Journal articles: 'Railway substructure'

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Habashneh, Muayad. "Special reinforcement solutions of railway permanent ways’ soil substructures." Acta Technica Jaurinensis 14, no. 3 (May 21, 2021): 339–63. http://dx.doi.org/10.14513/actatechjaur.00612.

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This mini review aims to summarize relevant international publications. Thus, based on this, giving a comprehensive review about the reinforcement solutions of permanent ways' soil substructure. Generally, the core weakness of soil is its inadequacy to resist tensile stresses. The main target of strengthening the soil is to enhance the engineering characteristics of the soil to build up specific parameters such as shear strength, compressibility, density, and hydraulic conductivity. In addition, special reinforcement techniques of railway permanent ways' soil substructures will be considered in this paper due to the increasing demand of improving railways and rehabilitation process. The main findings of this study that there are a lot of special reinforcement techniques which can be considered as effective solution for soil stabilization such as geosynthetic reinforcement.

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Li, Wei, Xuecheng Bian, Xiang Duan, and Erol Tutumluer. "Full-Scale Model Testing on Ballasted High-Speed Railway: Dynamic Responses and Accumulated Settlements." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 10 (July 13, 2018): 125–35. http://dx.doi.org/10.1177/0361198118784379.

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High-speed trains generate much higher vibrations in track structures than conventional trains and intensive train passages (e.g., on the Beijing–Shanghai high-speed railway line where the train passage interval is less than 5 minutes) cause accumulated permanent settlement in the railway track substructures, which will decrease track performance and jeopardize the safety of trains. Since very few field measurements on ballasted high-speed railways are available in literature, this paper presents experimental results of vibration velocity, dynamic soil stress, and the accumulated settlement of a ballasted high-speed railway from a full-scale model testing facility with simulated trains moving loads at various speeds. A portion of a realistic ballasted railway consisting of track structure, ballast layer, subballast, embankment, and piled foundation was constructed in a larger box. An eight-actuator sequential loading system was used to generate equivalent vertical loadings on the track structure for simulating the dynamic excitations due to train movements. Dynamic stresses measured in the track substructure layers (ballast, subballast, and embankment) were found to be strongly dependent on train speeds especially for speeds higher than 144 km/h. It was found that both the vibration velocity and the dynamic soil stress were greatly amplified as the train speed increased to 300 km/h, and the ballast layer effectively reduced the vibrations transmitted from the track structure to underlying soil. The accumulated settlement of the substructure did not reach a stable state even after 100,000 moving train loads at a speed of 300 km/h.

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IŽVOLT, Libor, Peter DOBEŠ, and Juraj PIEŠ. "Verification of boundary conditions of numerical modeling of the track substructure thermal regime – influence of the snow cover." Archives of Transport 4, no. 48 (December 31, 2018): 51–60. http://dx.doi.org/10.5604/01.3001.0012.8365.

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The initial part of the paper briefly characterizes a long-term experimental activity at the Department of Railway Engineering and Track Management (DRETM). The research of the DRETM focuses, besides other research activities and specific problems in the field of railway engineering (application of new structures and construction materials in conventional and modernized railway tracks, modernisation and rehabilitation of existing railway tracks for higher speeds, track diagnostics, influence of track operation on noise emissions and design of structural measures, possibility of application of recycled ballast bed material in the track substructure, ballast recycling technologies, ecological assessment of recycled material of the track substructure), on various factors affecting track substructure freezing. In 2012-2017, in the campus of the University of Žilina (UNIZA), an Experimental stand DRETM was built for the research purposes. The experimental stand DRETM consists of 6 types of track substructure placed in an embankment or a cut, in the 1:1 scale. Besides conventional building materials (crushed aggregate), these structures also include various thermal insulation materials (Liapor concrete, Styrodur, foam concrete). A significant part of the paper deals with numerical modeling of the freezing process of track substructure (an embankment with the embedded protective layer of crushed aggregate, fr. 0/31.5 mm) for various boundary conditions (air frost index, average annual air temperature), using SoilVision software. The aim of this research is to identify the thermal insulation effects of different thicknesses of snow cover on the depth of penetration of the zero isotherm into the track substructure (railway track). The paper conclusion specifies the influence of different snow cover thicknesses, or nf factor (factor expressing the dependency between the mean daily air temperature and the temperature on the ballast bed surface) and various climatic conditions (frost indexes and average annual air temperatures), affecting the railway infrastructure, on the resulting depth of freezing of the track substructure (railway track). These outputs will be in the further research used for the design of nomogram for determining the thickness of the protective layer of the frost-susceptible subgrade surface of the track substructure.

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Fei, Jianbo, Yuxin Jie, Chengyu Hong, and Changsuo Yang. "Comparative Analysis of Design Parameters for High-Speed Railway Earthworks in Different Countries and a Unified Definition of Embankment Substructure." Baltic Journal of Road and Bridge Engineering 15, no. 2 (June 25, 2020): 127–44. http://dx.doi.org/10.7250/bjrbe.2020-15.476.

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This paper compares design specifications and parameters for high-speed railway (HSR) earthworks in different countries (i.e., China, France, Germany, Japan, Russia, Spain and Sweden) for different track types (i.e., ballasted and ballastless), and for different design aspects (i.e., HSR embankment substructure, compaction criteria, width of the substructure surface, settlement control, transition section, and design service life). Explanations for differences in HSR implementation among different countries are provided and reference values of the design parameters are obtained. In an attempt to unify different types of HSR substructures around the world, a widely applicable definition of the stratified embankment substructure based on the practices adopted in different countries is proposed. The functions and requirements of each functional layer (i.e., the blanket layer, frost protection layer and filtering layer) are summarized.

