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Copyright of BHM Berg- und Hüttenmännische Monatshefte is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

After a long planning and approval phase, the main construction work on the A26 Linz motorway began at the beginning of 2019. The new A26 road section, large parts of which are underground, will not only significantly relieve the existing inner‐city traffic routes around Linz, but will also provide an additional Danube crossing in the form of a suspension bridge with a span of over 300 m. The main elements of the first Phase of construction are the Danube Bridge and two underground branches, north and south of the Danube, with excavated cross‐sections of up to 400 m2 and ramp tunnels with tight curves. The planning of an inner‐city construction project requires the comprehensive and careful consideration of the protection of the local residents with regard to the effects of noise and vibration. It also needs the impact of the construction work on the existing traffic routes to be reduced as much as possible. The material excavated from the Freinberg tunnel and the Danube South junction must be transported away via the Danube waterway. The project‐specific framework conditions, such as the very high number of tunnel portals, the sound reflections within the Danube valley and the low overburden require considerable measures to reduce their impact during the construction phase. [ABSTRACT FROM AUTHOR]

The small town of Weyer is located in Upper Austria on the B121 Weyerer Straße. The B121 leads through the historic market square of Weyer, which is characterised by confusing bottlenecks that can only be passed in one lane. For decades, these bottlenecks have caused congestion, mainly due to heavy traffic. For residents, the burden of air pollution and noise is high. The roads department of the Upper Austrian Government has been planning the construction of a bypass for many years. Construction finally started in the summer of 2022. The Weyer bypass construction lot is 1.2 km long and includes the construction of two NATM tunnels, a vertical escape shaft, a bridge over the river Dürnbach, two roundabouts, and one traffic junction. The tunnel construction works are carried out in urban areas, in loose material with little overburden and partly under existing buildings. These boundary conditions make the project a challenge for all involved at every stage. [ABSTRACT FROM AUTHOR]

After a long design and approval process, the construction works for the first phase of the A26 started in 2019. The A26 not only relieves the central part of the road network of the city of Linz but also allows the river Danube to be crossed by means of a bridge: a 300 m long bridge, anchored in the rock slopes forming the banks of the Danube. The elements of the first phase are the Danube bridge and the two underground motorway junctions, Danube North and South, with excavation cross‐sections of up to 400 m2 and the tight radii of the motorway on‐ramps. Besides these conditions, urban planning requirements such as the protection of residents against immissions caused by noise and vibration, and the increased negative impacts resulting from the traffic during construction have an effect on the construction works. The excavated material from the tunnel is transported off site by ship. The existing rock mass requires excavation by means of the drill‐and‐blast method. The project‐specific boundary conditions such as the high number of portals, the noise‐reflecting effect of the "Danube gorge" and the low overburden require substantial measures to limit and monitor the immissions. [ABSTRACT FROM AUTHOR]

The drainage system is a core element of tunnel construction and operation. Frequently, natural as well as technical boundary conditions lead to the deposition of scales (especially calcium carbonates) in the drainage system. As a preventive measure – in contrast to post‐depositional cleaning procedures – the use of scale inhibitors to treat the drainage water (hardness stabilisation) is an option. 'Green inhibitors' are tailored green organic substances that delay or prevent scale formation when added in small concentrations. Moreover, green inhibitors can change the material consistency of scale deposits (soft sinter). An additional advantage of their use is the good environmental compatibility compared to conventional inhibitors. Suitable test procedures can be used to select a substance or product and evaluate or optimise its dosage. The application of polyaspartic acid or polysuccinimide products as ecologically harmless and readily biodegradable agents has proven advantageous in tunnel structures. The choice of liquid or depot stone conditioning essentially depends on the scaling mechanism, in addition to the technical considerations, flow rates and water chemistry. Regarding discharge to existing receiving water bodies, the inhibitor concentration in the water can be measured and controlled by DOC analysis and fluorescence spectroscopy. This article presents contemporary and tunnel‐specific case studies. [ABSTRACT FROM AUTHOR]

