Critical Instability Criterion of Large-Diameter Shafts in Deep Topsoil Based on Ultimate Strain Analysis
Round 1
Reviewer 1 Report
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Author Response
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Reviewer 2 Report
In the paper, based on the ultimate analysis, the ultimate bearing capacity of a large diameter shaft is analyzed, and the shaft instability criterion taking into account the vertical additional force theory based on the ultimate strain theory is established and verified. The research of this paper has certain practical value and theoretical significance. The aim of the present study is to find out a reasonable and feasible method to judge the failure of a large-diameter shaft wall and to explore the failure mechanism of shaft wall concrete.
This paper combines theoretical analysis, experimental research, and numerical analysis, which is rich in content. It is recommended that the paper be accepted. However, this paper still needs to be modified and improved in the following aspects:
1. On page 5, line 113 contains a spelling error, “The main rock formation in this area is composed of sand layer”. It is recommended that you edit carefully and pay attention to spelling.
2. There may be an error in the first part of Eq. 5. It is recommended that you review the equation carefully.
3. In line 279, “Using the same method, the χ value of concrete with different grades could be obtained.” The method here is not explained clearly enough. How to obtain the χ value of concrete by the finite element method?
4. In table 2, the parameter ‘u0’does not appear in the relevant formula of the article. Is it a misstatement?
5. In lines 398-399, CONCLUSION, the conclusion (1) is expressed as “When the working stress of the shaft wall is greater than the ultimate bearing capacity, the shaft wall is thought to be damaged”. In lines 403-404, the conclusion (2) is expressed as “When the limit strain of shaft wall is greater than the reference value, it indicates that the shaft wall is damaged”. Is there any conflict between the two conclusions when the judged shaft wall is thought to be damaged?
Author Response
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Reviewer 3 Report
Dear autors,
The paper is well done, the paper represent a very structurated state-of-the art in the field in part of introduction .
The paper presents a topic of interest for researchers and practitioners. However, several improvements are needed.
1. The abstract should present the need for research, the methodology, the main results obtained and the future directions of research (much better highlighted). The abstrat need to be a single paragraph of about 200 words maximum – the abstrat need to be rebuilt.
2. To emphasize the need for this study.
3. To highlight the gaps filled by the present study.
4. The conclusions section should be completed with a review of the study
5. The references need to be redone, they are not according to the journal template, the numbering is missing in some places, maybe they should be supplemented.
The article is rather an expertise/technical report than a research study, the novelty of this study should be better highlighted.
Author Response
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Reviewer 4 Report
The paper presents an analysis to verify the stability of concrete shaft by an analytical procedure applied to a particular case, although some FEM results have also been reported. The paper presents important shortcomings for a scientific research and, a lack of coherence or some disconnections between different parts of the research can be observed. Therefore, from this reviewer’s point of view, I do not recommend the publication of this paper. The main drawbacks are detailed below.
The novelty is not highlighted or clarified respect to the literature. In the introduction, a handful of references have been listed but the suitability with the topic of this research is not evident or explained. The relationship of this research with the main aim and scope of this journal is neither clear.
The methodology followed in this research is absolutely not clear and neither the main scope of this research. Most of the procedures and equations presented in section 3 are known and they do not imply an evident scientific advance. The FEM presented in section 4 have been not described (geometry, mesh, material, boundary conditions…) and therefore they cannot be repeated. The relations of a specimen of 150x150x150mm (line324) with the topic of this research is not explained and this is contradictory with figure caption in figure 3. The interest of the particular case evaluated in section 5 must be justified from a scientific points of view, since it can be understood as a common technical calculation. Relevant parts of the paper should be justified by proper references i.e. comments on lines 38-40, the guidelines showed in section 2, and almost all of the hypothesis, assumptions and equations showed mainly in sections 3 and 4. In general, a strong lack of proper references to support the criteria and procedure followed can be observed. Why is it convenient to include the section 6? The discussion of the results here is partly repeated. Most of the conclusions addressed are not relevant from a scientific point of view.
Abstract should be reorganized and shortened, focusing on the main scope of the paper and describing the methodology followed. The goal of this research should be properly contextualized.
References must be numbered in order of appearance in the text according to the journal requirements. Some misunderstandings can be observed in some references i.e Cheng et al. 2020 (Two equal items appear in the list of reference), Li et al. 2020 or 2000?; reference to the superscript 23 in line 210?
Some figures should be reviewed, i.e. figure 1 is not proper and the information provided is scarce; figure 4 does not provide any relevant information since the inner and outer diameters can be listed in table 2.
Author Response
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Reviewer 5 Report
In this manuscript, the ultimate analysis method is adopted to study the ultimate bearing capacity and the ultimate strain of a large diameter shaft wall in Yanzhou coal mine. The ultimate bearing capacity of shaft wall under bidirectional stress state is investigated and the ultimate strain criterion of shaft instability is proposed based on the failure characteristics of shaft wall concrete. The conclusions are interesting and have a great significance in the mining fields. It is recommended that the manuscript be accepted. However, this manuscript still needs to be modified and improved in the following aspects:
1. The numerical conditions may have a great influence on the calculation results. The reviewer suggests that in the numerical analysis in section 5, the numerical model of shaft wall and details such as boundary conditions, constitutive model etc. should be provided.
2. The abstract can be modified as appropriate by referring to the quantitative expression method in the conclusion.
3. The format of the present manuscript should be modified according to the template of the journal, for example the format of Table 3 and Figs. 2, 7 and 8.
4. In line 140, the shaft wall concrete is reinforced with steel bar, while in the line 155, the shaft wall concrete is assumed to be continuous, homogeneous material. The authors should confirm that whether these assumptions conflict with each other.
5. The description in the line of 521 “the calculation method of borehole working stress is improved” is inappropriate and should be modified.
Author Response
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Round 2
Reviewer 3 Report
Dear Authors,
The paper presents a interesting topic for researchers and practitioners. However an improvement is needed.
1. The abstract should present the need for research, the methodology, the main results obtained and the future directions of research and it need to be 200 words maximum ” A single paragraph of about 200 words maximum. For research articles, abstracts should give a pertinent overview of the work. We strongly encourage authors to use the following style of structured abstracts, but without headings: (1) Background: Place the question addressed in a broad context and highlight the purpose of the study; (2) Methods: briefly describe the main methods or treatments applied; (3) Results: summarize the article’s main findings; (4) Conclusions: indicate the main conclusions or interpretations. The abstract should be an objective representation of the article and it must not contain results that are not presented and substantiated in the main text and should not exaggerate the main conclusions”
Author Response
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Reviewer 4 Report
The modifications and improvements carried out in the paper respect to the previous version are very scarce. Only, several punctual comments and references have been included, whereas a deeply review of the methodology and discussion of the results should be developed, which are absolutely necessary for a scientific paper, highlighting the parts which imply a contribution of this research from the others. The issues related with the lack of novelty, the contribution of this research to the previous knowledge, the scientific soundness, the scope and main goal of the research, the convenient of the cases analysed have not been properly clarified or justified. Some comments have been not attended or discussed. Regrettably, the present form of the paper has not been enough improved.
Author Response
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