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Dobeš, Peter. "Calibration of TDR Test Probe for Measuring Moisture in the Body of the Railway Substructure and its Subgrade." Civil and Environmental Engineering 11, no. 2 (December 1, 2015): 84–94. http://dx.doi.org/10.1515/cee-2015-0011.

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Abstract In the introduction of the paper there is characterized a way of monitoring the moisture in the railway substructure in the experimental stand, which is a part of the experimental workplace of the Department of Railway Engineering and Track Management. A substantial part of the paper is devoted to the calibration of TDR test probe for selected rock materials as a basic prerequisite for the determination of the actual moisture in the body of the railway substructure and subgrade.

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Lewandrowski, Tomasz, Paweł Muzolf, and Włodzimierz Idczak. "The approximate modelling of a “rail vehicle-railway track- substructure” system." Bulletin of the Military University of Technology 66, no. 2 (July 3, 2017): 107–21. http://dx.doi.org/10.5604/01.3001.0010.1893.

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A system “railway vehicle–railway track–substructure” was analysed. Rails were modelled as the Bernoulii-Euler beams on an elastic foundation. Two load cases were considered a) static load from the train to the railway track, b) dynamic load from the train moving with the constant velocity. As a result, the fourth-order differential equation was obtained. Both, material data and operating parameters were determined by components of the equation. To solve this equation, the finite difference method was used. This method was described considering such matters as space step, time step, discretization, and moving load modelling. Evaluation of usefulness of a selected method in modelling a railway infrastructure was the purpose of the authors. The obtained results were compared with results received by analytical way. The presented, simplified model: railway vehicle–infrastructure–substructure after appropriative validation will be used later on to analyse various technical solutions and materials in designing railway constructions. Keywords: numerical methods, finite difference method, railway infrastructure, dynamic impact factor

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Haji Abdulrazagh, Parisa, and Michael T. Hendry. "Case study of use of falling weight deflectometer to investigate railway infrastructure constructed upon soft subgrades." Canadian Geotechnical Journal 53, no. 12 (December 2016): 1991–2000. http://dx.doi.org/10.1139/cgj-2016-0083.

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Falling weight deflectometer (FWD) testing was conducted along with embankment and subgrade sampling over 210 km (130 miles) of Canadian National Railway’s Lac La Biche Subdivision, which runs between Edmonton and Fort McMurray, as a part of a larger investigation of the line for increased axle loads. The resulting measurements were evaluated for their ability to identify soft subgrades. Two analyses were conducted to this end. First, the statistical distribution of peak deflections recorded by the FWD was investigated for different types of subgrade material. Second, the properties of track substructure were studied by characterizing the deflection time histories using a dynamic model of a single mass on a viscoelastic foundation and least-squares curve fitting. Four characteristic types of deflection time histories were identified for differing substructure conditions. Simplified dynamic modelling of railway track substructure showed that where relatively thick embankment exists over subgrade, the response of track is overdamped behavior.

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Vukićević, Mirjana, Zdenka Popović, Jovan Despotović, and Luka Lazarević. "Fly ash and slag utilization for the Serbian railway substructure." Transport 33, no. 2 (December 12, 2016): 389–98. http://dx.doi.org/10.3846/16484142.2016.1252427.

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Approximately 7 million tons of fly ash and slag are produced in thermal power plants in Serbia every year, only 3% of which is used in the cement industry. About 300 million tons of the ash-slag mixture are disposed in landfills, occupying an area of approximately 1600 hectares and generating environmental issues. Fly ash from Serbian power plants has pozzolanic properties and due to low concentration of calcium compounds (less than 10% CaO), they do not have self-cementing properties. According to the ASTM C618-15, this ash is from class F. According to the European Standard EN 197-1:2011, this ash is siliceous (type V) ash. From April 2014 to May 2015, an investigation of engineering properties of fly ash and mixtures of fly ash and slag from landfill (without or with binders of cement/lime) was conducted at the Laboratory of Soil Mechanics at the Faculty of Civil Engineering of the University of Belgrade (Serbia) and at the Institute for Testing of Materials – IMS Institute in Belgrade. The laboratory test results were showed in the study ‘Utilization of fly ash and slag produced in the TPP JP EPS thermal power plants for construction of railways’. Four kinds of waste materials from Serbian power plants were laboratory tested: (a) an ash-slag mixture from landfills at the ‘Nikola Tesla A’ thermal power plant; (b) fly ash from silos in the ‘Nikola Tesla B’ thermal power plant; (c) an ash-slag mixture from landfills at the ‘Kostolac A’ and ‘Kostolac B’ thermal power plants and ‘Srednje kostolačko ostrvo’ landfill; (d) fly ash from the ‘Kostolac’ thermal power plant. The following physical and mechanical properties of ash and mixtures were investigated: grain size distribution, Atterberg limits, specific gravity, moisture-density relationship, shear strength parameters in terms of effective stresses, California Bearing Ratio (CBR), and deformation parameters. The paper presents the results of laboratory tests of the materials with and without binders, and based on the laboratory results and previous research, the paper presents possibilities of using fly ash and slag for the construction of railway substructure in the planned construction and reconstruction of railway network in Serbia. The obtained results indicate that tested fly ash and ash-slag mixture have met the technical requirements and that they have the potential to be used in railway substructure.

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Lazarević, Luka, Dejan Vučković, Milica Vilotijević, and Zdenka Popović. "Application of seismic tomography for assessment of the railway substructure condition." Structural Health Monitoring 18, no. 3 (May 29, 2018): 792–805. http://dx.doi.org/10.1177/1475921718774778.