Scale formation in water drainage systems occurs in diverse forms. In tunnel drainage systems in particular, calcium carbonate deposition can significantly impair water discharge, resulting in costly maintenance work and tunnel closures. This review paper presents and discusses the state of knowledge as well as the current challenges regarding scale formation in tunnel drainage systems in terms of typification, parameters controlling formation, such as hydrochemistry, interfacial phenomena, microbial activity, and countermeasures, such as appropriate adaptation of construction materials, drainage design, inhibitor use and cleaning. Detailed knowledge of the case‐specific scale formation environment and the scaling capacities of the waters provides the basis for the tailored development and evaluation of suitable strategies for successfully reducing maintenance efforts and tunnel closure. For this purpose, time‐ and site‐resolved monitoring of the composition of the solid phases, waters and the tunnel atmosphere during the implementation of the construction project and during the operation of the tunnel is paramount. [ABSTRACT FROM AUTHOR]

A field test was carried out in Koralmtunnel in order to enhance process understanding and to optimize the drainage system in a tunnel section that is complex in terms of hydrochemistry, water inflow and mineral (calcareous scale, iron ochre) and biological (microbial mats) deposits. The field test comprised three test fields with different system components and flow characteristics. The development of critical waters and deposits was recorded by continuous measurements of relevant water and air parameters by means of autonomous sensors/data loggers. Furthermore, the components were "forensically" examined with respect to scale formation. The experiments show the crucial importance of gas exchange (CO2, oxygen ingress), filling level (flow geometry/regime), residence time of waters and water‐air interaction in the drainage system. The type, material consistency, and amount of scale and biofilms depend significantly on specific gradients. Floating scale crusts formed in stagnant sections, biofilms and iron ochre deposits of soft consistency formed at higher flow rates. Seepage packs and siphons turned out to be potential sediment traps with decreasing flow‐through with no access. Drainage hoses and dimpled membranes tend to be beneficial because they can prevent air exchange at relatively high flow rates. High CO2 partial pressure within these components (measured and modeled) inhibits carbonate precipitation. The drainage system is locally designed as a series of direct cross‐drains with simple flow paths, restricted air exchange, precautionary cleaning access, and optional water hardness stabilization (liquid conditioning). [ABSTRACT FROM AUTHOR]

Unthinkable just a few years ago, the precise laser‐scanning survey of a kilometer‐long tunnel in one day by one operator has become possible. This article describes how 261 scans were taken with a RIEGL VZ‐400i laser scanner to digitize the Zentrum am Berg (ZaB) research tunnel with millimeter resolution. The data has been automatically registered during the acquisition process within the instrument. After applying multistation adjustment, a block adjustment postprocess step, the high accuracy of the point cloud with respect to a network of 35 retroreflective bireflex targets has been approved. For further applications such as analysis, simulation, or visualization, a homogeneous 3D‐meshed surface model has been created automatically from the point cloud representing an as‐built 3D documentation of the tunnel. [ABSTRACT FROM AUTHOR]

Tunnel surveys making use of photogrammetric three‐dimensional (3D) tunnel reconstruction reach resolutions in the millimeter range. Classical big data visualization approaches display point clouds only, neglecting this considerable resolution difference between structure and texture. The article suggests a data structure that separates structural and textural resolution by a regular grid on the unwrapped design surface for 3D, combined with a UV mapping technique as regularly used in computer graphics. For real‐time rendering of huge multiscale data sets, the result of photogrammetric commercial‐off‐the‐shelf reconstructions is transformed into a proprietary hierarchical data structure. It facilitates to only load currently relevant parts of the tunnel surface from the hard drive, and only upload and render currently adequate levels‐of‐detail onto the graphics card for seamless exploration of high‐resolution geometric and image 3D tunnel data of arbitrary length. The solution allows for smooth interactive analysis and annotation such as crack identification and mapping, inventory, deformation assessment, and dimensional measurements. Aspects of data generation are addressed and information is given about the data structure, showing examples from entire tunnel 3D representations to demonstrate the smooth behaviour of the real‐time rendering of huge data volumes in various scales on standard graphics hardware. [ABSTRACT FROM AUTHOR]

Building information modelling (BIM) is a frequently discussed topic in tunnelling since it promises less loss of information and reduced lifetime cost of underground infrastructure. There is still some way to go as standardisation in this sector is immature, the implementation of three‐dimensional (3D) BIM models is developed for pilot cases of tunnelling only, and data transfer between software tools is a challenge. The long linear structures of tunnels make a specific approach of parameterised and adaptive modelling necessary to meet the requirements of repetitive construction elements and the natural differences of forecast and actual excavation conditions. This approach renders the matching of construction elements in the model and service items feasible for determining quantities for the tender and billing in tunnel projects. In this article, we show that only 57 % of service items can actually be linked to a physical item in traditional two‐dimensional (2D) design and highlight the need to consider how to incorporate these items into a BIM model. We also use a case study to propose an approach for parameterised and adaptive modelling of repetitive construction elements and show a way of a continuous data transfer from the forecast tunnelling class distribution via 3D BIM modelling to a billing software without data loss. [ABSTRACT FROM AUTHOR]

