Theoretical Study on the Mechanism of Asymmetrical Large Deformation of Heading Roadway Facing Mining
Round 1
Reviewer 1 Report
The topic of the paper is specific, because it's not very common in the world to drive the gate parallel to the coal pillar. But, in my opinion, it is worth studying. The authors try, what is not very popular to solve the problem of gate stability with analytical solutions. However, I see there some inconsistencies.
Problem no 1
1. If you analyze the coal plastic zone, you assumed c = 0 and friction, what is correct. But in coal elastic zone again you ommited cohesion. Why? You cannot treat the coal seam as the loose element between two pistons - a roof and a floor.
2. In the equation you replace stress sigma with the force N! So you change the units here and after subsitituting the equation 6 is incorrect. You replace these values later as well.
3. The mental shortcut from eq. 5 to eq. 8 and then to eq. 9 is too fast. The same the result given as eq 13. And, in the equation you have KgH so [Pa], but N means [N] or [N/m], if you assume that 1-meter basic block is considered.
4. Again - I'm confusing about the model. You have here forces (F), moments (M) and stresses (gamma H) and you mixed them together in eq. 24. I suppose that again you consider 1 m of the rock mass beam, but the equations should be checked.
These sections should be explained and derived more clearly.
Problem no 2
Thanks to the calculations you get the rib deformation values of 5-20 cm, what is generally ok, but your study CONSIDER THE ELASTIC BEHAVIOUR of rocks. So, if you even accept 20-centimeter continuous deformation in ribs it is fard to accept 30 cm sag of roof rocks (page 10) and continuous 70-centimeter floor uplift (page 12). Accordingly the results you gave the conclusions (page 15, lines 538-548 and page 17). I understand that these are academic studies, so you can assume any conditions, but these are very far from the reality. The E modulus change the pronneness to deformation dramatically, usually thanks to water, and there occur roof deformations of 20-30 cm or floor heave of even 1 m but because of rock cracking. It's a pity that you didn't look at some papers presented the monitoring results of convergence form coal mines. E.g.:
Malkowski, P., Ostrowski, L., Bednarek, L.: The effect of selected factors on floor upheaval in roadways-in situ testing.,
Malkowski, P., Niedbalski, Z., Majcherczyk, T., Bednarek, L.: Underground monitoring as the best way of roadways support design validation in a long time period. ,
Moreover I have some other remarks:
Page 5, eq 4 - "h" instead of "m" in denomintaor, I guess
Page 6, line 215 - strength "index"
Page 8, 12, 15 - the figures with charts are too small to differentiate details. They should be enlarged.
Fig. 11, 15 - what does it mean: "roof position" or "floor position"? From coordinate system? where? Unclear
Fig. 13 - "inclined coal mine roadway"? - how inclined and why inclined?
many pages - units "MPa" and "GPa" - "P" - capital letter
Page 16, fig. 19 - you present the deformations in relation to vertical or horizontal line between AB and CD?
Page 16, line 550 - rendezvous area?
Page 17 - "advanced abutment pressure" - add, that that was studied with the help of "K"
Page 17, line 574 - Increasing immediate floor by bolting - so you again change the definition of immediate roof/floor. In my opinion, the thickness of immediate roof/floor depends on rocks themselves or you can assume it's stable - e.g. 3m. If you use rockbolts you get the reinforced zone but they can be inside the immediate roof/floor or cross it
So. I'm sorry, but I have too many doubte about the content to accept it without changes.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
I have problem with topic of the paper. I think, that topic of the article is out of scope journal Sustainability. Please explain, how topic fit to sustainibility. I think, that topic is more suitable for mechanics journals.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
The paper discusses a model of rock deformation around a mining tunnel, which is under abutment pressure. The paper is weak and needs improvement before it can be considered for publication. Consider my comments in the attached file.
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
I think, that topic of the article is out of scope journal Sustainability. I think, that topic is more suitable for mechanics journals. Therefore I suggest reject paper and I suggest send to the apropriate journal.
Author Response
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Author Response File: Author Response.pdf
