Damage Evolution and Fractal Characteristics of Granite under the Influence of Temperature and Loading

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Review

Journal: Applied Sciences (ISSN 2076-3417)

Manuscript ID: applsci-3035709

Type: Article

Title: Damage evolution and fractal characteristics of granite under the influence of temperature and loading

Comment: The article presents the results of research to study the damage characteristics and evolution law of granite under temperature and loading rate, uniaxial compression tests at different loading rates were carried out for granite specimens with different temperatures, and the damage characteristics and evolution law of granite were studied in conjunction with acoustic emission ringing, acoustic emission b-value, acoustic emission signaling constellation and fractal dimension.

 Decision: The article presents the results of the study. I have no objections to the content of the article, while I have a lot of reservations about editorial faults, which should be corrected before publication.

 Summary: The article can be published after correcting the editorial faults (see *.pdf file, please).

Comments for author File: Comments.pdf

Author Response

Respond reviewer

 

1.There should always be a space after "C," (in general, there should always be a space after ","), e.g.:

30°C, 40

This comment applies to errors throughout the article, please.

There should always be a space article ":" (in general, there should always be a space after ":"), e.g.:

showed: (1)

This comment applies to errors throughout the article, please.

There should always be a space after "." (in general, there should always be a space after "."), e.g.:

Please remove the space between the value and the degree symbol "°", e.g.:

300°C

Especially since in the second part of the article these spaces between the symbol "°" and value are

not present.

This comment applies to errors throughout the article, please.

Please to add a space between the words and "[", for example:

studies [18].

This comment applies to throughout the article, please.

 

Answer:The relevant format in this article has been modified.

 

2.

 

Please add to the titles of the horizontal and vertical axes, in addition on to the units, also the symbols

that denote these quantities.

Please also add in the text of the article after the names of the quantities the symbols that denote

them.

This comment applies to all figures throughout the article.

Answer:

 

This content has been added to the article and is located on lines 165.

 

3.One time quantities (e.g., M) are wriƩ en without ' ', and some symbols are wriƩ en inside ' ' (e.g., 'b').

Please standardize these designations throughout the article. In my opinion, all symbols denoting quanties should be in italic type. This comment applies to all symbols throughout the article, please.

Answer:The content has been modified on lines 201-205.

 

4.There should be spaces between "(leƩ er)" and the number, e.g.:

(j) 80°C, 0.005mm/sec.

The "C" is followed by some strange comma (what kind of punctuation mark is that?).

Those comments add to all figures throughout the article, please.

Maybe you need to add a "-" sign, such as:

Where: B - represents.

This comment applies to the entire article, please.

Answer:The content has been modified.

 

5.

 

 

 

Figures too small.

Spaces between "()" and the figure.

Lack of symbols after quantity names on axistitles. Those comments add to the entire article, please.

 

Standardize the spaces between the number and the unit. This comment applies to the entire article, please.

 

Standardize the spaces between the number and the unit. This comment applies to the entire article, please.

 

 

Spaces, also Figure 6 and 7.

 

Figures too small.

 

 

 

Figure too small.

 

As in figure 3.

Answer:The above problem has been modified.

 

6.

 

Please use the same number of decimal places for the same quantities. Please add symbols after the quantity names.

Those comments add to the entire article, please.

 

Answer:The above issue has been modified on lines 435 through 443.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript provides a comprehensive investigation of the mechanical behavior and damage characteristics of granite under varying conditions of temperature and loading rates. The use of acoustic emission parameters and fractal analysis adds depth to the understanding of the material's response, which is critical for applications in geological engineering. However, the clarity of the manuscript can be improved by addressing several grammatical issues, improving the consistency of technical terms, and providing more detailed explanations of the methods and their impact on the results. Further statistical analysis or comparative studies could strengthen the conclusions.

 

1. Abstract (lines 15-17): Replace "uniaxial compression tests at different loading rates were performed" with "uniaxial compression tests at different loading rates were performed" to maintain a more formal academic tone.

2. Introduction (lines 51-53): The term "shale cracking" is unclear in this context. If "shale" is used incorrectly, correct it to "slab cracking" if it's referring to large, flat pieces of rock, or clarify the term if it's intended to describe some other phenomenon.

