Prediction of Delayed Surface Subsidence Based on the Improved Knothe-n Model

Round 1

Reviewer 1 Report

The research aims to address the delayed surface subsidence caused by coal seam mining as a problem through an improved version of Knothe-n model. To this end, the data obtained from a FLAC3D-based numerical model and the maximum delayed surface subsidence in different period was calculated. The model is used to predict the surface subsidence in the Yutianbao subsidence area. The predicted model provides a scientific basis for environmental protection and safety management after coal seam mining. I read this manuscript carefully and the content is interesting. However, this manuscript needs to be carefully revised before it can be accepted. The following comments will be useful for enhancing the quality of this paper.

v  Title: please make the title concise, please change the title as “Prediction of delayed surface subsidence based on the improved knothe-n model”.

v Abstract:

·         The abstract is well written and organized, but rewrite the keywords: write the keywords according to the Alphabet (This will help others to search your paper easily).

·         Please double-check the Lines 16-18 in terms of grammatical errors

v  Introduction:

·         The length and the structure of the introduction is appropriate, but please mention the novelty of your research in the last paragraph of the introduction (highlight the novelty clearly).

·         Please diversify your citation; too many citations to your country

v Section 2:

·         Please make sure to write out the full abbreviated term (Line 83 'FLAC3D') for the first in the manuscript.

·         Please double-check the sentence Line 126 in terms of grammatical errors

·         Please double-check the equations to avoid any possible mistake

·        The method of data collection with numerical simulation should be clear; please write the details  

v Section 3,4:

·         I did not find any specific section for reporting your results; if it is possible please rename the title of the "section 3,4"

·         Please discuss the results in detail and make a comparison with the results of other research (cite related reference in this field)

·         It would be better to show the position of roof, floor, and surrounding rocks Line 108 in the Figure 4.

·         The content from Lines 227-243 is not clear; please double-check and rewrite.  

v Discussion: please add a discussion section to comparison your method with other methods, e.g., numerical [Smart Construction and Sustainable Cities, 1: 19(2023)], artificial intelligence [Smart Construction and Sustainable Cities, 1: 16(2023)][ Smart Construction and Sustainable Cities, 1: 8(2023)] etc. and also discuss the strength and limitation of your proposed method.

v  Section 5 (conclusion):

·        Please rewrite the first sentence of the conclusion; It is not clear grammatically

·         Please write the conclusion as a single paragraph; it should be as a home-taking message

·         Please write your methodology in detail in the conclusion and focus on your result

·         It is necessary to highlight the novelty of your research in the conclusion

·         Please add a section before the conclusion and write about the limitations and also insert a section before, within ,or after the conclusion for recommendations for future studies

v  References: Please delete the “[J]” in each reference;

v  Specific comments:

·         Please double-check the manuscript grammatically.

native edit is required.

Author Response

The research aims to address the delayed surface subsidence caused by coal seam mining as a problem through an improved version of Knothe-n model. To this end, the data obtained from a FLAC3D-based numerical model and the maximum delayed surface subsidence in different period was calculated. The model is used to predict the surface subsidence in the Yutianbao subsidence area. The predicted model provides a scientific basis for environmental protection and safety management after coal seam mining. I read this manuscript carefully and the content is interesting. However, this manuscript needs to be carefully revised before it can be accepted. The following comments will be useful for enhancing the quality of this paper.

(1) Title:

please make the title concise, please change the title as “Prediction of delayed surface subsidence based on the improved knothe-n model”.

Response: Thank you for your kind suggestion. I have used the title “Prediction of delayed surface subsidence based on the improved knothe-n model”. It is better than last one.

(2) Abstract:

The abstract is well written and organized, but rewrite the keywords: write the keywords according to the Alphabet (This will help others to search your paper easily).

Please double-check the Lines 16-18 in terms of grammatical errors.

Response: Thank you for your kind suggestion. I have written the keywords according to the Alphabet, “Keywords: Coal seam mining; FLAC3D; Knothe-n time function; Subsidence prediction”.

I have checked the corresponding paragraphs for grammatical errors and made corrections.

(3) Introduction:

The length and the structure of the introduction is appropriate, but please mention the novelty of your research in the last paragraph of the introduction (highlight the novelty clearly).

Please diversify your citation; too many citations to your country

Response: Thank you for your kind suggestion. I added a description of the relevant novelty in the last paragraph of the introduction, as follows “In view of this, The prediction of multi-parameter models is more accurate as they are based on a greater number of parameters. However, the difficulty associated with determining these parameters reduces the practicality of the model [21]. Knothe-n time function model proposed by Wang [22] is utilized for segmental cor-rection to propose a simple and more accurate prediction model.” Or “Finally, a novel Knothe-n segmentation function is obtained.”

