A Thorough Investigation of the Dynamic Properties of Granite under Cyclic Loading

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript describes a thorough experimental approach to investigate the dynamic properties of granite, which is a fundamental strength. The inclusion of various cyclic loading conditions and detailed measurements enriches the understanding of how granite responds dynamically. A stronger link between the findings of this study and existing research on similar topics should be established. Comparisons with prior work can validate the results and provide a broader perspective on the significance of the current research. However, figures text and legend are not readable and clear, please increase the font size so that it becomes clear and readable.

Comments on the Quality of English Language

The manuscript describes a thorough experimental approach to investigate the dynamic properties of granite, which is a fundamental strength. The inclusion of various cyclic loading conditions and detailed measurements enriches the understanding of how granite responds dynamically. A stronger link between the findings of this study and existing research on similar topics should be established. Comparisons with prior work can validate the results and provide a broader perspective on the significance of the current research. However, figures text and legend are not readable and clear, please increase the font size so that it becomes clear and readable.

Author Response

Comments 1: The manuscript describes a thorough experimental approach to investigate the dynamic properties of granite, which is a fundamental strength. The inclusion of various cyclic loading conditions and detailed measurements enriches the understanding of how granite responds dynamically. A stronger link between the findings of this study and existing research on similar topics should be established. Comparisons with prior work can validate the results and provide a broader perspective on the significance of the current research. 

Response 1: 

Thank you for your comments.

We agree comparison with prior work is good way to show strength of current study. In section 2, we have listed some of the published literatures regarding the study of dynamic property of granite. And a good comparison is made in Table 1, which demonstrated most of past studies only considered 3 or less controlling parameters (frequency, cyclic times, confining pressure, etc.), and did not cover a wider enough range in the experiment parameters. The findings in our experiment result are also compared with some published result in section 4. The revisions are marked in red in the revised manuscript.

Comments 2: Figures text and legend are not readable and clear, please increase the font size so that it becomes clear and readable.

Response 2:  We apologize for poor quality of the original figures. The pictures and tables are fitted in the paper and scaled too small. We have adjusted and redrew most of the pictures, and listed all the new figures and tables.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper is interesting, even if it is to be framed as a "case history" rather than as "scientific research", because for a few years devices based on emission of waves (acoustic, seismic, sonic, electric etc.), combined with compression tests, have been used to determine the technical characteristics of the rocks subjected to excavation or to deduce the primary stress field around a tunnel.

If you want to convince people of the goodness of your method, you must also describe its limitations. The stress state around a tunnel doesn’t depend only on the type of rock, but on numerous other parameters (e.g.: the diameter of the tunnel, the depth of the excavation, tectonics, morphology, water, etc.) which are not taken into consideration (at least mentioned).

Furthermore, all the work is based on tests performed on a "granite". The authors do not specify what type of granite, given that there are many types in nature. If the mineralogical composition changes (while remaining within the petrographic type defined as "granite") or the geological "history" of the rock changes (for example the tectonic structure of the area or the degree of alteration), even the technical characteristics change, and the interpretation of the test results is different.

If the authors' aim was to present a methodology, they could have also used concrete samples, if instead the intent was to define the technical characteristics of that particular granite, in relation to its behavior under excavation or to define the stress field around the tunnel, then appropriate assumptions and explanations are missing. The text requires in-depth analysis and specific explanations about the tunnel considered: the geological, tectonic, etc. of the area, the depth of the tunnel, its diameter, etc.

All the figures are too small, so all the writings are illegible (see the file attached). Therefore, it is impossible to verify what is described in the text.

Comments for author File: Comments.pdf

Author Response

Comments 1: If you want to convince people of the goodness of your method, you must also describe its limitations. The stress state around a tunnel doesn’t depend only on the type of rock, but on numerous other parameters (e.g.: the diameter of the tunnel, the depth of the excavation, tectonics, morphology, water, etc.) which are not taken into consideration (at least mentioned).

