Artikeldatenbank
Autor(en) | Titel | Zeitschrift | Ausgabe | Seite | Rubrik |
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Pikl, Franz Georg; Richter, Wolfgang; Zenz, Gerald | Large-scale, economic and efficient underground energy storage / Großtechnische, wirtschaftliche und effiziente untertägige Energiespeicher | Geomechanics and Tunnelling | 3/2019 | 251-269 | Topics |
KurzfassungThe conversion of the energy supply system towards renewable technologies is indispensable for climate and environmental protection. With the predominant use of inexhaustible but fluctuating renewable energy sources, energy storage capacities and physical networks are key infrastructure for sustainable functionality. Efficient pumped-storage hydropower can meet these demands. However, suitable sites for conventional surface reservoirs are facing natural limits, and new storage capacities in ecologically sensitive mountainous valleys are increasingly difficult to license. To gap these aspects this article reflects the construction of fully underground pumped-storage hydropower plants to cover multipurpose energy storage requirements. x | |||||
Innerhofer sen., Guntram; Greiner, Richard; Innerhofer jun., Guntram | Structural design concept for pressure shafts of hydro plants using the passive resistance of the rock mass / Bemessungskonzept für Druckschächte bei Nutzung des passiven Gebirgswiderstands | Geomechanics and Tunnelling | 3/2019 | 270-281 | Topics |
KurzfassungThe proposed method can be seen as an adaption of the “Seeber” concept considering developments in geomechanics, calculation methods and steel technology over the last decades. When exposed to inner pressure, the cracking condition is transgressed and steel linings will not protect the rock mass against cracking. Accordingly, the post-failure behaviour of the rock mass is an essential basis for structural design. The effects of crack water pressure on radial displacements and the width of gaps are considered. The resistant behaviour of the rock mass is determined by its minor primary principal stress. Under mountain ridges and slopes, there is no correlation between the minor stresses and the height of overburden. Obviously damage cases in concrete lined tunnels are the result of inappropriate assessment of principal stresses. A better approach is proposed based on fundamental considerations and FE calculations. Crack water pressure close to the level of the minimal principal stress will induce progressive hydraulic fracturing in the rock mass, which requires safe waterproofing sealing of the shaft. Grouting the coaxial gap in rock mass is a firm part of any design concept. In shafts sealed by membranes, the capability to bridge fissures must be proved by tests. In steel lined shafts, the usable passive resistance of rock mass is determined by the acceptable radial displacement. x | |||||
Kieffer, Scott; Dreese, Trent; Weil, Jonas; Kleberger, Johannes | Tools for optimizing rock mass grouting | Geomechanics and Tunnelling | 2/2019 | 121-128 | Topics |
KurzfassungOptimization of rock grouting procedures during construction is necessitated when sparse data sets and incomplete geologic understanding form the basis of initial design. Relying on geologic investigation findings that often have limited budgets, initial designs typically consider data from only a small volume of the entire rock mass to be grouted. During construction, thousands of production boreholes may be drilled and grouted, and each of these boreholes has the potential to provide valuable information for modifying the injection materials and construction means/methods. Implementation of procedural changes is greatly facilitated by the ability to efficiently assemble, query, visualize and interpret vast amounts of 3D data in near real-time. x | |||||
Kogler, Kurt; Hechenbichler, Johann; Gabriel, Patrick | Grouting measures in dam construction / Injektionsmaßnahmen im Talsperrenbau | Geomechanics and Tunnelling | 2/2019 | 129-140 | Topics |
KurzfassungGrouting measures in dam construction are of increasing importance in Europe, where many of the largest dams were constructed during the 1950s and 1970s. Nowadays, these dams often have to resist higher loads then they were originally designed for, and changes of reservoir management have increased loads on the structures in many cases. For this reason, many plant operators have decided to adapt dam structures for present-day use, to increase sustainability and guarantee serviceability. At the same time, the construction of new dams requires comprehensive planning as well as full cooperation between all areas of civil engineering and grouting technology. Grouting works are key elements of dam structures, which are usually not directly visible from the surface and therefore seldom perceived by the public. This paper gives an insight into the possibilities of grouting measures in dam construction and a brief overview of objectives of grouting measures and their assignment to components of dams as well as grouting measures for waterproofing curtains, pressure tunnels, pressure shafts, surge tanks and porous mass concrete. x | |||||
