Ballast fouling evaluation with ground penetrating radar

¹ Nova University of Lisbon, Faculty of Science and Technology, Caparica, Portugal
² National Laboratory for Civil Engineering, Department of Transportation, Lisbon, Portugal
³ Nova University of Lisbon, Faculty of Science and Technology, Department of Civil Engineering, Caparica, Portugal
⁴ LNEC, Department of Transportation, Lisbon, Portugal
⁵ CONSTRUCT - LESE, Faculty of Engineering (FEUP), University of Porto, Portugal

^* Corresponding author: am.marques@campus.fct.unl.pt

Abstract

In the transport infrastructures context, the support layers have a fundamental role in the degradation of the track condition, both in structural aspects and in terms of fouling of the materials that comprise them. Particularly in the field of railway research, ballast is the key element, and its fouling leads to track deterioration. Thus, the main focus of this work is based on the evaluation of the ballast fouling using Ground Penetrating Radar (GPR). In order to determine the applicability of the method on the evaluation of railway characteristics, laboratory samples and measurements carried out in situ, on sections of two railways in operation were analysed. In both cases the different ballast fouling levels were evaluated, using specialized software for this approach (temporal analysis); and then comparing these results with results of a frequency analysis in an automatic calculation program. This paper presents the possibilities of testing with GPR equipment by analysing an electromagnetic wave, in the temporal and frequency domain for the purpose of investigating the level of degradation of a railway track. Some recommendations are also made regarding the use of this method, adding the need for future developments in an attempt to reduce the number of destructive tests still practiced nowadays.