Investigation of Rock Joint and Fracture Influence on Delayed Blasting Performance
Round 1
Reviewer 1 Report
Research on Investigation of Rock Joint and Fracture Influence on Delayed Blasting Performance.Geological structures such as joints and faults in rock mass have significant influence on open pit mining.However, the paper has the following deficiencies and problems, and it is recommended to revise it carefully.Specific problems and shortcomings:
1.What is the rock type within the step height division of the test area, homogeneous or heterogeneous, and what are the characteristics of the rock hardness distribution in the drilling direction, and is there any influence that is not conducive to the delayed setting?
2.In the numerical simulation, how are the parameters related to the rock material considered? Is it consistent with the Barun mine?
3.Reasonably quote the source of the literature, pay attention to the source of the citation formula, and increase the Cai Runze literature appropriately
4. A=2.14×1011、B=1.82×109、R1=4.15、R2=0.95、w=0.5，you suddenly give these numbers without any further elaboration. People can easily get lost here. I recommend to elaborate more.
5. The model establishment and analysis in this paper lack the step slope surface, that is, the free surface setting.
6.The specific theory and numerical comparative analysis of rock mass strength should be added in the text. Part of the model of the chassis resistance line is not shown, and the relevant analysis is missing;
7.The reference documents are relatively new. The author has an in-depth understanding of the current research status, highlighting the characteristics of the paper and the research status, and the overall content meets the requirements of the journal.
8. What is the basis of theoretical calculation value in this paper, the author sees that the engineering background is Baiyunebo open-pit mine, but the relevant information is not obtained in this paper.
9. In the numerical simulation, the authors used PK model to simulate rock materials. The previous theoretical analysis considered the fracture energy of rock, but no explanation was found in the numerical simulation.
10.A detailed discussion on the results obtained has to be presented.What are the limitations and future scope of this work?
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
REVIEW
on article
Investigation of Rock Joint and Fracture Influence on Delayed Blasting Performance
Pengfei Zhang, Runcai Bai, Xue Sun, Tianheng Wang, Honglu Fei, Shijie Bao, Gang Hu
SUMMARY
The article is devoted to the analysis of the dynamic behavior of geological rocks under explosive impact. Modeling the behavior of geological formations under dynamic impacts, whether it be an explosion or a seismic load, is currently of great importance and is of scientific interest. However, the processes occurring under dynamic influences are complex due to the inhomogeneous structure, the unknown initial stress-strain state, as well as hidden defects and cracks. The article uses as an example a delayed explosion on a ledge of the high wall of the Baiyunebo quarry and also builds a non-linear model of the explosion. The simulation was carried out numerically using the ANSYS software.
The simulation results in the form of stress and strain fields were obtained in a flat setting.
The references list comprises 30 sources.
At the same time, there are numerous shortcomings in the article that should be eliminated. They are listed below.
COMMENTS
1. The abstract does not quite meet the requirements of the journal. The abstract is not ordered and chaotic. The scientific problem is not marked. The abstract should be a total of about 200 words maximum. The Editors strongly recommended the following structure of the Abstract: 1) Background: Place the question addressed in a broad context and highlight the purpose of the study; 2) Methods: Describe briefly the main methods or treatments applied. Include any relevant preregistration numbers, and species and strains of any animals used. 3) Results: Summarize the article's main findings; and 4) Conclusion: Indicate the main conclusions or interpretations. The abstract should be an objective representation of the article: it must not contain results which are not presented and substantiated in the main text and should not exaggerate the main conclusions.
2. The literary review is rather superficial. The authors analyzed only 8 references, that is poor for such a wide area. Authors should entirely rework the Introduction carefully and expand it.
3. The literature review should reveal the gap in scientific research and then authors can formulate the main aim of the work. In addition, there is no formulation of scientific novelty and objectives of the study. This should be added to the end of the Introduction section.
4. The structure of the article is distinguished from the requirements of the journal. Research Manuscript Sections should contain the following sections: Introduction, Materials and Methods, Results, Discussion, Conclusions. It's confusing and makes it hard to read.
5. The problem statement is not clear. What task is being considered? Flat or axisymmetric? What scheme was adopted and on what basis?
6. The boundary conditions and the general view of the task are unclear. It will be better if the authors to write the boundary conditions mathematically.
7. It is also not clear what kind of space we are talking about? Homogeneous or different?
8. Since the problem was solved in ANSYS, I recommend the authors to describe the solution algorithm in more detail. When solving dynamic problems by numerical methods, there are many features, ignoring which leads to significant errors.