To diversify the citations, I have added some citations from the International Journal of Rock Mechanics and Mining Sciences, and so on.

(4) Section 2:

Please make sure to write out the full abbreviated term (Line 83 'FLAC3D') for the first in the manuscript.

Please double-check the sentence Line 126 in terms of grammatical errors

Please double-check the equations to avoid any possible mistake

The method of data collection with numerical simulation should be clear; please write the details

Response: Thank you for your kind suggestion. I added the full name of the acronym after the first "FLAC3D" in the manuscript, FLAC3D (Fast Lagrangian Analysis of Continua 3D).

I carefully check the sentence on line 126 (now 156) for some corrections.” The average surface subsidence values of WC1-WC9 is 17.54 mm from July 2015 to July 2018 and from February 2018 to July 2018 is 0.8 mm, respectively”. Other paragraphs were checked and corrected accordingly.

The related formulas have also been modified, see lines 194-211 and line 241.

The data collection method for numerical simulation, and the data needed for the model I have added in rows 100-113 and Table 1

(5) Section 3,4:

I did not find any specific section for reporting your results; if it is possible please rename the title of the "section 3,4"

Please discuss the results in detail and make a comparison with the results of other research (cite related reference in this field)

It would be better to show the position of roof, floor, and surrounding rocks Line 108 in the Figure 4.

The content from Lines 227-243 is not clear; please double-check and rewrite.

Response: Thank you for your kind suggestion. I made some changes to sections 3 and 4 and renamed them, and I have added a new discussion section before the conclusion section, which will provide a discussion of the results of the study and comparisons with other research findings.

I have also labeled the corresponding text in Figure 4 .

And Lines 227-243 (now 285-301) have been checked and revised.

(6) Discussion:

please add a discussion section to comparison your method with other methods, e.g., numerical [Smart Construction and Sustainable Cities, 1: 19(2023)], artificial intelligence [Smart Construction and Sustainable Cities, 1: 16(2023)][ Smart Construction and Sustainable Cities, 1: 8(2023)] etc. and also discuss the strength and limitation of your proposed method.

Response: Thank you for your kind suggestion. I made some changes to sections 3 and 4 and renamed them, and I have added a new discussion section before the conclusion section, which will provide a discussion of the results of the study and comparisons with other

A separate discussion section has been added before the conclusion to compare the methods of this paper with other methods.

(7) Section 5 (conclusion):

Please rewrite the first sentence of the conclusion; It is not clear grammatically

Please write the conclusion as a single paragraph; it should be as a home-taking message

Please write your methodology in detail in the conclusion and focus on your result

It is necessary to highlight the novelty of your research in the conclusion

Please add a section before the conclusion and write about the limitations and also insert a section before, within, or after the conclusion for recommendations for future studies

Response: Thank you for your kind suggestion. I have merged the conclusion section into a single paragraph and rewrite the first sentence of the conclusion, At last I made a relevant novelty description.

“Conclusions: Based on the classical Knothe time model, the Knothe-n time function model is improved by segmentation processing, and obtained the new Knothe-n time function model that can more simplified and effectively to predict the delayed surface subsid-ence. Based on the measured data of the monitoring points in the subsidence area, numerical simulation is carried out by FLAC3D, and a large amount of data for model validation is obtained. The numerical simulation results are in good agreement with the calculation results of the improved model, which provides a new idea for future validation of the model. The improved model is used to predict the surface subsidence in the Yutianbao coal mining subsidence area. The root-mean-square error between the predicted and measured values of the maximum subsidence monitoring point is 1.12, and the root-mean-square error between the average predicted and measured values at the WC1-WC9 is 0.37, which verifies the accuracy and practicality of the improved Knothe-n time function model.”

I conclude with a new section before the conclusion that describes future research directions as well as model limitations

(8) References:

Please delete the “[J]” in each reference;

Response: Thank you for your kind suggestion. I have removed "[J]" in various places.

(9) Specific comments:

Please double-check the manuscript grammatically.

Response: Thank you for your kind suggestion. I checked the grammar throughout the manuscript. and corrected some grammatical errors.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript introduces an enhanced Knothe-N model for predicting the time history of surface subsidence in coal seam mining areas, accompanied by FLAC3D simulation results. However, insufficient documentation is provided regarding the finite element (FE) simulation details and the method used to link these results to improve the Knothe-N model. This raises concerns about the validity and scientific rigor of the approach, as it appears to deviate from essential physical perspectives.

Major issues

1) Lack of detailed documentation on the numerical simulation using FLAC3D, including the constitutive model, treatment of delayed settlement, mining processes, and justification for disregarding tectonic stress influences.

