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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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    <item>
      <title>Intelligent Optimization of Blasting Parameters in Railroad Tunnels Based on Blasting Quality Control</title>
      <link>https://trid.trb.org/View/2556941</link>
      <description><![CDATA[Blasting parameters are crucial factors that directly affect the quality of tunnel excavation. To achieve optimal blasting results, it is necessary to continuously optimize the blasting parameters throughout the construction process, taking into account geological conditions. However, current research mainly focuses on optimizing single-type borehole parameters and fails to simultaneously address the requirements for minimizing overexcavation, underexcavation, and fragment size. This study proposes an intelligent optimization method for blasting construction parameters that combines support vector regression (SVR) with the Non-Dominated Sorting Genetic Algorithm II (NSGA-II). Through grid search and genetic optimization algorithms, the SVR regression model is refined, establishing an accurate nonlinear mapping relationship between the borehole parameters of peripheral holes, auxiliary holes, and slot holes, and the resulting blasting effects. The NSGA-II algorithm is then employed to search for the Pareto optimal set of blasting construction parameters, with the goal of minimizing average linear overexcavation and the maximum fragment diameter. The technique for order of preference by similarity to the ideal solution (TOPSIS) method is used for multiattribute decision-making to identify the optimal blasting plan. The results show that the SVR model, optimized by the genetic algorithm, provides high prediction accuracy for blasting construction parameters, with determination coefficients of 0.89 and 0.97. Multiobjective optimization of blasting parameters using NSGA-II explores the effects of different parameter combinations on tunnel blasting outcomes. In designing and optimizing blasting parameters, particular attention should be paid to the optimization of peripheral and slot hole parameters to effectively control overexcavation, underexcavation, and fragment size. The intelligent optimization method proposed in this study, which integrates advanced intelligent algorithms with professional blasting construction knowledge, forms an efficient and intelligent optimization system. This system enhances the feasibility and accuracy of blasting construction plans.]]></description>
      <pubDate>Tue, 08 Jul 2025 09:57:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/2556941</guid>
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    <item>
      <title>Application of drilling monitoring parameters in tunnelling : with focus on excavation damage, rock mass characterisation and rock support design</title>
      <link>https://trid.trb.org/View/2491198</link>
      <description><![CDATA[The study focused on the possibility to predict blast damage and rock support requirements based on MWD. It showed the good possibilities to apply MWD in tunnelling, especially for rock support and characterising the rock mass more detailed. This work provides a framework for MWD data and its usage in practice for rock support installation. It takes the first steps towards correlating blast damage and rock mass properties based on MWD data.]]></description>
      <pubDate>Fri, 17 Jan 2025 15:16:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2491198</guid>
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    <item>
      <title>BeFo 427 - Numerisk modellering av spränginducerad skada runt bergtunneln med LS-DYNA</title>
      <link>https://trid.trb.org/View/2440066</link>
      <description><![CDATA[In Scandinavia, tunnels are mainly excavated by drilling and blasting. It is inevitable that the blasting induces damage in the form of cracks to the remaining rock mass, which relates to the after-blast effects on stability, water inflow, safety and costs of tunnels. The project aims to predict blast-induced cracks in the remaining rock mass numerically using LS-DYNA code. It was found that the frequency and depth of blast-induced cracks depended on various parameters, namely; explosive parameters (explosive type, charge length, initiation method, coupling ratio), drill hole parameters (burden, spacing and hole diameter) and in-situ rock mass parameters (geology, in-situ stress, rock strength and stiffness). Field tests to investigate blast-induced damage are costly and time consuming. As a four-year PhD project, a systemically numerical study will be carried out to investigate the effect of these factors on the frequency and distribution of blast-induced cracks based on small-scale tests and field investigations. The purpose is to optimize blast design and improve the contour blasting of tunnels.]]></description>
      <pubDate>Thu, 10 Oct 2024 14:37:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/2440066</guid>
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    <item>