Hognestad, Hans-Olav; Kieffer, Scott | Pre-excavation grouting in rock tunneling - Dealing with high groundwater pressures | Geomechanics and Tunnelling | 2/2019 | 141-146 | Topics |
KurzfassungIn rock tunneling, pre-excavation grouting (or, pre-injection) refers to systematic treatment of the rock mass ahead of an advancing tunnel face via pressure grouting. The main purpose of pre-excavation grouting is to reduce water inflows, or to improve geomechanical properties of the rock mass. This paper summarizes approaches for treating competent rock masses with systematic pre-injection of cementitious grouts through boreholes drilled from the working tunnel face. The focus is on traditional cement based grouting technology and drill-and-blast tunneling under high static groundwater pressures (> 20 bar). Post-injection, where drilling and grouting is performed somewhere behind the tunnel face, provides an additional means for achieving a high degree of watertightness, but is beyond the scope of this paper. x | |||||
Creütz, Mikael; Osterman, Fredrik | The Stockholm Bypass - Design and execution of grouting works - Pre-excavation grouting by means of rock fissure grouting with cementitious grouts | Geomechanics and Tunnelling | 2/2019 | 147-157 | Topics |
KurzfassungThe E4 Stockholm Bypass is a new route for the European highway (E4) past the Swedish capital Stockholm. The bypass will connect the southern and northern parts of Stockholm. To reduce the impact on the surroundings, 18 km of the total of 21 km of the Stockholm Bypass are being constructed in tunnels. The Bypass will be one of the longest road tunnels in the world, with a construction cost of 3.1 billion Euro (2009 prices). x | |||||
Wannenmacher, Helmut; Entfellner, Manuel; Krenn, Harald | Considerations for rock mass grouting for tunnelling in faulted rock masses with tubes á manchette / Überlegungen zu Gebirgsinjektionen für den Tunnelbau im gestörten Gebirgsverband mittels Manschettenrohren | Geomechanics and Tunnelling | 2/2019 | 158-167 | Topics |
KurzfassungGrouting into an open borehole is a process that has been well described academically. Numerous grouting techniques and grouting criteria are available for various applications and combinations of rock mass/ground. Tube á manchette (TAM) or sleeve port grouting systems have until now mostly been used in specialized civil engineering work in soft ground. In order to be able to carry out grouting successfully in faulted rocks, cased drilling is necessary in order to maintain the stability of the borehole for the insertion of the sleeve pipe. Under these premises, fundamental considerations for successful TAM grouting in faulted rocks are presented. The rheological properties of the grout used, the form and size of the injection opening and the strength and thickness of the sheathing compound significantly influence the penetration into the surrounding rock mass. Increased effective pressure is necessary in order to break through the sheathing compound and also to overcome friction losses during the grouting process. The necessity of high effective pressure and the emergence of the grout at the sleeve ports can, in contrast to an open borehole, increase the risk of jacking the ground in the course of grouting and this has to be carefully taken into account and investigated in advance. The interaction of effective grouting pressures and friction losses of the grouting system and their effect on the grouting process in faulted rock are described through the formulation of a general grouting criteria for TAM grouting. x | |||||
Walter, Andreas; Mihaylov, Vladislav; Wagner, Hanns | Development of a guideline for cross passage junctions in segmental lined tunnels / Entwicklung eines Planungsleitfadens für das Anfahren von Querschlägen bei maschinellem Vortrieb | Geomechanics and Tunnelling | 1/2019 | 19-32 | Topics |
KurzfassungThe connection between tunnels and cross passages places high demands on support and safety measures, especially for mechanized tunnelling with segmental lining. The critical task is to develop a temporary support system during the opening of the precast segmental lining until the inner lining of the cross passage has developed its full bearing capacity and is acting as a final support measure. For singleshell tunnels with waterproof linings, the serviceability of a durable waterproofing connection has to be ensured. A working group initiated by Austrian Federal Railways (ÖBB) has been concentrating on the opening of cross passages in TBM tunnels. The result of the research will be summarized in a guideline for the design of cross passage openings in tunnel with segmental lining. The guideline will describe the different systems already used for various scenarios according to the state of the technology. The paper summarizes the current state of the guideline and provides some recommended systems for lining support, waterproofing systems as well as some fundamental structural design models for the different support and coupling elements. x | |||||
