Surrounding Rock Deformation Mechanism and Control Technology for the Roadway in the Fault-Disturbed Zone under Special-Shaped Coal Pillars
, Dongxu Zhu 4, Wenhua Hao 1,2, Tiankuo Tang 1,2, Xutong Zhang 1,2 and Chenguang Zhu 4
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis paper takes the short-distance coal seam mining in Luwa Coal Mine as the engineering background to explore the surrounding rock deformation mechanism along the mining roadway in the fault disturbed zone under special-shaped coal pillars, Presented the roadway surrounding rock control technology and conduct on-site industrial test verification. The convergence rate on the roadway surrounding rock is controlled within 5%, and the deformation of roadway surrounding rock is under effective control. The superimposed influence of special-shaped coal pillars and fault disturbance on mining roadway is a very interesting topic for the mining field. The manuscript is acceptable after minor corrections.
（1） The abstract should be an accurate and concise summary of the entire manuscript. Please improve the abstract to highlight the main results and conclusions of this article's work.
（2） The introduction does not explain the research methods and significance of the problem. Please provide more details.
（3） In section 2.1, page 5, lines 170-171: The stress distributions in Section A-A and Section B-B are both bimodal, but in Figure 6, the stress distribution curve of section B-B is only a single peak distribution, is it reasonable.
（4） In Figure 9, all parameters involved should be annotated and explained.
（5） It is recommended to add an explanation of the shortcomings and applicability of this study in the discussion section.
Comments on the Quality of English LanguageIt is good.
Author Response
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Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThank you very much for inviting me to evaluate the manuscript entitled "Surrounding rock deformation mechanism and control technology for the roadway in the fault disturbed zone under special shaped coal pillars".
This study takes Shandong Luwa Coal Mine as the engineering background to establish a theoretical model for the mining roadway in the fault disturbed zone under special-shaped coal pillars. We study the superposed effects of overlying remaining special-shaped coal pillars and fault disturbance as well as the influence on the stress environment of mining roadway. Thereby, we will explore measures to control the stability of roadway surrounding rock when the mining roadway crosses the overlying remaining special-shaped coal pillars in the fault disturbed zone, thus providing basis for the arrangement of surrounding rock control along the mining roadway under similar conditions.
Some shortages or advices of the manuscript are listed as following:
1. The problems, methods, and significance in the introduction are not clearly explained.
2. More international references are recommended in the Introduction part.
3. Abstract need to be revised to better present your result and the main conclusions of your work.
4. Section 3.2 uses deviatoric stress to describe the deformation and failure of tunnels. What are the advantages compared to plastic zones?
5. The conclusion can be simplified. Please include only important information.
Comments on the Quality of English LanguageThank you very much for inviting me to evaluate the manuscript entitled "Surrounding rock deformation mechanism and control technology for the roadway in the fault disturbed zone under special shaped coal pillars".
This study takes Shandong Luwa Coal Mine as the engineering background to establish a theoretical model for the mining roadway in the fault disturbed zone under special-shaped coal pillars. We study the superposed effects of overlying remaining special-shaped coal pillars and fault disturbance as well as the influence on the stress environment of mining roadway. Thereby, we will explore measures to control the stability of roadway surrounding rock when the mining roadway crosses the overlying remaining special-shaped coal pillars in the fault disturbed zone, thus providing basis for the arrangement of surrounding rock control along the mining roadway under similar conditions.
Some shortages or advices of the manuscript are listed as following:
1. The problems, methods, and significance in the introduction are not clearly explained.
2. More international references are recommended in the Introduction part.
3. Abstract need to be revised to better present your result and the main conclusions of your work.
4. Section 3.2 uses deviatoric stress to describe the deformation and failure of tunnels. What are the advantages compared to plastic zones?
5. The conclusion can be simplified. Please include only important information.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThis paper used theoretical analysis and numerical simulation to to explore the surrounding rock deformation mechanism along the mining roadway in the fault disturbed zone under special-shaped coal pillars. After field measurements and verifications, the control technology can ensure the stability of the mining roadway in the fault disturbance area under special coal pillars. There are some minor revisions can be considered to improve this manuscript.
1. Roadway instability is often related to the support form, the author of the paper should specifically supplement the original support mode of the roadway, rather than simply put forward.
2. In the introduction, the influence of residual coal pillars and faults on the stability of mining roadway in existing studies is introduced, but not summarized.
3. The roadway was severely damaged during the mining of the lower working face, but the author only provided pictures instead of data to prove the serious deformation of surrounding rock.
4. The conclusion is too long and does not refine the innovation points and achievements of the manuscript.
Author Response
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Reviewer 4 Report
Comments and Suggestions for AuthorsThe paper reports a case study on the problem of serious deformation of roadway in the fault disturbed zone under special-shaped coal pillars. The theoretical analysis was used to propose a new technical scheme is proposed to prevent and control the deformation and instability of roadway surrounding rocks. It is a useful topic. This paper requires minor revision before being accepted for publication.
