Use of seismic surface wave testing to assess track substructure condition

Sussmann, Theodore R.; Thompson, Hugh B.; Stark, Timothy D.; Wilk, Stephen T.; Ho, Carlton L.

doi:10.1016/j.conbuildmat.2017.02.077

Cited by 25 publications

(17 citation statements)

References 6 publications

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“…Laboratory tests measuring settlement and permanent axial strain also observed that ballast with dry fouling material exhibits similar settlement behavior as clean ballast [5,7], which is in agreement with seismic surface wave measurements [15]. For example, seismic surface wave tests show higher Young's Modulus values for dry fouled ballast than clean ballast because the dry fouling material fills the voids of the ballast yielding a stiffer material [15]. This suggests that dry fouled ballast may not require the same attention as wet fouled ballast unless the area is subject to precipitation.…”

Section: Laboratory Fouled Ballast Testingsupporting

confidence: 64%

“…In general, increasing the moisture content of the fouling material decreases the laboratory [5] and field [15] measured strength and stiffness of the fouled ballast. For example, laboratory ballast box testing show significant increases in ballast settlement as clay-sized fouling material goes from dry to wet [5].…”

Section: Laboratory Fouled Ballast Testingmentioning

confidence: 99%

“…For example, laboratory ballast box testing show significant increases in ballast settlement as clay-sized fouling material goes from dry to wet [5]. Seismic surface wave testing also shows a reduction in Young's Modulus by a factor of two when the same section of fouled ballast was soaked with a fire hose [15].…”

Section: Laboratory Fouled Ballast Testingmentioning

confidence: 99%

See 2 more Smart Citations

Fouled Ballast Definitions and Parameters

Bruzek

Stark

Wilk

et al. 2016

2016 Joint Rail Conference

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Ballast fouling is a problematic track condition that can lead to inadequate ballast performance. Prioritizing remediation of fouled ballast sites is difficult because no relationship between ballast fouling and track performance exists and fouled ballast performance depends on the amount, grain-size, type, plasticity, and moisture content of the fouling material. This paper provides results of an international industry survey on fouled ballast definitions, parameters, limits/standards, and laboratory test results to aid development of a procedure for quantitatively assessing ballast fouling and assessing the ability to: transmit applied train loads to the subgrade, allow drainage, and maintain proper track geometry as required under §213.103.

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Section: Laboratory Fouled Ballast Testingsupporting

confidence: 64%

Section: Laboratory Fouled Ballast Testingmentioning

confidence: 99%

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Fouled Ballast Definitions and Parameters

Bruzek

Stark

Wilk

et al. 2016

2016 Joint Rail Conference

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“…A wide review of non-destructive experimental methods with application to railway track-bed ballast is presented in [20]. The modern seismotomographic methods Spectral Analysis Surface Waves (SASW) and Multichannel Analysis of Surface Waves (MASW) [21], [22], which are used for subgrade diagnostics, are potentially applicable for investigation of ballast layer. Application of non-destructive methods, like ground-penetrating radar for monitoring of transport structures is presented in [23].…”

Section: Introductionmentioning

confidence: 99%

Experimental study of railway ballast consolidation inhomogeneity under vibration loading

et al. 2020

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Railway ballast tamping is one of the cost-expensive renewal and maintenance works of railway superstructure. The quality of ballast consolidation influences its resistance to residual deformations and long-term deterioration of track geometry. The process of ballast compaction along the sleeper under the vibration loading is complex and depends on many factors. The ballast flow processes under the vibration loading can produce both consolidation and un-consolidation of ballast material. The present study is devoted to the experimental investigation of ballast consolidation inhomogeneity. The method of ballast local consolidation measurement is proposed. The method is based on the velocity of impact wave propagation that is measured with device. The application of modern microcontroller and sensor techniques provided simple and reliable multi-point velocity measurements in a ballast layer. That enables well enough spatial resolution of ballast consolidation inhomogeneity. The measurement analysis has shown more than 4 times higher consolidation under the sleeper center than for unconsolidated ballast.

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“…Once a value is assumed for track modulus, the rail vertical deflection profile can be estimated using Equation ((1), and from the rail vertical deflection profile, Yrel can be calculated as the relative vertical deflection between the rail surface and the rail/wheel contact plane at a distance of 1.22 m from the nearest wheel ( Figure 1a) [11,30]. The main shortcoming in this method is that the Winkler model assumes a track modulus is constant along the track while the field data shows that a track modulus stochastically varies along the track [31,32]. Therefore, the estimation of the track modulus from the Yrel measurements needs more advanced numerical models.…”

Section: Winkler Modelmentioning

confidence: 99%

Continuous Evaluation of Track Modulus from a Moving Railcar Using ANN-Based Techniques

Ngoan¹,

Gül²,

Nafari³

2020

Vibration

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Track foundation stiffness (also referred as the track modulus) is one of the main parameters that affect the track performance, and thus, quantifying its magnitudes and variations along the track is widely accepted as a method for evaluating the track condition. In recent decades, the train-mounted vertical track deflection measurement system developed at the University of Nebraska–Lincoln (known as the MRail system) appears as a promising tool to assess track structures over long distances. Numerical methods with different levels of complexity have been proposed to simulate the MRail deflection measurements. These simulations facilitated the investigation and quantification of the relationship between the vertical deflections and the track modulus. In our previous study, finite element models (FEMs) with a stochastically varying track modulus were used for the simulation of the deflection measurements, and the relationships between the statistical properties of the track modulus and deflections were quantified over different track section lengths using curve-fitting approaches. The shortcoming is that decreasing the track section length resulted in a lower accuracy of estimations. In this study, the datasets from the same FEMs are used for the investigations, and the relationship between the measured deflection and track modulus averages and standard deviations are quantified using artificial neural networks (ANNs). Different approaches available for training the ANNs using FEM datasets are discussed. It is shown that the estimation accuracy can be significantly increased by using ANNs, especially when the estimations of track modulus and its variations are required over short track section lengths, ANNs result in more accurate estimations compared to the use of equations from curve-fitting approaches. Results also show that ANNs are effective for the estimations of track modulus even when the noisy datasets are used for training the ANNs.

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Use of seismic surface wave testing to assess track substructure condition

Cited by 25 publications

References 6 publications

Fouled Ballast Definitions and Parameters

Fouled Ballast Definitions and Parameters

Experimental study of railway ballast consolidation inhomogeneity under vibration loading

Continuous Evaluation of Track Modulus from a Moving Railcar Using ANN-Based Techniques

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