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This article presents results obtained in the research conducted on railway infrastructure in Serbia, which aimed at prediction of substructure condition based on the analysis of track quality. It presents the results of seismic tomography application as non-destructive procedure for assessment of railway substructure condition. Track geometry quality was assessed according to analysis of longitudinal level data, which was recorded during regular track geometry inspections. Track section for application of seismic tomography was chosen on the basis of analysed track geometry data recorded during the regular track geometry inspections in 2006, 2008, 2009, 2012, 2013 and 2014. Tomographic imaging of railway platform on Test Section enabled the creation of two-dimensional finite element model, which was used for determination of propagation speed of seismic P-waves. Seismic tomography on Test Section, which is the part of the international railway line Belgrade–Vrbnica, was performed in 2014. Obtained tomographic image was discussed and compared to track geometry data recorded during the regular track geometry inspections.

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Mosayebi, Seyed-Ali, Jabbar-Ali Zakeri, and Morteza Esmaeili. "Vehicle/track dynamic interaction considering developed railway substructure models." Structural Engineering and Mechanics 61, no. 6 (March 25, 2017): 775–84. http://dx.doi.org/10.12989/sem.2017.61.6.775.

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Byun, Yong-Hoon, Won-Taek Hong, and Jong-Sub Lee. "Characterization of railway substructure using a hybrid cone penetrometer." Smart Structures and Systems 15, no. 4 (April 25, 2015): 1085–101. http://dx.doi.org/10.12989/sss.2015.15.4.1085.

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Wang, Heng, Ling-Ling Zeng, Xia Bian, and Zhen-Shun Hong. "Train Moving Load-Induced Vertical Superimposed Stress at Ballasted Railway Tracks." Advances in Civil Engineering 2020 (February 21, 2020): 1–11. http://dx.doi.org/10.1155/2020/3428395.

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Ballasted railway track is an important factor that forms railway transportation over the world, which may face severe damage during operation due to the deterioration of the track ballast geometry. A practical method of evaluating train moving load-induced vertical superimposed stress in substructure by incorporating the effects of ballast characteristics and multilayered substructure is presented. The proposed method is validated by comparing with the field measurements compiled from the literature with the calculated value. It is found that the prediction accuracy of the proposed method is within ±10%, in comparison with field measurements. Meanwhile, it should be emphasized that the predicted value by traditional methods was 1.4–5.0 times field measurements. Also, key factors affecting the predicted accuracy are identified through parameter analysis by using the proposed and the traditional methods.

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Jíra, Josef, Jitka Jírová, Michal Micka, and Jitka Řezníčková. "COMPARATIVE ANALYSIS OF BEARING CAPACITY OF REINFORCED AND NON-REINFORCED RAILWAY EMBANKMENT." Acta Polytechnica CTU Proceedings 11 (August 28, 2017): 22. http://dx.doi.org/10.14311/app.2017.11.0022.

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A comparative analysis using the programme ANSYS (FEM) deals with the generation of the computation model and with the assessment of the influence of the geogrids and the vertical lime-cement columns on the bearing capacity and deformation of the railway embankment on the less load-bearing subsoil. The graphic outputs give an overview of the field layout of equivalent stresses and deformation in the construction of the railway substructure.

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Yusupov, Bekhzad, Yanjun Qiu, Galibjon Sharipov, and Chaoyang Wu. "Characterization of Vertical Response of Asphalt Trackbed Concrete in Railway Substructure to External Loads." Advances in Materials Science and Engineering 2020 (March 13, 2020): 1–12. http://dx.doi.org/10.1155/2020/3578281.

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Optimizing the dynamic responses of a slab track system is a key aspect to improve the quality of a railway track structure. In this paper, numerical modelling and simulation of vertical dynamics of the railway track structure engaging the asphalt concrete in substructures were carried out. Thus, a 3D finite element (FE) model was developed. The developed model was validated by comparing its outputs, that is, acceleration with the measured ones from realistic experimental data. The good agreement between the simulated and measured data which resulted from the validation confirmed that the proposed model has a capability of simulating the complex dynamic performances of the train-track-ground system under different loading conditions. Analyses of the determined results from the simulation model performances revealed that three specific factors, which were the speed of the train, the temperature, and thickness of the asphalt concrete trackbed, mainly influenced the dynamic behavior of the railway structure. Thereby, those factors were taken into consideration while evaluating the dynamic responses and designing the asphalt concrete trackbed in railway substructures.

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Popović, Zdenka, Luka Lazarević, Ljiljana Brajović, Milica Mićić, and Nikola Mirković. "Improvement recommendations for railway infrastructure maintenance." E3S Web of Conferences 157 (2020): 01001. http://dx.doi.org/10.1051/e3sconf/202015701001.

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Based on the railway network performance, Infrastructure Manager is obligated to define the Maintenance plan for railway infrastructure, which contains corresponding values for intervention limits and alert limits. This paper considers vehicle response to track excitation due to the rail defect (code 2202 according to defect classification). It is indicated that theoretical models and acceleration measurements could be used to assess the quality of track geometry and ride comfort. The importance of early detection of irregularities of superstructure and substructure was emphasized. Moreover, the importance of inspection and preventive maintenance on the modern railway infrastructure was considered. According to the previous, the authors recommend non-destructive methods for inspection and early detection of irregularities of railway infrastructure.

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Montalbán, Laura, Julia Real, and Teresa Real. "Mechanical characterization of railway structures based on vertical stiffness analysis and railway substructure stress state." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 227, no. 1 (July 9, 2012): 74–85. http://dx.doi.org/10.1177/0954409712452348.