In the operating phase of a road tunnel, not only maintaining or increasing the availability in the network but the economic optimization regarding the life cycle costs of the structure are also important priorities. A consistent application of the Building Information Modelling (BIM) methodology can theoretically make a useful and targeted contribution, as it provides a complete digital model of the structure with all installed elements and the information required for the operator tasks. In the research project FE https://doi.org/15.0623/2016/RRB "Building Information Modeling (BIM) in Tunneling," the Institute of Tunneling and Construction Management and the Institute of Computing in Engineering (both Ruhr University Bochum) in cooperation with BUNG Ingenieure AG developed the basics for a BIM‐based operating model of road tunnels with funding from the Federal Highway Research Institute commissioned by the Federal Ministry of Transport and Digital Infrastructure. In the article, the results of the research are presented on the basis of specific use cases of a BIM‐based operation and maintenance management. [ABSTRACT FROM AUTHOR]

In the past decades, Norwegian tunnelling has undertaken a major digital development in all operations from planning to the excavation phase. The breakthrough is driven by digital contract requirements from forward‐leaning clients and innovative industrial stakeholders, aiming for ever more efficient, quality‐oriented and risk‐reducing operations. A formal milestone documenting this development was the publication of Digitalisation in Norwegian Tunnelling in 2019. From 2019, most contracts of new infrastructure tunnels must deliver a level 3 Building Information Modeling (BIM) model. Control systems for drilling jumbos are fully digitalised. All drilling must be monitored and documented with Measurement While Drilling techniques. Via cloud servers, the drilling information is interpreted and delivered live to face engineers for decision support. Sensors are used to monitor rock grouting flow and pressure in each drill hole. Digital electronic detonators with exact delay time are used for blasting. Geotechnical mapping is carried out on field tablets. High‐resolution scans with RGB imaging must be carried out on the exposed rock surface and after rock support/linings. The next step is to utilise all the collected data to a higher degree by advanced analysis with machine learning (ML) and similar techniques for automation and optimisation. This study reviews and exemplifies the digital focus and achievements in core operations in Norwegian tunnel excavation. [ABSTRACT FROM AUTHOR]

During the renovation of the Gotschna Tunnel from 2019 to 2020, prefabricated elements made of Compex were used for the first time as a deformable yielding zone in the invert zone. The client, construction management, construction company and supplier of the compressible elements worked closely together to implement the design specifications. Consequently, the expectations of the special building material in terms of the production quality of the prefabricated elements and handling on the construction site were more than met. The parties involved in the construction thus see potential for further applications and further developments of Compex. [ABSTRACT FROM AUTHOR]

Tunnel geothermal systems hold the potential to promote decarbonization of the building heating and cooling sector. They can be integrated into existing infrastructure, resulting in low additional costs. In addition, these systems have large contact areas with the ground leading to larger heat fluxes. However, tunnel geothermics is relatively unknown and rarely used. Thus, the objective of this study is to provide an overview of the two primary tunnel geothermal system types as well as their application and potential. Open hydrothermal systems use the tunnel drainage water as a heat source, whereas closed absorber systems harness the heat flux from the subsoil and the warm tunnel interior via heat exchangers. The evaluation of the global application of existing and planned tunnel geothermal systems shows that all open systems are currently located in mountainous regions with a thick rock overburden. In contrast, closed absorber systems are mostly installed in urban tunnel infrastructures. The spatial distribution of geothermal tunnel systems has a focus in central Europe with Switzerland, Germany and Austria being the countries with the highest number of installed systems. Finally, this study also presents a brief summary of existing methods to determine the geothermal potential of tunnels. [ABSTRACT FROM AUTHOR]