      <title>Explosions in road tunnels part 3 : Target failure probability and design values</title>
      <link>https://trid.trb.org/View/2397929</link>
      <description><![CDATA[With the introduction of the Eurocodes [1-6], countries are encouraged to take into account explosion loads in the design of their road tunnels. From “Explosions in road tunnels, Part 1: A study into the explosion scenarios” [7] it has been concluded that 1) the loads as mentioned in the Eurocode are not representative for the total spectrum of explosion loads and 2) based on the Eurocode it is not possible to design tunnels satisfactory for explosion loads. To be able to design tunnels for explosions, it is necessary to have an understanding of all the possible explosion scenarios that can take place, the probability of occurrence of these scenarios and their consequences in terms of pressure and impulse. In “Explosions in road tunnels, Part 2: A quantitative risk analysis” [8] a quantitative risk analysis (QRA) has been performed, resulting in an overview of all possible LPG induced scenarios and their respective risk. In this “Part 3: target failure probability and design values”, we present a method to calculate the design values for the peak pressure and impulse, based on an economic analysis [9,10]. Given the Quantitative Risk Analysis [8] as basis, the following steps are taken: 1. Determining the explosion characteristics for the various scenarios in terms of peak pressures and impulses. This was done on the basis of existing reports and, where necessary, on estimates; 2. Determining the desired target failure probability. The target failure probability has been determined based on a simple economic consideration. No complex calculations have been done and available literature has been used instead, including the JCSS Probabilistic Model Code; 3. Determining the design values for the loads, depending on some relevant parameters (importance, type of traffic, length) and the conditions to which this applies. This has been done based on a relatively simple analysis.]]></description>
      <pubDate>Tue, 25 Jun 2024 15:25:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2397929</guid>
    </item>
    <item>
      <title>Nonlinear analysis of a tunnel slab under a hydrogen explosion</title>
      <link>https://trid.trb.org/View/2397928</link>
      <description><![CDATA[Hydrogen explosions consequent to hydrogen-fuelled vehicle (HFV) accidents in a tunnel could cause great losses of lives and property due to its special characteristics, such as high pressure blast waves. Reliable predictions on the structural response of a tunnel impacted by blast waves are crucial to develop effective mitigation technologies to protect the integrity of the structure. This case study conducts a numerical analysis of a tunnel ventilation slab subjected to an explosion. wave calculated by a CFD study on this specific scenario. The focus here is the mechanical structural response of a reinforced concrete (RC) slab caused by the pressure time history of the explosion wave in the case tunnel. Two different finite element codes (ANSYS Mechanical APDL and DIANA) are applied comparing the respective results. The effects of the reinforcement diameter, reinforcement position, concrete strength and boundary condition are studied and discussed. Numerical results show that the RC slab suffers significant damage under larger explosive impulses. The influences of reinforcement position and concrete strength on the RC slab deflection are very slight. However, reinforcement diameter and boundary condition play an essential role in the RC slab dynamic response. Improving reinforcement diameter and reducing the freedom of the RC slab can effectively enhance the properties of the RC ventilation slab under hydrogen explosion loads.]]></description>
      <pubDate>Tue, 25 Jun 2024 15:25:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2397928</guid>
    </item>
    <item>
      <title>Risk evaluation of road and railroad overbuilds</title>
      <link>https://trid.trb.org/View/2397922</link>
      <description><![CDATA[Railroad and road overbuilds are a kind of substructures that involves large costs which often leads to a need for increased land use close to and on top of the overbuild. If the transportation network which is overbuilt includes transportation of dangerous goods, the risk situation will be complex related to rare events with a potential to cause substantial damage, e.g. collapse of buildings on the over site development. In Sweden there are at present no national or regional rules or guidelines showing how to address or evaluate this risk situation. The lack of guidelines leads to difficulties in implementing this type of project. Brandskyddslaget has developed a proposal for what the basis for such risk assessment decisions might look like. We believe that a cost/benefit analysis will make an important piece of the puzzle in the decision-making basis for the selection of dimensional explosive load and thereby accepting the resulting residual risk, as it gives a more complete picture of the actual risk-reducing effect which leads to a less subjective risk evaluation. This can serve as one of several perspectives addressed in risk-informed decision making.]]></description>
