Kapitel

• FrontmatterBacher, Michael; Eichlseder, Helmut; 10.3217/978-3-85125-996-4-00
• The 33 KM Long Koralm Tunnel – Final Challenges in the Implementation of a Major ProjectSchneider, Klaus; Steiner, Helmut; 10.3217/978-3-85125-996-4-01The Koralm railway is a double-track, electrified new railway section between the Austrian provincial capitals of Graz in Styria and Klagenfurt in Carinthia. The maximum operational speed is 250 km/h. The length is about 130 km and its centerpiece, the twin-tube Koralm Tunnel, is around 32.9 km long. The tunnel construction work began in 2008 and ended with the final tunnel breakthrough in 2020. The railway equipment work began in 2019 and should be completed by the end of 2024. Commissioning will take place in 2025, and regular passenger traffic will begin at the end of that year.
• Current Status of the Semmering Base TunnelGobiet, Gerhard; Thaller, Thomas; 10.3217/978-3-85125-996-4-02The tunnel construction work for the Semmering Base Tunnel (SBT) is now in its final phase. Approximately 98 % of the required tunneling has been completed and installation of the tunnel equipment has already begun. The Gloggnitz and Göstritz Ost drifts are the final tunneling challenges, with around 450 m of highly geologically challenging tunnel excavation remaining in both tracks. Tunnel lining work in the constructed sections of the Semmering Base Tunnel is progressing rapidly and has even been partially completed (western section of construction lot SBT2.1). The renovation and rebuilding of Mürzzuschlag station is now entering in its final phase. To date, new tracks and platforms have been constructed, including platform roofs. A reception building, station forecourt and a large Park & Ride facility on the north side of the station have also been built. The tender for the track equipment, SBT4.1 GU Tunnelausrüstung, was prepared in parallel with the ongoing construction work and is currently in the award phase since its publication in June 2023. The first stage of the tender for the slab track (SBT5.1) has also already been published Europe-wide. This will ensure the technical equipment starts in mid-2025 and the slab track is installed by mid-2027.
• Tunnel Renovation Program AUSTRIA - Next LevelFromm, Andreas; List, René; 10.3217/978-3-85125-996-4-03Within the framework of the ASFINAG tunnel renovation and extension program based on the EU directive on road tunnel safety, around 50 individual projects were completed in the TERN network with a total volume of around EUR 1.7 billion. As of April 2019, all relevant projects have been successfully completed on schedule, thus significantly increasing tunnel safety in Austria. ASFINAG is now facing the next major challenges. These are due to the ageing of facilities, IT security requirements, electricity saving requirements, short life cycles of safety equipment and finally also due to the necessary compliance with the EU directive on road tunnel safety 2029 in Austria's Non-TERN network. The investment volume required for this is more than EUR 4 billion until 2035 and the actual measures required are still being evaluated on an ongoing basis. This enormous project and investment volume presents ASFINAG with almost insurmountable tasks. These begin with maintaining tunnel availability for users and end with the actual feasibility in cooperation with stakeholders, planning companies, construction companies, authorities, equipment suppliers. It is also questionable whether sufficient capacity is available at suppliers and in the personnel sector.
• Sustainable Energy ConsumptionRiedl, Benjamin; Bösl, Johannes; Gündogdu, Ersin; 10.3217/978-3-85125-996-4-04This paper discusses the importance of implementing photovoltaic systems in tunnels to reduce operating costs and contribute to global climate targets. The amount of electricity consumed in a tunnel depends on various factors, with energy requirements typically highest during the day. Different options for installing PV modules are explored, considering factors such as orientation, sizing, and dimensions. A case study of the Schönberg noise protection gallery in Austria demonstrates how a photovoltaic system can help cover a tunnel’s consumption needs and even generate surplus energy. Furthermore, the paper explores sustainable cooling methods for electrical rooms in the North Operations Building of the Kramer tunnel in Germany. By utilizing fire water and groundwater as cooling sources, the study aims to enhance energy efficiency and reduce operating costs. The design includes a detailed analysis of cooling load calculations, investment costs, and amortization times for the proposed systems. Results indicate that while initial investment costs for groundwater cooling may be higher, the long-term operational savings make it a more cost-effective and environmentally friendly option. This research contributes to the development of sustainable cooling technologies for electronic infrastructures, with potential applications across various industries.
• Energylabel & Ecodesign for Austrian RoadtunnelPatigler, Mario; 10.3217/978-3-85125-996-4-05With 94 GWh and a share of approximately 75% of the total electrical energy consumption within ASFINAG, its tunnel facilities are the main energy consumers. This fact motivates to optimize the analysis of energy consumption in ASFINAG’s tunnel facilities. Through standardized equipment we want to develop the comparability of tunnel energy consumption by use of an energy benchmark. Following the energy classification of electrical devices, the goal is to categorize the tunnels in terms of energy in the future. To achieve this objective, an evaluation system will be developed that focuses on both the quantitative comparability of tunnel facilities and the qualitative assessment based on sustainable or improved equipment. 1. Quantitative quality index This analysis is based on actual data of energy consumption. The hypothesis is to examine the analogy between equally equipped tunnels by analyzing the energy consumption values of the installed consumers. 2. Qualitative quality index The quality in terms of sustainable improvements for the consumption of electrical energy is assessed by defining efficiency-enhancing measures in the equipment of technical systems. The hypothesis is based on the fact that higher-quality installations lead to an improvement in the energy balance of the facility.
• Sustainable Tunnel Operation Generation of Electricity Through Thermal and Pressure-Driven AirflowsSturm, Peter; Harbauer, Dietmar; Seebacher, Roland; Fruhwirt, Daniel; Krischan, Klaus; 10.3217/978-3-85125-996-4-06The energy demand for the operation of a road tunnel is considerable. This results on one hand in high operation costs and – as the production of electricity is not free of fossil fuels – in a significant CO2 footprint. There is an evident need to reduce energy costs as well as to improve the CO2 footprint. Due to the high energy costs, alternative options for generating electricity are being considered. The question arises as to whether mechanical ventilation systems can be used in reverse operation to generate electricity in road tunnels when pressure-driven air flows are present. This paper deals with aspects of pressure-driven air flows in general and their use for generating electricity in electrical machines. As a first step, an analysis was carried out for standard 2-lane tunnels with different lengths and meteorological pressure differences. As a second step, recorded pressure differences between portals or shafts were evaluated for selected Austrian road tunnels. The calculation of the annual energy quantities for possible electricity generation was based on the actual pressure differences in tunnel systems in the Austrian motorway and expressway network. Based on the available measurement data, those tunnel systems that have a high meteorologically related pressure difference were selected for further consideration. Taking into account the aerodynamic conditions and the expected efficiencies of electricity generation, an expected annual amount of energy can be estimated.