3. Section 2.1 (lines 120-126): Clarify the capabilities and limitations of the "DH3820 strain measurement" by providing more technical details or specifications to help the reader understand why this particular range and resolution is important for the experiments.

4. Section 3.1 (Lines 152-154): It is recommended that a brief explanation be added as to why the Young's modulus behaves as observed at different temperatures, possibly related to changes in the microstructural properties of the granite.

5. Figure legends (throughout): Ensure consistency in the presentation of temperatures in figures; for example, "30℃" should be formatted consistently in all mentions, including figure legends.

6. Section 3.2 (lines 177-179): The description of acoustic emission parameters would benefit from a more detailed explanation of how these parameters correlate with damage mechanisms in granite.

7. Equations (Lines 180-184): Include clearer definitions or descriptions of each variable within the equations used to calculate the acoustic emission parameters to aid the reader's understanding.

8. Discussion of Results (Lines 430-435): More thoroughly discuss the implications of the observed peak stress and elasticity behaviors under varying temperatures to strengthen the link between experimental results and practical applications.

Comments on the Quality of English Language

There are several instances of awkward phrasing and grammatical errors that require thorough proofreading. For example, there is excessive use of "and" in some sentences that could be simplified for clarity and conciseness.

Author Response

Respond reviewer

 

Abstract (lines 15-17): Replace "uniaxial compression tests at different loading rates were performed" with "uniaxial compression tests at different loading rates were performed" to maintain a more formal academic tone.

Answer: This part of the article has been replaced and its improvements are marked in red.

This content has been added to the article and is located on lines 15-17.

 

2.Introduction (lines 51-53): The term "shale cracking" is unclear in this context. If "shale" is used incorrectly, correct it to "slab cracking" if it's referring to large, flat pieces of rock, or clarify the term if it's intended to describe some other phenomenon.

Answer: The article should have been slab cracking at that point and has now been revised.

This content has been added to the article and is located on lines 55.

 

3.Section 2.1 (lines 120-126): Clarify the capabilities and limitations of the "DH3820 strain measurement" by providing more technical details or specifications to help the reader understand why this particular range and resolution is important for the experiments.

Answer: Figure 1 (h) Vertical strain and lateral strain measurements using resistance strain gauges. Because the strain gauge resistance and sensitivity coefficient are small, to ensure accurate measurements, the DH3820 strain gauge with the smallest parameters in the device, which has a range of ± 50000 με and a minimum resolution of 0.5 με, was used. The strain indication error was not greater than 0.2% ± 2με.

This content has been added to the article and is located on lines 130-135.

 

4.Section 3.1 (Lines 152-154): It is recommended that a brief explanation be added as to why the Young's modulus behaves as observed at different temperatures, possibly related to changes in the microstructural properties of the granite.

Answer: This is because the temperature of the granite first decreases and then increases the mechanical law of change [1,3]. A microscopic study revealed that with an increase in the temperature of the granite pores to 40 ℃, a sudden decrease [4] occurs with an increase in the temperature and an increase. At the same time, in the temperature interval of 50 ℃-200 ℃, the formation of cracks is not enough to offset the change in porosity caused by the closure of the cracks [5], so the decrease in the porosity of the pores at 40 ℃ leads to the rapid entry of the rock into the pressure-tight zone of rock, which in turn leads to a decrease in the modulus of elasticity of the rock and the peak stress; however, as the increase in the temperature porosity increases, the expansion of thermal damage cracks cannot offset the effect of increased porosity, which in turn leads to the development of damage within the granite requiring a greater axial pressure.

This content has been added to the article and is located on lines 177-187.

 

5.Figure legends (throughout): Ensure consistency in the presentation of temperatures in figures; for example, "30℃" should be formatted consistently in all mentions, including figure legends.

 

Answer: The sections of the article have been revised as required.

 

6.Section 3.2 (lines 177-179): The description of acoustic emission parameters would benefit from a more detailed explanation of how these parameters correlate with damage mechanisms in granite.

