Long-term deformation of railway tracks considering train-track interaction and non-linear resilient behaviour of aggregates – a 3D FEM implementation

Varandas, José N.; Paixão, André; Fortunato, Eduardo; Coelho, Bruno Zuada; Hölscher, P.

doi:10.1016/j.compgeo.2020.103712

Cited by 33 publications

(14 citation statements)

References 47 publications

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“…The methodology considered in this study to simulate the longterm behavior of the transition zone consists of a pseudo-time loop approach (Varandas et al, 2014a). The application of such approach to 3D FEM is challenging and a validation of this longterm simulation methodology was presented by the authors in an earlier study (Varandas et al, 2020), focusing on an homogenous foundation scenario. This approach assumes that the effect of the transient response of the train-track system, when trains pass by, can be separated from the long-term plastic deformation behavior of the track bed aggregates and subsequent settlement development, caused by the accumulation of cyclic loads from traffic.…”

Section: Long-term Simulation Methodologymentioning

confidence: 99%

“…As described in detail by Varandas et al (2020), this iterative approach comprises up to seven steps in each iteration (iter), as depicted in Figure 4. The process starts with a static calculation of an initial state (A) to determine the initial stress field caused by the geostatic load, σ geo .…”

Section: Long-term Simulation Methodologymentioning

confidence: 99%

“…Following previous calibration works by the research team (Varandas et al, 2020), the parameters of the ballast high-cycle strain accumulation model that were considered for this study are the following:…”

Section: Ballast High-cycle Strain Accumulation Modelmentioning

confidence: 99%

“…To obtain more insight into the long-term behavior of transition zones in ballasted tracks and considering the available tools and the computational challenging task, the authors adopted a full tri-dimensional FEM approach (Varandas et al, 2020) that has the following main features: 1) it incorporates a robust high-cycle strain accumulation model of the ballast layer based on the classical plasticity theory that considers both the frictional and volumetric degradation mechanisms (Suiker and de Borst, 2003); 2) it considers the dynamic vehicle-track interaction using a non-linear hertzian contact formulation, the sleeper-ballast interaction using a bilinear formulation and the consequent non-linearity that results from the vehicles running on uneven longitudinal track profiles; 3) it accounts for the non-linear resilient behavior of the ballast layer, which is critical to adequately evaluate the stress levels that, in turn, are required as inputs for the strain accumulation model.…”

Section: Introductionmentioning

confidence: 99%

“…a FIGURE 4 | Main steps implemented in Pegasus for the calculation of the track settlements. Each complete iteration (iter) is separated in six or seven steps(Varandas et al, 2020).…”

mentioning

confidence: 99%

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Dynamic Behavior in Transition Zones and Long-Term Railway Track Performance

Paixão

Varandas

Fortunato

2021

Front. Built Environ.

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Transition zones between embankments and bridges or tunnels are examples of critical assets of the railway infrastructure. These locations often exhibit higher degradations rates, mostly due to the development of differential settlements, which amplify the dynamic train-track interaction, thus further accelerating the development of settlements and deteriorating track components and vehicles. Despite the technical and scientific interest in predicting the long-term behavior of transition zones, few studies have been able to develop a robust approach that could accurately simulate this complex structural response. To address this topic, this work presents a three-dimensional finite element (3D FEM) approach to simulate the long-term behavior of railway tracks at transition zones. The approach considers both plastic deformation of the ballast layer using a high-cycle strain accumulation model and the non-linearity of the dynamic vehicle-track interaction that results from the evolution of the deformed states of the track itself. The results shed some light into the behavior of transition zones and evidence the complex long-term response of this structures and its interdependency with the transient response of the train-track interaction. Aspects that are critical when assessing the performance of these systems are analyzed in detail, which might be of relevance for researchers and practitioners in the design, construction, and maintenance processes.

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Section: Long-term Simulation Methodologymentioning

confidence: 99%

Section: Long-term Simulation Methodologymentioning

confidence: 99%

Section: Ballast High-cycle Strain Accumulation Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…a FIGURE 4 | Main steps implemented in Pegasus for the calculation of the track settlements. Each complete iteration (iter) is separated in six or seven steps(Varandas et al, 2020).…”

mentioning

confidence: 99%

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Dynamic Behavior in Transition Zones and Long-Term Railway Track Performance

Paixão

Varandas

Fortunato

2021

Front. Built Environ.

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Simplified geotechnical rheological model for simulating viscoelasto‐plastic response of ballasted railway substructure

Punetha

Nimbalkar

Khabbaz

2021

Num Anal Meth Geomechanics

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A proper understanding of the mechanical behaviour of the substructure layers is crucial for optimising the design and performance of a ballasted railway track. The recent advent of high‐speed trains and heavy haul freight wagons has heightened this need more than ever. The accurate prediction of the long‐term performance of the railway tracks under increased speed and loads still remains an intriguing challenge for researchers and design engineers. In this context, the present paper proposes a simplified geotechnical rheological model to evaluate the viscoelasto‐plastic response of the track substructure layers. The proposed approach combines plastic slider, elastic springs and viscous dampers to predict the transient response during a train passage, and the irrecoverable deformation accumulated in the track substructure over an operational period. The model simulates tri‐layered substructure (ballast, subballast, and subgrade) in comparison with existing rheological approaches employing either single or dual‐layered substructure. The model is validated against the field data published in the literature. An acceptable agreement between the predicted results and the field data verifies the accuracy of the model. Parametric investigations are conducted to study the influence of train and track parameters on the cumulative track deformation. The results demonstrate the enhanced capability of the rheological model to adequately capture the crucial effects of axle load, train speed and thickness of granular layers on the accumulation of track settlement. The proposed method can provide an effective tool for the practising engineers for quick prediction of changes to the geometry of railway tracks over their operational periods.

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Detecting Dangerous Places in a Continuous Welded Rail Track Taking into Consideration Trains Impact

Kornienko

Zamorin

2022

International Scientific Siberian Transport Forum TransSiberia - 2021

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Long-term deformation of railway tracks considering train-track interaction and non-linear resilient behaviour of aggregates – a 3D FEM implementation

Cited by 33 publications

References 47 publications

Dynamic Behavior in Transition Zones and Long-Term Railway Track Performance

Dynamic Behavior in Transition Zones and Long-Term Railway Track Performance

Simplified geotechnical rheological model for simulating viscoelasto‐plastic response of ballasted railway substructure

Detecting Dangerous Places in a Continuous Welded Rail Track Taking into Consideration Trains Impact

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