Railway Ballast Monitoring by GPR: A Test Site Investigation

Abstract

Effective maintenance of railways requires a comprehensive assessment of the actual condition of the construction materials involved. In this regard, Ground-Penetrating Radar (GPR) stands as a viable alternative to the invasive and time-consuming traditional techniques for the inspection of these infrastructures. This work reports the experimental activities carried out on a test-site area within a railway depot in Rome, Italy. To this purpose, a 30 m-long railway section was divided into 10 sub-sections reproducing different various physical and structural conditions of the track-bed. In more detail, combinations of varying scenarios of fragmentation and fouling of the ballast were reproduced. The set-up was then investigated using different multi-frequency GPR horn antenna systems. The effects of the different physical conditions of ballast on the electromagnetic response of the material were analysed for each scenario using time-and frequencydomain signal processing techniques. Parallel to this, modelling was provided to estimate fouling content. Interpretation of results has proven the viability of the GPR method in detecting signs of decay at the network level, thereby proving this technique to be worthy of implementation in asset management systems.

GPR Data Collection and Processing Strategies for Railway Ballast Evaluation

“…Similar results have been reported more recently in [16]. On the base of an experimental activity carried out at the testsite scale level, authors confirm the relationship between the above frequency-based occurrences and high-frequency surveys (i.e.…”

“…Amongst the others, Methods for the detection of fouling on ballasted railway track-beds based on time-frequency approaches are presented in [5,15,16]. The time-dependent frequency properties can be inferred by decomposition of the signal using dedicated functions, in both time and frequency domains.…”

“…In turn, the water retained by the fouling material heavily affects its dielectric properties. In this regard, the STFT algorithm was performed in [16] on GPR traces collected on a railway track-bed at varying fouling rates and water content levels, demonstrating the viability of the method in assessing the ballast fouling under different wet conditions.…”

Mapping the Physical and Dielectric Properties of Layered Soil Using Short-Time Matrix Pencil Method-Based Ground-Penetrating Radar

“…Other approaches using the frequency spectra of the received GPR signals were proposed in order to characterize the target [15]- [17]. Several attempts for railway-ballast monitoring and assessment have been based on the frequency-based evaluation of porous media [16], [18]- [21]. In [16], the magnitude spectrum was used as a feature and then classified by using a support vector machine (SVM) for railway-ballast assessment.…”

“…In [16], the magnitude spectrum was used as a feature and then classified by using a support vector machine (SVM) for railway-ballast assessment. The effects of the different physical conditions of ballast on the electromagnetic response of the material were analyzed for each scenario using time-and frequency-domain signal processing techniques [18]. In 2017, the assessment of geometric features of the ballast aggregates within a railway track-bed was proposed [20].…”