DT/NIT - Comunicações a congressos e artigos de revistahttp://repositorio.lnec.pt:8080/jspui/handle/123456789/10077922026-04-04T21:00:07Z2026-04-04T21:00:07ZLaboratory investigation and modelling of alternative materials for sub-ballast and formation rehabilitation in a heavy haul railway lineCastro, G.Quispe, J.Motta, R.Moura, E.Costa, R.Bernucci, L.Paixão, A.Fortunato, E.http://repositorio.lnec.pt:8080/jspui/handle/123456789/10188582025-11-27T12:23:45Z2026-01-01T00:00:00ZLaboratory investigation and modelling of alternative materials for sub-ballast and formation rehabilitation in a heavy haul railway line
Castro, G.; Quispe, J.; Motta, R.; Moura, E.; Costa, R.; Bernucci, L.; Paixão, A.; Fortunato, E.
The sub-ballast layer plays a key role in railway track performance, especially under heavy haul conditions such those of the Carajás Railway (EFC) – Brazil, where axle loads are expected to increase to 40 t/axle – a level achieved by few railways globally. Reusing ballast undercutting waste and soils is also critical, given the large volumes generated and the need for proper disposal when reuse is not feasible, in compliance with environmental regulations. This study explores the potential reuse of ballast undercutting waste and soils from the railway track region in sub-ballast applications for heavy-haul railway infrastructure. The goal is to define performance requirements for these alternative sub-ballast materials such as fine silty-sand and lateritic gravelly-sandy soils when compacted using the Rail-mounted Formation Rehabilitation Machine (RFRM) system, which performs multiple rehabilitation functions to meet design standards based on geotechnical parameters. The study includes laboratory testing and numerical modelling to support decision-making regarding the implementation of a RFRM system. Laboratory tests include physical, strength, deformability, compaction, and mechanical behaviour evaluations, some using a developed compaction quality evaluation box-test equipment. Numerical models, calibrated with experimental data, simulate various load, material, and moisture conditions under EFC-specific configurations. The findings concluded that RFRM compaction alone is insufficient for structural performance under 40 t/axle loads unless the formation soil is adequately improved and the previous conditions is guaranteed. The study showed that only lateritic gravelly-sandy soils with suitable geotechnical properties and recycled fouled ballast waste (RFBW) are compatible with RFRM compaction under 40 t/axle loads if treated with cement due to their favorable mineralogy which improved compaction and strength. The study supports the technical and environmental feasibility of reusing fouling ballast waste in sub-ballast layers and offers practical guidance for designing track rehabilitation solutions in heavy-haul contexts. It is recommended that different vibratory plate compaction configurations be analyzed further as well as the resilient and long-term behavior of the investigated materials.
2026-01-01T00:00:00ZBallasted Railway Track–Bridge Transition Zone Monitoring Methods: Recent Developments, Challenges, and ProspectsSiahkouhi, M.Rashidi, M.Miri, A.Ghiasi, A.Paixão, A.http://repositorio.lnec.pt:8080/jspui/handle/123456789/10186122025-07-21T12:49:12Z2025-05-01T00:00:00ZBallasted Railway Track–Bridge Transition Zone Monitoring Methods: Recent Developments, Challenges, and Prospects
Siahkouhi, M.; Rashidi, M.; Miri, A.; Ghiasi, A.; Paixão, A.
