011 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co.
Jesel T.,Amberg Engineering AG |
Amberg F.,Amberg Engineering AG |
Rohrer T.,AlpTransit Gotthard AG
Geomechanik und Tunnelbau | Year: 2016
In the course of designing the Gotthard Base Tunnel, extensive questions were considered about the tunnelling conditions to be expected and the resulting requirements for the TBM. Naturally this mainly concentrated on the achievable advance rates and the associated costs. The tunnelling works have now been completed and the essential assumptions and decisions from the design phase could be confirmed. Experience does however also show that the behaviour of the rock mass could not always be correctly predicted in its entireness and a corresponding flexibility in the use of support measures is unavoidable, which is only possible with suitable tunnelling equipment and machinery. The present article collects the essential data and facts from the TBM drives and described the areas where significant deviations arose. Particular attention is paid to the following subjects and the corresponding effects: wear to the cutterhead, heavy water ingress, rockburst, reciprocal influencing of the two tunnel drives under poor geological conditions and the collapse in the Tenelin Zone. The stated matters are described with a comparison against the assumptions made in the design phase and a complemented with few of the lessons learnt. Im Zuge der Planung des Gotthard Basistunnels wurden umfangreiche Überlegungen angestellt, über die zu erwartenden Vortriebsverhältnisse und die sich daraus ergebenden Anforderungen an die TBM. Im Fokus standen dabei naturgemäß vor allem auch die erreichbaren Vortriebsleistungen und die damit verbundenen Kosten. Die Vortriebsarbeiten sind abgeschlossen, und die wesentlichen Annahmen und Entscheide aus der Planungsphase konnten bestätigt werden. Die Erfahrung zeigt aber auch, dass das Verhalten des Gebirges nicht immer vollumfänglich zutreffend vorausgesagt werden konnte und eine entsprechende Flexibilität beim Einsatz der Sicherungsmittel unumgänglich ist, was nur mit einer dafür geeigneten Vortriebsinstallation möglich ist. Der vorliegende Beitrag stellt die wesentlichen Daten und Fakten aus dem TBM- Vortrieb zusammen und zeigt auf, in welchen Bereichen sich deutliche Unterschiede ergeben haben. Ein besonderes Augenmerk wird auf folgende Themen und die entsprechenden Auswirkungen gelegt: Verschleiß am Bohrkopf, hoher Wasseranfall, Bergschlag, gegenseitige Beeinflussung der beiden Tunnelvortriebe bei schlechten geologischen Verhältnissen und Niederbruch in der Tenelin-Zone. Die aufgeführten Punkte werden mit einem Vergleich der Annahmen aus der Projektierung und den effektiv angetroffenen Verhältnissen beleuchtet sowie mit einigen Hinweisen zu den Lessons learned abgerundet. © 2016 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin
Schar R.,ENOTRAC AG |
Steinmann N.,AlpTransit Gotthard AG |
eb - Elektrische Bahnen | Year: 2015
Nearly 25 years after the federal vote of the Swiss people to build the New Alpine Railway Lines, the Gotthard base tunnel will go into commercial service in December 2016. After such a long time of realization and so short before starting operation, there are enough findings to evaluate the process for such a huge project. In this paper, the authors try to show with a few examples how such a project can be led to success despite the large, partly unexpected and constantly changing challenges.
Hofle H.,Alptransit Gotthard AG
Geomechanik und Tunnelbau | Year: 2013
The two shafts located at Gotthard Base Tunnel in Sedrun - each 800 m deep - are serving during final tunnel operation as ventilation and as supply shafts. During construction phase of the main tunnels, each 57 km in length, they have been used as access and supply shafts for the construction of the central section of the Gotthard Base Tunnel. The central lot consists of the two single lane tunnels with 9 km length each and also of the multifunction area Sedrun. The preliminary works started in 1996 and were finished 2003 from when the first shaft was used as logistical access for the construction of the main tunnels. Until 2012 the whole operation of the tunnel construction as well as major parts of final fit out of the rail equipment has been carried out by using supply shaft 1. Shaft 2 which had been finished slightly later was mainly used as ventilation shaft and for transport of heavy and large sized equipment. The presentation describes the construction-technology and the requirements with regard to the needs of the construction phase. © 2013 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.
Simoni R.,AlpTransit Gotthard AG
Proceedings of the Institution of Civil Engineers: Civil Engineering | Year: 2014
When it opens in 2016 the 57 km long Gotthard base tunnel under the Swiss Alps will be the world’s longest. Together with the 15 km Ceneri base tunnel to the south, which will open 3 years later, it will provide a vritually flat railway across Switzerland. The tunnels aim to reduce significantly the amount of envrionmentally damaging lorry traffic crossing the country between Germany and Italy as well as cut north–south passenger train journeys by 1·5 h. This paper reports on the backround to the £7 billion project, describes the design and construction of the twin-bore tunnel and its sophisticated railway systems, and summarises lessons learned from over 10 years of tunnelling in hard rock up to 2·5 km underground. © ICE Publishing: All rights reserved.
Simoni R.,AlpTransit Gotthard AG
Beton- und Stahlbetonbau | Year: 2013
With construction of the new Gotthard Rail Link, Switzerland is creating transport history. The two base tunnels under the Gotthard and Ceneri are not only pioneering technical achievements, they also symbolise the materialisation of a nation's will. As long ago as 1992, Switzerland's voters authorised the New Rail Link through the Alps (NRLA) under the Gotthard and Lötschberg. In a further referendum in 1998, they created the Public Transport Finance Fund (FinöV) to secure the financing of major Swiss railway projects. The Gotthard Base Tunnel, at 57 km the world's longest railway tunnel, will go into operation in 2016. In 2019, the flat route through the Alps is scheduled to be completed with the Ceneri Base Tunnel. This will restore the competitiveness of rail over road for transalpine transport. With the shorter and flatter route, productivity in goods traffic can be significantly increased. Rail passengers benefit from substantial time gains. Also with the NRLA, Switzerland integrates itself into the European high-speed network. Copyright © 2013 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.