Research on Energy Absorption Characteristics of Polypropylene Foam Concrete Buffer Layer in High Ground Stress Soft Rock Tunnel

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. What is the main question addressed by the research?
This paper studied the influence of the porosity of EPP foam on the compression strength and energy absorption performance.

2. Do you consider the topic original or relevant in the field?
Does it address a specific gap in the field? Yes, this topic is relevant to civil engineering, and this paper address the specific gap in this field, i.e. the EPP foam concretes with different porosity performance under compression tests.

3. What does it add to the subject area compared with other published material?
This paper studied the energy absorption performance depends on different porosity

4. What specific improvements should the authors consider regarding the methodology?
What further controls should be considered? Instead of the porosity, the author can control the pore size to investigate the influence of pore size on its performance

5. Are the conclusions consistent with the evidence and arguments presented and do they address the main question posed?
yes

6. Are the references appropriate?
yes

7. Please include any additional comments on the tables and figures.
The author should make the tables and figures more concise and informative. For example, the figure 7 and 18 can be combined.

 

This paper systematically studied the influence of EPP volume content on the compression behavior of the EPP concrete, which is useful for the relative community. Thus, suggested to be accepted. But before accepting, there are few minor issues needed to be solved:

1: the author should add a scale bar on figure 4

2: The stress value of Figure 18 is inconsistent with previous data, please make corrections.

3: the author should explain more about how to define the value of ultimate compression and dense volume strain, by evaluating the strain rate or any other method. which are important values for the energy absorption calculations. 

4: Please modify the sentence in line 484 to 486, which incorrect and misleading. 

Comments on the Quality of English Language

quality of English language is ok. 

Author Response

Opinion1: the author should add a scale bar on figure 4

Reply：We have made the necessary revisions according to my feedback. Please refer to Figure 3 of the revised manuscript for details.

 

Opinion2: The stress value of Figure 18 is inconsistent with previous data, please make corrections.

Reply：We have made the necessary revisions according to my feedback. Please refer to Figure 17 of the revised manuscript for details.

 

Opinion3: the author should explain more about how to define the value of ultimate compression and dense volume strain, by evaluating the strain rate or any other method. which are important values for the energy absorption calculations.

Reply：Optimization has been carried out and corresponding explanations have been provided, please refer to the original text for details.

 

Opinion4: Please modify the sentence in line 484 to 486, which incorrect and misleading.

Reply：We have made the necessary revisions according to my feedback. Please refer to the revised manuscript for details, which has been marked.

Reviewer 2 Report

Comments and Suggestions for Authors

The reviews are in the attached pdf. Thank you.

Comments for author File: Comments.pdf

Author Response

Opinion1:Introduction

Supporting references is needed for statement under introduction. Suggest as follow:

Reply：We have made improvements according to the suggestions. Please refer to the revised manuscript for details, which has been annotated.

 

Opinion2:Development of EPP Concrete

    It is important to reorganize the content of the article in accordance with a scientific article, since otherwise it would be considered a technical report.

Include part of the content of sections 2, 3 & 4 in Materials and Methods, and part in a Results section (if you wish, you can unify results and discussion).

Begin subsection 2.1 with at least one sentence to contextualize the tests. Figures 1 and 2 can be unified into one, including (a) and (b).

Check the beginning of lines 150 & 165 (adopt 2.3.1. & 2.3.2 for subsections).

Reply：We have made improvements according to the suggestions. Please refer to the revised manuscript for details, which has been annotated.

 

Opinion3:Physical and Mechanical Properties Test of 2 EPP Concrete Specimens

Rearrange the content with the instructions given above.

On the other hand, it seems that there is a typo in the title of the section (2?).

Reply：We have made improvements according to the suggestions. Please refer to the revised manuscript for details.

 

Opinion4. Analysis of Mechanical Properties and Energy Absorption Performance of Confined Compression

Rearrange the content with the instructions given above.

In Figures 8&11, it is better not to interfere with the text with the line of the function curve.

Correct some typos in equations (font type and sizes)

Correct typo in Figure 10 (e) (include equal sign).

Lines 349-367: clarify and simplify.

Correct typo in Figure 18 (f) (include “Volumetric strain”).

Reply：We have made improvements according to the suggestions. Please refer to the revised manuscript for details, which has been annotated.

 

Opinion5. Energy Absorption Performance of Laminated Specimens under Confined Compression

Rearrange the content with the instructions given above. It is before the conclusions where a discussion section (or unified results and discussion if preferred) should be included. Correct some typos in Figures (try to keep the same font sizes if the axis label is the same length and content).

Reply：We have made improvements according to the suggestions. Please refer to the revised manuscript for details, which has been annotated.

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Dear researchers:

  They have responded that they have implemented the changes, and yet they have practically not implemented any (i.e. the effect due to Terzaghi is not mentioned, there are still typos -i.e. "conclusion(s)", the sections do not fit a research article , references do not have the Mdpi format,...).

Check that they have uploaded the correct manuscript. And if so, please don't answer that you have implemented or corrected it when you haven't. If you don't want to make a correction or accept a suggestion, that's fine, but please answer why.

Thank you

I suggest you read carefully the report1, which was carefully done.

The reviewer advises major revisions to be considered for publication.

  Sincerely the reviewer

Author Response

Reviewer 's comments are revised as follows:

Opinion1: the author should add a scale bar on figure 4

Reply：We have made the necessary revisions according to my feedback. Please refer to page 6 and Figure 3 of the newly revised article for details.

 

Opinion2: The stress value of Figure 18 is inconsistent with previous data, please make corrections.

Reply：We have made the necessary revisions according to my feedback. Please refer to page 21 and Figure 17 of the newly revised article for details.

 

Opinion3: the author should explain more about how to define the value of ultimate compression and dense volume strain, by evaluating the strain rate or any other method. which are important values for the energy absorption calculations.

Reply：The modifications have been made, please refer to pages 16-17 and 18 of the new manuscript for details.

 

Opinion4: Please modify the sentence in line 484 to 486, which incorrect and misleading.

Reply：The modifications have been made, please refer to page 19 of the new manuscript for details.