      <pubDate>Tue, 25 Jun 2024 15:25:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2397922</guid>
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    <item>
      <title>Hydrogen tunnel risk assessment : numerical study of selected hydrogen incidents and implementation in the Austrian tunnel risk model</title>
      <link>https://trid.trb.org/View/2397920</link>
      <description><![CDATA[With an increasing share of alternative propulsion energies, potential effects of these systems on tunnel safety become an important issue. This is in particular the case for hydrogen used as energy carrier, where the nature of fire incidents might completely change due to explosions and temporary but violent jet fires. In order to investigate the potential impact of hydrogen incidents on tunnel safety the Austrian Federal ministry for climate action, environment, energy, mobility, innovation and technology launched a dedicated research project – the HyTRA project. Based on a qualitative event-tree analysis considering the reviewed research findings, five hydrogen scenarios were derived. With respect to latest research findings on hydrogen incidents in tunnels and based on available engineering tools, consequence models have been developed and implemented in the Austrian tunnel risk model. The resulting consequence numbers indicate that hydrogen incidents can lead to significantly higher consequences than conventional tunnel fires in modern unidirectional road tunnels. The results strongly depend on the relation between incident time line and emergency response. A realistic and precise treatment of the emergency response time line in a tunnel risk assessment of an actual tunnel is therefore critical, if hydrogen vehicles become relevant in the future.]]></description>
      <pubDate>Tue, 25 Jun 2024 15:25:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/2397920</guid>
    </item>
    <item>
      <title>Safe extinguishment of fire exposed compressed natural gas (CNG) and hydrogen (H2) cylinders</title>
      <link>https://trid.trb.org/View/2397917</link>
      <description><![CDATA[Vehicles that are powered by gaseous fuel, e.g., compressed natural gas (CNG) or hydrogen (H2), may, in the event of fire, result in a jet flame from a thermally activated Pressure Relief Device (TPRD), or a pressure vessel explosion in case the cylinder rupture before the TPRD activates. There have been a few incidents where the TPRD was unsuccessful to prevent a pressure vessel explosion in the event of fire, both nationally in Sweden and internationally. Possible reasons are damaged cylinders, that the TPRD was cooled by the rescue service or a local fire exposure far away from the TPRD. If the pressure vessel explosion would occur inside a road tunnel, the resulting consequences are even more problematic. In 2019 RISE investigated the fire safety of CNG cylinders exposed to local fires. The results from that test series raised the question about what the differences would be in the case of water application. Therefore, one purpose of the new fire test series conducted during 2021 was to investigate whether extinguishment with water may compromise the safety of vehicle gas cylinders in the event of fire. Extinguishments comprise the situation that may occur when deluge systems are activated in ro-ro cargo space or in tunnels, or in the case of manual extinguishment. In total seven fire tests were carried out. The fire tests show that the TPRD indeed can be cooled with water, e.g., from a deluge system, and thus preventing it from activation. Despite, this did not compromise safety as the water also cooled the cylinder, and the three types of cylinders that were tested were robust enough to handle the situation; either the gas slowly leaked through the fire-damaged composite material, the TPRD activated, or the cylinder maintained the gas and its strength throughout the test.]]></description>
      <pubDate>Tue, 25 Jun 2024 15:25:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/2397917</guid>
    </item>
    <item>
      <title>The use of natural gas vehicles in underground facilities : application to the Paris-La-Défense underground network</title>
      <link>https://trid.trb.org/View/2397916</link>
