Stresses in Saturated and Unsaturated Subgrade Layer Induced by Railway Track Vibration
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript refers to the actual problem of railway ballast bed/subgrade failures due to soil liquefaction. However, the manuscript methodology and description have serious flaws that should be improved. The literature review is mostly directed at the studies of the material effects and loading caused by wheel-rail interaction. However, another source of the low-frequency vibration and impacts is not mentioned – sleeper voids (unsupported sleepers). They have different mechanism than the geometrical irregularities – impact due to void closing. The subgrade liquefaction under vibration loading is almost always preceded and accompanied with sleeper voids. Please refer to the studies of the sleeper–ballast dynamic impact and residual settlements accumulation in zones with unsupported sleepers, identification of sleeper support conditions using a mechanical model supported data-driven approach, experimental investigation of the dynamic behavior of railway track with sleeper voids, etc.
The other remarks:
1) The 4Hz is not really vibration loading. It corresponds rather to cyclic loading that causes no dynamic effects. The term “Track Vibration” in the title and in the text should be correspondingly replaced.
2) What was the reason for value of applied load values are 15, 25, and 35 kN? Was the model scaled?
3) Please present the diagrams of the loadings in time.
4) “Figure 6. Linear Variable Differential Transformer (LVDT).” Would be better to write “Track deflection measurement using LVDT”
5) Please present the diagrams of the deflections (LVDT) in time.
6) The 20 diagrams of one type with only 3 x-points could be grouped together and with 2 columns.
Author Response
Response to comments is included in the attached file
Author Response File: 
Author Response.doc
Reviewer 2 Report
Comments and Suggestions for AuthorsThe article provides a commentary on the results of a laboratory analysis focused on the influence of the degree of saturation of the subgrade when the rail grid is loaded with different forces and frequencies. The influence of different methods of achieving a given degree of saturation is also described. The article thus brings very useful insights that can be used within the professional community.
Nevertheless, I have the following comments on the content of the article:
1. Row 154-156: The given data on the optimal grain size in relation to the dimension of the geogrid aperture is inaccurate and, since 2006, this data has been improved in the professional community based on a number of follow-up professional articles.
2. Fig. 1: I recommend presenting the graph in the form where the smallest grain is on the left and the largest on the right.
3. Fig 2: It can be seen from the left picture that the geogrid had square apertures while in the right picture they are rectangular. This is desirable to clarify.
4. Row 328: The unit "gm" appears to be wrong here.
5. Row 396: Here it is stated that the maximum possible frequency of the device is 2 Hz, while in the framework of the experiments results were found even at a frequency of 4 Hz. This is desirable to explain.
6. Row 485 and 488: The reference to Figure 11 is apparently erroneous. This image is probably missing from the article.
7. Row 538: Complete the unit for the specified frequency values.
8. Row 551: "Figures 12 and 14" should be "Figures 12 to 14".
9. Row 555: The given abbreviation WC is not related to Figure 12.
10. Row 557: The text "Figure 12 displays" should probably be "Figure 13 displays".
11. Fig 12-17: Explanation of the abbreviations WT, DT, WC, DC, V is missing. I recommend additions to the label under the graphs.
12. Row 577: The text "that Figure 17" should probably be "that Figure 15".
13. Row 579: The sentence “Furthemore …” should refer to Figure 17.
14. Row 592-594: The stated conclusions cannot be verified in any of the depicted graphs.
15. Row 597: There is a discrepancy in the numbers here, as "thirty-three figures" does not match the number of figures 18 to 38.
16. Row 601-602: The conclusion "the exception of the case of a load amplitude of 15 kN" should be expanded, as it is the same with an amplitude of 35 kN.
17. Row 627: "Figure 20" should probably be "Figure 21". Furthermore, the term "Senior 60%" is apparently erroneous and should be replaced by "Saturation 60%" (same line 683).
18. Row 634-636: The given percentage expression is a bit misleading, because when comparing the values of the absolute increments of pressure, we could come to a different conclusion.
19. Row 691: Add the "amplitude 25" data with the related unit.
20. Row 743: The given assessment "lateral pressure increased by 7 and 28%" does not correspond to the graph. On the contrary, the graph shows that there was a 7% decrease.
21. Row 753: Comment on Figure 37 (saturation 60%) is missing.
22. Row 787: "dawn" should probably be "down".
23. Row 796-799: Adjust paragraph formatting.
Generally: It is desirable to carefully proofread the quality of the text. I found a number of redundant spaces, inconsistent labeling of physical units as numerical data, inconsistent labeling of axes in graphs, etc. In several places, the formatting of the text is incorrect, upper and lower case letters are mixed up, spaces between words are missing, some words are inappropriately separated by a hyphen, they are not used before abbreviations introduced in the text, etc.
Comments on the Quality of English LanguageI recommend a careful review of the technical terms in the text. There are obvious mistakes in it, e.g. "slipper" should probably be "sleeper", "rack geometry" should probably be "track geometry", "rail truck" should probably be "trail track", "deferent" should probably be " different". I also recommend considering the terms "deforestation", "battery of tests", "sealed by warping", "instilled".
Author Response
Response to reviewers comments is included in attached file
Author Response File: Author Response.doc
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript was improved according to the recommendations but some flaws need minor revisions:
1)The review of the studies is a simple description but it should be more critical with a comparison to other studies and a conclusion. E.g. in the theoretical study “Fang et al. (2024) presented a paradigm..” – actually, the paradigm/phenomenon of the dynamic impact was presented 3 years before the study.
2)The loading frequency cannot be scaled.
3)The diagrams with only 4 points could be presented in 2 columns. The x-axis should be presented in range 1-4Hz and not 0-5Hz. The y-axis could be also stretched to fill not informative areas.
Author Response
Response to reviewers is included in attached file
Author Response File: Author Response.doc