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Yoshida, Naoto, Kenichi Suzuki, and Shunichi Suzuki. "The replaced of substructure of railway viaduct in metropolitan areas." IABSE Symposium Report 102, no. 30 (September 1, 2014): 847–52. http://dx.doi.org/10.2749/222137814814067004.

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KONISHI, Junichi. "Substructure of Railway Bridges in Meiji Era-A historical Introduction." HISTORICAL STUDIES IN CIVIL ENGINEERING 15 (1995): 145–58. http://dx.doi.org/10.2208/journalhs1990.15.145.

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Yang, Yanxin, Jianlin Ma, and Yong Huang. "A WIRELESS RAILWAY MONITORING SYSTEM OF PROBLEMATIC SUBSTRUCTURE IN TUNNEL." Stavební obzor - Civil Engineering Journal 28, no. 2 (2019): 233–47. http://dx.doi.org/10.14311/cej.2019.02.0019.

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Zhang, T. W., Y. J. Cui, F. Lamas-Lopez, N. Calon, and S. Costa D’Aguiar. "Modelling stress distribution in substructure of French conventional railway tracks." Construction and Building Materials 116 (July 2016): 326–34. http://dx.doi.org/10.1016/j.conbuildmat.2016.04.137.

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Guo, Wei, Chen Zeng, Xu Xie, and Dan Bu. "Pseudodynamic Hybrid Simulation of High-Speed Railway Bridge-Track System with Rotational Friction Damper." International Journal of Structural Stability and Dynamics 20, no. 06 (June 2020): 2040014. http://dx.doi.org/10.1142/s0219455420400143.

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This paper evaluates seismic performance of a three-span high-speed railway (HSR) simply supported bridge-track system equipped with multi-joints rotational friction damper (MRFD) using pseudodynamic hybrid simulation. In hybrid simulation, a simplified nonlinear model based on the reference of high-speed railway model is used as a numerical substructure. The experimental substructure is a rotational friction damper (RFD) specimen consisting of two rotational joints. The feedback-force of the RFD specimen is multiplied in different multiples to consider the different clamping force of MRFD with more rotational joints. Results of cyclic tests indicate that the RFD specimen has a good ability to mitigate seismic damage of bridge-track system. Then, pseudodynamic hybrid simulations were performed in the longitudinal direction of the bridge to examine the seismic performance of MRFD. The effect of various ground motions and the influence of different clamping forces of MRFD were investigated. Test results confirmed the applicability of MRFD in HSR bridge-track system.

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Nie, Ru-song, Wu-ming Leng, Qi Yang, Yohchia F. Chen, and Fang Xu. "Comparison and evaluation of railway subgrade quality detection methods." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 2 (October 6, 2016): 356–68. http://dx.doi.org/10.1177/0954409716671551.

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Subgrade is a critical component of railway systems since it provides a stable platform for the track substructure. The implementation of quality assurance methods is very important during the construction of a new railway subgrade and in monitoring the working performance of operating railways. There are several indicators available to measure the compaction and mechanical performance of a completed subgrade system, including compaction degree ( K), porosity ( n), modulus of subgrade reaction ( K30), basic bearing capacity ([Formula: see text]), strain moduli ( Ev), dynamic modulus of deformation ( Evd), and light dynamic penetration ( N10). The objective of this research was to compare and evaluate the frequently used engineering methods in order to select the important and reliable indicators of field parameters. Four soil models with different degree of compaction were considered in the common laboratory tests and detection methods in China to determine the construction quality. The implementation and test results of these methods were analyzed and compared. The study results indicate that K correlates with n linearly. There is also a good correlation among K30, Ev, and Evd. As a recommendation, K is considered as the controlling indicator for compaction performance, and Ev2 and Evd are considered as the controlling indicators for railway subgrade stiffness evaluation. The bearing capacity or strength indicators may be added to the quality detection work in heavy-haul railway construction.

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Stančík, Vojtěch, Pavel Ryjáček, and Miroslav Vokáč. "Thermal and load rate-dependent interaction between embedded rail system and bridge." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 233, no. 3 (August 30, 2018): 326–36. http://dx.doi.org/10.1177/0954409718795092.

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Recent developments in the technology of a modern embedded rail system grant many new possibilities for improving the railway infrastructure. An embedded rail system significantly reduces noise and the dynamical impact affecting both the infrastructure and the rolling stock itself. An embedded rail system may be used for constructing any type of railway infrastructure including high-speed railways. Its attributes are also suitable for modernization of the current steel railway bridges or constructing new structures, where slender bridge decks are required. However, in a railway track equipped with an embedded rail system, stress increments rise due to its restricted expansion movement. This effect is naturally higher when the embedded rail system is placed on a bridge, because of their different deformation possibilities. For a wider use of embedded rail system, examining the interaction behavior between the embedded rail system and the substructure is a matter of essential importance. Furthermore, the nonlinear character of embedded rail system polymer-based components needs to be considered when examining their interaction behavior. Therefore, this paper aims at investigating the nonlinear coupling functions of an embedded rail system under the effects of temperature and load rate. For this purpose, a comprehensive analysis consisting of laboratory experiments, material tests of the embedded rail system components and subsequent numerical validation was performed. Results are concluded in the paper.

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Fischer, S. "Investigation of effect of water content on railway granular supplementary layers." Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, no. 3 (2021): 64–68. http://dx.doi.org/10.33271/nvngu/2021-3/064.