2) Inadequate justification for the validity of simulation results due to unclear presentation of monitoring points and lack of direct comparisons with monitored data.

3) It is not clear how to utilize the simulation data for the proposed fitting method. In other words, the meaning of the delay is not clear. Is it caused whether by stress release due to mining or by creep phenomena.

4) Equation (3) is deemed overly simplistic, possibly dependent on observational data and location-specific factors.

5) The relationship between Tables 3 and 4 are not understandable.

Minor issues

1) Unclear legend in Figure 1, suggesting relocation outside the figure for clarity.

2) Grammatical errors or typos observed throughout.

3) Table 1: Unit and value of the density

Author Response

The manuscript introduces an enhanced Knothe-N model for predicting the time history of surface subsidence in coal seam mining areas, accompanied by FLAC3D simulation results. However, insufficient documentation is provided regarding the finite element (FE) simulation details and the method used to link these results to improve the Knothe-N model. This raises concerns about the validity and scientific rigor of the approach, as it appears to deviate from essential physical perspectives.

Major issues

(1) Lack of detailed documentation on the numerical simulation using FLAC3D, including the constitutive model, treatment of delayed settlement, mining processes, and justification for disregarding tectonic stress influences.

Response: Thank you for your kind suggestion. The data collection method for numerical simulation, and the data needed for the model I have added in rows 100-113 and Table 1. Also, the rationale for not considering the effects of tectonic stresses is explained in lines 100-101, and the mining process is described in line 121.

(2) Inadequate justification for the validity of simulation results due to unclear presentation of monitoring points and lack of direct comparisons with monitored data.

Response: Thank you for your kind suggestion. This advice is important to me. First, I re-defined the monitoring points on the geological plan and added more points to make the monitoring data more representative, as shown in the figure 1.

The monitoring data are presented in Table 2 and compared with the model calculation results later on, with the comparison results located in Table 4.

(3) It is not clear how to utilize the simulation data for the proposed fitting method. In other words, the meaning of the delay is not clear. Is it caused whether by stress release due to mining or by creep phenomena.

Response: Thank you for your kind suggestion. Numerical simulations can provide a wealth of data for fitting the parameters of functional models, and they can be used for both fitting and model validation. Also, in the introduction at line 37, it is clarified that the delayed settlement is caused by stress release due to mining.

(4) Equation (3) is deemed overly simplistic, possibly dependent on observational data and location-specific factors.

Response: Thank you for your kind suggestion. This advice is important to me. In the modification of the formula, I perfected the different forms of formula 2, while further optimizing formula 3 to make it more general, and finally obtained formula 9.

(5) The relationship between Tables 3 and 4 are not understandable.

Response: Thank you for your kind suggestion. I have simplified the naming of Table 3 Table 4, both tables are a validation of the new function model, respectively, the maximum subsidence point in the function model versus the numerical simulation results and the average settlement of WC1-WC9 versus the field monitoring values.

Minor issues

(1) Unclear legend in Figure 1, suggesting relocation outside the figure for clarity.

Response: Thank you for your kind suggestion. Figure 1 has been adjusted for clarity accordingly.

(2) Grammatical errors or typos observed throughout.

Response: Thank you for your kind suggestion. I went through the entire piece of content again and made corrections where there were multiple grammatical errors and unclear expressions..

(3) Table 1: Unit and value of the density

Response: Thank you for your kind suggestion. I have corrected the units and values of the densities in Table 1.

Author Response File: Author Response.pdf

Reviewer 3 Report

The topic of the manuscript is interesting from the practical point of view. The main disadvantage of the work is weak scientific validity of the problem solved. The manuscript can be published in the journal Applied Sciences after some revision.

Point 1. The authors are quite right that surface subsidence occurs during coal seam mining. This phenomenon is well known and described in the literature. However, the manuscript under review lacks information on the manifestation of these processes outside the study area. The only reference to international experience is the work of S. Knothe, published in 1952. I would recommend the authors to make a more detailed description of the studied phenomenon. This will give the article a more scientific character.

Point 2. In addition to Point 1, it may be added that land subsidence is a process that accompanies practically all mineral and groundwater exploitation. It would be desirable to highlight this issue in the introduction.

Point 3. The quality of Fig. 1 needs to be improved. In addition, although the study area is quite large, the subsidence monitoring points are concentrated along a single line in the western part of the area. It is not clear from the figure why the points are so chosen. 

Point 4. Table 1 needs to be corrected. It lacks information on stratigraphy and the unit for density should be corrected.

Point 5. The FLAC3D software algorithm used in the paper should be described in general terms. The improvement of Knothe-n time function should be explained in more detail.