This paper discusses the concept and the practical experiences of excavating an under‐river crossing with a slurry shield (D = 13.45 m) to construct a single‐tube road tunnel. Unstable sand and gravel as well as harder chalk zones in the invert area combined with high groundwater pressure require the tunnel face to be actively supported at all times. Over long stretches the overburden to the river bed is only around 0.5 D, which means that a delicate balance has to be struck between achieving the minimum support pressure required to stabilise the tunnel face while at the same time preventing blow‐out. An innovative segment sealing system with integrated expanding insert combined with a push‐fit dowel system achieves a high degree of protection from moisture and voids. The evacuation and rescue concept for the single‐tube road tunnel is based on a refuge running under the carriageway. This evacuation channel is accessed via staircases in recesses at the side. Ground freezing is used to stabilise the sand during excavation of the recesses at around 4 bar water pressure. [ABSTRACT FROM AUTHOR]

The Stockholm bypass (E4 Förbifart Stockholm) is being built by the Swedish Transport Administration (Trafikverket) – the office responsible for transport infrastructure in Sweden. The project aims to improve connections between the regional town centres and reduce congestion on the main urban roads. The route, which runs mainly underground, employs numerous contractors and has a planned construction period of 14 years, preceded by a 10‐year planning phase. This article looks at three projects: the FSE 61 Akalla Interchange, the FSE 309 Lovön Interchange and in particular, the FSE 613 Akalla Tunnel. The Akalla Tunnel is driven as a conventional full‐face excavation with pre‐grouting and supported with rock bolts and steel‐fibre‐reinforced shotcrete. The tunnel excavation is followed by the interior work comprising precast concrete walls, a suspended membrane reinforced with shotcrete, ceiling foundations and the carriageway structure. [ABSTRACT FROM AUTHOR]

Copyright of BHM Berg- und Hüttenmännische Monatshefte is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The approx. 3 km long twin‐tube Rudersdorf tunnel is part of the Fürstenfeld Motorway S7. In addition to jet grouting and steel pipe umbrella sections, the excavation is mainly carried out according to the NATM. After the contract had been signed, the contractor proposed a value engineering concept including a stepped (almost) full excavation with a short ring closure. This concept avoids jet grouting sections and reduces sections with steel pipe umbrellas and the temporary top heading invert. A fair risk transfer between both contractual partner enables the full technical and economic potential of the project to be released and guarantees a win‐win situation. The modified construction methodology consequently also requires a change of tasks and responsibility for the contractual partners for the project. This paper highlights the main topics of the contractual modifications required and explains the handling of the ground risk with examples. [ABSTRACT FROM AUTHOR]

The Artificial Ground Freezing (AGF) has demonstrated its versatility as an effective approach for both temporary ground stabilization and ground water control in almost all types of saturated soils. This paper describes the use of a closed circuit freezing system in the construction of four cross passages. The passages connect 4.8 km long twin road tunnels that have recently been constructed at depths of up to 60 m under Suez Canal in Ismailia, Egypt. The paper starts by describing the ground conditions at the locations of the cross passages and by presenting the results of laboratory tests conducted on unfrozen, frozen and thawed soil specimens. The main design criteria considered in designing the freezing works are discussed and the freezing and cross passages construction works are described. The frozen body was carefully monitored during the freezing process and construction of passages. Records of the adopted monitoring program are presented and discussed. Significant observations that contribute to effective planning of future freezing works are also presented. [ABSTRACT FROM AUTHOR]

Copyright of BHM Berg- und Hüttenmännische Monatshefte is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tunnels within primary road networks are complex systems. The prerequisite of a good level of service is the seamless interaction of the various tunnel components (structural elements and technical equipment). Due to their heterogeneous nature, electrical and structural components are subject to divergent aging processes which require recurring maintenance procedures and rehabilitation measures. Considering the diversity of specifications and requirements among electrical/mechanical and structural components, it is evident that there is a considerable mismatch of maintenance cycles among them. Hence, tunnel asset management faces the challenge to develop strategies to integrate both the necessary functional integrity of the individual components over their respective lifecycle and the requirement of an optimized management for the overall system. Yet, the synchronization of measures towards maximizing system availability must not contradict positive wear‐and‐tear contingencies of the various tunnel components. Evidence based forecasting and reliability centred decision models are key elements of modern life cycle management. They must include interdependencies between the diversity of components and their manifold maintenance cycles. [ABSTRACT FROM AUTHOR]