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Purpose. To determine the relationship between water content of continuously graded granular supplementary layers for railway substructure and their inner shear resistance and load bearing capacity. Methodology. Four different samples were produced as standard granular products from andesite. Two of them are common base courses for road construction in Hungary, the other two are common railway supplementary layers. The author performed laboratory measurements (multi-level shear box tests) that are adequate for the evaluation of inner shear resistance. The measurements of load bearing capacity and Proctor tests were executed in the laboratory of Colas Hungaria Ltd. The author performed measurements with the optimal water content values of each sample, as well as lower and higher values than them. This can show how the given granular material is sensible to the change of water content. Findings. It was proved that the granular supplementary layers, which are standardized products in road construction (as base courses), also seems to be adequate in railway construction; they are not so sensible to the variation of their water content. It does not mean that the other two granular layers are not adequate for railway substructures, but the application of road products have to be considered as substitute products. Originality. The author tried to emphasize the adequacy of rock mining for construction of ballasted railway tracks, as well as the optimal use of mineral wealth in every country with its results. Practical value. The obtained results of the present paper can be useful in the area of rock mining, and railway infrastructure engineering. During construction procedures the optimal water content values should be taken into considerations for compaction to be able to reach maximal compactness (density), but too high water content has to be avoided, which is based on the results. They can be also considered in the design phase.

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Eller, B., and S. Fischer. "REVIEW OF THE MODERN BALLASTED RAILWAY TRACKS’ SUBSTRUCTURE AND FURTHER INVESTIGATIONS." Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport, no. 6(84) (December 18, 2019): 72–85. http://dx.doi.org/10.15802/stp2019/195831.

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Nielsen, Jens CO, Eric G. Berggren, Anders Hammar, Fredrik Jansson, and Rikard Bolmsvik. "Degradation of railway track geometry – Correlation between track stiffness gradient and differential settlement." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, no. 1 (December 26, 2018): 108–19. http://dx.doi.org/10.1177/0954409718819581.

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Based on the track geometry car recordings performed from 1999 to 2016 on a section of the Swedish heavy haul line Malmbanan, the vertical track geometry degradation is analysed for wavelengths in the interval 1–25 m. The upper layer of the subgrade on parts of the rail section is peat (depths of up to 2 m), while it is moraine on others leading to a significant longitudinal variation in substructure stiffness. The degradation rates of irregularities in the longitudinal level and the influence of track maintenance (tamping) on the track geometry are studied. In parallel, a method for continuous measurement of track vertical stiffness along the line, allowing for the detection of track sections with poor support conditions, is described and demonstrated. Synchronised measurements of the longitudinal level and the track vertical stiffness are evaluated to determine whether there is a correlation between a high stiffness gradient due to variations in substructure stiffness and a high growth rate of local track geometry irregularities. It is shown that recurrent severe local track geometry irregularities often occur on track sections where there is a combination of a low magnitude and a high gradient in the substructure stiffness. In such cases, tamping may not be a cost-efficient long-term solution to the problem. Instead, upgrading of ballast and subgrade layers should be considered as an option. It is concluded that measurement of track vertical stiffness is an efficient method for the maintenance planning of a more robust railway track, which also minimises the life cycle cost and environmental footprint.

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Byun, Yong-Hoon, Won-Taek Hong, and Jong-Sub Lee. "Application of dynamic and static cone penetrometer for characterization of railway substructure." Japanese Geotechnical Society Special Publication 2, no. 46 (2016): 1628–31. http://dx.doi.org/10.3208/jgssp.kor-39.

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Bian, Xuecheng, Hongguang Jiang, and Yunmin Chen. "Preliminary Testing on High-speed Railway Substructure Due to Water Level Changes." Procedia Engineering 143 (2016): 769–81. http://dx.doi.org/10.1016/j.proeng.2016.06.124.

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Esmaeili, Morteza, and Payman Yousefi Mojir. "Substructure Nonlinear Effects on Sleeper Design Pressure in Heavy Haul Railway Tracks." Journal of Transportation Engineering 137, no. 9 (September 2011): 656–64. http://dx.doi.org/10.1061/(asce)te.1943-5436.0000264.

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Naeini, Mahdi, Alireza Mohammadinia, Arul Arulrajah, and Suksun Horpibulsuk. "Cyclic behavior of semi-rigid recovered plastic blends in railway track substructure." Transportation Geotechnics 28 (May 2021): 100514. http://dx.doi.org/10.1016/j.trgeo.2021.100514.

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Ali, Ayaanle Maxamed. "Manual RC Bridge Analysis and Designing." Volume 5 - 2020, Issue 8 - August 5, no. 8 (August 17, 2020): 116–78. http://dx.doi.org/10.38124/ijisrt20aug019.

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Bridges is a structure intended to carry the road traffic or other moving load to pass through the obstacles. The bridge may be roadway bridge, railway bridge,a canal, pipelines, etc. the main obstacles can be river, valley, and others.Bridges are very important in the modern roads and railway transportation system, generally serving as social infrastructure system. During constructing bridge there are three main components of the bridge, and they are (substructure, superstructure, bearing), etc. this study is concern about the manual analysis and design of the bridge, it’s built for the purpose of providing passage over the obstacles, generally something that can obstacle to cross otherwise.

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Tian, Li, and Cong Zhu. "Numerical Simulation of Ship-bridge Collision Based on LS-DYNA Technique." Advanced Materials Research 243-249 (May 2011): 6230–36. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.6230.

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A collision between a 2600 DWT oil tanker and the substructure of one railway continuous beam bridge is simulated using ANSYS/LS-DYNA. In the simulation, the dynamic interaction between the soil and piles is consideredthrough contact coupling algorithm and nodes sharing algorithm. The time history of ship collision force, penetration and velocity of the ship for the two different algorithms are presented, and relations of them are given. In addition, energy dissipation in every parts, deformation response and stress distribution of the substructure are analyzed in detail. The results indicate that rules of ship-bridge collision given by the two algorithms are in good agreement. Finally, reliability of the simulation in this paper is demonstrated through the comparison with specifications.

