Study on Damage Evolution and Resistivity Variation Regularities of Coal Mass Under Multi-Stage Loading

Round 1

Reviewer 1 Report

The manuscript: applsci-598260 titled “Study on Damage Evolution and Resistivity Variation Regularities of Coal Mass under Multistage Loading”, presents an interesting study that attempts to investigate the monitoring of damage evolution and resistivity of coal by using an Acoustic Energy method. The manuscript is well written and with proper English. Experimental results and research methods followed were sufficiently described. Figures are well displayed. The abstract and Conclusions sufficiently present the conducted research. However, Chapter “Discussion” focuses more on the discussion of past results and only briefly refers to results provided from this study. Some of the findings mentioned in the Conclusions are discussed in Chapter “Discussion”. Therefore, minor revision is suggested prior to publication in the Journal of Applied Sciences.

Author Response

Response to Reviewer 1 Comments

Point: The manuscript: applsci-598260 titled “Study on Damage Evolution and Resistivity Variation Regularities of Coal Mass under Multistage Loading”, presents an interesting study that attempts to investigate the monitoring of damage evolution and resistivity of coal by using an Acoustic Energy method. The manuscript is well written and with proper English. Experimental results and research methods followed were sufficiently described. Figures are well displayed. The abstract and Conclusions sufficiently present the conducted research. However, Chapter “Discussion” focuses more on the discussion of past results and only briefly refers to results provided from this study. Some of the findings mentioned in the Conclusions are discussed in Chapter “Discussion”. Therefore, minor revision is suggested prior to publication in the Journal of Applied Sciences. 


Response:

Dear Professor,

Thank you very much for your comments about our paper, we have substantially revised our manuscript after reading the comments provided from you.

First of all, we would like to thank reviewer for your affirmation of our manuscript. Secondly, we feel it is necessary that Chapter “Discussion” focuses more on the discussion of past results and only briefly refers to results provided from this study, so we read the article and references carefully again and again, and we have added the main experimental results in this study. The experimental results of electrical resistivity and cumulative AE ringing counts are analyzed in depth once again, at the same time, it is analyzed that electrical resistivity is extremely susceptible to the test conditions. And electrical resistivity is calculated by using cumulative AE ringing counts, which can precisely determinate jump point of resistivity and forecast the occurrence time of coal-rock dynamic disasters.

We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. And here we did not list the changes but marked in red in revised paper.

Once again, thank you very much for your comments and suggestions.

Reviewer 2 Report

The manuscript presents experimental results about Acoustic Emissions and resistivity variation regularities in coal mass, with the idea to provide useful information to forecast the failure.

The following points need for clarification:

1) No information is provided on the number of analysed specimens and on environmental and boundary conditions.

2) Apparently, the adopted damage description D (eq.1) is effective to describe damage evolution under tensile or bending, rather than uniaxial compression.

3) Measure D_c strongly depends on the sample size (DOI: 10.1007/s11012-012-9595-5)

4) In Fig.7 apparently the qualitative behaviour of resistivity with or without accounting for damage is the same. In addition, the sudden increase of resistivity takes place at the instant of failure, making very difficult using it as a precursor of the collapse.

Last but not least, the English form must be revised.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors improved the manuscript

Author Response

Point 1: Moderate English changes required

 Response 1: Please provide your response for Point 1.

We have employed an English major to polish our wording carefully in red in our manuscript.

Point 2: Does the introduction provide sufficient background and include all relevant references?

 Response 2: Please provide your response for Point 2. 

We also gave a description that the scale effects are not taken into account in the model in Line 99~101, and we have increased the background.

Detailed modification is as follows:

Invernizzi S.; Lacidogna G.; Carpinteri A. Particle-based numerical modeling of AE statistics in disordered materials. Meccanica, 2013, 48, 211–220.

Point 3: Is the research design appropriate? and Are the results clearly presented?

Response 3: Please provide your response for Point 3. 

We make more detailed comments on scale effects in “Discussion” and point out the next work to be improved in Line 409~426.

Detailed modification are as follows:

Carpinteri A.; Corrado M.; Lacidogna G. Three different approaches for damage domain characterization in disordered materials: Fractal energy density, b-value statistics, renormalization group theory. Mech. Mater. 2012, 53, 15-28.

Carpinteri A.; Lacidogna G.; Niccolini G.; Puzzi S. Morphological fractal dimension versus power-law exponent in the scaling of damaged media. Int. J. Damage Mech. 2009, 18, 259-282.

Carpinteri A.; Lacidogna G.; Pugno N. Structural damage diagnosis and life-time assessment by acoustic emission monitoring. Eng. Fract. Mech. 2007, 74, 273-289.

Carpinteri A.; Lacidogna G.; Pugno N. Richter's laws at the laboratory scale interpreted by acoustic emission. Mag. Concrete Res. 2006, 58, 619-625.

Point 4: Are the methods adequately described?

Response 4: Please provide your response for Point 4. 

We add the boundary conditions of the formula in Line 271~285.

Point 5: Are the conclusions supported by the results?

Response 5: Please provide your response for Point 4. 

We have further revised our conclusions in Line 440~445 for supporting by the results.