The 8,900 m long Rohtang Tunnel lies in the Indian Himalayas north of the Manali tourist region. It avoids the dangerous route over the Rohtang Pass, which is at an elevation of almost 4,000 m, shortening the Manali‐Leh Highway by approx. 50 km and enabling access to the northern regions of the state of Himachal Pradesh and onto Jammu and Kashmir even during the winter. It was envisaged that the tunnel would be driven from two sides by drilling and blasting. The horseshoe‐shaped cross‐section with an excavation diameter of more than 13 m carries two lanes of vehicle traffic, two footpaths and an emergency egress beneath the carriageway. In addition to the extreme conditions that were a feature of this project – portals at an altitude of over 3,000 m, with corresponding severe winters, avalanches and mudslides, etc. – the NATM was also driven to its limits. Friable soils instead of blast rock, water ingress in excess of 250 l/s, high rock pressure with extreme deformations and rapid changes in rock formations presented major challenges to all involved. Tunnelling operations are now nearing completion and the road tunnel will be open to traffic later this year. [ABSTRACT FROM AUTHOR]

To secure the availability and usability of the motorway network, the Federal Roads Office (Fedro) developed new solutions for the renovation of road tunnels while keeping them open to traffic and initiated a pilot project. The aim is to replace a non‐reinforced inner shell at night and ensure the availability of all lanes during the day. The solution involves partially removing the existing inner shell, then installing a drainage and waterproofing system, and finally installing a new inner lining of self‐compacting concrete during the night. The success of this pilot project led to the decision to renovate two more tunnels without delay. The strategy is based on optimising the basic variant by reducing the lining thickness using ultra‐high performance fibre reinforced cementitious composite (UHPFRC) instead of conventional concrete or installing thin precast segmental lining in UHPFRC instead of conventional formwork. Fedro's innovative method will make it possible to renovate road tunnels over the long term while maintaining daytime traffic flow without massively impacting their substance. [ABSTRACT FROM AUTHOR]

Based on mining experience and historical conventional construction processes a new type of construction has evolved – the New Austrian Tunnelling Method (NATM). NATM changed the view on the rock mass surrounding the tunnel from the forcing to the load‐carrying component. NATM is a proven methodology for conventional tunnelling applied worldwide. New observation– and measurement techniques as well as digital models (e.g. geological model) will be increasingly integrated within the Building Information Modelling (BIM) process. BIM provides a sound basis of vital information for decision support across different project phases. [ABSTRACT FROM AUTHOR]

The sealing of tunnel walls involves the use of membranes which, depending on the situation, are constantly exposed to the leaching action of groundwater, or of water emanating from the surrounding rock. In terms of ecological product compatibility, the question arises as to whether pollutants may be released in the process. Various geomembranes are examined in more detail and subjected to an evaluation system. It emerges that in particular geomembranes with especially worrying components such as phthalates should generally be kept away from the environment for precautionary reasons, even though some phthalate plasticisers have not yet been evaluated by the EU. Phthalates are characterised by the fact that they are released from the membranes in considerable quantities. [ABSTRACT FROM AUTHOR]

In current tunnelling practice, Finite Element (FE) simulations form an integral element in the planning and the design phase of mechanised tunnelling projects. The generation of adequate computational models is often time consuming and requires data from many different sources, in particular, when manually generated using 2D‐CAD drawings. Incorporating Building Information Modelling (BIM) concepts offers opportunities to simplify this process by using geometrical BIM sub‐models as a basis for structural analyses. This paper presents a Tunnel Information Model (TIM) as a BIM specifically tailored to fit the needs of mechanised tunnelling projects and a "BIM‐to‐FEM" technology, that automatically extracts relevant information (geology, alignment, lining, material and process parameters) needed for FE simulations from BIM sub‐models and subsequently performs FE analysis of the tunnel drive. The results of the analysis are stored centrally on a data server to which the user has continuous access. A case study from the Wehrhahn‐Metro line project in Düsseldorf, Germany, is presented and discussed to demonstrate the efficiency and the applicability of the proposed BIM‐to‐FEM workflow. [ABSTRACT FROM AUTHOR]