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Su, Qian, Wei Jiang, Kai Jiang, Yu Jie Li, and Ling Ling Yang. "Nighttime Monitoring and Assessment Technology of Subgrade Settlement for Chengdu-Guanxian Line during Operation Period." Advanced Materials Research 742 (August 2013): 13–18. http://dx.doi.org/10.4028/www.scientific.net/amr.742.13.

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The criterion for residual deformation of Substructure of ballasteless track on railway passenger dedicated line is extremely strict in order to satisfy the safety and comfort requirements of the high-speed train during operation period, urgent need to strengthen the ballastless track lines settlement deformation observation, prediction and assessment technology. Based on Chengdu-Guanxian line, this paper puts forward observation programs of subgrade settlement combined with the characteristics of Subgrade Settlement through the analysis of the influence factors of subgrade settlement deformation and key consideration about the factors of nighttime observation precision. It shows that the monitoring and assessment technology could meet the requirements through the analysis of field data, it can be guidance of railway management departments to make maintenance plan. Some advices provide reference for the monitoring and assessment of high-speed railway subgrade settlement during operation period.

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Ma, Weibin, Jinfei Chai, Zifeng Zhu, Zili Han, Chaofeng Ma, Yuanjun Li, Zhenyu Zhu, et al. "Research on Vibration Law of Railway Tunnel Substructure under Different Axle Loads and Health Conditions." Shock and Vibration 2021 (June 28, 2021): 1–14. http://dx.doi.org/10.1155/2021/9954098.

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In this paper, 25-ton and 27-ton axle heavy trucks are used to carry out moving loading and dynamic real vehicle test on the cracked section, the intact section, and the repaired section of a railway tunnel foundation to test the dynamic performance of the tunnel basement structure with the change of axle loads and health conditions. By analyzing the influence law of dynamic response and fatigue life of heavy haul train under different basement conditions (intact, damaged, and repaired), the adaptability of railway tunnel equipment to freight trucks axle load is clarified. The results show that (1) the intact section of the tunnel can meet the normal operation of 25-ton and 27-ton axle load freight trains in good condition. (2) The normal operation of 25-ton and 27-ton axle load freight trucks is seriously affected by the cracked section of the tunnel. When the cracks in the tunnel basement are gradually hollowed out by groundwater, serious traffic accidents such as vehicle shaking and derailment are likely to occur. (3) The repaired section of the tunnel can meet the normal operation of 25-ton and 27-ton axle load freight trains after adopting the integrated comprehensive treatment of “Anchor-Injection-Drainage”. The research results will have reference significance for the condition assessment and disease treatment of the basement structure of the heavy haul railway tunnel.

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Chen, Ren-Peng, Han-Lin Wang, Peng-Yun Hong, Yu-Jun Cui, Shuai Qi, and Wei Cheng. "Effects of degree of compaction and fines content of the subgrade bottom layer on moisture migration in the substructure of high-speed railways." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 4 (June 7, 2017): 1197–210. http://dx.doi.org/10.1177/0954409717710838.

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Moisture migration and distribution in the substructure are found to be the important reasons for water-related problems in high-speed railways. In this study, a numerical model of a double-line ballastless track-bed consisting of a substructure (subgrade surface layer, subgrade bottom layer and subsoil) and a superstructure (including two concrete bases right above the substructure) was established. The superstructure was considered as an impermeable boundary in this model, while two fissures were set at the joint edges of the left-line concrete base and the surface layer, simulating the infiltration area of rainwater. The effects of degree of compaction and fines content of the bottom layer due to moisture migration in the high-speed railway substructure were investigated on this model by applying and analyzing the 2013 rainfall data of Hangzhou, China, for a three-year period. The results show that the saturation zones develop in the subgrade, after a three-year period, with the size increasing with the increase in the degree of compaction or fines content due to higher water retention capacity and lower permeability of the soil. Furthermore, the variations of volumetric water content at different depths of the left-fissure profile indicate that as the degree of compaction or fines content increases, the arriving time of the wetting front increases, but the fluctuation amplitude of the volumetric water content after the arrival of the wetting front decreases on the whole. The degree of compaction appears to present a more significant impact on these two parameters. In particular, a threshold value of the degree of compaction between 0.90 and 0.93 is observed, prolonging the arriving time of the wetting front remarkably at a certain elevation. Besides, it takes a longer time for the wetting front to pass through the interface between the surface layer and the bottom layer for each case. From a practical point of view, it will be beneficial to employ drainage methods to drain out the water before it reaches the bottom layer.

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Mehrali, Mohammad, Morteza Esmaeili, and Saeed Mohammadzadeh. "Application of data mining techniques for the investigation of track geometry and stiffness variation." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, no. 5 (April 25, 2019): 439–53. http://dx.doi.org/10.1177/0954409719844885.

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Railway tracks are one of the most important national assets of many countries. The major part of the annual budget of railway companies concerns repairing, improving, and maintaining railway tracks, which is a challenge for railway managers. The logical method of repair and maintenance should take into account all the economic and technical aspects of the problem and proper management of track maintenance—without knowing the factors and parameters responsible for the track failure—quality control methods, and finally, the choice of the appropriate repair methods. Railway track geometry is the main factor that identifies the track behavior and condition. It is based on measuring the geometric parameters of the track determined by the track quality indices. The existing track quality indices mostly represent the geometrical condition of the railway track superstructure. In the past years, the effects of track bed stiffness on the track condition have been investigated. This paper investigates the railway track condition based on the railway track geometry parameters as well as the vertical track stiffness. A method for continuous measurement of track stiffness along a railway line is described and demonstrated. By measuring the track geometry parameters and stiffness, the superstructure and the substructure condition of the railway track are assessed. In addition, the relation between these data is investigated by using data mining techniques such as classification, decision tree, clustering, and dominant wavelength filtering. It is shown that filtering the data based on the dominant wavelength provides the best correlation between the track geometry in the vertical direction and stiffness.