      <description><![CDATA[Considering the current strong development of natural gas vehicles and their use in many underground infrastructures, this paper focuses on the corresponding risk induced in such situations. It consists in applying the analysis of the consequences of the huge and complex underground network of the La Défense business center, in the suburbs of Paris. The different types of natural gas vehicles were considered, compressed natural gas (CNG) and liquified natural gas vehicles (LNG). Based on existing knowledge in risk analysis, the main dangerous phenomena that can occur for those vehicles, jet fire, vapor cloud explosion, and tank burst, were all considered and modeled for each technology. To evaluate the release source term, the very beginning for both jet fire and flammable cloud characterization, the classic gas release model was used while considering the pressure decrease in the tank to get the mass release time variation. This was mainly interested in estimating the resulting jet fire heat release rate and duration and the corresponding impact on the global heat release curve. As far as vapor cloud explosion (VCE) is concerned, the worst-case situation, more precisely the largest flammable mass is obtained in the first seconds following the release beginning. The specificity for VCE represents the tunnel confinement's influence on the pressure wave propagation. In such an environment, the commonly used multi-energy approach, based on semi-spherical wave propagation is inappropriate, reflexion phenomena should be introduced to provide a better prediction. The consequence modeling shows that, for both technologies, the worst dangerous phenomena remain the tank burst, especially for LNG where the lethal effect may affect most of the people present in the tunnel, for CNG lethal effect should reach 30 m and more for the same tank burst scenario.]]></description>
      <pubDate>Tue, 25 Jun 2024 15:25:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/2397916</guid>
    </item>
    <item>
      <title>Risk analysis of fire and explosions in road tunnels</title>
      <link>https://trid.trb.org/View/2397914</link>
      <description><![CDATA[As we all know, road tunnels play a critical role in transportation infrastructure, enabling the safe and efficient movement of people and goods. However, they also pose unique challenges in terms of safety, particularly when it comes to the risk of fire and explosion events. In the past 20 years, risk analysis in the area of fire and explosion safety has evolved to a much broader accepted area of expertise. Risk analysis helps to make decisions about life, structural safety and economic optimizations. Methods have developed, data is better accessible, and calculations are faster. However, also the safety in tunnels itself evolves: other fuels, truck platooning and smart mobility are developments that needs to be taken into account in new or updated risk analyses. In this paper a look into the history and the future on risk analysis in fire and explosion risk in road tunnels, is given.]]></description>
      <pubDate>Tue, 25 Jun 2024 15:25:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/2397914</guid>
    </item>
    <item>
      <title>Hydrogen vehicles safety in underground traffic infrastructure : overview of HyTunnel-CS findings</title>
      <link>https://trid.trb.org/View/2397912</link>
      <description><![CDATA[This keynote presents the overview of the HyTunnel-CS project and some of its main research findings on inherently safer use of hydrogen vehicles in underground traffic infrastructure. The detailed description of all project results can be found in the deliverables at the website www.hytunnel.net and related published journal and conference papers. Here the focus is mostly on a part of HyTunnel-CS research programme related to mitigation and prevention of “new” hazards, i.e. blast wave and fireball following high-pressure hydrogen tank rupture in a fire in confined space. The dynamics of blast wave and fireball development after tank rupture in a tunnel is compared against the case in the open atmosphere. It is demonstrated that hydrogen tank rupture in confined space fire is unacceptable and everything possible must be done to prevent it. Safety concerns about fire test protocol of Global Technical Regulation on Hydrogen and Fuel Cell Vehicles No.13 (GTR#13) are explained. It is concluded that passing the GTR#13 fire test at its lower specific heat release rates compared to possible real fires does not mean the provision of hydrogen storage tank safety in real life conditions. The first ever model for tank-TPRD system design for engulfing fire of arbitrary intensity is presented. The examples of tank-TPRD system design that exclude both a tank rupture in engulfing fire and the pressure peaking phenomenon are given. It is underlined that this safety design will not close the issue of localised fire which must be solved in one or another way, e.g. by using innovative explosion free in a fire self-venting (TPRD-less) tanks. The safety strategy for underground parking of hydrogen-powered cars is formulated and results of safety design of TPRD diameter and release direction are demonstrated.]]></description>
      <pubDate>Tue, 25 Jun 2024 15:25:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/2397912</guid>
    </item>
    <item>
      <title>Rock Excavation Best Management Practice Phase I (Rock Cut Perimeter Blasting BMP)</title>
      <link>https://trid.trb.org/View/1959643</link>
