Study on Cold Resistance Performance of Composite Subgrade Structure in Seasonal Frozen Regions
Round 1
Reviewer 1 Report
The work has undoubtedly an important practical aspect. From a scientific point of view, work is poor and incomplete. The work selected the thickness of the XPS layer, and then examined the temperature distribution in the substrate over several dozen days. The XPS layer has been shown to reduce soil freezing, which is obvious. The measurement of temperature distribution is valuable. I assume here that I understood the work well and that it is a real measurement. However, I do not know how Figures 6 and 7 were obtained.
Returning to the results - the effect of temperature acting on the side of the XPS layer is also obvious. The authors cite as many as 32 papers (including a number of their own) although in principle to understand the article is enough elementary knowledge at the student level. The use of the oil shale is also probably not the authors' idea, and in any case this is not the subject of the article. I did not find any aspects of this composite in the article.
The work did not raise many interesting issues, namely:
- how to solve a problem of discontinuities between boards of XPS with a larger surface,
- how the introduction of the XPS layer changes the rigidity of the substrate,
- does the production and use of XPS really have a high ecological aspect, since energy is needed to produce XPS, it is not a natural material and is difficult to bio-degrade.
The article only touches on the very minor aspect of protecting the ground surface against freezing. The topic is important from a practical point of view, but the article is scientifically weak.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript describes an experiment to measure the effect of buried extruded polystyrene (XPS in paper) on the thermal regime below it. I don't see any flaws in the method.
My concern, as a research paper, is that there is nothing novel or a general scientific interest in the results. The effects of thermal insulation are clear and very well known. The effects can generally be determined by simple thermal modeling using physical properties.
More minor comments are (by line number):
118: high compressive? strength? The bending strength is pretty low.
121-128: While I agree there is not a "linear" relationship between the effects of XPS thickness on the thermal regime, it can easily be determined as mentioned earlier.
139: why is Kx capitalized here and not agreeing with equation (1)?
140: Kelvin is designated with a capital letter.
158-163: This section comes out of nowhere. Nothing in the intro discusses why oil shale residue is suddenly important
Table 2 & 3: Does this matter? The chemical composition does not really matter in this study.
Table 5: no superscript in density units?
180: Better to use 'x' or the work 'by' instead of * in the dimensions
201: "is depicted" not "was depicted". There is significant grammar that needs addressing throughout the paper
Figure 3: Are these hourly averages? 15-minute averages?
Figures 6 & 7: Are these simulations? If so, why not use the same model with the figure 3 data as a boundary condition, and compare to the measured results? Seems like a major missing part to me.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Please I uploaded a noted version of the paper where my suggestions are included.
Comments for author File: Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
After the authors' explanations, I accept their arguments.
Reviewer 2 Report
Format is fine; my general scepticism about relevance remains, but that is all
