PSI - Issue 84

Ilaria Catapano et al. / Procedia Structural Integrity 84 (2026) 119–126

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Specifically, after the zero timing, a time gating procedure was applied to remove the signal contribution appearing at a time instant corresponding to the time of flight required for the transmitted signal to propagate from the dipole to the pile and back through the soil along the line of sight (i.e., 10 ns).

Fig. 4. Surface measurement configuration (S). The surface trace of the survey is shown by the black dashed line - left. Raw radargram for a pile depth of 2 m - central. Raw radargram for a pile depth of 3 m - right.

Fig. 5. Borehole measurement configuration (BH). The trace of the survey is shown by the black dashed line - left. Raw radargram for a pile depth of 2 m - central. Raw radargram for a pile depth of 3 m -right.

The tomographic images corresponding to the two considered pile depths are shown in Fig. 6. The figure shows the presence of two anomalies: a common one appearing at about 1.2 m and another one appearing at 2 m and 3 m, respectively. These latter anomalies have different characteristics and suggest the position of the end of the pile.

Fig. 6. Microwave tomographic image for the S measurement configuration referred to a pile depth equal to 2m (left panel) and 3 m (right panel).