• Validation of Simplified Variable Speed Control for Road Tunnel Jet FansOnoda, Kaito; Ishizawa, Ryoichi; Hatamoto, Keigo; Sako, Hibiki; Sakaguchi, Toshiaki; Vardy, Alan; 10.3217/978-3-85125-996-4-07In 2010, the first variable speed control system for tunnel jet fans was installed in the Kobe Nagata Tunnel in Japan. Its purpose was to achieve energy savings in comparison with constant speed control. The original installation, which was based on a 3-level inverter, became due for replacement after more than a decade of successful use. The decision was made to replace it with a system based on a 2-level inverter with the aim of improving space factors, weight, and maintainability. The present paper deals with the entire replacement process that began with the development and verification of the simplified (i.e. 2-level) variable-speed control, followed by validation tests during the migration from the original system. The functionality and effectiveness of the new system are described and future potential is discussed.
• Influence of Acoustic Tunnel Monitoring AKUT on Tunnel SafetyHoyer, Katharina; Schmidt, Regina; Kammerer, Harald; Graf, Franz; Dobrounig, Mark; Kalina, Thomas; 10.3217/978-3-85125-996-4-08The acoustic tunnel monitoring system AKUT is used in Austrian motorway tunnels since 2015 to detect critical events during tunnel operation. Through the automatic acoustic detection of unusual noises, the system detects potentially dangerous conditions or abnormal noises. By increasing detection possibilities, detection times can be reduced and subsequent traffic control as well as safety and rescue measures can be implemented faster. This can reduce the risk potential in case of an accident. Since the first installation of AKUT the detection times have been recorded in an event database, which is continuously updated. On this basis the detection times with and without AKUT can be objectively evaluated and the safety benefit of the system can be determined: • Faster event detection allows for faster activation of safety equipment. • Faster activation of traffic lights at the portal prevents people to enter hazardous zones. • Faster activation of warning systems can reduce the subsequent accident rate after vehicle breakdowns and accidents. Based on the event data, an approach for the tunnel risk model TuRisMo has been developed. This has included establishing statistical fatalities numbers for the model tunnels selected through detailed fire simulations. Subsequently, reduction factors for application in the standard risk analysis model have been extracted. In this paper, the influence and changes to the event tree of the Austrian instruction RVS 09.03.11 will be presented. The result of the study allows a data-based quantitative consideration of AKUT as an additional safety measure in road tunnels.
• Evacuation Safety and Human Emotional Responses in Smoke-Filled Tunnels for Machine Learning InsightsSeike, Miho; Li, Wenhao; Fujiwara, Akimasa; Chikaraishi, Makoto; 10.3217/978-3-85125-996-4-09To clarify the relationship between emotion and walking behavior in tunnel fires, we conducted evacuation experiments using model-scale tunnel with smoke and investigated participants’ emotions, physiological signals, and walking speed. For applying machine learning to recognize emotions during evacuation in the future, we estimated the causal relationship using structural equation modeling and found that heart rate, systolic blood pressure, and standard deviation of N-N interval influenced the walking speed to be faster, while diastolic blood pressure influenced the walking speed to be slower.
• A 3D Parametric Study To Assess the Impact of a Fixed Fire Fighting System on the Evacuation Conditions in Paris La Défense Road TunnelsBourlet, Nicolas; Host, Adrien; Jaffier, Florent; Guiral, Florent; Waymel, Frederic; 10.3217/978-3-85125-996-4-10Techniques and technologies that aimed at limiting the risks and consequences of fires in road tunnels are regularly developed and optimized. In this context, Fixed Fire Fighting Systems are increasingly seen as a method capable of ensuring user safety and infrastructure protection. The objective of the study presented in the paper is to evaluate in a parametric and comparative manner the influence of Fixed Fire Fighting Systems in Paris la Défense tunnels, on environmental conditions encountered by the users during their evacuation. One of the subjects is also to ensure their compatibility with other safety provisions such as the emergency ventilation system. For this, a 3D CFD prototype representing a generic section of Paris la Défense tunnels has been developed. Several scenarios are carried out to take into account different structure geometries, different configurations of smoke extraction principles (longitudinal, transverse or natural), different types of fire size, different configurations of sprinkler systems as well as different initial longitudinal air speeds in the tunnel. A conclusion is then drawn based on a qualitative multicriteria analysis including the sensitivity of the parameters studied on the evacuation conditions of users, distinguishing the zone close to the fire (zone of action of the sprinklers) from the zone further away.
• Enhancing Evacuation Strategies: A Multifaceted Approach Using Real Time Cognitive AssessmentPerez-Jimenez, Christian; Clark, Gary; Singh, Aslan; Cole, Martyn; Smith, Richard; Realis, Atkins; 10.3217/978-3-85125-996-4-11This paper introduces an inventive method using real-time cognitive technology to aid tunnel operators in evaluating and enhancing evacuation strategies and safety provisions in tunnels during fire incidents. By integrating eye tracking, face emotion recognition technology, and warm smoke tests into emergency exercises, this approach highlights improvement potential in the emergency procedures (self-evacuation) as well as identifying mitigation measures and assessing the benefit of implementing them. Unlike prior studies [1], [2], [3] focusing on human attributes in evacuations, this approach emphasizes the operator's control over evacuation systems and actions, crucial in improving the safety level during an evacuation process. This study details the application of this approach in a private UK road tunnel during a live exercise involving over 20 evacuees. Special attention is given to how safety is perceived within the bus, incident zones, cross-passages, non-incident areas, as well as at the tunnel portals and how findings were used to define mitigation measures and assess their impacts on evacuation.
• Evaluation of Trackway Ventilation System for the New Metro Line in SingaporeChua, Jessleen; Louis, Gerald; Cai, Linfan; Poon, Ernest; Wijaya, Hadi; Thong, Melvyn; 10.3217/978-3-85125-996-4-12Maintaining acceptable temperatures within the tunnels of underground metro systems is crucial particularly in countries with tropical climates like Singapore and the trackway ventilation system plays a vital role in achieving this. As the performance of the train airconditioning (A/C) system is affected by the temperature in the tunnel, it is important to have a properly designed and effective trackway ventilation system to extract heat dissipated by the trains when they are dwelling at the stations. Underground stations for the existing metro lines in Singapore are equipped with an Under- Platform Exhaust (UPE) system at each platform to extract the heat dissipated from the train air-conditioning system condensing units which are mounted at the train undercarriages. However, the UPE system may not be effective for extraction of the heat from the train a/c systems for the Cross-Island Line (CRL) because the A/C unit condensing units of the CRL trains are mounted on the roof of the train carriages. In this paper, Computational Fluid Dynamics (CFD) is used to evaluate the effectiveness of the three types of trackway ventilation systems, namely the UPE, Over-Track Exhaust (OTE), and the combined OTE and Under-Platform Air Supply (UPAS) systems for adoption in the CRL underground stations. Results show that the combined OTE and UPAS system is the most effective in maintaining the lowest inlet air temperatures at the A/C units. It also has the least impact on the station A/C system during train dwelling at the stations.