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Berggren, Eric G., Amir M. Kaynia, and Björn Dehlbom. "Identification of substructure properties of railway tracks by dynamic stiffness measurements and simulations." Journal of Sound and Vibration 329, no. 19 (September 2010): 3999–4016. http://dx.doi.org/10.1016/j.jsv.2010.04.015.

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Duong, T. V., Y. J. Cui, A. M. Tang, J. C. Dupla, J. Canou, N. Calon, A. Robinet, B. Chabot, and E. De Laure. "Physical Model for Studying the Migration of Fine Particles in the Railway Substructure." Geotechnical Testing Journal 37, no. 5 (June 3, 2014): 20130145. http://dx.doi.org/10.1520/gtj20130145.

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Liu, Yang, Zhen-dong Qian, Dong Zheng, and Qi-bo Huang. "Evaluation of epoxy asphalt-based concrete substructure for high-speed railway ballastless track." Construction and Building Materials 162 (February 2018): 229–38. http://dx.doi.org/10.1016/j.conbuildmat.2017.12.028.

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Punetha, Piyush, Sanjay Nimbalkar, and Hadi Khabbaz. "Simplified geotechnical rheological model for simulating viscoelasto‐plastic response of ballasted railway substructure." International Journal for Numerical and Analytical Methods in Geomechanics 45, no. 14 (July 6, 2021): 2019–47. http://dx.doi.org/10.1002/nag.3254.

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Pazdera, Lubos, and Jaroslav Smutny. "Evaluation of the Railway Substructure in the Turnout with the Movable Frog by Help of Decomposition." Applied Mechanics and Materials 827 (February 2016): 300–303. http://dx.doi.org/10.4028/www.scientific.net/amm.827.300.

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The aim of the paper is focused on the analysis of the stress measurement in the railway substructure in the turnout with the movable frog prototype designed for a high speed. The evaluations were compared the measurement and the results obtained with theoretical presumptions. The Discrete Wavelet Transformation for the decomposition of the stress measurement and its evaluation is described. Two sections in the turnout with the movable frog were used for the measurement and signal analysis.

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Sadeghi, J., and P. Barati. "Improvements of conventional methods in railway track analysis and design." Canadian Journal of Civil Engineering 37, no. 5 (May 2010): 675–83. http://dx.doi.org/10.1139/l10-010.

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The aim of this research is to improve the accuracy of conventional railway design methods by addressing the main track substructure parameters omitted in the current track design approach. Nonlinear and discrete properties of the track support system were studied and their influence on the calculation of railway design parameters was measured by conducting a field investigation and using finite element analysis. It was demonstrated that wheel loads and accumulative track loading are the key factors influencing nonlinear behavior of the track support system. Mathematical expressions were developed for the impact of the nonlinearity of the track support system based on the track analysis results, and correction factors were established for rail bending moments and rail deflections calculated by current methods. It was shown that the incorporation of these factors improves the accuracy and reliability of the conventional track design method.

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Wang, Hui, Guo Ding, Huan Tang, and Ling Kun Chen. "Numerical Seismic Analysis of Simply-Supported Girder Railway Bridge under High-Speed Train Load." Applied Mechanics and Materials 80-81 (July 2011): 566–70. http://dx.doi.org/10.4028/www.scientific.net/amm.80-81.566.

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Along with rapid development of high-speed railway in many countries, recently research on seismic response of high-speed railway bridge under train load has raised much concern among researchers. The whole bridge finite element model is establish to analysis the seismic responses of simply-supported girder railway bridge subjected to high-speed train in this paper, ICE series high speed vehicle is employed as train live load, the vehicle is simulated by moving spring-mass system, The track irregularities can be obtained by Simpack software, the birdge incluing superstructure and substructure is three-dimensional space beam element, the bottom of piers is proposed consolidated. elastic seismic responses of bridge system and elastic-plastic deformation of piers considering different train speeds are calculated. The calculation results indicate that, seismic responses of bridge system are increase with the increase of train speed and earthquake intensity, and the bottom of piers will step into elastic-plasticity stage under high-level earthquake, the plastic hinges occurred within 1.4 meters of bottom of pier. The numerical results can provide some references for design of high-speed railway bridge.

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Sadri, Mehran, Tao Lu, Arjen Zoeteman, and Michaël Steenbergen. "Railway track design & degradation." MATEC Web of Conferences 211 (2018): 11006. http://dx.doi.org/10.1051/matecconf/201821111006.

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The long-term behaviour of railway track has attracted increasing attention in recent years. Improvements in long-term structural performance reduce demands for maintenance and increase the continuous availability of railway lines. The focus of this paper is on the prediction of the sensitivity of a track design to long-term deterioration in terms of track geometry. According to the state of the art literature, degradation is often investigated using empirical models based on field measurement data. Although a rough maintenance forecast may be made employing empirical models, the predictions are not generic, and the physical processes which govern track degradation under train operation remain unclear. The first aim of this study is to present a mathematical model to elucidate the underlying physics of long-term degradation of railway tracks. The model consists of an infinitely long beam which is periodically supported by equidistantly discrete sleepers and a moving unsprung mass which represents a travelling train. The mechanical energy dissipated in the substructure is proposed to serve as a measure of the track degradation rate. Secondly, parametric studies on energy dissipation are conducted to identify effects of various track design parameters on the susceptibility of the track to degradation, as well as the effect of the train speed. It has been shown that the track/subgrade stiffness is the most influential parameter on degradation whereas other system parameters do influence the degradation rate but at lower magnitudes. The conclusions can be used to optimise the track design in the early stage for better long-term structural performance of railway tracks.