1. The description of the research results in the abstract, especially the stress distribution model of the bottom plate in different sizes, is not clear, so I suggest that the abstract should be rewritten.
2. Are the parameters of the rock strata selected in the numerical simulation checked, which has a great impact on the accuracy of the simulation results?
3. The author adopted large-diameter pressure relief drilling and anchor cable reinforcement support on site. How to determine its parameters?
4. The field monitoring only records the surface displacement of the roadway. Is there any other monitoring method to determine the stability of the surrounding rock of the roadway?
Comments on the Quality of English LanguageMinor editing of English language required
Author Response
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Reviewer 5 Report
Comments and Suggestions for AuthorsThe manuscript is devoted to studying the stress-strain state of rock mass in conditions of influence of a fault and a specific-shape coal pillar that remained on the upper seam. Authors carried out an analytical study and a numerical simulation and offered recommendations to ensure stability of a roadway in the case under consideration.
MAJOR COMMENTS
1) To my mind, there are some terms used in an inappropriate way. Authors widely used the term “working face” but sometimes they mean a large rectangular block of a coal that will be mined by a working (longwall) face and sometimes a mining (working) face. In my opinion, the most appropriate term for a large block of coal is “longwall panel” or “panel” because in underground coal mining the term “face” means the surface where the mining work is advancing. The term “longwall panel” (“panel”) is the common one in longwall mining. It is very important to differentiate the terms “working face” and “panel” otherwise it is not clear what you mean: a mining face or a block of coal.
In my view, the term “stope” (“stope pressure”) is not appropriate for longwall coal mining. The common term “stope” usually means an excavation from which ore has been removed in a series of steps.
2) Figure 8. Stress Distribution in Section B-B. It is not clear why there is no stress in the right part of this figure. According to the scheme presented on Fig.6, there is geostatic stress without the influence of bearing pressure. It should be noticed that It is impossible to have the similar stress distribution under the central part of the pillar (right part of Fig.8,A) and under one's edge (left part of Fig.8,A). To my mind, such a stress distribution is impossible and looks like a mistake.
MINOR COMMENTS
- 2.5×104Kn/m3.4KN/m3. (Line 296). You should correct this and remove the extra dimension (Kn/m3). The correct option is 2.5×104 kN/m3
- Table 2. Theoretical stress-strain solution on the gangue cover of the goaf. This table contains physical and mechanical properties of the goaf material but not stress-strain solution. In my view, you should correct the caption of this table.
- Density of goaf gangue shown in table 2 is 1200 kg/m-3. But since the average degree of fragmentation of rock of an immediate roof (and a main roof) is about 1,3 and their density is about 2500 kg/m-3 it is not clear why the density of the goaf gangue is so low. An expected density in this case may be about 2000 kg/m-3.
Author Response
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Reviewer 6 Report
Comments and Suggestions for AuthorsThe manuscript is well-organized and well-written. All figures have high readability. The generality of the proposed rhetorical model is suggested to incorporate to attract broader audiences.
Author Response
It is an honor to receive your recognition of this work. We have revised and updated the language, abstract, data, charts, and references of the paper to further improve its quality and accuracy. We believe that these changes will make the document clearer, easier to understand, and more convincing.
Reviewer 7 Report
Comments and Suggestions for AuthorsThe paper considers the deformation mechanisms of a road zone with a fault with coal pillars. All this in relation to coal mining.
The material extraction work generates tensions in the surrounding areas, also adding to the effect of the failure. The result is that the pressures respond to three peaks and two crests, with a form of wear in the area of the fault and with pressures of different signs in the support pillars. Several solutions are proposed.
The work is very specific, describing a rare process in this type of extractions. The work seems well studied, but the main flaw is the little exposure at the initial moment of the research. The area in which the mine is located is not described. The methods used are not explained. No data is provided about the materials presented.
The work must be rewritten considering elementary issues and not describing the mathematical part of the model in such detail.
Besides: No experimental data is provided, nor the way to obtain it. Is it a theoretical work? Nothing is explained.
Figure 3c) classification?
Figure 4, Photos should be numbered and what they mean indicated.
Figure 5, brings together several parameters, how were they obtained? How have the density and geological parameters been measured?
The equations should be referenced in the text.
Line 168: where is section C-C? B-B?, A-A?. The figure must be referred to before.
Why have these sections been selected?
Author Response
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Reviewer 8 Report
Comments and Suggestions for AuthorsGeneral comments
I strongly suggest to add a chapter/section where the research must be explained. Some tests are only mentioned in a later stage of the manuscript. The readers should know what and how the research was conducted.
I have doubts if the expression “special-shaped coal pillars” is the more appropriate to describe the case under study. These “pillars” are never described.... Do you mean “working area”? The situation should be better explained.
