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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]

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]

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]

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 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]

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]

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]

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]