• Condensation in Below Ground Metro StationsJolley, Paul; Gilbey, Mark; Jones, Robert; 10.3217/978-3-85125-996-4-13Metro systems with significant water ingress can create conditions where condensation forms on surfaces. This may present safety issues (such as trips, slips, and falls), lead to costly asset degradation and look unsightly for passengers. Modelling condensation in buildings is well understood, where temperatures change slowly, and air velocities are relatively low. However, modelling condensation formation in a station environment where train driven airflows can cause high air velocities and fast fluctuations in temperatures, presents a greater challenge. This paper demonstrated how 1D modelling can be used to assess the formation of condensation in existing metro stations with significant tunnel water ingress. Using this analysis method, this paper will show that if the leakage cannot be prevented, a heated supply system gives an effective mitigation against condensation.
• Metro Ventilation System in Seismic AreasBorchiellini, Romano; Papurello, Davide; Barbetta, Carlo; 10.3217/978-3-85125-996-4-14Globally more people live in urban areas than in rural areas. By 2050 67% of the world’s population is projected to be in urban areas. This demographic datum clearly shows that future megalopolis will have to face a challenge in the urban traffic and surely the underground metro network will expand. The paper analyzes the main Countries in the world that have seismic risk and their codes/standards that are locally used. The analysis is carried out where a full document is available. Major attention lwill be placed on Europe where a common approach is available with Eurocode 8 (EN 1998-1 Design of Structures for Earthquake Resistance). The focus will be on the Italian Code NTC 2018, which is in line with Eurocode 8. The paper focuses on non-structural components and analysis of the equipment of the ventilation system concerning the seismic forces. Comments on the seismic forces in underground soil and analysis of data. General information regarding seismic tests on the vibration table is given to understand the feasibility of a seismic qualification of equipment. Where seismic requirements are limited to stability a static analysis is sufficient or a dynamic one still feasible, conversely where a functionality or operational status is required the preferred route leads to a seismic test.
• Experiences From Five Years of PM Monitoring in Railway Tunnels of Austrian Federal Railways (ÖBB)Fruhwirt, Daniel; Bacher, Michael; Steiner, Helmut; 10.3217/978-3-85125-996-4-15Railways are considered a green transport system due to a high degree of electrification. However, due to abrasive- and wear processes railways do emit non-exhaust particles. On the one hand these particles represent a special concern related to the consequences on human´s health and the environment. On the other hand, particles emitted from railways comprise a high share of conductive material, which potentially causes issues in the operation of railway infrastructure. In order to gain more information about the quantity of emissions and PM loads in railway tunnels, extensive measurement campaigns have been conducted in Austrian railway tunnels. The results show large differences in the hourly and daily average PM concentrations, which result from differences in the tunnel characteristics, traffic volume and the position in the tunnel. Iron, copper and manganese have been identified to represent the major share in the emitted particles. Furthermore, PM filter service life has been evaluated in an in-situ installation. The nominal end of filter service life was achieved within a period of two to three months.
• Rehabilitation of Boston Harbor Tunnel – The “Quarter Duct” SolutionStacey, Conrad; Beyer, Michael; 10.3217/978-3-85125-996-4-16Structural rehabilitation of the Sumner Tunnel under Boston Harbor will be finalised in late 2024. Associated with the structural work, the in-tunnel parts of the ventilation system had to be re-constructed. Conceived as a structural project, the base requirement was for the reconstructed ventilation to be no worse than existing. However, reconstructing the 1930s scheme carried significant schedule risk and uncertainty in the ability to achieve the Owner’s Quality requirements. In addition, it would have missed an opportunity to dramatically improve the smoke management. Working within strict project constraints, an innovative reimagining of the ventilation ducts’ operation improved smoke control performance using existing ventilation plant capabilities, and with only a quarter of the previous duct being rebuilt. Testing of the ventilation system before and after rehabilitation qualitatively and quantitatively demonstrated the improvements made to the smoke management. Insights from the iterative concept development, and details of the testing procedure are provided. An innovative Ventilation Test Vehicle was used to perform environmentally friendly warm smoke tests with very little demand on tunnel closure time. The ventilation concept dramatically improved fire safety, minimised change to pre-existing operations, and saved construction time, and tunnel closure time.
• Commisioning Tunonfe lsAralt, Tor Tybring; 10.3217/978-3-85125-996-4-17Commissioning starts with approval of design documents, and ends with user acceptance test. In between is FAT and SAT. Planning must prepare for confirmation of fulfilment. The main success factor is that it is possible to identify and verify all demands. SAT must be planned and performed by the owner himself or someone representing him, and should not be left to the contractor.
• Enhancing Tunnel Fan Reliability Through Advanced Factory Acceptance Test (AFAT) to Prevent FailuresSuarez, Justo; Teoh, Jye; Bach-Esteve, Albert; 10.3217/978-3-85125-996-4-18This paper introduces the concept of the Advanced Factory Acceptance Test (AFAT) and highlights its potential to mitigate tunnel fan failures. Conventional Factory Acceptance Test (FAT) primarily focuses on basic performance criteria, such as flow, pressure, efficiency, and noise level for axial fans and thrust and noise level for jet fans. It often falls short in identifying and addressing potential issues that may lead to postinstallation fan failures. AFAT takes into account additional critical factors to guarantee fan reliability and durability. These factors encompass structural integrity, material quality, vibration analysis and thermal performance. AFAT can detect latent defects, design inconsistencies, and manufacturing deviations that often go unnoticed during a conventional FAT. Through AFAT, stakeholders in a tunnel ventilation project can reduce the risk of unexpected fan failures, enhancing operational safety and minimizing costly downtimes. This paper proposes AFAT as a best practice to be promoted in the tunnel ventilation industry.
• Advances in the Digital Documentation of Railway Tunnel InspectionRebhan, Matthias J.; Grubinger, Stefan S.; Schüppel, Andreas; Deutinger, Simona; Schwarzenberger, Gernot; 10.3217/978-3-85125-996-4-19Like other infrastructure, railway tunnels require inspection to ensure their safety and to detect damages at an early stage, representing a major challenge for those involved. Thus, in addition to the inspection, the tunnel down time can be a major disruption in operation. Under economic aspects, the inspection itself with all the subsequent work required is very timeconsuming. In the area of rail networks, comprehensive preparations are necessary to be able to plan track barriers and bypass measures accordingly to minimise any undue influence on availability. This paper presents the results of an initial test phase of using a digital documentation solution in order to generate a rapid localisation and a corresponding time advantage when carrying out the inspection activities. By offering the use of a multitude of bases, a standardisation of damage patterns is carried out and a collaborative cooperation of multiple inspection personnel is possible. Depending on the data stock, digitised as-built models in the form of a plan, digital plan documents and existing or generated digital twins can be used. Thus, making it possible to locate the damages already in the course of the inspection and therefore enable a comprehensible documentation of the inspection activity and an automated generation of inspection reports. In the course of a series of field tests along four tunnels of the Tauern Line of the Austrian Federal Railways, the digital procedure was validated in form of a pilot project. Within this paper the first results, together with the advantages of a digital inspection are presented.