      <description><![CDATA[The authors examined Colorado Department of Transportation (CDOT) design procedures, blasting methods, blast calculations, and aesthetic considerations to specify best management practices for highway rock cut operations for the CDOT that could be followed when a Contractor or Permittee is proposing to blast. Though aesthetics are highly subjective, the authors developed a method to assign quantitative values for aesthetics, called the Percent Aesthetic Enhancement (PAE). The PAE is constituted as a quantitative assessment that defines the level of effort required for the enhancement of aesthetic features in final road cuts. By following these practices, the CDOT Engineer-In-Charge can ensure that the Contractor accomplishes the work in a safe manner while preserving scenic, aesthetic, and environmental resources.]]></description>
      <pubDate>Mon, 30 May 2022 11:32:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/1959643</guid>
    </item>
    <item>
      <title>Renewable fuels during underground work : low risk, obvious benefit but nevertheless a utopia?</title>
      <link>https://trid.trb.org/View/1956183</link>
      <description><![CDATA[An electrification of society is ongoing. Swedish mines are often long-term workplaces with good supply of electricity. For tunnels under construction (tunneling), the situation is the opposite; a temporary workplace with limited supply of electricity. This means that a considerable electrification of the work will be very difficult to implement. For work machines that are used underground, there are currently no alternatives to diesel-powered machines on the market to await. For trucks, however, there are several alternatives to diesel on the market. To and from construction tunnels, a large amount of material is transported, such as rock, stone, gravel and ballast. Part of the transport work can be carried out by train or barge, but it is still usually required a truck transport at each end of the train or barge set. Synthetic diesel (HVO100) or Biodiesel B100 (FAME/RME) could be used as a fuel, but there will probably not be a sufficient amount of HVO100 to buy at a commercially reasonable price. When it comes to Biodiesel B100, this product has a lower sustainability. At the moment it seems difficult to reach the political ambitions of a fossil-free society without using methane (i.e. biogas) or diesel ethanol (ED95) in underground work.]]></description>
      <pubDate>Fri, 20 May 2022 14:06:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/1956183</guid>
    </item>
    <item>
      <title>How electric vehicles change the fire safety design in underground structures</title>
      <link>https://trid.trb.org/View/1956155</link>
      <description><![CDATA[Driven by climate change, the need to reduce the production of climate-wrecking gases, especially CO2, is resulting in a diversification in the mobility sector. Therefore, the number of vehicles using so-called new energy carriers (NEC), in particular electric drive concepts, is constantly increasing. Electric vehicles itself as well as the mixture of vehicles are causing new fire risks, which are currently hardly known. Moreover, this risks are even intensified when occurring in underground facilities.These circumstances are demanding for research on those new fire risks. The German research project SUVEREN is focussing on the described deficit. Various fire tests with NECs, including different types of lithium-ion batteries, have been conducted. Furthermore, a design fire curve for modern passenger cars regardless their propulsion system was developed. This curve can be utilized for designing underground facilities when using performance-based design.]]></description>
      <pubDate>Fri, 20 May 2022 14:06:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/1956155</guid>
    </item>
    <item>
      <title>Dangerous goods vehicles in road tunnels, a significant modification of French risk analysis</title>
      <link>https://trid.trb.org/View/1956149</link>
      <description><![CDATA[A risk assessment methodology is used in France to help choosing the dangerous good vehicles authorised in tunnel. This methodology was updated in order to better take into account ADR categories principle and to integrate feedback experience of applications. CETU has proposed two major modifications. Firstly, the method, which was mainly based on a binary logic (dangerous goods authorised or not), now makes it possible to adopt intermediate solutions in accordance with the principle of ADR categories. Secondly, the analysis is now systematically multi-criteria whereas, previously, it was only multi-criteria if the risk of death from accident with release of dangerous goods was not significant. These two proposals were discussed with specialized companies and agreed. Then, CETU has undertaken the development and has taken into account tests performed by specialised companies on intermediate versions. The new methodology is now operative and integrate the management of unavoidable uncertainties. It mixes systematic approach and scenario-based approach in the sense of [1] and also quantitative and qualitative assessments.]]></description>
      <pubDate>Fri, 20 May 2022 14:06:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/1956149</guid>
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