Many researchers have studied the dynamic response of ballasted railway track–bridge transition zones (RTBTZs) using different
instrumentation systems. The primary factor contributing to the frequent abnormal dynamic behavior of the RTBTZ is differential settlement
between the earthworks and structures, which is the main target for RTBTZ monitoring. These settlements result in an uneven longitudinal
rail profile in the foundation and embankment soils, and in the upper layers (ballast, subballast, and form layer). This paper provides a
comprehensive review based on potential new technologies for railway infrastructure monitoring. Limitations of different monitoring systems
such as point scale monitoring, the sensor’s long-term performance, different sensors for different output responses, and developing simplified
numerical modeling based on recorded data are discussed. In addition, opportunities to conduct efficient monitoring using a new generation of
sensors such as fiber optic sensors, smart self-sensing sensors, microelectromechanical system (MEMS) sensors, wireless sensing ballast
particles (SmartRock), large-scale sensoring, and remote sensing techniques such as drones and light detection and ranging (LiDar) are
presented
2025-05-01T00:00:00ZDynamic response of ballasted High-Speed Railways: insights from experimental measurements and 3D nonlinear numerical modellingVarandas, J.Paixão, A.Tijera, Á.Crespo-Chacón, I.Estaire, J.Fortunato, E.http://repositorio.lnec.pt:8080/jspui/handle/123456789/10185972025-07-21T12:49:05Z2025-03-01T00:00:00ZDynamic response of ballasted High-Speed Railways: insights from experimental measurements and 3D nonlinear numerical modelling
Varandas, J.; Paixão, A.; Tijera, Á.; Crespo-Chacón, I.; Estaire, J.; Fortunato, E.
High-Speed Railways provide efficient transportation but impose significant dynamic forces on ballasted tracks,
accelerating ballast degradation and increasing maintenance demands. This study aims to understand and
mitigate these effects by investigating the dynamic behavior of ballasted tracks under high-speed train passages.
A field campaign conducted on the Madrid-Barcelona high-speed line involved comprehensive instrumentation
of the Brihuega railway segment to capture dynamic responses. These data were used to calibrate and validate an
advanced three-dimensional numerical model incorporating nonlinear material properties and Coulomb friction
interfaces in an innovative approach. The validated model accurately replicated vertical displacements and
revealed that elastic deformations are primarily confined to the railpads and ballast layer, with minimal impact
on deeper layers. Non-linear Coulomb friction modeling introduced in the ballast/sub-ballast interface enhanced
stress transfer simulations, confirming negligible sliding between these two layers. Decreasing railpad stiffness
from 100 to 60 kN/mm reduced ballast stresses by 10 % and improved load distribution, promoting longer track
service life, while increasing rail displacements and reducing overall track stiffness by 20 %. This study concludes
that railpad stiffness optimization can balance track resilience and degradation mitigation, providing a sustainable approach to infrastructure management. The validated numerical model offers a versatile tool for
simulating complex track behaviors, enabling predictions of unmeasurable parameters like stress paths in the
track bed. Future work should address long-term loading effects and non-uniform track conditions, advancing
track design and maintenance strategies for high-speed rail networks
2025-03-01T00:00:00ZEstudos experimentais sobre a avaliação do potencial da escória de aço como material alternativo para balastro ferroviárioPaixão, A.Fortunato, E.Delgado, B.Fonseca, A.http://repositorio.lnec.pt:8080/jspui/handle/123456789/10185962025-07-21T12:48:54Z2025-05-13T00:00:00ZEstudos experimentais sobre a avaliação do potencial da escória de aço como material alternativo para balastro ferroviário
Paixão, A.; Fortunato, E.; Delgado, B.; Fonseca, A.
Alguns subprodutos industriais, como a escória de forno de arco elétrico (EAF), têm ganhado relevância como alternativa sustentável aos agregados britados naturais, na utilização em balastro ferroviário. Este trabalho apresenta uma síntese de estudos experimentais recentes que avaliaram a resistência mecânica e a evolução morfológica de partículas de escória EAF e o comportamento geomecânico do meio particulado sob cargas cíclicas. Ensaios laboratoriais revelaram que as partículas de escória EAF apresentam elevada angularidade e resistência, mantendo características semelhantes ou superiores às do granito ao longo da degradação por abrasão. Além disso, ensaios triaxiais cíclicos mostraram que este material possui maior resistência à quebra, menor deformação permanente e módulo resiliente superior, especialmente sob condições de cargas elevadas, comuns em vias heavy haul. Estas características indicam que a escória EAF é uma alternativa viável aos materiais tradicionais, contribuindo para a redução de impactos ambientais associados à extração e processamento de rochas naturais. Este trabalho reforça a necessidade de encetar revisões normativas para ampliar a utilização de materiais alternativos na construção ferroviária, promovendo práticas mais sustentáveis.
2025-05-13T00:00:00Z