9. I recommend the authors to check all figures and formulas for quality following the requirements of the journal. All symbols in the article must be disclosed and definitions given.
10. The materials used for the calculations are described in the results section, and this is also confusing. I recommend moving this to the Materials and Methods section.
11. The article does not have a Discussion section. I recommend that the authors add a Discussion section and compare their findings with those of other researchers.
12. Conclusions should be specified in terms of scientific novelty. What scientific result has been obtained, what knowledge has been acquired, and what existing ideas about the geological joints under blast load have been developed? I would like to see clear formulations of research prospects, as well as the applied value of the result and its application in practice.
12. The article does not have the Authors' contribution. It should be written with the requirements of the journal. For example: "Conceptualization, X.X. and Y.Y.; methodology, X.X.".
13. The References list should be written with the requirements of the journal. Please, add DOI or link for each source.
14. I recommend the authors to significantly improve the English in the text of the article.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
The article has been revised and many comments have been corrected.
Nevertheless, the article still needs improvement.
1. Abstract. The Abstract has been revised but results are presented poor. I recommend the authors improve the Abstract.
2. Literature review comprises only 8 sources. I have already asked the authors to extend the literature review. Otherwise, it is not clear how the authors can set the scientific problem and find scientific novelty.
3. In personal response, the authors write: "The rock mass with crack is studied. The stress variation rule under blasting is studied. The model is axisymmetric. Mises criterion is used to judge the failure of rock mass." Please, reflect it in the article mathematically. The readers should not have questions in the scientific problem setting.
4. Regarding boundary conditions. If you simulate the numerical task you have to limit the area of solving. So, the boundary conditions in the numerical interpretation may differ from the analytical one and significantly affect the results.
5. I recommend that the authors not only answer my current and previous questions, but also make appropriate changes to the text of the article.
Author Response
Response Letter
First of all, the authors should mention that they highly appreciate the editor and reviewers’ comments on the manuscript (MS). With great care, the authors reviewed the comments and suggestions and have incorporated major revisions into the MS. Hopefully, the revised version could satisfy the editor and the two reviewers. Listed below are the authors’ point-by-point responses to the editor and reviewers’ comments. The revisions are highlighted in the revised MS.
1 Comments from the Editor
1.1 Comment 1
Abstract. The Abstract has been revised but results are presented poor. I recommend the authors improve the Abstract.
Authors’ Response
1.2 Comment 2
Literature review comprises only 8 sources. I have already asked the authors to extend the literature review. Otherwise, it is not clear how the authors can set the scientific problem and find scientific novelty.
Authors’ Response
1.3 Comment 3
In personal response, the authors write: "The rock mass with crack is studied. The stress variation rule under blasting is studied. The model is axisymmetric. Mises criterion is used to judge the failure of rock mass." Please, reflect it in the article mathematically. The readers should not have questions in the scientific problem setting.
Authors’ Response
We agree with the reviewer. Changes have been made in the text, as follows:Through the analysis of the above two formulas, when the detonation wave generated by the explosion acts on the rock mass, when the Mises stress σvm of the rock in the near explosion source area exceeds the set dynamic compressive strength σcd, the point fails, and in the far zone of the explosion source, the calculated tensile stress σt of the point in the rock mass is greater than the set dynamic tensile strength σtd, the point fails, and in the near zone of the explosion source, the calculated cumulative plastic strain εp of the point in the rock mass exceeds the set failure strain εpf. In short, the possibility of rock mass failure increases, which is convenient to more realistically simulate the dynamic force of rock mass after the detonation wave and symbiotic gas.
Based on the existing reference manual "Engineering Geology Handbook" and engineering geological survey report, the relevant strain rate parameters are selected, and it is believed that the dynamic compressive strength of the rock will be significantly enhanced under high loading strain rate, and the conversion relationship between the dynamic compressive strength σcd and the static compressive strength σc is as follows.
1.4 Comment 4
Regarding boundary conditions. If you simulate the numerical task you have to limit the area of solving. So, the boundary conditions in the numerical interpretation may differ from the analytical one and significantly affect the results.
Authors’ Response
1.5 Comment 5
I recommend that the authors not only answer my current and previous questions, but also make appropriate changes to the text of the article.
Authors’ Response
We agree with the reviewer. However, we still would like to give some clarification according to the reviewer’s concern.
Author Response File: Author Response.doc
Round 3
Reviewer 2 Report
Quite better. Almost not bad.
I recommend the article for publishing.