Atzl, Georg; Josmann, Gerd; Handke, Dieter; Zevnik, Jaka; Fleissner, Werner; Moritz, Bernd; Schiesser, Karl; Kiesling, Andreas | Ground pressure-dependent segment opening options for cross passages on Koralm Tunnel contract KAT3 - Development of support types for cross passage excavation to segment-lined tunnel / Gebirgsdruckabhängige Tübbing-Öffnungsvarianten für Querschläge beim Koralmtunnel KAT3 - Entwicklung von Sicherungstypen zum Einfahren von Querschlagvortrieben in Tübbingröhre | Geomechanics and Tunnelling | 1/2019 | 33-44 | Topics |
KurzfassungThe southern tube of the Koralm Tunnel, contract KAT3, is being conventionally excavated with two-pass lining, while the northern tube is being driven by TBM with single-pass segment lining. The tunnel tubes are located in quite different geotechnical conditions, with soft ground of high and low permeability, major fault zones and hard rock. Cross passages are provided about every 500 m of the 12 km long tunnel section. Different support types are required for the opening of the segment lining and connection to the excavation of the cross passage. In hard rock, the support consists of anchors, tail void grout and permanent bolts between the segments. In soft ground, a temporary pre-stressed steel structure is provided, with longitudinal dowels at ring joints and special segments with increased reinforcement for the special case where cross passage excavation enters the segment-lined tunnel. x | |||||
Ring, Benno; Gollegger, Johannes | Watertight segmental lining at drained cross passages under high water gradients | Geomechanics and Tunnelling | 1/2019 | 45-52 | Topics |
KurzfassungThe Follo Line tunnels consist of a watertight single shell segmental lining with gaskets. The cross passages are drained, but watertightness is required between the two structures, which is a challenging boundary condition for design and construction. This paper focuses on the structural design of the intersection between the tunnels and the cross passages, which is performed with considerable effort. Special attention is brought to the water pressures acting in this area. Some of the challenges during project execution are discussed as well. x | |||||
Mihaylov, Vladislav; Zenz, Reinhard | Boßler Tunnel - Use of shear dowels between segment rings at cross passages / Boßlertunnel - Anwendung von Schubdübeln bei den Sondertübbingen im Bereich der Verbindungsbauwerke | Geomechanics and Tunnelling | 1/2019 | 53-61 | Topics |
KurzfassungIn the course of the construction of the new Wendlingen-Ulm line, the Boßler Tunnel with a length of 8,806 m is under construction between Aichelberg and Filstal. Both single-track main tunnel tubes are for the most part excavated by TBM and lined with segments. The main tunnel tubes have an overburden of up to 280 m and are separated by a rock pillar ranging in width from 5 to 30 m. For safety reasons, seventeen cross passages connect the main tunnels, each at a spacing maximum of 500 m. Cross passage excavation requires the opening of the main tunnel lining and therefore the removal of lining segments. In order to ensure stability of the tunnel lining during the construction phase, special lining segments are used for the main tunnel in cross passage areas. Special lining segments are adapted with additional reinforcement and built-in components. Shear forces in the circumferential joints are transmitted by shear dowels. x | |||||
Iasiello, Cosimo; Torralbo, Juan Carlos Guerra; Pérez Caldentey, P.E. Alejandro | Cross passages between TBM tunnels: The experience in Spanish high-speed railway tunnels | Geomechanics and Tunnelling | 1/2019 | 62-68 | Topics |
KurzfassungThis paper describes, by means of two practical examples, the different approaches employed to design and build cross passages between segmental lined tunnels for high speed railway lines in Spain. The increment of principal stresses at the cross passages leads to the need of an additional support system for the tunnel lining. The chosen solution for this support system depends mainly on the ground conditions, the tunnel overburden and contractor's local experience. The first example is related to the Pajares Tunnels bored in the San Emiliano formation and the second one collects the experiences of the Guadarrama tunnels bored in very hard gneiss and granite rocks. The aim of this paper is to establish some key aspects to be considered when choosing the cross passage design and the corresponding excavation process. x | |||||
Frodl, Stephan | Support structures for segments at the construction of cross passages in different soil conditions / Unterstützungskonstruktionen für Tübbinge beim Herstellen von Querschlägen in unterschiedlichen Baugrundverhältnissen | Geomechanics and Tunnelling | 1/2019 | 69-81 | Topics |
KurzfassungEmergency exits must be available at certain intervals in tunnels for safety reasons. For this purpose, cross passages are excavated to a second tunnel tube, to shafts with staircases or separate exit tunnels. For the excavation of these emergency exits in TBM drives with segmental lining, openings have to be provided in the segmental lining. This article outlines different systems to make openings in segmental linings. The choice of a suitable system depends on various constraints, e.g. the geometric dimensions of the tunnel tube and the cross passages or the prevailing soil conditions. In addition, the loadbearing capacity and serviceability is also very important. x | |||||