Response 1: Very good suggestion. Recently, the detection method using dynamic field is quite promising in geological investigation. And we want to investigate if this kind of method can be used for accurate rock stress state detection or not. As you have mentioned, the detection of stress state is affected by various conditions, even the micro petrographic structure will affect the deduction. Thus, we want to focus on only one type of rock available to us, this same rock will be tested in the field later. With the acquired rock test result, a simplified numerical model similar to the target inspection tunnel will be build, using the test data, to do the reverse analysis comparison. Additional information on the numerical model setup is described in newly added Figure 2. The geometry of the studied tunnel for this inspection is 6 meters wide, 8 meters tall, and buried 23 meters deep. The boundary of the numerical model was 20 meters away from the tunnel limit. The length of the tunnel excavation was 20 meters. The tunnel wall surface is currently fresh rock cut without lining.

Comments 2: 

Furthermore, all the work is based on tests performed on a "granite". The authors do not specify what type of granite, given that there are many types in nature. If the mineralogical composition changes (while remaining within the petrographic type defined as "granite") or the geological "history" of the rock changes (for example the tectonic structure of the area or the degree of alteration), even the technical characteristics change, and the interpretation of the test results is different.

If the authors' aim was to present a methodology, they could have also used concrete samples, if instead the intent was to define the technical characteristics of that particular granite, in relation to its behavior under excavation or to define the stress field around the tunnel, then appropriate assumptions and explanations are missing. The text requires in-depth analysis and specific explanations about the tunnel considered: the geological, tectonic, etc. of the area, the depth of the tunnel, its diameter, etc.

Response 2: The current work result can only be applied to one type of granite given from the project site. We agree the mineralogical composition will affect the interpretation of the analysis result. And the future plan is to test one more type of rock type, and compare their XRD and XRF component difference. And later, concrete will used as a study target for comparison. This could lead to some interesting findings.

Comments 3: All the figures are too small, so all the writings are illegible (see the file attached). Therefore, it is impossible to verify what is described in the text.

Response 3: We apologize for poor quality of the original figures. We have adjusted and redrew most of the pictures. Also, the font has been adjusted for the corresponding part of the text.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

1. It is better to remove relations a, b in Figure 1 (upper figure) and place them in another appropriate place.

2. What does "part II" mean in figure 2? Please explain.

3. The caption of Figure 3 should be corrected.

4. The quality and clarity of the figures is very low, the legends are unreadable.

5. Why frequency has a greater effect on the dynamic behavior of selected samples than the confining pressure.

6. The horizontal axis of Figure 8a and similar figures must be corrected. The horizon axis for each stress amplitude, number of cycles should be from 1 to 50.

7. It is better to mention the numerical studies done in this field; “Numerical modeling of jointed rock samples under unconfined and confined conditions to study peak strength and failure mode. Arab J Geosci 14, 174 (2021)”

8. The text has many corrections in terms of editing and writing.

9. The reproducibility of the experiments is not discussed. Can it be said with certainty that all samples had the same microstructure?

10. Have XRD and XRF tests been performed on the samples and are their compositions known or not?

11. What is the application of the proposed relationships obtained in the second part of the manuscript and where can them be used.

Comments on the Quality of English Language

Moderate editing of English language required.

Author Response

Comments 1: It is better to remove relations a, b in Figure 1 (upper figure) and place them in another appropriate place.

Response 1: Agree, thank you for your advice.
The a and b relationships in Figure 1 have been removed.

Comments 2: What does “part II” mean in figure 2? Please explain.

Response 2: Thank you for your advice.
Part II of this research is to use the tested result for the inverse analysis of the stress state of the tunnel rock by applying the granite dynamic response and it’s constitutive model. This process has be explained with more detail in newly added figure 2. Thus, the workflow figure is reconstructed, with part II deleted.

Comments 3: The caption of Figure 3 should be corrected.

Response 3: Agree. The title of figure 3 has been changed.

Comments 4: The quality and clarity of the figures is very low, the legends are unreadable.

Response 4: Thank you for your comments.
We have adjusted and redrew most of the pictures to make them more readable.

Comments 5: Why frequency has a greater effect on the dynamic behavior of selected samples than the confining pressure.

Response 5: Very good question.
A common understanding believes confining pressure impose a stronger suppression on the dynamic modulus of rock in low frequency. Our study result shows (Fig. 7,8,13,18,19), the loading frequency cause more distinctive effect (shape of hysteresis loop, slope of the fitting curve, range of changing, etc.). This is a good indication for our future application purpose in the reverse analysis, in which, the stress condition can be differed from at different load test with controlling frequency.