• Safety Challenges in an Underground Hyperloop System: A Preliminary InvestigationPachera, Matteo; Vanneste, Maarten; Verrecas, Thijs; Kulig, Bartek; 10.3217/978-3-85125-996-4-20A new link between the train station and the airport of Rotterdam in the Netherlands is under study to increase the passengers’ capacity and reduce travel time. One of the proposed solutions is an hyperloop tunnel that travels under the city for about 2 km. This article provides an overview about the safety challenges of an underground hyperloop system. In case of fire on board or sudden loss of cabin pressure, tenability conditions deteriorate quickly due to the small size of the vehicle. The preferred option is to travel to the next station and evacuate passengers from there before they become incapacitated. In case two stations are too far apart, additional evacuation routes are required: through the tunnel or in separate evacuation stations. In the first case the tunnel should be equipped with ventilation (for pressurization and smoke confinement) and evacuation routes. In the second case smaller stations are necessary. Alternatively, additional safety measures can be installed on board (water suppression and oxygen masks) to increase the time passengers can stay in the vehicle. The integration of the different safety measures should be further investigated following the development of the project and of the hyperloop technology.
• Widespread of Electric Vehicles and the Provision of Knowledge About Fire Accidents for Expressway Maintenance Workers in JapanYokota, Masahiro; Yamazaki, Ken-ichiro; Yamazaki, Tetsuya; Sgawara, Chihiro; Suzuki, Toshio; 10.3217/978-3-85125-996-4-21In October 2020, the Japanese government declared “carbon neutrality by 2050” and set out a policy to take comprehensive measures to achieve 100% electric vehicle sales in new passenger car sales by 2035. On the other hand, the world situation is changing rapidly, and the spread of electric vehicles is changing due to economic conditions, resource, and energy supply systems, etc., and the impact on Japan must also be predicted. Furthermore, the spread in Japan of electric vehicles is expected to change further due to future technological innovations, electricity demand, and infrastructure development trends. Therefore, it is necessary to prepare to maintain safe and comfortable expressway function without panic even when that stage is reached. In this paper, we conducted a domestic and international survey on the spread of BEVs, fire accidents and their characteristics, and specific measures to reduce these risks. In addition, by confirming the current awareness of expressway maintenance worker regarding electric vehicle fire accidents, we have summarized the knowledge, issues, countermeasures, equipment, etc. necessary for future tunnel fire safety.
• Preliminary Tests of Mechanical Abuse - Nail Tests of LIBsDavide, Papurello; Beatrice, Braghiroli; Silvia, Bodoardo; Julia, Amici; Romano, Borchiellini; 10.3217/978-3-85125-996-4-22Current tunnel safety concepts are based on the experience of conventional fuel vehicle accidents. The transition in the coming years will involve the use of alternative fuels such as hydrogen, natural gas and the use of electric vehicles. Among them, it seems that in the near future medium-sized and small vehicles will be powered electrically by lithium-ion batteries (city cars). The main problem of electric vehicles with Lithium-Ion batteries (LIBs) lies in the heat release rate (HRR), and toxic compounds released by LIB fire. Thermal runaway to a fire can be triggered by temperature, electricity, and mechanical abuse. The latter is more complex to manage via the Battery Management System (BMS) or cell architecture. In the present work, preliminary results of LIBs tested by nail test, inside a calorimeter are shown. The LIB cell tested and modelled is a SAMSUNG INR-18650-29E. Such a cell was tested at 100% SOC reaching temperatures above 800 °C and a maximum pressure value of about 4 bar. The concentration of CO inside the chamber was measured. The measured CO level ranged from 3000-4000 ppm(v), comparable to other research. The model implemented on COMSOL consists of two components: a 1D model that aims to simulate the electrochemical behaviour of the battery through a pseudo-two-dimensional (p2D) model, while the 3D model simulates heat transfer only.
• Particle Concentration Levels in a Subway Station - The Effects of Various Locations and Diameters of Relief Shafts in TunnelsAbouali, Omid; Östblom, Erik; Sahlin, Per; 10.3217/978-3-85125-996-4-23In this article, we investigate how ventilation shaft diameter and placement in a subway tunnel can influence the concentration of particulate matter (PM) in stations. The trains' rolling and braking systems have been considered the particles' source. The stations have two large escalators, and their doors are open. The airflow in the studied systems is driven exclusively by the piston effect of the moving trains. The IDA Tunnel version 2 software package has been utilized for the simulations. The results indicate significant fluctuations in PM levels on subway platforms. The average PM concentration on a platform associated with single-track tunnels is almost 5 percent lower than on a platform connected to double-track tunnels, considering similar headway and relief shaft geometry. In the case of single-track tunnels, the shaft location plays a less critical role, while the impact of shaft diameter is more pronounced. For double-track tunnels, the shaft location becomes more crucial. A single relief shaft placed near the stations primarily increases the PM level on the platform, making a shaft location at the tunnel center preferable. The variation in PM levels on the platform for single- and double-track tunnels is approximately 13 percent across shaft locations and cross-sectional areas.
• Emission Management in Railway Tunnels With a 1D-3D Simulation ApproachAntoniou, Evangelos; Colleoni, Arnaud; Linden, Tom; Cuzzola, Francesco; 10.3217/978-3-85125-996-4-24Railway tunnel maintenance involving grinding operations poses a significant challenge due to the emission of hazardous exhaust gases and dust, making the tunnel an unsafe working environment for personnel. To address this issue, simulations become crucial for designing and operating an efficient tunnel ventilation system, essential to mitigate these risks. The simulation workflow outlined in this paper brings together a fast and quasi-real time 1D systems model approach with a detailed 3D Computational Fluid Dynamics (CFD) simulation. This approach not only predicts the duration required for the dust and exhaust levels to reach acceptable safety thresholds, but also assesses the energy consumption of a given ventilation system. This study eventually underlines the ease and speed with which different scenarios can be tested, emphasizing how accessible this approach is without requiring extensive simulation expertise from end-users.