Transport infrastructure is a fundamental cornerstone for mobility of the population and also functions as a motor for the economy. New digital methods along the value chain will be used to digitally support the process in the future, from the very first project idea, through tendering and construction to the maintenance of infrastructure projects. The four levers of digital transformation – data, automation, networks and access – will have a significant impact on this process in infrastructure construction. Networking of data sources and storage of data in off‐grid databases is already possible, a development which enables project participants to analyse the construction data, process it and at the same time use it as a documentation basis during the development phase and for later maintenance measures. Such a well‐founded digital database can be used to evaluate, optimize and completely document construction‐related processes. This paper deals with various digital application areas in infrastructure construction and provides an overview of digitalisation developments in this field. [ABSTRACT FROM AUTHOR]

Starting with geological field mapping in the tunnel, a process can be implemented to transform all geological observations into data structures for later use in BIM systems. All necessary basics are already available and a reference implementation has been programmed. When corresponding standards become available, which will be the case in the next one to two years, universal interchangeability of the information will also be provided. This will ensure that the ground model can be maintained through the life cycle, and the ground – as part of the Digital Twin of the structure – is available in later project phases like operation, maintenance, enlargement und renaturation. [ABSTRACT FROM AUTHOR]

A fire can occur in many areas of a transport system. Detecting fires at an early stage and rapid automated fire‐fighting can significantly minimize or completely prevent damage to rolling stock and infrastructure. In addition to effective fire‐fighting, people should be safeguarded, the systems should be economical, and activation should cause a minimum of damage. Despite the positive effects of using automatic fire‐fighting systems in terms of building protection and reducing the fire load, there may be negative effects on escaping persons during the escape phase. Different systems such as the high‐pressure water mist system and the deluge system are investigated by CFD simulation and evaluated with regard to their use during the escape and external rescue phases. [ABSTRACT FROM AUTHOR]

The 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). The challenges have been many, for example how to evaluate the hydraulic rock mass properties for such a vast tunnel stretch and then find the most suitable grouting design, the contractor's ability to deliver proper grout properties and suitable grouting equipment, the time and resources needed for QA/QC of the grouting works and the need for adaption of the grouting works to true geological conditions. Not to mention the complexity of monitoring water ingress during construction for the Client to show that the sealing demands are being met according to the environmental permits for water works operations. The Stockholm Bypass is by far the largest rock fissure grouting operation undertaken for road tunnels in Swedish history. [ABSTRACT FROM AUTHOR]

Abstract: Tunnelling 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. [ABSTRACT FROM AUTHOR]

Asfinag (Autobahnen- und Schnellstraßen-Finanzierungs AG) has the commission to oversee the entire Austrian high-speed road network. Tunnel safety is an important focus. In the period between 2004, when the tunnel improvement programme started, and the first months of 2019, about EUR 5.7 billion will have been invested in the upgrading of tunnels as well as the optimisation of tunnel safety equipment. Along with these investments, there is also a focus on optimising the performance of lifecycles without risking non-compliance with safety standards. Tunnel refurbishment measures are planned and carried out on the basis of regular checks and assessments, taking into consideration requirements with regard to both construction engineering and electrical equipment while at the same time pursuing the aim of optimising cost-effectiveness. This paper also addresses the challenges resulting from the fact that the lifecycle of the tunnel structure differs from that of the tunnel equipment. Both the medium-term and the long-term planning of refurbishment measures should be prepared in detail to the greatest extent possible, so that the organisation can best guarantee both safety and cost-effectiveness. [ABSTRACT FROM AUTHOR]

