Combined Migrations and Time-Depth Conversions in GPR Prospecting: Application to Reinforced Concrete

Abstract

In this paper, we propose the combination of different migration results achieved on the same data in order to account for different values of the propagation velocities of the electromagnetic waves within the considered Ground Penetrating Radar (GPR) profile. These different values can be the result of a variable lithological composition or (more probably for short Bscans) the results of different moisture levels, or both. Here, we separately consider the two cases of horizontal or vertical variability of the propagation velocity with a transition zone between two zones with constant propagation velocity. Moreover, we also propose a time-depth conversion accounting for these different values of the propagation velocity along the considered GPR Bscan. The method is applied to real data gathered in the field with regard to a concrete coverage containing liner layers.

A posteriori insertion of information for focusing and time–depth conversion of ground‐penetrating radar data

“…However, a mere joining of these two pieces would result into a visible seam effect in correspondence of I 1 . Therefore, a linear vertical transition along a belt centred on I 1 is introduced too, which erases this effect (Persico & Morelli, 2020, 2021).…”

“…Therefore, it makes the use of information heuristically deduced a posteriori, that is after a first basic solution of the problem. This strategy was already applied on real data gathered in the field (Persico & Morelli, 2020, 2021), and it provided fully reasonable results, even if no excavation was possible at the moment.…”

“…‘Combined migration and combined time–depth conversion’ section briefly explains the concepts of the combined migration and time–depth conversion. This is proposed for the sake of self‐consistency, but for more details, the interested reader is referred to Persico and Morelli (2020,2021). Then, the above listed scenarios will be sequentially considered.…”

Finetuning ground penetrating radar velocity analysis from hyperbola fitting using migration

“…Velocity analysis using migration is not a new method but, to date, rarely used. Persico and Morelli (2020) used migration to detect variations in propagation velocity both horizontally and vertically in the GPR profile in reinforced concrete. Based on detected velocity variations, they proposed a time‐depth conversion that accounts for the velocity variations.…”

2D Wavelet Decomposition and F-K Migration for Identifying Fractured Rock Areas Using Ground Penetrating Radar

“…Besides, clutter also affects the migration results [41]. Therefore, some researchers complemented strategies to enhance the migration results (e.g., [42,43]). A typical migration approach is F-K migration, which operates frequency and wavenumber in the Fourier domain and then inverses to the time domain [44].…”