• Application of ARTU Software and Multizone Fire Modelling for Risk Analysis: A Road Tunnel Case StudyFronterrè, Michele; Scozzari, Rugiada; 10.3217/978-3-85125-996-4-25In the previous editions of the Graz Tunnel Conference (2020 and 2022), the ARTU software was presented through a case study (a 6 km tunnel with longitudinal ventilation). ARTU calculates the societal risk related to fire in tunnels combining probabilistic and deterministic approaches and different sub-models: fluid dynamics, queue formation, egress, interaction between environment and people. The current release of ARTU incorporates a multizone fire model - developed along with Lund University - that permits a better description of the smoke stratification and backlayering, compared to 1D fluid dynamic model. In the present paper the current version of ARTU is presented through the results of the risk analysis of a 3 km road tunnel with jet-fans and smoke extraction shafts. Risk analysis results are expressed by means of FN curve and damage expected value. The results are compared with the ones obtained by the previous version of ARTU, which was based on 1D fluiddynamic and did not include multizone fluid-dynamic model. In order to analyze the effect of the back-layering phenomenon on the overall risk, a sensitivity analysis is done modifying longitudinal velocity and observing how this impacts the results obtained through the multizone fluid-dynamic model. An in-depth study is performed about the smoke layer height, using CFD simulations to check the stratification prediction made by the multizone model.
• AI in Roadtunnel – Supporting the Man-In-The-Loop in Roadtunnel (SMaRT)Böhnke, Philipp; Schumann, Tom; Kemper, Dirk; Hernandez, Alvaro García; 10.3217/978-3-85125-996-4-26This paper gives an overview about the latest research results of ave company together with the RWTH Aachen University in the field of AI based incident detection. The presented approaches and results were mainly gained in the context of the research project “Supporting the Man-in-the-loop in Roadtunnel (SMaRt)” funded by the German Federal Ministry of Education and Research (BMBF). The workload of tunnel operators is constantly increasing, leading to overloads and affecting safety. Today's systems for traffic monitoring and incident detection in road tunnels usually follow a two-stage approach. A sensor bases automated incident detection system is followed by “final detection” and/or the cause of the incident by the tunnel operator. Depending on the reliability of the incident detection system used, this means more or less "extra" work for the "man-in-the-loop" – the tunnel operator. Within the 3-year project SMaRt (2021-2024) AI based methods are developed to improve incident detection and thereby to reduce the workload of the operators. AI is used on three levels, namely the sensor- (“Intelligent Induction Loops” and video), the data fusion- and the GUI-level. The results show that AI algorithms can help combine loop and video technology to take advantage of both technologies.
• Application of AI to the 1D Ventilation Analysis of a 43KM Complex Road Tunnel Network: Madrid Calle30Sanz, Juan Manuel; Kluijver, Fabián De; López, Alberto; Berges, Javier; Martinez, Mar; Peris, Guillem; 10.3217/978-3-85125-996-4-27Madrid Calle 30 ring road tunnels are a very complex road tunnel network, with a total extension of 43 km opened in 2007. In order to update the ventilation control algorithms, it has been necessary to analyze the records of all sensors and ventilation equipment since inauguration with the objective of characterize the current capacity of the system, the influence of the different parameters and learn from the analysis of past events. Due to the extension and complexity of the network, and the huge amount of field data available, an Artificial Intelligence (AI) system (Respira®, from SENER) has been used to evaluate the current performance of the system. In parallel, a 1D simulation model of the whole ventilation system (as a digital twin) has been generated. The uncertainty in some parameters of the 1D model, and its size and complexity, has driven the design team to automatize its calibration. A surrogate model of the 1D model was built on Python by training it with a sample of 3,000 1D simulations, where uncertain parameters were modified randomly within ranges given by expert knowledge. Differential Evolution method is used for calibration [1], obtaining a set of parameters that minimizes an error function between the model prediction and the field data. With this calibrated digital twin, it has been possible to optimize the ventilation algorithms for the different events foreseeable in the different areas of the M30.
• Estimating the Seasonal Performance of a Surface Refrigeration Cooling for an Underground MineThompson, Jolyon; Gilbey, Mark; Sbarba, Hugo Dello; 10.3217/978-3-85125-996-4-28Tunnel ventilation and mine ventilation overlap in several areas. One key area is in the analysis of heat and how this can affect processes and people. A range of ventilation and thermal models have developed in parallel to support both industries, with occasional crossindustry use. In this paper we describe the cross-industry use of a mine ventilation model with a transient thermal tunnel ventilation model that WSP developed. The paper describes how the models were used together to answer important questions that could not readily be answered by one of the models alone. The notional mine used for the case study would have experienced hot conditions at the working faces. A cooling plant at the surface was analyzed as they can be cost effective compared to an underground cooling plant. However, with the working faces a long way from the plant the cooling effect can be compromised by the time the air gets to where it is needed. The accurate evaluation of heat transfer between the rocks and the ventilation air, including seasonal impacts, is therefore important. Tunnel ventilation models have good capability to model strata heat transfer and can be used in conjunction with the mine ventilation models to understand system performance. In this paper we also report on the performance of a surface cooling plant accounting for such heat transfer from the ground and go on to describe how the position to the cooling plant relative to the surface can have an important impact on how effective the cooling can be.
• Design of a Ventilation System in a Tunnel Bored With a TBM machine in the Case of Methane Emission From a Rock MassBorowski, Marek; Zwolińska-Glądys, Klaudia; Szmuk, Andrzej; Kuczera, Zbigniew; Piech, Kamil; 10.3217/978-3-85125-996-4-29Methane emissions from rock masses pose a significant hazard in underground works, leading to delays and, in the worst case, tragic accidents for workers. Therefore, before beginning mining work, it is necessary to properly design and optimize the ventilation system to ensure safety in the tunnel and prevent possible explosions. This paper presents a case of methane emissions observed before the drilling of the road tunnel. Initially, no emissions problem was expected. However, by preparing drainage wells to reduce water pressure in a rock mass, methane outflow was noticed. The presented analysis covers the design of a ventilation and safety system developed for drilling a tunnel along the S-19 expressway in south-eastern Poland. This two-tubed tunnel is being bored using a TBM and is expected to reach a final length of over 2.2 km. In response to the noticed risk, a ventilation and security system was developed, and a simulation of air dispersion and methane concentration distribution was performed. The developed ventilation and security system is intended to enable the tunnel drilling to continue without interruption, even in the event of significant gas inflows.
• Risk Analysis of Road Tunnels: A Quantitative Risk Analysis Model for Assessing the Effects of FireHaddad, Razieh Khaksari; Harun, Zambri; 10.3217/978-3-85125-996-4-30The most important factor influencing fire safety in tunnels is the interaction between the fire, tunnel users, traffic, and fire safety measures. A quantitative risk analysis model has been developed to analyse the fire risk, LBA Quantitative risk analysis model (LBAQRA). This paper presents details of this quantitative risk analysis model, consisting of a quantitative consequence analysis model and a quantitative frequency analysis, which was used for this study. The quantitative consequence analysis model includes three sub-models; queue model, distribution model, and egress model to estimate the number of exposed tunnel users, their evacuation times, the extent of damage due to fires, and eventually the number of fatalities and injuries. Frequency analysis is carried out through an event tree which was built on the tunnel fire rate in UK road tunnels. This fire rate is updated considering tunnel length, time of fire incident, traffic condition, accident type, vehicles involved, and location of fire. The study of the impact of various ventilation strategies on the F/N curve showed the positive effect of the activation time of the ventilation system on societal risk. The sensitivity analysis of the model indicates that the number of fatalities increased for longer detection times and the initial fire rate and the probability of congested traffic have a direct influence on the final frequency of fire scenarios.