The construction of the Tauern Tunnel in the early 1970s was a milestone in the development of the New Austrian Tunnelling Method (NATM). The experience gained then formed the basis for the development of new technologies, which made tunnelling more efficient and safer and were applied consistently in the design and construction of the second tube. The present article describes the geological conditions, compares the geology with the original tunnel and then explains the starting points for the geomechanical design framework. The basic considerations for the planning of the tunnelling work are described, particularly for squeezing rock behaviour. Then there is a discussion of the geotechnical monitoring and implementation of the design during the excavation of the tunnel, with particular consideration of the problem of long-duration creep deformation and the difficulties in the project-specific determination of warning values. Finally, the conditions encountered along the new tube are summarised and compared with the design and geotechnical conditions of the first tube. This includes a description of the extremely complex and difficult tunnelling conditions in incompetent rock when passing through the approx. 300m long section in slope debris. Der Bau der ersten Röhre des Tauerntunnels in den frühen 70er Jahren des letzten Jahrhunderts stellte einen Meilenstein in der Entwicklung der Neuen Österreichischen Tunnelbauweise (NÖT) dar. Die damals gewonnenen Erfahrungen bildeten die Grundlage für die Entwicklung neuer Technologien, die den Tunnelbau effizienter und sicherer machten und bei Planung und Bau der 2. Röhre konsequent angewendet wurden. Vorliegender Beitrag erläutert nach einer Vorstellung der geologischen Rahmenbedingungen und einem Vergleich mit der Geologie der ersten Röhre die Ausgangspunkte für die geomechanische Rahmenplanung. Die grundsätzlichen Überlegungen bei der Vortriebsplanung, insbesondere für druckhaftes Gebirgsverhalten, werden dargestellt. In weiterer Folge wird auf die geotechnische Überwachung und Umsetzung der Planung während der Vortriebsarbeiten eingegangen, wobei besonders die Problematik von langanhaltenden Kriechverformungen und die Schwierigkeiten bei der projektspezifischen Festlegung von Warnwerten betrachtet werden. Abschließend werden die im Zuge des Vortriebs angetroffenen Verhältnisse zusammengefasst und eine Gegenüberstellung mit der Planung und den geotechnischen Verhältnissen der ersten Röhre durchgeführt. Dabei werden auch die äußerst komplexen und schwierigen Vortriebsbedingungen im Lockergestein bei der Durchörterung der ca. 300 m langen Hangschuttstrecke behandelt. [ABSTRACT FROM AUTHOR]

Based on the experience of former tunnel construction projects, the project management appointed an independent quality assurance consultant in addition to quality control by the site supervision for the construction of the intermediate slab and the concrete pavement of the new second tube of the Tauern Tunnel (direction Salzburg). In relation to the concrete pavement with exposed aggregate finish and the intermediate slab, quality assurance measures included the inspection of the suitability certificates and expert support in construction preparation and concreting. Compliance with the technical conditions of contract was also monitored continuously. For the road pavement construction, particular emphasis was placed on the quality of the pavement concrete and the exposed aggregate finish. For this reason, the first few days of pavement construction were subjected to increased checks, until the concrete production, transport logistics and construction crew had got used to the specific conditions in the tunnel and a homogeneous exposed aggregate finish could be guaranteed with the required functional properties like skid-resistance and noise-reducing texture. Construction of the intermediate slab was prepared in advance by casting a test slab as agreed with the specialist in order to check that the required construction quality could be achieved with the chosen process. The experience with the test slab led to an optimisation of the construction process and the implementation of this and maintenance of the quality requirements were supervised during the construction work. Für die Herstellung der Zwischendecke und der Betonfahrbahn der neuen zweiten Röhre des Tauerntunnels (Richtungsfahrbahn Salzburg) wurde von der Projektleitung aufgrund der Erfahrungen aus vorhergehenden Tunnelbaulosen zusätzlich zur Qualitätskontrolle durch die örtliche Bauaufsicht eine begleitende Qualitätssicherung durchgeführt. In Bezug auf die in Waschbetontechnik ausgeschriebene Betonfahrbahn und die Zwischendecke umfassten die qualitätssichernden Maßnahmen die Begutachtung der Eignungsnachweise und die sachverständige Unterstützung der Bauvorbereitung und des Deckeneinbaus. Zusätzlich erfolgte eine laufende Beurteilung der Einhaltung der technischen Vertragsbestimmungen. Für den Straßendeckeneinbau wurde besonderes Augenmerk auf die Qualität des Deckenbetons und der hergestellten Waschbetonstruktur gelegt. Zu diesem Zweck wurden die ersten Tagesleistungen bei der Deckenherstellung einer verdichteten Kontrollprüfung unterzogen, bis sich die Betonproduktion, die Transportlogistik und die Einbaumannschaft auf die spezifischen im Tunnel vorherrschenden Verhältnisse eingespielt hatten und eine homogene Waschbetonoberfläche mit den geforderten funktionalen Eigenschaften bezüglich Griffigkeit und lärmmindernder Textur sicher gestellt werden konnte. Für die Herstellung der Zwischendecke wurde im Rahmen der Arbeitsvorbereitung ein Probefeld in Abstimmung mit dem Sachverständigen hergestellt, um die Erreichbarkeit der geforderten Bauwerksqualität mit dem gewählten Einbauverfahren zu überprüfen. Die Erfahrungen aus dem Probefeld führten zu einer Optimierung des Einbauverfahrens. Die Umsetzung der Erkenntnisse aus dem Probefeld und Einhaltung der Qualitätsanforderungen wurden bei der Ausführung begleitend überwacht. [ABSTRACT FROM AUTHOR]

