Implementation of spectral analysis of surface waves approach for characterization of railway track substructures

Quantification of the Mechanized Ballast Cleaning Process Efficiency Using GPR Technology

“…The estimated EMWV (cm/ns) value in the surveyed material was then entered as an initial input. Dependent on this value, the maximum thickness of the ballast layer, from where the reflected pulse could be recorded, was computed preliminarily using Equation (2). The number of samples per trace was set to 512 and 1024.…”

“…Qian et al [1] developed a non-intrusive technique, as a fundamental element of Railroad Infrastructure 4.0, to determine the distribution of ballast pressure under the sleeper using the bending moment profile across the concrete sleeper, and the estimated rail seat loads as inputs, to compute the state of ballast support employing an optimization algorithm. Tamrakar et al [2] used spectral analysis of surface wave technique (SASW) to estimate the mechanical properties of ballast and evaluated the complications in the implementation of the SASW method for characterization of ballast and foundation soil or subgrade. Mvelase et al [3] employed laser technology to examine the influence of railway ballast roundness on shear strength resulting in improved in situ quality evaluations in regards to ballast layer maintenance or replacement.…”

Ground track response behaviour induced by train speed using seismic wave method

“…Basically, the shear wave velocity of track is crucial to be measured to prevent the uncertainties during analysis the track performance and safety otherwise the measurement of track modulus and shear strength will be estimated. Even though the seismic method frequently used as rapid assessment in monitoring soil profile at subsurface area, Tamrakar et al [8] and Sussmann et al [9] found the difficulties in assessing railway track when using spectral analysis of surface wave (SASW) due to presence of ties and rail over the tracks including large variation in ballast and subgrade characteristics. In seismic surface wave testing, geophone and accelerometer are commonly used as receiver wave signal transition.…”

“…However, in ballast and subgrade characterization, high frequency accelerometer is essential to receive wide range frequency signal especially for deeper strata. Unlike geophone which strongly discouraged to be used in subsurface determination/analysis due to their mass [8] and lack/ inadequate high frequency response to characterize ballast [10]. Besides, according to Tamrakar et al [8] mounting effectiveness can influence the quality acquisition data.…”

“…Unlike geophone which strongly discouraged to be used in subsurface determination/analysis due to their mass [8] and lack/ inadequate high frequency response to characterize ballast [10]. Besides, according to Tamrakar et al [8] mounting effectiveness can influence the quality acquisition data. Major challenge of past study to develop a viable method for fastening or anchoring the mounted accelerometer to detect the generated surface waves and comprehend the effect of wave propagation on track structure [10,11].…”