A Multi-Depth Deflectometer/Global Navigation Satellite System Method for Measuring Concrete Slab Track Deformation
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis paper investigates GNSS based multi-depth deflectometry to characterize slab track layers. While the overall presentation and flow of sections is good, there are a few suggestions for improvement. A section by section review is as follows:
1. Introduction
The authors present a clear background of slab track layer measurement techniques used and how GNSS has been used to enhance such measurements. A good number of relevant references have been cited.
However, the concept of using MDD and GNSS has not been sufficiently motivated. While the authors briefly allude to the need for improved measurements of deformation in slab track layers, it is not clear how why the choice of GNSS + MDD was made and how will this method potentially improve upon these measurements? What are the specific parameters with respect to deformation measurement that this method will help with?
2. Materials and Methods
The authors provide a comprehensive overview of the measurements apparatus, the data acquisition methodology and the GNSS system used.
3. Results analysis
This section is particularly well written. No further changes required
4. Analysis and Discussion
The authors present detailed results through well illustrated graphs and charts. However, a more detailed discussion of how the MDD and GNSS method obtained results compare with other measurement methods will greatly improve the overall strength of the discussion. While the present method has been well illustrated, it is not completely clear what specific advantages and improvements this method provides.
Author Response
The reviewer 1's comments are as follows:
This paper investigates GNSS based multi-depth deflectometry to characterize slab track layers. While the overall presentation and flow of sections is good, there are a few suggestions for improvement. A section by section review is as follows:
1. Introduction
The authors present a clear background of slab track layer measurement techniques used and how GNSS has been used to enhance such measurements. A good number of relevant references have been cited.
However, the concept of using MDD and GNSS has not been sufficiently motivated. While the authors briefly allude to the need for improved measurements of deformation in slab track layers, it is not clear how why the choice of GNSS + MDD was made and how will this method potentially improve upon these measurements? What are the specific parameters with respect to deformation measurement that this method will help with?
Answer) Thank you for the comment. First of all, the paper is fully revised. Specially, abstract and conclusions are rewritten mostly. Please see the following answers and explanations to the review:
- As the reviewer pointed out that concept of using MDD and GNSS is not explained satisfactorily, the paper is fully revised with putting strong points for explaining the new concept of MDD/GNSS in detail with newly added pictures, schematics and new analysis results based on the measurements.
- In addition the reason of why the GNSS/MDD was designed and made is explained in detail in revised version. The revised paper also contains detail explanations about that how the MDD/GNSS system can potentially improve upon the track slab's settlement measurements comparing to classic mechanical MDD which has a fatal drawback of fixed condition (fixity) problem.
- From the measurement analysis of the MDD/GNSS as described in the revised paper, we can get a valuable specific parameters with respect to deformation measurement such as the difference in deformation measurement between MDD positions and absolute settlement of GNSS-rover. From the difference in settlement between position 1 and other positions of the MDD/GNSS, we can analyze that the restoration of the track foundation soil was not enough to provide full contact between the soil and the slab. From simplified assumption about the existence of the void space below the slab, we can get void space (cavity) size with reduced flexural stiffness due to generation of cracks on the slab.
2. Materials and Methods
The authors provide a comprehensive overview of the measurements apparatus, the data acquisition methodology and the GNSS system used.
Answer) Some more schematics, explanations and pictures are added for providing better understanding of the measurements apparatus, the data acquisition methodology and the GNSS system used.
3. Results analysis
This section is particularly well written. No further changes required.
Answer) More results analysis is performed based on the measurement.
4. Analysis and Discussion
The authors present detailed results through well illustrated graphs and charts. However, a more detailed discussion of how the MDD and GNSS method obtained results compare with other measurement methods will greatly improve the overall strength of the discussion. While the present method has been well illustrated, it is not completely clear what specific advantages and improvements this method provides.
Answer) For providing a more detailed discussion for the MDD /GNSS measurement compared with other measurement method, a total station measurement is added and analyzed for comparison. As described above, fatal drawback of the classic MDD is explained in an added schematic diagram. With a combined system of MDD/GNSS, this limitation can be overcome.
Reviewer 2 Report
Comments and Suggestions for AuthorsPlease follow the questions as below:
1. Please polish the Abstract. Please add sentences to explain the meaning and the creative points of the study. Please also check the logic of the abstract. The improvement work should be highlighted.
2. Please check the logic of the Introduction. The background and the necessary of the study should be carefully considered and described. The improvement of the research also should be highlighted.
3. The references should be enriched. The advance of the suggested method should be declared by comparing with other testing method, i.e., optical fiber sensors? Please read the following reference: “Optical fiber sensors for monitoring railway infrastructures: a review towards smart concept. Symmetry, 2021, 13(12), 2251; Strain transfer theory of industrialized optical fiber-based sensors in civil engineering: a review on measurement accuracy, design and calibration. Sensors and Actuators A: Physical, 2019, 285, 414-426”
4. Please highlight the creative work in Introduction. What is the advance of the study?
5. The description on the data collection and analysis should be enriched. Can the data quality be affected by the climate condition? Please explain it.
6. The comparison analysis should be given in Section 4. How about the cost of the study? Please carefully discuss it.
7. Please clearly describe the results: what kind of detail result have been obtained from the study and the major contribution. Please revise the conclusion.