• Some Questions Related to CFD Modeling of Pressurized Tank Burst in Road TunnelsLecocq, Guillaume; Heudier, Laure; Truchot, Benjamin; Mos, Antoine; Willmann, Christophe; 10.3217/978-3-85125-996-4-31The current paper focuses on high-pressure reservoirs and the consequences of their potential burst, related to scenarios of thermal or mechanical aggressions, in tunnels. CFD modeling can be used to account for the effects of such scenarios. An intrinsic advantage of such an approach consists in integrating the specific geometrical effects (tunnel walls, presence of vehicles) on the pressure wave propagation. To meet such an objective, experimental data are required to offer an opportunity for validation. Data from the literature and new ones from INERIS are detailed in this paper, with their strengths and weaknesses to identify relevant test cases for CFD. Phenomenological tools are tested against experimental cases of bursting tank in a free field to evaluate their prediction capability for pressure. These tools could be used along with CFD in a global modeling framework. CFD is tested against fictious free-field cases, investigating the effect of the thermodynamic model on the results. The numerical method for propagating the pressure wave in realistic tunnels is also studied.
• Integration of New Energy Carriers in French Specific Hazard Investigations: Overview of Principal IssuesWillmann, Christophe; Charles, Pauline; 10.3217/978-3-85125-996-4-32A national work group comprising specialists in specific hazard investigations has been set up by the CETU with the aim of adapting specific hazard investigations to the new energy carriers vehicles. Two main adaptations have been made. The first concerns the adaptation of the criticality matrix ranking, so as to take into account the specificities of gas dangerous incidents in terms of frequency and severity. The second concerns the adaptation of the detailed scenario analysis to take account of two dangerous incidents involving gas, kinetic vapour cloud and tank rupture explosions, which are more instantaneous than fires (the dangerous incident that is the most feared in tunnels).
• Innovative Approach To Improve the Safety of Tunnels and Tunnel Control CentresKammerer, Harald; Lehan, Anne; Klampfer, Bernhard; 10.3217/978-3-85125-996-4-33Developments in the field of digitalization of the road and its infrastructure are strongly aimed at connected and automated driving. The collection of vehicle mobility data and its use for traffic monitoring and control can make a significant contribution to preventive event detection and the early initiation of protective measures in tunnels. By using real-time risk assessment in tunnels, it is possible to intervene in a controlling manner before the event occurs and thus mitigate or even completely avert negative effects. The potentials arising from mobility data are faced with major challenges, e.g. how to check the integrity of these large volumes of data, and how to select, merge, analyse and evaluate them systematically. Here, the application of Artificial Intelligence is considered as a very promising method. With that in mind, the research project KITT investigated for the first time the possibility of carrying out a risk assessment in tunnels in real time by using weak AI. Furthermore, it was investigated which additional vehicle data from C-ITS could be available in the future in tunnels. It is expected that their targeted use will contribute to a significant increase in tunnel safety and to maintain the availability of tunnels.
• CFD-assisted Flow Rate Measurements in Ventilation Ducts of long Road TunnelsAngeli, Diego; Levoni, Paolo; Salerno, Elisabetta; Barozzi, Gioivanni Sebastiano; Verraz, Paolo; Petitcolin, Cedric; 10.3217/978-3-85125-996-4-34Large-size air ducts with irregular cross section, such as the ventilation channels of road tunnels, offer formidable difficulties in the measurement of the flow rate. Despite a large bulk of experiences, the measurement techniques developed so far are not completely satisfactory in terms of accuracy or repeatability. Moreover, technical standards only consider very simple cross-section shapes, and prescribe the adoption of a prohibitive amount of measurement points. This motivated the development of an alternative technique for the reconstruction of the air flow rate, where the signals from a custom-built, multi-point measurement rig composed of 16 Pitot-Prandtl tubes are supported and integrated with Computational Fluid Dynamics (CFD) predictions. The technique was tested on two cross-sections of the extraction line in service at the Mont Blanc Tunnel (TMB). Preliminarily, CFD analyses were performed over a range of Reynolds numbers typical for that application. These were used to post-process the point-velocity data collected on field and to reconstruct the flow rate. Results of the testing campaign are presented here, along with a general description of the technique. Preliminary outcomes of the tests are encouraging and indicate that the present approach could be applicable to a larger variety of case studies.
• Jet Fan Installation Factor Correlations for Conventional Jet Fans and MojetsTarada, Fathi; Bertacche, Pier; Stantero, Luca; 10.3217/978-3-85125-996-4-35This paper presents the results of nearly 1,000 CFD calculations undertaken with two jet fan diameters, two jet fan installations, two different surface roughness values, for a range of tunnel velocities, with various jet fan spacings, with varying clearances between the jet fan and the tunnel surface and with two types of jet fans (conventional and MoJet). The CFD calculations were undertaken with the ANSYS Fluent code and were validated by reference to the full-scale tunnel measurements reported by Tarada et al [5]. The calculations modelled a 2-lane road tunnel with hard shoulder - 9.6 m wide, 6 m high and 500 m long, along with its associated jet fans (including their rotating blades). Cell counts for each CFD simulation ranged from 20 to 35 million, using polyhedral and prism cells for maximum accuracy. The results of our CFD calculations were correlated in the form of mathematical expressions, which account for each of the considered influencing parameters (jet fan diameter, type of installation, surface friction factor, tunnel velocity, jet fan spacing and clearance, and jet fan type). We report on the open provision of these correlations via web tools, to facilitate their use by designers and researchers in this field.
• CFD Investigation of the Improvement of Smoke Control in a Tunnel Equipped With a Longitudinal and a Transverse Ventilation SystemRemion, Gabriel; Mos, Antoine; Salizzoni, Pietro; Marro, Massimo; Lanzini, Stefano; 10.3217/978-3-85125-996-4-36Smoke control in the case of a tunnel fire is vital to ensure an atmosphere allowing tunnel users to evacuate. Depending on the type of ventilation, namely the longitudinal or the transverse ventilation system, the aim is respectively either to push the smoke longitudinally towards a tunnel exit or to evacuate the smoke transversally by the tunnel ceiling. In France, the regulation imposes a sufficient mechanical airflow to prevent any smoke back-layer and to ensure an efficient smoke exhaust. Previous experiments implemented in a small-scale tunnel have shown the potential of solid barriers, or containment screens, attached to the tunnel’s ceiling. The shape of dampers of the transverse ventilation strategy was also questioned. Wide rectangular dampers appeared to be significantly more efficient than narrower or square dampers, which are commonly installed. Both technical propositions increased significantly the robustness of both ventilation systems by reducing the airflow required to prevent any smoke back-layer from occurring. Reducing the required airflow goes along with reducing the power need of the ventilation system. It tackles the issues of energy consumption and the improvement of the robustness of existing ventilation systems. It also eases the dimensioning and cost of ventilation systems installed in new tunnels. In the present work, a numerical Computational Fluid Dynamics model of those experiments has been validated by comparison with experimental data measured in both tunnel configurations. The StarCCM+ software was used. It allowed verifying numerically significant benefits of solid barriers for the longitudinal ventilation system. Regarding the transverse ventilation system, it also verified its increased robustness allowed by rectangular dampers compared to commonly used square dampers. The validation of this numerical model is a first step in a wider work aiming at numerically testing the equipment in other configurations.