As can be seen from Figure 8, when the loading frequency is 1 HZ, the shape of the hysteresis loop of granite is in the shape of pointed leaf. This shows the fast elastic deformation response and small plastic deformation of granite at this stage. As the frequency decreases, the area of the hysteresis loop decreases dramatically, which indicates the decreases of energy loss during loading and unloading. In contrast, the shape of the hysteresis loop is almost the same for granite under different confining pressures, indicating that the degree of elastic and plastic changes in granite is similar, and the difference in the energy loss is not very obvious. Similar supporting evidence can be found in "X.H. Ni, Failure characteristic of granite under cyclic loading with different frequencies, Applied Mechanics and Materials, 2014, pp. 1967-1970.".

Comments 6: The horizontal axis of Figure 8a and similar figures must be corrected. The horizon axis for each stress amplitude, number of cycles should be from 1 to 50.

Response 6: Agree. Figure 8. Has been adjusted.

Comments 7: It is better to mention the numerical studies done in this field; “Numerical modeling of jointed rock samples under unconfined and confined conditions to study peak strength and failure mode. Arab J Geosci 14, 174 (2021).

Response 7: Agree.
“Numerical modeling of jointed rock samples under unconfined and confined conditions to study peak strength and failure mode. Arab J Geosci 14, 174 (2021)”and other similar study result have been supplemented in the paper. The revision is marked in red.

Comments 8: The text has many corrections in terms of editing and writing.

Response 8: Thank you for your comments.
We have made several proof readings and corrected some grammar errors. The revision is marked in red.

Comments 9: The reproducibility of the experiments is not discussed. Can it be said with certainty that all samples had the same microstructure?

Response 9: Agree. Due to difficulty of sample preparation and complex loading configurations, each test is conducted only on one sample. The microstructure of each sample cannot the same, and thus, may lead to slightly different testing result. While, the fitting curve for each controlling parameter (frequency, confining pressure, amplitude, etc.) shows a clear and convergent trend, which is the most important result for our future use. And thus, we did not repeat our test, and would conclude that the test result is convincing from the data analysis. And the future plan is to test one or two more type of rock type, and compare their XRD and XRF component differences. And later, concrete will used as a study target for comparison. This could lead to some interesting findings.

Comments 10: Have XRD and XRF tests been performed on the samples and are their compositions known or not?

Response 10: Very good suggestion.
Currently, XRD and XRF on the acquired granite sample is not conducted yet. For the first step, we want to focus on only one type of rock available to us, this same rock will be tested in the field later. With the acquired rock test result, a simplified numerical model similar to the target inspection tunnel will be build, using the test data, to do the reverse analysis comparison. Later study will expand to two and more type of rocks. And, the mineralogical composition and microstructure analyze will be carried out to identify the reasons for different dynamic response behavior.

Comments 11: What is the application of the proposed relationships obtained in the second part of the manuscript and where can them be used.

Response 11: Thank you for your comments.
The purpose of this research is for the invert analysis of the stress state of granite rock tunnel wall, from the dynamic response model and the constitutive relationship we obtained in this study. The ideology and application setup is explained in figure 1 and newly added fugue 2. Detailed explanation is also added in the context marked in red. 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Manuscript entitle “A thorough investigation on the dynamic properties of granite under cyclic loading " offers valuable insights into the dynamic behavior of granites and provides a practical tool for predicting their response to cyclic loading. The paper's clear presentation, comprehensive experimental data, and potential applications in engineering and geology make it a noteworthy contribution to the field. The authors revised the manuscript significantly.      

Comments on the Quality of English Language

Manuscript entitle “A thorough investigation on the dynamic properties of granite under cyclic loading " offers valuable insights into the dynamic behavior of granites and provides a practical tool for predicting their response to cyclic loading. The paper's clear presentation, comprehensive experimental data, and potential applications in engineering and geology make it a noteworthy contribution to the field. The authors revised the manuscript significantly.      

Reviewer 2 Report

Comments and Suggestions for Authors

The authors responded to all my comments and modified the text where necessary. The text is much more understandable and clear. The figures are now readable.

The paper can now be published.

Reviewer 3 Report

Comments and Suggestions for Authors

there is no comment.

Comments on the Quality of English Language

Minor editing of English language required.