Deformation Characteristics and Response Factors of Rock Bolt Body in Roadway with Layered Composite Roof
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe article contains interesting numerical tests on determining the impact of the bedding on the load and deformation of the rock bolt support. The presented research results well identify the threats to which the independent bolt support is exposed and, above all, indicate the planes of weakened cohesion in the rock mass. The obtained test results may be helpful at the stage of selecting rock bolts and cable anchors exposed to large lateral deformations. Below are some comments and suggestions: 1. In the introduction, it is worth mentioning that in the conditions of a stratified rock mass, flexible bolts such as cable anchors are particularly suitable, as they are also characterized by high resistance to dynamic loads (doi:10.3390/app13031326;doi:10.3390/app13010015);
2. In the subsection 2.1, please slightly expand the information regarding mining issues: what is the daily progress and how is the post-mining space liquidated. In addition, please describe natural hazards in a few sentences; first of all, it should be determined whether the operating area is at risk of tremors; 3. For Figure 2, please add a top view to show the location of the rock bolts and cable anchors;
4. In the subsection 2.2, please write more clearly how the bolts were removed from the rock mass;
5. In the subsection 3.2, write what model of bolt fixing was included in the modeling, whether it was full column, sectional…..;
6. A few introductory sentences should be added at the beginning of subsection 4.2 and the Figures should be placed below them. Additionally, please write whether any FISH script was used for modeling;
7. In the subsection 5.2, please write what impact horizontal stresses have on bolt deformations;
8. In the subsection 5.3, please add the maximum load capacity of the bolts and write the safety factor with which the bolts operate;
9. In the sixth chapter, several references should be added in which the influence of bedding and horizontal stresses on the deformation and load of the bolt was investigated - so that the results constitute a form of discussion;
10. Line 308, please note that the graphs show axial and shear loads in kN, while the title indicates stress values ​​that have the unit of MPa;
11. In the conclusions, please add one statement regarding the recommendation for the mining plant regarding the recommendation of securing the excavation and monitoring the bolt support.
Author Response
Thank you for your good comments and suggestions. Those comments or suggestions are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied the comments or suggestions carefully, and we hope to meet with approval. The major corrections in the paper and the responses to your comments are uploaded in the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe paper has analysed the deformation characteristics and response factors of rock bolt body in roadway with layered composite roof. By using FLAC3D, a roadway model of the layered composite roof was developed and mechanical behaviors of rock bolts were simulated. On that way, the deformation and failure characteristics and influencing factors of rock bolts in the layered roadway roof under different surrounding rock conditions were simulated and analyzed. The paper is correctly written, but with too much text and descriptions of the figures and tables in my personal opinion. From the engineer point of view, there is no formula that would more closely explain the process of simulation analysis of rock bolt deformation. This simulation process is described only through the figures, diagrams and tables. However, the paper has a potential to be of interest for underground construction engineers. Accordingly, this manuscript needs improvement before it may be processed further. The comments and suggestions are listed below:
1. Authors do not follow the recommended template for this Journal. Please see the Instructions for authors and prepare your manuscript for submission process according to Journal’s requirements.
2. Highlights should be included in the text as a paragraph. I recommend you to include the highlights in the Introduction section (line 87) to improve the quality and readability of the paper.
3. After that paragraph, I recommend you to create a new paragraph where all chapters (sections) in the manuscript will be described in one to two sentences. This paragraph actually presents the organization (structure) of the manuscript.
4. In the Introduction section and in the whole text, I suggest you to avoid the term “References”. Change it to the author’s name.
5. In the section 5.2 Simulation Analysis of Rock Bolt Deformation, Figure 8 seems incomplete. Only first three rock bolts are marked while other three rock bolts are not marked. Please explain this.
6. A similar case is in the section 6.2 Analysis of Simulation Results, Figure 11 also seems incomplete because the last three rock bolts are not marked. In addition, Figure 11 (d) should be larger and more visible, analogous to others (a), (b) and (c).
7. Future research should be added in the Conclusion section.
Author Response
Thank you for your good comments and suggestions. Those comments or suggestions are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied the comments or suggestions carefully, and we hope to meet with approval. The major corrections in the paper and the responses to your comments are uploaded in the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThis manuscript investigates the deformation and failure characteristics of rock bolts in layered roadway roofs under various surrounding rock conditions, employing simulation and analysis. The numerical results are compared with actual deformations observed in rock bolts, focusing on aspects such as stress and deformation. The research topic is interesting and informative for readers in this field. However, several questions and concerns emerged during the review process.
1. It is unclear how the deformed bars in Figure 3 were collected, as no sources or photos are provided. The manuscript should clarify this process and provide references.
2. The description of the investigated roadway lacks actual images and site photos, which are essential for validating the collected data. Including these visuals is recommended.
3. Many variables and terms lack references or explanations, such as BHRB500, M24, and MSZ2360. It is crucial to provide explanations or equivalent widely recognized terms for the benefit of readers outside China.
4. Figure 2 requires improvements in readability and informativeness. The use of different line thicknesses and colors for annotations, dimensions, and outlines would enhance clarity, particularly in understanding the roadway and support scheme (41072 Roadway).
5. Data sources or references for information presented in Section 2.1, including geological maps or 3D images of the roadway, should be provided for better context.
6. Please clarify the meaning of terms like 'top corner positions' visually in the provided images or figures. For example, does it indicate whether 'West one' refers to rock bolt #1 and 'East one' to rock bolt #6.
7. Please describe how rock bolts were extracted (collected) from the 41072 Roadway to prevent further damage or deformation during removal. Actual photos collecting those bars from the site are recommended to be included in the manuscript.
8. Please Define 'column #1 (Number)' in Table 1 and explain how height information correlates with bedding planes (e.g., 0.5m, 0.4m, 0.6m).
9. Please clarify the arrangement rationale of rock bolt rows in the out-of-plane direction, considering the confusion noted between Y direction thickness and bolt row placement.
10. Please explain the 'large deformation calculation mode' used in the model with references if applicable. No explanation and details are provided regarding the calculation mode.
11. Please include the refined mesh grid (0.1 m × 0.1 m × 0.1 m cell specification) from Figure 5 to illustrate the model's detailed aspects.
12. Please address discrepancies between soil layer profiles in numerical models (Figures 2 and 5) and provide explanations if differences exist.
13. Elaborate on determining cs-scoh value concerning coal and rock mass after experimental testing, including references for reduction factors (line 196).
14. Please discuss any sensitivity analysis conducted on parameter changes in the numerical simulation, particularly regarding how variations affect rock bolt deformation shapes regarding “the simulation results of the rock bolt deformation are relatively consistent in deformation form and degree, indicating that the model parameters are selected reasonably, the calculation sequence is in good agreement with the actual excavation process, and the model can be used to analyze the deformation of the bolt body"
15. Please provide additional information and references on the FLAC3D numerical simulation software used in the study.
16. It appears that all references are exclusively from authors within the same country, which is unusual. Please consider diversifying the references to include contributions from researchers worldwide, as there are many scholars doing significant work in this field.
Comments on the Quality of English LanguageMinor editing of language would be recommended.
Author Response
Thank you for your good comments and suggestions. Those comments or suggestions are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied the comments or suggestions carefully, and we hope to meet with approval. The major corrections in the paper and the responses to your comments are uploaded in the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe paper has been significantly improved and revised according to my comments. In my opinion, it can be accepted to be published in Applied Sciences.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe reviewer's comments and concerns are addressed in the revised manuscript.