Answer: The phenomenon of elastic waves generated in all directions by material damage is called material acoustic emission [2]. Its trend corresponds to the change in stress and strain in the damage process of rock under loading. Therefore, acoustic emission signals can be monitored to reflect the accumulation of damage, crack initiation, and crack penetration in the rock. Further, acoustic emission ringing can describe the number of cracks inside the rock according to the number of signals generated by rock damage, while the acoustic emission b-value can reflect the intensity of rock damage development through fluctuations [6-7]. It can be used as a characteristic parameter of the rock damage signs, thus introducing the acoustic emission b-value and acoustic emission ringing to analyze the development of the internal damage rule of change in the rock, in which:

This content has been added to the article and is located on lines 189-201.

 

7.Equations (Lines 180-184): Include clearer definitions or descriptions of each variable within the equations used to calculate the acoustic emission parameters to aid the reader's understanding.

Answer: where M is the magnitude, the value of which can be obtained by dividing the acoustic emission amplitude by 20; N is the number of shocks within the range of values of M, which is usually taken to be the number of impacts exceeding the acoustic emission amplitude; a is a constant, usually depending on the type of rock; and b is the proportion of small-value events relative to large-value events.

This content has been added to the article and is located on lines 201-205.

 

8.Discussion of Results (Lines 430-435): More thoroughly discuss the implications of the observed peak stress and elasticity behaviors under varying temperatures to strengthen the link between experimental results and practical applications.

Answer: 

Discussion

In an actual project, tunnel excavation will occur due to upper building construction, adjacent tunnel construction, and other reasons, leading to different degrees of disturbance in the surrounding rock of the tunnel, which can cause to rock damage. This paper revealed that a high-temperature tunnel at 40°C under the influence of internal rock damage caused by a greater reduction in the mechanical properties of the rock increases the strength of the rock, but the development and destruction of rock damage are more concentrated in the late stage, resulting in tunnels being more prone to rock bursts and other engineering disasters. Using acoustic emission localization and acoustic emission localization fractals, to further analyze the form of rock damage development, the loading rate of the larger internal damage of the rock multilocation development of the final crack into the network was determined. In summary, high-temperature tunnels at 40°C should be prepared in advance to prevent tunnel peripheral rock from becoming prone to large cracks, while tunnels at 60°C and 80°C should experience controlled rock disturbance to reduce peripheral rock explosions and other engineering disasters.

This content has been added to the article and is located on lines 456-469.

 

1. [1]Yang,H. T.; Xu, J.;Wang, L.;Nie, M.;Ren, H. N. Experimental Study on Temperature Effect of the Mechanical Properties of Granite.Chinese Journal of Underground Space and Engineering,2013,9(01): 96-
2. Gong,C.;Zhao, K.;Bao, H.;Zhao, K.;Zeng, P.;Wang W. J. Acoustic emission source evolution and fractal features during creep failure of red sandstone .Rock and Soil Mechanics,2021,42(10): 2683-2695.
3. Xu,X. L.;Gao, F.;Ji, M.Damage Mechanical Analysis of Fracture Behavior of Granite Under Temperature.Journal Of WuHan University Of Technology,2010,32(01):143-147+165.
4. Zhang,Z. Z.;Gao, F.;Gao, Y. A.;Xu, X. L.;Hou, P. Fractal structure and model of pore size distribution of granite under high temperatures.Chinese Journal of Rock Mechanics and Engineering,2016,35(12): 2426-
5. Géraud,Y.;Mazerolle, F.;Raynaud,  Comparison between connected and overall porosity of thermally stressed granites. Journal of structural Geology, 1992, 14(8-9): 981-990.
6. Su,X. b.; Ji, H. G.;Quan, D. L,Geng, J. M.;Zhang, G. G. Relationship between spatial variability of rock strain and b value under splitting condition.JOURNAL OF CHINA COAL SOCIETY,2020,45(S1): 239-
7. Zhang,L. M.;Ma, S. Q.;Ren, M. Y.;Jiang, S. Q.;Wang, Z. Q.;Wang, J. L. Acoustic emission frequency and b value characteristics in rock fallure process under various confining pressures.Chinese Journal of Rock Mechanics and Engineering, 2015, 34(10): 2057-

 

Author Response File: Author Response.docx