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Pieš, Juraj, and Lenka Môcová. "Application of TDR Test Probe for Determination of Moisture Changes of Railway Substructure Materials." Transportation Research Procedia 40 (2019): 74–81. http://dx.doi.org/10.1016/j.trpro.2019.07.013.

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MORIKAWA, Takashi, Tomoyuki DEURA, Makoto TANABE, and Hiroyuki OKUDA. "1403 A substructure-based transient acoustic analysis of railway structures to the impact load." Proceedings of Design & Systems Conference 2006.16 (2006): 96–99. http://dx.doi.org/10.1299/jsmedsd.2006.16.96.

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Jiang, Hongguang, Xuecheng Bian, Yunmin Chen, and Jie Han. "Impact of Water Level Rise on the Behaviors of Railway Track Structure and Substructure." Transportation Research Record: Journal of the Transportation Research Board 2476, no. 1 (January 2015): 15–22. http://dx.doi.org/10.3141/2476-03.

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Giannakos, Konstantinos. "Design Loads on Railway Substructure: Sensitivity Analysis of the Influence of the Fastening Stiffness." International Journal of Railway 7, no. 2 (June 30, 2014): 46–56. http://dx.doi.org/10.7782/ijr.2014.7.2.46.

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Duong, Trong Vinh, Yu-Jun Cui, Anh Minh Tang, Jean-Claude Dupla, and Nicolas Calon. "Effect of fine particles on the hydraulic behavior of interlayer soil in railway substructure." Canadian Geotechnical Journal 51, no. 7 (July 2014): 735–46. http://dx.doi.org/10.1139/cgj-2013-0170.

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The conventional railway substructure in France was built by emplacing ballast directly on subgrade. Over years of operation, the interpenetration of ballast and subgrade created a soil layer between them. Under different conditions, this naturally formed layer, namely interlayer, can contain different quantities of fine particles, becoming more or less sensitive to changes in water content. As the water content changes are governed by the hydraulic behavior of the interlayer soil, assessing the influence of fine particle content on the hydraulic behavior of interlayer soil is of importance. To this end, the hydraulic behavior of an interlayer soil taken from Sénissiat (near Lyon, France) was investigated using two infiltration columns, a large-scale column equipped with tensiometers and a time domain reflectometer (TDR) for suction and volumetric water content measurements, respectively, and a smaller column equipped with high-capacity tensiometers only. Different fines contents were considered and wetting–drying cycles were applied to the soil specimens. The hydraulic conductivity was determined by applying the instantaneous profile method. The results obtained showed that (i) hysteresis exists for both the soil water retention curve and the hydraulic conductivity changes with suction; (ii) the effect of wetting–drying cycles is insignificant; (iii) adding 10% fine particles to the natural interlayer soil gives rise to changes in the soil water retention curve but does not induce significant changes in hydraulic conductivity; (iv) the unsaturated hydraulic conductivity of interlayer soil with 10% fine particles added is close to that of soil sieved at 2 mm, suggesting that the unsaturated hydraulic conductivity of interlayer soil is mainly governed by fine particles through the suction effect. By contrast, in a saturated state, the value for the interlayer soil with 10% fine particles added was found to be higher, suggesting that in this case the hydraulic conductivity is mainly governed by the water transfer through macropores.

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Shi, Hui, Zujun Yu, Hongmei Shi, and Liqiang Zhu. "Recognition algorithm for the disengagement of cement asphalt mortar based on dynamic responses of vehicles." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 233, no. 3 (August 30, 2018): 270–82. http://dx.doi.org/10.1177/0954409718794018.

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Disengagement of emulsified cement asphalt mortar will increase the dynamic action between the vehicle and the track; as a consequence, the rate of cement asphalt mortar disengagement will increase further. This is a serious threat for the safe operation of high-speed railways and the service life of rail equipment. In this study, a vertical coupled model for the vehicle–China Railway Track System II-type slab track with cement asphalt disengagement was established. The cement asphalt mortar was divided into units in order to simulate the arbitrary length of disengagement. Under different conditions, the effects of the cement asphalt mortar disengagement on the dynamic characteristics of the coupled model were analyzed. The results show that when the length of disengagement exceeds 0.65 m under the condition of horizontal complete disengagement, the dynamic responses of the system increase much sharply than the condition of horizontal partly disengagement. Because of the difficulty in identifying defects in the track substructure, a novel method was proposed to rapidly identify the cement asphalt mortar disengagement based on the dynamic responses of the coupled system and particle swarm optimization–support vector machines. The feature vectors were extracted from the acceleration of the wheelset, which were used as training samples in support vector machines. The classification results show that the recognition algorithm based on the acceleration of the wheelset and support vector machines is effective. The location of the track plate with the cement asphalt mortar disengagement at lengths of 0.65 m, 1.3 m, and 1.95 m can be identified with an acceptable accuracy. The robustness of the proposed algorithm under different vehicle speeds, track spectrums, and signal–noise ratios was verified. Recognition of defects in the track substructure using sensors mounted on in-service vehicles has the potential to provide a valuable tool for ensuring the safe operation of railways and for developing a maintenance plan.

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Journal articles on the topic 'Railway substructure'

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