A 2.5D finite element approach for predicting ground vibrations generated by vertical track irregularities

Bian, Xuecheng; Chao, Chen; Jin, Wan-feng; Chen, Yunmin

doi:10.1631/jzus.a11gt012

Cited by 40 publications

(3 citation statements)

References 17 publications

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“…Railways built in mountainous regions often require the use of retaining walls [28]. When a retaining wall is introduced as part of the track infrastructure to retain the embankment fill, its dynamic response to train passage should also be considered [29], particularly for heavy-haul rail lines. However, long-term railway operations may be adversely affected by the additional deformation on the roadbed caused by retaining structures [30].…”

Section: Introductionmentioning

confidence: 99%

An Analysis of Dynamics of Retaining Wall Supported Embankments: Towards More Sustainable Railway Designs

Feng,

Luo,

Lyu

et al. 2023

Sustainability

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Retaining walls are structures used to retain earth materials on a slope. Typically, they are designed for static loads, but for highway and railway infrastructures, vehicle-induced dynamic responses are also relevant. Therefore, retaining wall structures are often designed with a factor of safety that is higher than necessary, because it can be challenging to quantify the magnitude of expected dynamic stresses during the design stage. This unnecessary increase in material usage reduces the sustainability of the infrastructures. To improve railway retaining wall sustainability, this paper presents the results from a field monitoring campaign on a heavy-haul rail line with a retaining wall, studying the dynamics induced in response to 30-ton axle load trains running at speeds of between 5 km/h and 100 km/h. The site comprises an earth embankment supported by a gravity retaining wall, with accelerometers on the sleepers, roadbed surface, and retaining wall, velocity sensors on the roadbed, and strain gauges on the rail web to record wheel–rail forces. The vibration intensities collected from various locations are processed to explore the peak particle velocities, maximum transient vibration values, and one-third octave band spectrums. Two transfer functions define the vibration transmission characteristics and attenuation of vibration amplitude along the propagation path. The long-term dynamic stability of the track formation is studied using dynamic shear strain derived from the effective velocity. The peaks of observed contact forces and vibrations are statistically analyzed to assess the impact of train speed on the dynamic behavior of the infrastructure system. Next, a 3D numerical model expresses the maximum stress and displacements on the roadbed surface as a function of train speed. The model evaluates the earth pressures at rest and vehicle-induced additional earth pressures and horizontal wall movement. The investigation provides new insights into the behavior of railway track retaining walls under train loading, and the field data are freely available for other researchers to download. The findings could facilitate the design of more sustainable retaining walls in the future.

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Section: Introductionmentioning

confidence: 99%

An Analysis of Dynamics of Retaining Wall Supported Embankments: Towards More Sustainable Railway Designs

Feng,

Luo,

Lyu

et al. 2023

Sustainability

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“…However, some published studies have revealed that dynamic characteristics of subgrade systems subjected to mov-ing train loads will violate the corresponding assumptions in the plane strain condition, although the cross-section of the subgrade is considered invariant along the direction of the moving load. The 2.5D finite element method was introduced by Yang et al [17] for understanding the dynamic responses in subgrade systems, and it has been increasingly used with the advantages of high efficiency, high accuracy and the ability to consider complex sections [10,[17][18][19][20][21], compared with a higher demand for meshing by employing a 3D finite element model. The accuracy of simulated results obtained using the 2.5D approach depends on several factors, including the number and corresponding size of meshes, resolution in the time-frequency domain and wave adsorption boundary.…”

Section: Brief Introduction Of Basic Theorymentioning

confidence: 99%

“…The dynamic responses on each node of the mesh element in the time-space domain (x,y,z,t) can be calculated from the frequency-wavenumber domain (x,y,ξz,ω) using a dual Fourier transform. Any details on corresponding basic theories and equations can be found in the previous literature as mentioned above [17][18][19][20][21]. The present 2.5D finite element procedure was written using the commercial software MAT-LAB R2019b.…”

Section: Brief Introduction Of Basic Theorymentioning

confidence: 99%

Effects of the Ground Reinforcement on the Dynamic Behaviors of Compacted Loess Embankment with Ballasted Track

Wei

Wang

et al. 2023

Buildings

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An embankment is needed to satisfy the requirements for the longitudinal slope of railway lines, and ground reinforcement is also generally required in loess regions. The present study attempted to understand the effects of different ground reinforcement measures on the dynamic characteristics of a track–embankment–ground system. To this end, the critical speeds and the distributions of dynamic stress and environmental vibration were analyzed using a 2.5D finite element method. Three typical ground reinforcements, including dynamic compaction ground (DCG), soil–cement compacted pile composite ground (SCG) and CFG pile composite ground (CFGG), were used. The results indicate that the train speed (critical speed I) at which the maximum vertical displacement of the track occurs is universally higher than that (critical speed II) at which the wave propagation phenomenon occurs. The lower boundary limit of the peak region in the dispersion relationship can be selected as the reference value of critical speed II. Moreover, the values of critical speed I obtained using the DCG, SCG and CFGG models were around 92, 105 and 127 m/s, respectively. For critical speed II, the values were 75, 80 and 115 m/s. Once the train speed exceeded critical speed II, the vibration was confined to the embankment in the CFGG model, as evidenced by the isolation of the wave propagation from the embankment to the ground as well as the increasing dynamic stress in the embankment. After reinforcement, the dynamic stress, dynamic influence depth (DID), critical speed and resonant frequency increased. Additionally, the DID stayed around the 3–6 m range at all speeds.

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Vibration Isolation of In-filled Trench in Layered Ground Under High-Speed Train Load with Track Irregularity

Zhang

Gao

Song

2017

Environmental Vibrations and Transportation Geodynamics

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A 2.5D finite element approach for predicting ground vibrations generated by vertical track irregularities

Cited by 40 publications

References 17 publications

An Analysis of Dynamics of Retaining Wall Supported Embankments: Towards More Sustainable Railway Designs

An Analysis of Dynamics of Retaining Wall Supported Embankments: Towards More Sustainable Railway Designs

Effects of the Ground Reinforcement on the Dynamic Behaviors of Compacted Loess Embankment with Ballasted Track

Vibration Isolation of In-filled Trench in Layered Ground Under High-Speed Train Load with Track Irregularity

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