Development of Condition Assessment Index of Ballast Track Using Ground-Penetrating Radar (GPR)

Abstract

The condition of the ballast is a critical factor affecting the riding quality and the performance of a track. Fouled ballast can accelerate track irregularities, which results in frequent ballast maintenance requirements. Severe fouling of the ballast can lead to track instability, an uncomfortable ride and, in the worst case, a derailment. In this regard, maintenance engineers perform routine track inspections to assess current and future ballast conditions. GPR has been used to assess the thickness and fouling levels of ballast. However, there are no potent procedures or specifications with which to determine the level of fouling. This research aims to develop a GPR analysis method capable of evaluating ballast fouling levels. Four ballast boxes were constructed with various levels of fouling. GPR testing was conducted using a GSSI (Geophysical Survey Systems, Inc.) device (400, 900, 1600 MHz), and a KRRI (Korea Railroad Research Institute) GPR device (500 MHz), which was developed for ballast tracks. The dielectric permittivity, scattering of the depth (thickness) values, signal strength at the ballast boundary, and area of the frequency spectrum were compared against the fouling level. The results show that as the fouling level increases, the former two variables increase while the latter two decrease. On the basis of these observations, a new integrated parameter, called a ballast condition scoring index (BCSI), is suggested. The BCSI was verified using field data. The results show that the BCSI has a strong correlation with the fouling level of the ballast and can be used as a fouling-level-indicating parameter.

Evaluating the Properties of Railway Ballast Using Spectral Analysis of Ground Penetrating Radar Signal Based on Optimized Variational Mode Decomposition

“…The optimization of the number of modes for reaching such a purpose has been investigated [16,17]. Considering the fact that the magnitude of the frequency spectrum of these interferences is often smaller compared to that of valid frequency components, a method based on spectrum envelope has been used to identify the valid frequency components contained in the signal, by which the optimum number of modes of the VMD is determined [12,17]. This method can be expressed by applying the Fourier transform to the GPR signal.…”

“…The possibility of characterizing the ballast stiffness can also be proved. Recent related work can be found in [12].…”

State-of-the-Art Review of Ground Penetrating Radar (GPR) Applications for Railway Ballast Inspection

“…In the past 20 years, researchers worldwide have carried out many in-depth studies on ballast layer inspection along with the improvement in railway inspection technology and equipment [ 60 , 61 , 62 , 63 ]. Some of the technologies have been applied widely in developed countries, such as Europe and the United States.…”

Evaluation of Void Defects behind Tunnel Lining through GPR forward Simulation

“…Ground penetrating radar (GPR) is a technology that uses high-frequency radio electromagnetic waves to perform non-destructive testing of targets in the medium [2][3][4]. Owing to its advantages of high resolution, high efficiency, intuitive results, and non-destructive nature, it is widely used in geological exploration [5], road surface inspection [6], underground pipeline detection [7], archaeological detection [8,9], etc.…”