Geophysical Survey and Monitoring of Transportation Infrastructure Slopes (TISs): A Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This is an excellent summary, providing a comprehensive overview of all the geophysical techniques applicable to slope stability studies. It is an interesting contribution that deserves publication. Below these lines some potential improvements to the document are indicated.

Sections 3.1, 3.2, and subsequent sections indicate the parameters that can be detected directly or indirectly by each of the geophysical techniques. It would be helpful to summarize this in a table indicating the geophysical method and parameter.

Line 536: 3.3. Ground Based Radar (GBR) - normally we use the term Ground Penetrating Radar, more often.

The database used for Figure 3 appears sparse; for example, regarding GPR, there are only articles mentioned in 2019. There are no references to GPR in other years. For example:

 

2017: https://www.researchgate.net/publication/284228388_Ground_Penetrating_Radar_Investigations_of_Landslides_A_Case_Study_in_a_Landslide_in_Radziszow

2024:

https://www.mdpi.com/2072-4292/16/2/415

and many others

 

In the conclusions or at the end of the results, a summary table is missing for discussion purposes to facilitate the synthesis of the research. For each parameter or aspect of landslides, water, tension cracks, etc., which methods work best? And which ones work worst? What combination of methods is ideal for the main situations that may arise?

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The paper provides a comprehensive review on the application of geophysical methods in slope monitoring for transportation infrastructure, covering current research status, technological trends, and future directions. The theme is well-defined, the structure is clear with strong logical coherence, effectively highlighting both the technical advantages and bottleneck issues of geophysical technologies in slope monitoring.

General comments:

1. The novelty of focusing specifically on transportation infrastructure slopes (rather than general landslides) should be emphasized more clearly in the introduction and conclusion, to better distinguish this review from previous ones.
2. The integration of geophysical monitoring with geotechnical and remote sensing methods is mentioned but could be discussed in more depth, particularly in terms of data fusion strategies and interpretational frameworks.
3. A comparative table summarizing key advantages and limitations across all methods would be beneficial.

Other comments:

4. In Line 141, Figure 1 describes frost-heave cycles as part of slope instability indicators, yet this phenomenon is not explicitly illustrated in the figure. The authors should either add graphical representations of frost-heave cycles or remove related descriptions. Additionally, while trees are clearly shown on the post-landslide slope in Figure b, they are absent in Figure a. Consistency in graphical representation should be improved.
5. Lines 157-161 discuss the impact of cracks on slope deformation, which is redundantly reiterated in Lines 162-168, both mentioning rainfall effects. These two sections should be consolidated. Specifically, the "failure dynamics" mentioned in Line 163 lacks corresponding literature support in subsequent citations (which only reference crack impacts on safety factors). Either add references addressing failure dynamics or modify the description in Line 163.
6. Section 2.1.4 (Line 177) titled "Interactions Between Processes" exclusively discusses frost-heave and wet-dry cycles. This content should either be moved to Section 2.1.1 or expanded to include other process interactions.
7. Methods listed in Figure 2 (Line 242) are not fully addressed in Sections 3.1-3.3: mam and nmsd methods are missing. The das method is categorized as "active" in the figure but described as "passive" in Section 3.2.2. Clarify why das is placed in 3.2.2 rather than 3.2.1, and resolve the active/passive classification discrepancy.
8. In Line 277, Reference 84 is cited twice consecutively when describing IPT applications to TISM, creating redundancy. Integrate the second citation into the preceding sentence.
9. The temporal context in Line 329 (EI applications to TISM) is unclear. Reorganize cited references by: type/method/time/monitoring-type/dimensions or type/method/monitoring-type/time/dimensions. Confirm whether only one canal application exists internationally; if not, expand this section.
10. Table 2 (Line 514) shares the same temporal ambiguity as Table 1 - apply the same reorganization recommendations. Additionally, inconsistent alignment between "Monitoring Type" and "Grid Geometry" columns requires correction.
11. A contradiction exists: Line 537 claims GPR is "the most widely used method in civil engineering," yet Lines 555-556 state its real-world applications remain "sporadic without significant active periods." Resolve this inconsistency. The single-case table in Line 557 should either be integrated into text or expanded with more examples.
12. The standalone section at Line 695 is underdeveloped. Either merge it with the multi-method summary in Line 693 or supplement additional content.
13. Section 9.3 (Line 837) repeatedly mentions machine learning but lacks quantitative performance metrics (e.g., exact efficiency improvements). Add specific performance enhancements and recent evolutionary trends.
14. Section 9.6 (Line 918) claims "UAVs enable real-time monitoring" without addressing technical constraints (e.g., battery life, data transmission latency). Supplement these limitations.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

This paper examines the application of geophysical methods for Transportation Infrastructure Slope Monitoring. Key aspects regarding the geophysical methods most commonly employed are well described. Also final recommendations for future research are detailed and useful.

In my opinion, the idea behind the paper is very useful for those who deal with the decision-making level in transport and infrastructure management. I therefore believe that the paper can be published. My only observation, to give more value to the paper, concerns the opportunity to include some images of geophysical results, in particular regarding the integration of methods. The paper, in fact, is lacking from this point of view and a greater effort by the authors in implementing the graphical part would be very useful. In my opinion, it is enough to select some cases (also mentioned in the text) and show a graphical representation of them.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript was revised by referring to the reviewers' comments.