8. Please improve the English in the whole manuscript.
Comments on the Quality of English Language
Please improve the English in the whole manuscript.
Author Response
Please see the following answers and explanations to the review:
The reviewer 2's comments and suggestions are as follows:
Please follow the questions as below:
- Please polish the Abstract. Please add sentences to explain the meaning and the creative points of the study. Please also check the logic of the abstract. The improvement work should be highlighted.
Answer)
Thank you for the comment. First of all, the paper is fully revised and checked by a native English proofreader again. Specially, abstract and conclusion are rewritten fully and logically. Some new sentences are added to explain the meaning and the creative points of the study. Thank you for this comment.
2. Please check the logic of the Introduction. The background and the necessary of the study should be carefully considered and described. The improvement of the research also should be highlighted.
Answer) The introduction is also rewritten to explain the important points of the study. A schematic diagram is also added with new sentences in the introduction to exlain the background and the new concept of the study logically.
3. The references should be enriched. The advance of the suggested method should be declared by comparing with other testing method, i.e., optical fiber sensors? Please read the following reference: “Optical fiber sensors for monitoring railway infrastructures: a review towards smart concept. Symmetry, 2021, 13(12), 2251; Strain transfer theory of industrialized optical fiber-based sensors in civil engineering: a review on measurement accuracy, design and calibration. Sensors and Actuators A: Physical, 2019, 285, 414-426”
Answer) The references are added more and rearranged. Related references which were recommended by the reviewer are added also for introduction of the state of the art optical sensoring technique.
4. Please highlight the creative work in Introduction. What is the advance of the study?
Answer) As described, an improvement and creative idea for the new concept of using MDD/GNSS technique is introduced logically with a brief schematic for illustration. The fixed condition (fixity) problem inherited in classic MDD is overcome by this new concept of MDD/GNSS system.
5. The description on the data collection and analysis should be enriched. Can the data quality be affected by the climate condition? Please explain it.
Answer) The data collection and analysis part of the paper is explained widely and in detail including related equations and sentences. It was briefly explained how the climate condition can affect the GNSS data in euquation to compute coordinates of the GNSS receivers
6. The comparison analysis should be given in Section 4. How about the cost of the study? Please carefully discuss it.
Answer) Total station measurement is added for comparison purpose. However, it is required for total station system to set it up manualy and to measure settlement at the site every time. It is very tedious and troublesome works that can cause erroneous measurement due manual setting. Unfortunately, cost analysis was not handled due to this reason.
7. Please clearly describe the results: what kind of detail result have been obtained from the study and the major contribution. Please revise the conclusion.
Answer) We have rewrite all sentences in analysis chapter and conclusions chapter fully. Please check these again.
8. Please improve the English in the whole manuscript.
Answer) As we described in answers for #1 comments, the manuscript is fully rewritten and an English proofreader made a lot of corrections. We added some sentences more.
Reviewer 3 Report
Comments and Suggestions for AuthorsNon-destructive on-line monitoring is used more and more in responsible constructions, for example, slab track layers for hast trains. Since it affects the safety, as it follows how the railway structure deformed under the load of the train, this study is very important.
However, it seems that the system proposed in this study is too complicated and consists of several elements. It would be good in the introductory part to show the variety of non-destructive/sensors/measuring devices and newer solutions, for example, one of the most promising, simple and easy to implement is the FBG sensor, for example, referring to DOI: 10.1109/PIERS59004.2023.10221310. Especially due to the fact that the FBG sensors are well embedded in concrete structures.
Also, in order to emphasize the innovation of the article, it is recommended to increase the number of reference articles that are not older than 5 years.
The conclusions in the article are too general, so it is recommended to include numerical values ​​or trends from the performed measurements.
In general, the article is interesting, very practical and relevant to these issues, as well as of great practical importance.
Author Response
Thank you for the comment. First of all, the paper is fully revised. Specially, abstract, introduction and conclusion are rewritten mostly. Please see the following answers and explanations to the valuable review:
Reviewer 3's comments and suggestions are as the followings:
1) Non-destructive on-line monitoring is used more and more in responsible constructions, for example, slab track layers for fast trains. Since it affects the safety, as it follows how the railway structure deformed under the load of the train, this study is very important.
However, it seems that the system proposed in this study is too complicated and consists of several elements. It would be good in the introductory part to show the variety of non-destructive/sensors/measuring devices and newer solutions, for example, one of the most promising, simple and easy to implement is the FBG sensor, for example, referring to DOI: 10.1109/PIERS59004.2023.10221310. Especially due to the fact that the FBG sensors are well embedded in concrete structures.
Also, in order to emphasize the innovation of the article, it is recommended to increase the number of reference articles that are not older than 5 years.
Answer) New references are added in the introduction part including newly published articles in this area.
The conclusions in the article are too general, so it is recommended to include numerical values ​​or trends from the performed measurements.
Answer) As described, the conclusion is fully rewritten with new sentences. The analysis part is also fully revised with new analyzed results. Please check these newly added points.
In general, the article is interesting, very practical and relevant to these issues, as well as of great practical importance.
Answer) Thank you so much. We hope this system can contribute much to the development of sensing system in measurement of railway track behavior.