This report gives an overview of the ventilation scheme for both tubes of the Tauern Tunnel with particular attention to the rebuilding of the multi-storey ventilation cavern. The cavern was designed and constructed in the 1970s – along with most of the ventilation system – and provides the ventilation for the central sections of both tubes with a ventilation shaft about 600 mm deep. While the original scheme intended sheet metal ducts partly suspended from the cavern vault, all the extract air ducts now had to be constructed of reinforced concrete as part of the construction of the second tube on account of the requirement for fire resistance. This also included the replacement of existing suspended sheet metal ducts. The design work was a particular challenge because the structural design and detailing also had to consider the complicated existing structure and the aerodynamic (flow resistance) and logistical (maintenance of traffic and continuous operation of ventilation) aspects. Im vorliegenden Bericht wird eine Übersicht über das Lüftungskonzept der beiden Röhren des Tauerntunnels gegeben, wobei besonders auf die Umbauarbeiten der mehrgeschossigen Lüfterkaverne eingegangen wird. Die Kaverne wurde – wie der Großteil der Lüftungsanlage – bereits in den 1970-er Jahren für beide Tunnelröhren geplant und errichtet und gewährleistet mit einem rund 600 m hohen Lüftungsschacht die Be- und Entlüftung der zentralen Lüftungsabschnitte für beide Tunnelröhren. Während beim ursprünglichen Konzept zum Teil vom Kavernengewölbe abgehängte Blechkanäle vorgesehen waren, müssen im Zuge des Neubaus der zweiten Tunnelröhre und der Sanierung der Bestandsröhre sämtliche Abluftkanäle wegen der geforderten Hitzebeständigkeit in Stahlbetonbauweise ausgeführt werden. Daher musste auch für die bereits bestehenden, aufgehängten Blechkanäle Ersatz geschaffen werden. Die Planungsarbeiten erwiesen sich als besonders herausfordernd, da die statisch-konstruktive Planung auch die komplexen bestehenden Bauwerke und zusätzlich lüftungstechnische (Strömungswiderstand) und logistische (Verkehrsaufrechterhaltung und laufender Lüftungsbetrieb) Aspekte zu berücksichtigen hatte. [ABSTRACT FROM AUTHOR]

The extent of tunnel refurbishment has increased constantly in recent years. The particular importance of meticulous and thought-out planning has been demonstrated on recent projects. The original drawings often provide an insufficient basis for design work and have to be checked, verified or supplemented by targeted investigation measures. A brief glance at the list of claims from a refurbishment project can clearly demonstrate the potential savings, which could have been produced by relatively cheap investigations. For the planning and design of the refurbishment of the first tube of the Tauern Tunnel, many staged investigation surveys were therefore carried out. The investigation measures carried out and their results and effect on the design and tender documents for the refurbishment of the existing tube of the Tauern Tunnel are described in this article. In den letzten Jahren ist der Umfang der Tunnelsanierungen stetig gestiegen. Die bei Sanierungsmaßnahmen besonders große Bedeutung einer sorgfältigen und durchdachten Planung konnte bei den jüngst ausgeführten Projekten erkannt werden. Alte Baupläne sind oft nur eine sehr unzureichende Planungsgrundlage, die durch gezielte Erkundungsmaßnahmen abgesichert, verifiziert oder ergänzt werden sollten. Ein kurzer Blick auf die Liste der Mehrkostenforderungen bei Sanierungsprojekten zeigt in eindrucksvoller Weise das Einsparpotenzial, das mit vergleichsweise kostengünstigeren Erkundungsmaßnahmen hätte erzielt werden können. Für die Planung der Sanierung der ersten Röhre des Tauerntunnels wurden daher mehrere, zeitlich gestaffelte Erkundungsprogramme durchgeführt. Die durchgeführten Erkundungsmaßnahmen sowie deren Ergebnisse und Auswirkungen auf die Planung und Ausschreibung der Sanierung der Bestandsröhre des Tauerntunnels werden im vorliegenden Beitrag vorgestellt. [ABSTRACT FROM AUTHOR]