Tellioglu, Volkan | Observations on cracking in concrete tunnel segments - An assessment of correlations | Geomechanics and Tunnelling | 1/2019 | 82-95 | Topics |
KurzfassungFaced with the combined challenge of aging sewer infrastructure and rapid population growth, the Abu Dhabi Sewerage Services Company (ADSSC) has embarked on a bold approach to build an enhanced sewer infrastructure with a deep gravity sewer tunnel at the centre. The primary lining of the new 41 km-long deep sewer tunnel has been completed by tunnel boring machines (TBM). The concrete segmental lining has an internal diameter varying from 4 to 5.5 m internal diameter and is located at depths of 20 to 80 m below the ground surface. This paper discusses the results of observations made on segment cracking experienced at different stages in the installation of concrete lining for the first of three TBM drives in Contract T-02 of the Abu Dhabi Strategic Tunnel Enhancement Program (STEP). It also attempts to quantify correlations and ranking among various mechanical and geometrical variables of ring installation based on their contribution to segment cracking. The method of assessment used in the case study has been successfully verified on a separate project, which encouraged the author to develop and propose a generalized procedure for investigation to serve as a roadmap in the future projects with segment cracking issues. x | |||||
Joham, Kurt | From conventional to mechanised tunnelling - A technical and operational challenge / Vom konventionellen zum maschinellen Vortrieb - Eine technische und baubetriebliche Herausforderung | Geomechanics and Tunnelling | 6/2018 | 636-646 | Topics |
KurzfassungThe article provides a summarised report about the redesign of the 8, 822 m long Boßler Tunnel from the originally intended shotcrete method to a mechanically driven tunnel. The twin-bore Boßler Tunnel is the main contract on the Albaufstieg (Alb ascent) section of the new DB line from Wendlingen to Ulm as part of the major DB project Stuttgart-Ulm. In 2012, the tunnel was tendered by the DB AG for construction by conventional methods with shotcrete support, but a bid for the Boßler Tunnel was received from the consortium Porr, Hinteregger, Östu/Stettin and Swietelsky with an alternative proposal to drive a 2,900 m long section of the tunnel with a machine. The contract was awarded with the alternative proposal and during the construction of the Boßler Tunnel, a change was then made to complete mechanised tunnelling in a unique technical and operational process. The report provides an insight into the challenges of a change to the overall construction system, undertaken after the award during the construction period, for the driving of altogether 17,500 m of tunnel bores. Construction operations, logistics, design for construction, additional investigation measures and contractual parameters were reorganised and redesigned on a tight schedule. Starting with the original 5,800 m TBM drive and the start of tunnelling in April 2015, the entire Boßler Tunnel was actually constructed as a mechanically driven single-pass tunnel by June 2018. x | |||||
Wunderle, Maximilian; Abele, Matthias | Geotechnical challenges during the construction of the Albabstieg Tunnel in prediction and construction / Geotechnische Herausforderungen beim Bau des Tunnel Albabstieg in Prognose und Ausführung | Geomechanics and Tunnelling | 6/2018 | 647-658 | Topics |
KurzfassungThe construction of the Albabstieg Tunnel on the Wendlingen-Ulm railway line had to overcome several geotechnical challenges. For the filling of the ground replacement body as a foundation for the slab track from recycled tunnel excavation material, it turned out that the Jurassic limestones are only conditionally suitable as a qualified fill material. The aggregates processed on site can only be used as fill material if cement stabilised. Beside the main issue of karst investigation, above ground by means of geophysical methods and underground using a conventional drilling grid, two longer sections of pipe screens had to be constructed: in the area of an unsealed landfill intersected by the tunnel cross-section and in the area of shallow overburden in the Lehrer Tal. Tunnelling under a residential area with historic cellars had to be accompanied by an intensive monitoring of blasting due to highly variable rock strength. Low-emission tunnelling could only be achieved with additional measures of blasting optimization. With the interdisciplinary co-operation between client, geotechnical consultant, designer and contractor, these special challenges were successfully overcome and the construction works were completed within cost and schedule. x | |||||
Halwachs, Michael | Guidelines for health and safety and fire safety on underground construction sites / Richtlinien für Sicherheit, Gesundheitsschutz und Brandschutz auf Untertagebaustellen | Geomechanics and Tunnelling | 6/2018 | 659-665 | Topics |
