Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper presents a non-destructive testing method for bored piles in plinth foundations using ground-penetrating radar (GPR). It elaborates on the experimental testing process, the GPR configuration employed, and the data processing methods. The detected anomalies in the bored piles are presented. The innovative aspect of this study lies in the use of BSEF combined with B-scan to synthesize perimeter tomography. The article provides a clear explanation of the working principles of GPR and the corresponding formulas. I think it can be acceptd after fixing some minor issues.

1. Ambiguous numerical values in the last line of the abstract should be clarified.
2. Consistent formatting for figures and tables is required.

Author Response

• Ambiguous numerical values in the last line of the abstract should be clarified.

reponse: corrected text

• Consistent formatting for figures and tables is required

reponse: revised figures and tables

Thanks for your review

Reviewer 2 Report

Comments and Suggestions for Authors

This study presents a geophysical investigation aimed at detecting bored piles concealed beneath massive plinth foundations using ground penetrating radar. While the study documents an applied case of GPR investigation beneath a deep and massive plinth foundation, its innovation is limited and primarily lies in the uncommon field configuration rather than in methodological or theoretical advances.  As such, the work may be better suited for a technical bulletin, case study journal, or engineering report outlet rather than a high-impact scientific journal.
(1) The introduction does not adequately justify the novelty or relevance of the study. A more comprehensive and critical survey of recent research is needed to establish the scientific context and motivate the chosen methodology.
(2) To meet academic standards, the paper should clearly distinguish between Discussion (interpretation, comparison, limitations, implications) and Conclusion (summary of findings, final remarks, outlook).
(3) The manuscript primarily offers a descriptive account of the survey procedures, field configuration, and data acquisition steps, it falls short in providing deeper scientific analysis or interpretation of the results.

Author Response

1) The introduction does not adequately justify the novelty or relevance of the study. A more comprehensive and critical survey of recent research is needed to establish the scientific context and motivate the chosen methodology.

response: introduction update
(2) To meet academic standards, the paper should clearly distinguish between Discussion (interpretation, comparison, limitations, implications) and Conclusion (summary of findings, final remarks, outlook).

response: article update
(3) The manuscript primarily offers a descriptive account of the survey procedures, field configuration, and data acquisition steps, it falls short in providing deeper scientific analysis or interpretation of the results.

response: article update

Thanks for your review

Reviewer 3 Report

Comments and Suggestions for Authors

Dear author,

thank you for this nice case study, which is really interesting and not a common investigation. It is worth presenting this study in a publication and I appreciate your effort.

The measurement work done is very sound and as I understood the processing also.

Unfortunately I did not understand all paragraphs. The paper would definitely be much easier to read after proof reading by a native speaker. I already marked some paragraphs that were not understandable for me. It would be good if you could try to rephrase them. Sometimes the sentences are very long. It would also be good to shorten them or divide them into more sentences. I attach a pdf with my comments.

Comments for author File: Comments.pdf

Author Response

Thank you for your review.

I've attached a PDF of the update manuscript, highlighting your suggested corrections so you can easily check them.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The authors present an improved GPR-based approach for deep-foundation pile detection, covering data acquisition, velocity tomography, and back-scattered field analysis. The work is substantial; however, the paper suffers from limited methodological novelty and insufficient experimental validation. Specifically, it lacks an essential innovation tailored to the unique challenges of detecting deeply buried piles, and only a single case study (Liscione bridge pedestal) is provided. Comparative tests across different soil types and pile diameters are absent, undermining reliability. Detailed comments are as follows:

1. The opening sentence of the abstract lists various GPR applications (rebar detection, concrete characterization, etc.) but fails to focus on the central problem—“deep-foundation pile detection”—and its specific difficulties.
2. The phrase “indirect detection difficulties” in Chapter 1 is vague. Please specify technical challenges (e.g., electromagnetic shielding by pedestal concrete) and highlight the paper’s breakthrough (e.g., innovative lateral scanning via excavation faces).
3. Line 89 mentions the need to study signal attributes for low-contrast targets, yet no concrete method (e.g., Hilbert transform for instantaneous amplitude/phase extraction) is given. Also, explain why broadband antennas (line 69) were chosen instead of single-frequency ones, and clarify the trade-off.
4. Section 2.2 describes multi-frequency antennas (200/300/500 MHz) without stating their operational strategy: simultaneous emission, sequential measurements, or data fusion scheme.
5. Section 2.4, on the bistatic configuration, omits the antenna spacing (which affects illumination and resolution). The phrase “same origin point” contradicts the placement of Tx/Rx on opposite trench walls; a schematic is necessary.
6. Chapter 3 lacks a discussion of method limitations, especially the applicability boundary of BSEF in low-contrast media (e.g., when ε difference < 3).
7. Section 4 claims BSEF superiority but offers no comparative evidence. Lines 276–278 assert that “azimuthal tomography successfully identifies anomalies,” yet no comparison with conventional methods (e.g., common-offset scanning) is provided.

 

Author Response

1. The opening sentence of the abstract lists various GPR applications (rebar detection, concrete characterization, etc.) but fails to focus on the central problem—“deep-foundation pile detection”—and its specific difficulties.

response: ok, abstract update

1. The phrase “indirect detection difficulties” in Chapter 1 is vague. Please specify technical challenges (e.g., electromagnetic shielding by pedestal concrete) and highlight the paper’s breakthrough (e.g., innovative lateral scanning via excavation faces).

response: ok inserted in text (fig 1)

1. Line 89 mentions the need to study signal attributes for low-contrast targets, yet no concrete method (e.g., Hilbert transform for instantaneous amplitude/phase extraction) is given.

response: ok inserted line 150

1. Also, explain why broadband antennas (line 69) were chosen instead of single-frequency ones, and clarify the trade-off.

response: ok inserted in text (eq. 8)

1. Section 2.2 describes multi-frequency antennas (200/300/500 MHz) without stating their operational strategy: simultaneous emission, sequential measurements, or data fusion scheme.

response: ok update in paragraph 2.4 (relevant to B-scan acquisitions)

1. Section 2.4, on the bistatic configuration, omits the antenna spacing (which affects illumination and resolution).

response: update at the beginning of paragraph 2.4 with list of separations

1. The phrase “same origin point” contradicts the placement of Tx/Rx on opposite trench walls; a schematic is necessary.

response: clarified in the text update both at the beginning of the paragraph and with the figure

 

1. Chapter 3 lacks a discussion of method limitations, especially the applicability boundary of BSEF in low-contrast media (e.g., when ε difference < 3).

response: clarified in the text update and included in the bsef method limits

1. Section 4 claims BSEF superiority but offers no comparative evidence. Lines 276–278 assert that “azimuthal tomography successfully identifies anomalies,” yet no comparison with conventional methods (e.g., common-offset scanning) is provided.

response: ok, test update and new figures inserted to develop these requirements

Thanks for your review

Round 2

Reviewer 4 Report

Comments and Suggestions for Authors

The authors have addressed all my concerns and the current quality can be published in journal of remote sensing.

Author Response

I've fixed the references between figures and text. Each figure is referenced in the text. I've reformatted the figures and improved the layout compared to before. I corrected some English spelling and grammar mistakes. Thank you for your review.