Ground Penetrating Radar Simulation for Estimating Track Bed Thickness and Material Characterization.

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Date

2024-06

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Addis Ababa University

Abstract

One of the most important substructures is the railway, which is a vital component of a country and demands significant investment. A railway track bed's surface layer is a multilayered structure. Three sublayers are often present: the top surface layer, known as ballast, the intermediate surface layer, sometimes known as sub-ballast, and the subsequent surface layer (Subgrade). An essential instrument for evaluating the status of railroad track beds is ground penetrating radar (GPR), which makes it possible to estimate the thickness of the track bed and classify the materials. . However, accurate interpretation of GPR data is challenged by the resolution limitations of GPR and the similar permittivity of track material sublayers. This study aims to verify and optimize GPR simulations using GprMax to improve the accuracy of determining track bed thickness and characterizing materials within railway infrastructure. The research methodology involves simulating various parametric conditions such as ballast fouling, variable track bed layer thicknesses, and different moisture content scenarios (wet and dry conditions). A structured approach is employed, starting with the establishment of study area characteristics, followed by configuring the geometry and materials in GprMax. The appropriate GPR antenna and frequency settings are then defined, and simulation settings and boundary conditions are established to ensure numerical stability and accuracy. Simulations are conducted, and the results are analyzed through post-processing techniques to examine the impact of parameter changes on GPR responses. Visualization capabilities of GprMax are utilized to compare simulated GPR scans under different conditions. The simulated results are validated against known field data or theoretical expectations to verify the simulation setup and parameters. The study concludes that GPR simulations in GprMax can effectively model the impact of ballast fouling, layer thickness variations, and moisture content on GPR signals. These simulations provide valuable insights into improving GPR data interpretation, promoting cost-effective maintenance strategies by reducing the need for extensive physical testing. This research contributes to enhancing the reliability and efficiency of GPR in railway infrastructure maintenance.

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Keywords

Ground Penetrating Radar (GPR), Track bed, GprMax software, Post-processing and Numerical modeling (Simulation).

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