KurzfassungUnderground construction sites represent a complex challenge for all project participants. Precisely in the area of health and safety as well as fire safety, therefore, good coordination is necessary in order to successfully counteract the increased accident and health risks. Clear definition of tasks and responsibilities is therefore essential. Through a continuous risk management process, it is possible to ensure from the design phase to the construction phase that risks can be minimized in advance and that the best risk reduction measures can be derived. The Guideline and Regulation for the Planning, Construction and Maintenance of Roadways (RVS) 09.01.51 “Health and Safety on underground construction sites” provides the necessary basis for this and thus represents an essential tool for all project participants to improve the level of safety. x | |||||
Leitner, Andreas; Goger, Gerald | Revision of the Austrian Standard ON B 2203-1 for work contracts in conventional tunnelling (NATM) / Update der österreichischen Werkvertragsnorm ÖNORM B 2203-1 für den zyklischen Vortrieb | Geomechanics and Tunnelling | 6/2018 | 666-679 | Topics |
KurzfassungThe works contract for cyclic driving ÖNORM B 2203-1 has made a significant contribution to the successful completion of numerous tunnel construction projects in the last four decades. As part of a required update in the industry, no reason was seen to change the set of rules of the present classification system and the essential principles of the existing standard. The focus of the revision has therefore been - on the basis of the experience of the last decades in the implementation of tunnelling projects - on the one hand in the analysis and rating of support elements and additional measures and on the other hand in the provisions of the standard for water implications. Through these updates, in good old tunnel construction tradition, cooperative project management on a high constructional level will continue to be ensured. x | |||||
Spiegl, Markus; Galler, Robert; Sander, Philip | Application of the ÖGG guideline for cost estimates on international megaprojects / Kostenermittlung für internationale Großprojekte auf Basis der ÖGG-Richtlinie | Geomechanics and Tunnelling | 6/2018 | 680-692 | Topics |
KurzfassungTransportation infrastructure projects are characterised by long project phases, a high number of project participants, hard-to-predict influences and their uniqueness. The new version of the ÖGG “Guideline for the Cost Determination for Transportation Infrastructure Projects” builds on experience of the previous version and sets new accents in practical applicability, e.g. through the use of risk fact sheets. Structured cost and risk management is no longer conceivable without adequate software. The integral cost and schedule analysis is a further step towards improved cost and project schedule stability. The guideline was published in English at the same time, which supports its use in international consulting. x | |||||
Buyer, Andreas; Pischinger, Gerald; Schubert, Wulf | Image-based discontinuity identification / Bildgestützte Trennflächenidentifikation | Geomechanics and Tunnelling | 6/2018 | 693-700 | Topics |
KurzfassungKnowledge about the joint network is important in rock engineering. It controls the stability and strength of blocky rock masses. Thus, the joint network is mapped in more or less detail, regarding the specifications. To do so, different methods have evolved over the years. One of these methods is digital mapping, based on the visual and spatial appearance of the distinct joints. This mapping usually is done by an experienced geologist. However, the trend in digital mapping is towards a supervised but mainly autonomous identification of discontinuities. One aspect of this automated process is the recognition of joints in digital outcrop images by their optical attributes. This contribution presents a density based joint plane detection. By the combination of a vector based joint plane detection and a pixel based joint trace detection, not only joints, but also the foliation in the investigated tunnel face could be extracted very accurately. The approach represents the current state of research and further improvements are to be expected. x | |||||
Monsberger, Christoph M.; Lienhart, Werner; Moritz, Bernd | In-situ assessment of strain behaviour inside tunnel linings using distributed fibre optic sensors / Beurteilung des In-situ-Dehnungsverhaltens der Tunnelschale mittels verteilter faseroptischer Messsysteme | Geomechanics and Tunnelling | 6/2018 | 701-709 | Topics |