The fault area should be better characterised (width; composition; weathering degree; …).
The results of the physical and mechanical tests should be discussed. Just a description is not enough...
Authors use data without mention their origin.
More criticism is mandatory when discussing the results.
Specific comments
Lime 19 - “shaped coal pillars, Presented the roadway”
Check.
Line 53 - “and proposed to ensure the mining of lower coal seam and roadway maintenance”
Check the sentence. Something is missing....
Line 87 - “seams. [16] However”
Check.
Line 103 - “The thickness of the 3upper coal seam is 1.2-2.4m, and the average coal thickness is 2.04m”
Please, add the appropriate references for the engineering background.
Line 108 - “Influenced by DF87 fault”
More information about this fault zone is mandatory: width, composition; weathering degree; ….
Line 119 - “bot + metal mesh”
bot?
Line 124 - “Under the superposed effects of upper coal pillars and fault disturbance, the stress state on the underlying strata was changed”
How do you know?!
Line 132 - “The principal stress field in the roadway under coal pillars deflected”
How do you know?! This is only a supposition ...
Line 139 - “track roadway, After drilling and”
Check.
Line 140 - “measurement methods，process, classify, and mark them, as shown in Figure 3”
Check.
Line 142 - “(a) Processing (b) Cutting (c) Classificatio (d) Marking”
Processing or sampling? Check “Classificatio”.
Line 146 - “experimental mechanical parameters are shown in Figure 5”
The density is a physical parameter....
Line 149 - “is relatively large; The direct”
Check.
Line 152 - “roof collapse; The basic roof”
Check.
Line 154 - “The compressive strength is high and not easy to break. Under the action of bearing pressure, it is not easy to break and deform, and has strong anti-interference ability”
The results need to be compared with similar rocks.
Line 166 - “to certain law. [19,20]”
Check.
Line 170 - “rock stress. [21] The”
Check.
Line 187 - “initial stress zone. [22,23]”
Check.
Line 206 - “the parameters are taken as m=2.04m, c0=1.0MPa, φ=32°, k=3, γ=25kN/m3, H=380m, β=1.5”
Why these parameters?
Line 244 - “zone. [25-27]”
Check.
Line 249 - “the fault plane. [29]”
Check thought the manuscript. I stop here this survey.
Line 308 - “Then, 1/20 of the corresponding mechanical parameter in the mudstone was selected”
Why 1/20? Please, explain the rational for such option.
Line 550 – “In order to verify the control effect of surrounding rock along the mining roadway in the fault disturbed zone under special-shaped coal pillars, the cross line detection method was adopted to monitor the surrounding rock deformation”
Only here the readers know what tests were performed. I suggest to add a Methodology section where all procedures should be explained.
Line 556 – “As shown in Figure 20 and Figure 21”
Are the results according to similar situations? More criticism is welcome.
Figures
Figure 1 – Please, improve the figure. The location of the several areas is not clear.
Figure 6 – Please, add the meaning of the lettering .... Is the distribution model of abutment pressures based on measurements or is a guess?!!!!
Figures 7 and 8 – The width of the pillars can reach more than 30 meters? Do you mean “width of working face”? Please, check trough the text.
Figure 13 – The lettering is too small.
Figure 17a – The graph is from the authors?
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 7 Report
Comments and Suggestions for AuthorsThe work has incorporated the suggestions. Has improved a lot
Author Response
It is an honor to receive your recognition of this work. Thank you sincerely again.
Reviewer 8 Report
Comments and Suggestions for AuthorsGeneral comments
I have doubts if the Introduction chapter is the best option to describe the research in detail. I suggest to add a chapter/section where the research should be explained.
The results of the physical and mechanical tests should be discussed. Just a description is not enough... Are the values higher/lower than others found in similar materials?
More criticism is mandatory when discussing the results. Please, compare the results with similar studies. Are the results of numerical calculation and stress distribution according to the similar cases? Or such comparison is not possible?
The chapters 5 and 6 can be merged.
Specific comments
Line 13 – “In mining a short-distance coal seams, concentrated stresses in the floor generated by the re-maining special-shaped coal pillars in the upper slice will directly influence the stress environment of the lower slice roadway. Besides, fault disturbance will further destroy the stability of the roadway surrounding rock, resulting in severe ground pressure.”
The readers do not know what are the topics under investigation. Please, avoid starting with conclusions…
Line 155 – “The experimental results show that the coal lithology is relatively soft, and the average compressive strength is 6.94MPa”
Please, mention the standards used. The expression “arithmetic mean” or “mean” is better than “average”.
Figures
Figure 1 – Remains unreadable…. The sections 33Lower01 working face and 33Upper01 goaf does not match…. In Figure 11 the spatial position is better perceived.
Figure 3a – Is about drilling….
Author Response
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