• An Analysis of the 3D Critical Region Length in Longitudinally Ventilated Tunnels During Fire EventsAyala, Pablo; Amo, Luis; Alexis, Cantizano; 10.3217/978-3-85125-996-4-37Computational models are valuable tools for designing fire ventilation systems in tunnels. However, these models can be very complex and computationally expensive. Moreover, smoke behavior depends on many factors, such as tunnel geometry, ventilation velocity, fire intensity, tunnel slope, etc. Hybrid or multiscale models are alternatives that can lower the computational demand and still produce trustworthy results. These models combine regions with different levels of detail: one-dimensional (1D) and three-dimensional (3D). The 1D regions offer simpler results through faster computation, while the 3D region provides greater realism and detail, albeit at the cost of increased computational resources and time. Defining the 3D region is critical and challenging, as it significantly influences the model's accuracy and efficiency. Its length, i.e., critical length, can be determined by employing various criteria, mainly based on relevant parameters such as the hydraulic diameter or the heat release rate (HRR). In this study, the downstream critical length of a fire in a longitudinally ventilated tunnel is analyzed through a numerical study comprising 108 simulations conducted with FDS 6.8.0. The assessment considers the impact of HRR, tunnel cross-sectional area, and ventilation velocity on the critical length. As HRR increases, downstream critical length grows, expanding the simulation domain and computational cost. Similarly, the critical length slightly rises as the cross-sectional area decreases, but further studies needed for quantitative analysis. These conclusions are drawn from defining critical length based on the tunnel's longitudinal temperature gradient. Furthermore, various models are introduced to illustrate the dimensionless relationship between the critical length and HRR, confirming that a linear relationship is not suitable when longitudinal ventilation is present. The dependency of the critical length on ventilation velocity is quite significant, greatly improving the model's fit when taken into account.
• Longitudinal Ventilation System for a Long Road-Tunnel: Optimal Design With Batteries of Jet Fans and Challenges To Overcome Extreme Foggy Weather ConditionDhar, Sunit Kanti; 10.3217/978-3-85125-996-4-38An optimal design solution for a long road-tunnel mechanical ventilation system with an application of batteries of jet fans at a location where extreme foggy weather conditions prevails for a third of the year. The main purpose is to make it practically feasible, by applying the concept of longitudinal ventilation system, as well as optimizing the design to keep the vehicular pollutants under control and fully functional to high standard of international design parameters and criterion, even during heavy fog and rainfall, for normal mode ventilation, particularly during congestion and slow-moving traffic, as well as to cater to an effective smoke management at any probable locations of the fire scenarios. The design will be innovative for application for such a long road-tunnel with heavy traffic profile, and very practical for application that will harmonize with good engineering practices and international codes and guidelines with an objective to achieve highest standards of safety criteria, both during normal and emergency situations.
• Advanced Characterisation of a Fan Submitted to Piston EffectBéraud, Elisa; Houseaux, Benoit; Tekam, Sydney; 10.3217/978-3-85125-996-4-39In the frame of the "Grand Paris Express" network, Eiffage designed a test cell to test the behaviour of a model fan to the train piston effect. The test cell has already been presented in the last TSV conference. In this paper, it is proposed to focus on the model fan. The model fan has been first tested by manufacturer in the unexplored area of negative pressure and negative flowrate both in forward and reverse mode. Then it has been operated on the Eiffage test cell with successive negative and positive forced pressure on hundreds of thousands of cycles. Aeraulic, electric and mechanical parameters recording have been conducted on the model fan during these tests. The behaviour of the fan in wind milling mode has also been tested in insufflation and extraction mode when submitted to a flow generated by train passage and piston effect. In parallel, CFD simulations have been conducted on the model fan in steady mode to determine the velocity profile on the blades and to illustrate the passage of air through the impeller with a negative airflow. It has also been carried out for an unsteady case.
• Optimizing Safety in Short High-Slope Road Tunnels: Smoke Propagation and Ventilation System ResponseIvanek, Krešimir; Keser, Robert; Drakulić, Miodrag; Špiljar, Željko; 10.3217/978-3-85125-996-4-40This study focuses on fire protection in short, steep road tunnels, with an emphasis on ensuring passenger safety during evacuation. It introduces a ventilation system designed to address the challenges posed by rapid smoke flow. The system includes a reversible ventilation system in the traffic tunnel tube, accommodating bi-directional traffic, and an overpressure ventilation system in the pedestrian evacuation tunnel. An early smoke detection feature is integral, rapidly activating the tunnel and the overpressure-protected evacuation gallery ventilation systems, ensuring early warning and passenger safety. The study employs advanced numerical simulations using the OpenFOAM software [1], focusing on a fire scenario with a heat-release rate of 120 MW within the initial 10 minutes, a critical evacuation period. Simulations consider traffic congestion and vehicle shapes. The findings provide insights into 3D time-dependent smoke propagation within the tunnel, accounting for its unique structure, vehicular obstructions, and buoyant effects from thermal energy release. Results also offer information on the stack effect progression and smoke propagation velocities, crucial for the effective operation of the ventilation system, ultimately enhancing passenger safety during evacuation.
