Investigating the Mechanism of Continuous–Discrete Coupled Destabilization of Roadway-Surrounding Rocks in Weakly Cemented Strata under Varying Levels of Moisture Content

Round 1

Reviewer 1 Report

Aiming at the influence of different water content on the surrounding rock of the roadway in weakly consolidated formation as the research background, the paper uses FLAC-PFC two simulation software to coupling the continuous and discrete elements. And analyzes the surrounding rock of the roadway in weakly consolidated formation from the perspectives of macro displacement change, microcracks and force chain development. The evolvement law of damage - fracture - instability of roadway in weakly consolidated formation under different moisture content is summarized. At the same time, the failure mode of anchor solid caused by the disaster of surrounding rock is summarized and analyzed. The research results of this paper are of great significance to the numerical simulation of underground mining, which can more accurately invert and reproduce the occurrence of the strong ore pressure disaster in the west weakly consolidated formation, and provide a basis for the control of roadway surrounding rock in the weakly consolidated formation. But the paper also has the following deficiencies, it is suggested to modify:

1. The introduction of the article does not explain the shortcomings and trends of the existing research in the summary of previous studies;

2. On page 4, "Figure 2. PFC wall and FLAC coupled boundary force conversion models ", the picture clarity is not enough, and it is suggested to adjust the clarity for better reading;

3. The summary of the article is not full enough, and the summary of the 11 th page test summary analysis is not perfect. It is suggested that the critical threshold of the water content affecting the surrounding rock of the roadway be explained;

4. The description of moisture content in Figure 4 on page 5 of the article is not clear enough，I recommend writing either "Medium sandstone: 7.72%" or "7.72% medium sandstone." If "%" signifies the moisture content, the same must be mentioned clearly in the figures;

 5. There are some problems in the article, such as misuse of words in some places, inconsistent expression before and after, and grammatical errors. The author is asked to carefully modify the wording of the article. For example, "Coal and sandstone fitting curves under different moisture contents……", "Deformation cloud diagram of the surrounding rock in the tunnel with different water content rates……" is suggested to be modified about the water content.

Author Response

We thank the experts for the valuable suggestions, and we have revised all the issues in the manuscript, and the revision instructions are detailed in the annex.

Author Response File: Author Response.pdf

Reviewer 2 Report

In this paper, the finite difference method and discrete element method are used for coupling simulation analysis. The deformation and failure law of surrounding rock under different water content of roadway roof is analyzed, and the instability mode of roadway and the anchorage failure model in anchorage system are explored. The evolution law of surrounding rock of weakly cemented roadway is explored by means of macro and micro, continuous and discrete methods, which provides new methods and reference basis for future research.

I have some comments and suggestions that can improve the integrity and clarity of the article.

1. The annotation of the force chain in Figure 12 (a) is inconsistent with the figure, which affects the reading of the article. It is recommended to provide clear figures and adjust the annotations in the pictures;

2. The description of Figure 14 in the article is not clear enough. The five stages in the figure are not discussed in the article narrative or do not correspond to the text. It is suggested that each stage be analyzed or the stage name be attached to each paragraph;

3. Terminology should be consistent throughout the paper. For example, the expressions of "water content rates ≤5.5%" in the abstract, "0% water content" in Table 1 on page 5, and "water content rates" in Figure 9 on page 9 are inconsistent, so it is suggested that the author carefully proofread and select appropriate terms.

4. The proportion of Chinese literature in the references is too high, try to increase the number of international journal papers as much as possible.

Author Response

We thank the experts for the valuable suggestions, and we have revised all the issues in the manuscript, and the revision instructions are detailed in the annex.

Author Response File: Author Response.pdf

Reviewer 3 Report

• Detailed comments are attached

Comments for author File: Comments.pdf

 Minor editing of English language required

Author Response

We thank the experts for the valuable suggestions, and we have revised all the issues in the manuscript, and the revision instructions are detailed in the annex.

Author Response File: Author Response.pdf

Reviewer 4 Report

This paper investigates the evolution law of water content changes in roadway surrounding rock of weakly cemented strata. The research findings hold considerable significance for understanding and mitigating disasters in underground roadways within weakly cemented strata, while also offering a valuable approach for numerically simulating weakly cemented rock. Nevertheless, the paper exhibits certain shortcomings that warrant modification. In this regard, the following suggestions are recommended:

1.     The article introduction for the article contribution part of the narrative is not sufficient, failed to highlight the content of the topic of the article.

2.     The title of this manuscript mentioned the numerical approach of continuous–discrete coupling, but few review on the numerical approach in introduction. Please supplement it and emphasize the priority of this method in weakly cemented strata modelling.

3.     The background of this research may refer to a mine located in western China, but no details presented in model construction section.

4.     In this paper, the model analysis is not accurate enough and needs to be numerically described. For example, on page 8, the instability range of each water content in the deformation law of roadway is compared and described.

5.     Authors presented detailly about the principle of continuous–discrete coupling and model boundary conditions. However, no describe about mesh size/element number.

6.     References are mainly concentrated in Chinese articles, it is recommended to add some authors from other countries, not limited to China.

7.     The syntax of some sentences in the text needs further modification, “The grid segment node reaction force principle calculates the external force exerted on the nodes at both ends of each grid segment of the coupled boundary.” Etc. Too many subject nouns suggest modifying the sentence structure.

8.     Most of figures are blurry. Font size should be unified, like figure 3. Unit should be pointed out in caption of figure, like figure 8.

9.     Conclusion 4 is suggested to be deleted.

Minor editing of English language required.

Author Response

We thank the experts for the valuable suggestions, and we have revised all the issues in the manuscript, and the revision instructions are detailed in the annex.

Author Response File: Author Response.pdf

Reviewer 5 Report

1. The title of this manuscript should be revised to be a clearer and corresponding to the main content. 

2. In this manuscript, the authors mentioned several different water contents. Are these different water content based on real geological reports, or they are the assumed values?

3. The research significance and research gap are not clearly presented.

4. Why is continuous-discrete method chosen? What are the advantages of this method? Is there any other method suitable for this research topic?

5. What is 'weakly cemented rock'? Is there a definition of it?

6. It's hard to find the cohesion between different paragraphs.

7. It's better to conduct several lab test to examine the effects of various water content rates on the mechanical properties of the weakly cemented rock for verification of the numerical simulation results.

8. All the symbols in the tables should be given the definitions of them.

9. Is the model a 2D or 3D ?, and what are the rationales of choosing 2D/3D?

10. The weakly cemented rock is affected by the water content rates, and there is a 'time effect' during this process, did the authors consider this 'time factor'?

It's hard to find the cohesion among each part of this manuscript. As a whole research paper, each part should have a strong connection. The authors are suggested to use conjunctional words/phrases.

A professional language editor is needed for this manuscript.

Author Response

We thank the experts for the valuable suggestions, and we have revised all the issues in the manuscript, and the revision instructions are detailed in the annex.

Author Response File: Author Response.pdf

Round 2

Reviewer 5 Report

Compared with the previous edition, this revised one is better.

 

A second time of language editing is suggested by professional language editor.

Author Response

We thank the experts for their valuable advice, and we recolor the language in the manuscript, as shown in the manuscript, and detail the changes in the annex.

Author Response File: Author Response.pdf