KurzfassungIn modern tunnelling, deformation monitoring is an important component to ensure a safe construction. It is state of the art to measure displacements at the inner side of the tunnel lining using total stations. In addition, pointwise geotechnical sensors, e.g. electric strain gauges, may be installed in geological fault zones, which, however, do not deliver a complete picture of the internal deformations. The Institute of Engineering Geodesy and Measurement Systems (Graz University of Technology) supported by the Austrian Federal Railways (ÖBB-Infrastruktur AG, SAE Fachbereich Bautechnik/Tunnelbau) developed a fibre optic sensing system, which realizes thousands of measurement points inside the tunnel lining. The distributed measurements can be used to assess the in-situ strain behaviour as well as to localize failures (e.g. cracks) in the lining. This paper reports about the calibration of the fibre optic system under well-known laboratory conditions and the practical utilization of the system in mechanized and conventional tunnelling. The results demonstrate the high potential of distributed fibre optic systems and their capability especially in the operational phase to extend classical measurement methods in tunnelling projects. x | |||||
Goger, Gerald; Bisenberger, Tobias | Tunnelling 4.0 - Construction-related future trends / Tunnelbau 4.0 - Baubetriebliche Zukunftstrends | Geomechanics and Tunnelling | 6/2018 | 710-721 | Topics |
KurzfassungThe digitalisation of construction-related processes will increasingly penetrate the individual development phases of tunnel construction projects (design, construction and operation). The digital transformation will affect all tunnelling processes through its four key levers: “digital data, automation, networks and digital access”. Topics such as Industry 4.0, digital twins, Building Information Modelling or Lean Management will lead to a rethink in the construction industry. The constant use of data sources and the storage of data in independent databases is already possible. This makes it possible for the project participants to analyse collected construction-related data, to process it and to make it available through an online portal. This results in the possibility to evaluate, optimize and document construction processes on a well-founded data base. Complex construction management systems will be described with digital models, and the use of digital knowledge systems will support the decision-making process for stakeholders. The fundamental philosophy of the New Austrian Tunnelling Method should not be called into question by standardised calculation algorithms and tunnelling software. In this contribution, visionary future trends are outlined for cyclical and continuous tunnelling methods, which should stimulate a controversial discussion. x | |||||
Füllenbach, Christel | Smarter Tunnelling / Smarter Tunnelling | Geomechanics and Tunnelling | 6/2018 | 722-728 | Topics |
KurzfassungSafety, time and costs belong to the most important influencing factors in tunnelling. The Smarter Tunnelling concept can positively influence these factors by speeding up work processes, avoiding limited safety zones and saving time and money. Smarter tunnelling not only describes the use of machines that are remotely monitored, but also the integration of an entire intelligent system into a tunnelling project. For this purpose, all machines used have to communicate with each other and with a central data processing unit. To implement this digitization and automation in tunnelling projects, networking with intelligent sensors and actuators as well as special software are used. In order to achieve a trimming of work processes at the same time, it is necessary to streamline data processing through IT solutions. This paper presents the Epiroc solutions, which have been specially developed for the tunnel construction sector. x | |||||
Wehrmeyer, Gerhard | Development trends in mechanised tunnelling / Entwicklungstendenzen im maschinellen Tunnelbau | Geomechanics and Tunnelling | 6/2018 | 730-737 | Topics |
KurzfassungThis article reports on the development of tunnel boring machines (TBMs) in the past decades and the current state of the art. The development is presented with a look back and a look forward into the near future. Starting with the questions on the development of diameter and operating pressure of closed tunnelling machines, the perspective is expanded to general developments and current trends in machine technology for soft ground and hard rock. Finally, the possibilities and potentials arising from environmental requirements, further increases in performance and digitalization in mechanized tunnelling are shown. x | |||||
Hörlein, Norbert | Hard rock tunnelling in Norway / Tunnelbau am Polarkreis | Geomechanics and Tunnelling | 5/2018 | 424-433 | Topics |
KurzfassungTunnelling in Scandinavia differs in several ways from the methods used in Central Europe. Porr Bau GmbH has been working since the end of 2016 with the subsidiary PNC on the first tunnelling project for the company in Norway. The project Fv.17 is located in Nordland, 10 km south of the Arctic Circle. The narrow coastal road is to be upgraded with two new tunnels. The Norwegian fjords are well known as vacation destinations and for their nature, but building tunnels in this environment is challenging, and the rock conditions are also demanding. The rock types described in the tender changed, leading to high water inflow. Systematic rock grouting needed to be carried out to finish the tunnel drive. x |