• How Information Security Can Be Ensured in Tunnel SystemsHudecek, Gerhard; 10.3217/978-3-85125-996-4-41Based on Directive (EU) 2016/1148 of the European Parliament, the European Cyber Security Strategy [1] was transposed into Austrian law (NIS Act) at the end of 2018. The aim was to ensure a high level of security of network and information systems. The requirement was to take appropriate and proportionate technical and organisational security precautions and to report security incidents. ASFINAG, as the Austrian motorway operator, was identified as the operator of elementary services by notice dated 12.11.2019. One of these essential services is tunnel control. By 11.11.2022, proof of NIS conformity had to be provided to a so-called qualified body. A tunnel system is now equipped with a large number of IT and OT systems and components. These are connected with each other and connected to remote monitoring centres for control and monitoring. This creates a multitude of potential security risks, which can lead to an impairment of the function of safety equipment and to a reduction in the availability of the tunnel. Until the establishment of the NIS Act (NIS-G) [2], ASFINAG very successfully pursued the strategy "never touch a running system". I.e. it was well planned, well built and well maintained. Software changes were avoided as far as possible. In order to comply with the NIS-G, this strategy had to be completely changed to "keep the system up-2-date", which means very frequent software changes. ASFINAG currently operates 167 tunnel systems, so the NISFIT © programme was developed on how to make these systems "cybersecure". In order to achieve a sufficient level of information security, the following key points must be addressed: A seamless IT asset management in order to know where which systems and components are installed and in operation, as well as to be able to assess potential risks. Another important element is physical security on site as well as remote access management. Only those persons who are authorised to do so should be allowed secure access. Thirdly, active monitoring of the systems, including regular virus scans and penetration tests, is required. To make all this possible, as well as the requirement to report security incidents within the specified time, a Security Operation Centre (SOC) has been implemented. In the end, ASFINAG succeeded in proving to the auditing authority in due time that all necessary measures for network and information system security (NIS) had been implemented.
• One-Dimensional Critical Velocity Formulation – An Assessment of the Deficiency of the Current Models and the Introduction of a New ConceptSanchez, J. Greg; 10.3217/978-3-85125-996-4-42A review of the most classic set of critical velocity (Vc) equations in the tunnel ventilation industry is presented. Assumptions, and limitations in the derivation of Vc are explained. A new methodology is presented, which takes into account the fundamental laws of physics described in the conservation of mass, momentum, energy, and combustion. Simple, but robust enough to capture the different velocities, temperatures and mixing of gases to calculate the minimum velocity that is required to control the backlayer of smoke in the event of a tunnel fire. The results presented are in agreement with expectations – lower fire heat release rate, lower Vc; higher fire heat release rate, higher Vc. The new methodology results do not asymptote to 3.5 m/s, as the classic Vc set of equations point, but progressively increases Vc as the fire heat release rate increases. Geometrical aspects of the tunnel are taken into account to provide a proper set of results.
• Confinement Velocity for Smoke in Tunnels – How to Poke a Stick at itBeyer, Michael; Stacey, Conrad; 10.3217/978-3-85125-996-4-43In 2023, NFPA 502 changed from the absolute prevention of backlayering (critical velocity) to allowing some backlayering (confinement velocity). That made sense for tunnel safety. However, it is not clear how to design for that. NFPA 502 does not provide any guidance on how to determine such a confinement velocity and there is no reliable calculation method that can be used for real (full-scale) tunnels. The complexity of determining confinement velocity and the parameters that influence backlayering are explored. Those influences are quantified via a CFD model validated for critical velocity, also understanding the importance of parameters like wall roughness, wall temperature etc. Surprisingly, in some circumstances, confinement velocity is no less than critical velocity. Guidance on how to approach confinement velocity for real projects is also offered.
• Design, Refurbishment and Operation of the Ventilation in the Road Tunnel Complex in PragueZápařka, Jiří; Pořízek, Jan; Šajtar, Ludvík; 10.3217/978-3-85125-996-4-44In this article we would like to present the history of the ventilation system of the city tunnel complex in Prague. We will focus on fire ventilation, ventilation to reduce the environmental impact and also on the operation of the tunnel complex. The existing part of the tunnel complex is 8.7 km long and was commissioned in stages between 1997 and 2015 and is in operation today. The project of the last section in the eastern part of the city circuit, 7.1 km long MO-LS "Eastern link", is currently in the phase of documentation for planning permission. When the last section of the city circuit is completed, 16 km of tunnels will be in operation.
• Hydrogen Powered Vehicles in a Tunnel Incident – Risks and ConsequencesAggarwal, Martin; Fruhwirt, Daniel; Fößleitner, Patrik; Heger, Oliver; Pertl, Patrick; Schmidt, Regina; Trattner, Alexander; 10.3217/978-3-85125-996-4-45The mobility sector is subject to a massive transition from fossil fuels to new energy carriers. The driving force is the reduction of greenhouse gas emissions in order to minimize the impact on global climate. Hydrogen represents a promising fuel as it can be used in combination with internal combustion engines as well as fuel cells. However, due to its physical and chemical properties it potentially poses high risks in an incident scenario. This mainly refers to its wide flammability limits as well as the common way of storage at nominal pressures of 350 bar (busses and trucks) and 700 bar (passenger cars). This paper presents the findings of the Austrian research project “HyTRA” that aimed at an evaluation of potential hazards in tunnel incident scenarios involving hydrogen powered vehicles. Five scenarios with a high potential risk have been identified and investigated related to the consequences for tunnel users and the tunnel facility. Ultimately, a comparison to incident events with conventional vehicles gives information about the consequences for the level of tunnel safety.
• LeanTech in Road TunnelsFrey, Simon; Brandt, Rune; Schnetz, Jean-Paul; 10.3217/978-3-85125-996-4-46Due to historical developments and the desire to provide road users with the safest possible infrastructure, today's practice results in complex and cost-intensive electromechanical equipment in road tunnels. The Swiss Federal Roads Office (FEDRO) initiated the LeanTech research project aiming at reducing the system and operating costs by streamlining the specifications without reducing noticeably aspects relating to safety, availability, and maintenance. The currently applicable requirements on the operating and the electromechanical equipment in road tunnels were critically examined in a systematic process. In terms of LeanTech, the question was whether and how requirements can be optimised with neither reducing the safety of the road users nor the availability of the infrastructure. A total of 2182 requirements were identified that could be optimised without affecting compliance with the minimum requirements for tunnel safety. The applied multiple-step analysis concluded that the optimisation potentials of 2113 requirements were too small to allow for an in-depth investigation in this research project. From the remaining requirements, 41 were examined in detail. This resulted in 9 adaptation proposals with major impacts in terms of LeanTech, which can be implemented easily and promptly. In addition, 12 recommendations for action were proposed for more thorough investigations.
• Looking to the Future From PIARC's PerspectiveKaundinya, Ingo; 10.3217/978-3-85125-996-4-47This paper presents the new topics which PIARC’s road tunnel committee (TC4.4) will address in the current work cycle 2024-2027. TC4.4 will deliver in total 13 outputs until the end of 2027. Current topics include: Sustainability of Tunnel Operation, Active Modes of Transport (walking, cycling, wheelchair) in Road Tunnels, Digitalization of Road Tunnel Design and Management, Road Tunnel Operation and Safety Issues related to the Usage of New Energy Carriers (NEC) in Road Vehicles, update of the online Road Tunnel Manual, dissemination and possible update of the DG-QRAM Software, organization of the 3rd International Conference on Road Tunnels Operation and Safety and organization of two International Seminars in Low- and Medium-Income Countries (LMIC).
• Reports of the Institute of Thermodynamics and Sustainable Propulsion Systems10.3217/978-3-85125-996-4-48