Author Response

The topic of the manuscript is interesting from the practical point of view. The main disadvantage of the work is weak scientific validity of the problem solved. The manuscript can be published in the journal Applied Sciences after some revision.

Point 1. The authors are quite right that surface subsidence occurs during coal seam mining. This phenomenon is well known and described in the literature. However, the manuscript under review lacks information on the manifestation of these processes outside the study area. The only reference to international experience is the work of S. Knothe, published in 1952. I would recommend the authors to make a more detailed description of the studied phenomenon. This will give the article a more scientific character.

Response: Thank you for your kind suggestion. This advice is important to me. To diversify the citations, I have added some citations from the International Journal of Rock Mechanics and Mining Sciences, and so on.

Point 2. In addition to Point 1, it may be added that land subsidence is a process that accompanies practically all mineral and groundwater exploitation. It would be desirable to highlight this issue in the introduction.

Response: Thank you for your kind suggestion. When revised, I began the introduction by emphasizing that land subsidence is actually a process that accompanies all mineral and groundwater extraction.

Point 3. The quality of Fig. 1 needs to be improved. In addition, although the study area is quite large, the subsidence monitoring points are concentrated along a single line in the western part of the area. It is not clear from the figure why the points are so chosen.

Response: Thank you for your kind suggestion. First, I re-defined the monitoring points on the geological plan and added more points to make the monitoring data more representative, as shown in the figure 1.  When I made the changes, I added reasons related to point selection in lines 94-96.

Point 4. Table 1 needs to be corrected. It lacks information on stratigraphy and the unit for density should be corrected.

Response: Thank you for your kind suggestion. I corrected the density units in Table 1 and also added bulk modulus and shear modulus, stratigraphic information is labeled in the geologic plan view.

Point 5. The FLAC3D software algorithm used in the paper should be described in general terms. The improvement of Knothe-n time function should be explained in more detail.

Response: Thank you for your kind suggestion. The data collection method for numerical simulation, and the data needed for the model I have added in rows 100-113.

In the modification of the formula, I perfected the different forms of formula 2, while further optimizing formula 3 to make it more general, and finally obtained formula 9.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

revision is not satisfied.

English is very poor

Author Response

The research aims to address the delayed surface subsidence caused by coal seam mining as a problem through an improved version of the Knothe-n model. To this end, the data obtained from a FLAC3D-based numerical model and the maximum delayed surface subsidence in different periods was calculated. The model is used to predict the surface subsidence in the Yutianbao subsidence area. The predicted model provides a scientific basis for environmental protection and safety management after coal seam mining. I read this manuscript carefully and the content is interesting. However, this manuscript needs to be carefully revised before it can be accepted. The following comments will be useful for enhancing the quality of this paper.

Response: Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions

(1) Title:

please make the title concise, please change the title to “Prediction of delayed surface subsidence based on the improved knothe-n model”.

Response: Thank you for your kind suggestion, We agree with this comment. we have used the title “Prediction of delayed surface subsidence based on the improved knothe-n model”. It is better.

(2) Abstract:

The abstract is well written and organized, but rewrite the keywords: write the keywords according to the Alphabet (This will help others to search your paper easily).

Please double-check the Lines 16-18 in terms of grammatical errors.

Response: Thank you for your kind suggestion. We agree with this comment. I have written the keywords according to the Alphabet, “Keywords: Coal seam mining; FLAC3D; Knothe-n time function; Subsidence prediction”.

I have checked the corresponding paragraphs for grammatical errors and made corrections.

(3) Introduction:

The length and the structure of the introduction are appropriate, but please mention the novelty of your research in the last paragraph of the introduction (highlight the novelty clearly).

Please diversify your citations; too many citations to your country

Response: Thank you for your kind suggestion. We agree with this comment. I added a description of the relevant novelty in the last paragraph of the introduction, as follows “Because of this, The prediction of multi-parameter models is more accurate as they are based on a greater number of parameters. However, the difficulty associated with determining these parameters reduces the practicality of the model [21]. Knothe-n time function model proposed by Wang [22] is utilized for segmental correction to propose a simple and more accurate prediction model.” Or “Finally, a novel Knothe-n segmentation function is obtained.”

To diversify the citations, I have added some citations from the International Journal of Rock Mechanics and Mining Sciences, and so on.

(4) Section 2:

Please make sure to write out the full abbreviated term (Line 83 'FLAC3D') for the first in the manuscript.

Please double-check the sentence Line 126 in terms of grammatical errors

Please double-check the equations to avoid any possible mistake

The method of data collection with numerical simulation should be clear; please write the details

Response: Thank you for your kind suggestion, we agree with this comment. I added the full name of the acronym after the first "FLAC3D" in the manuscript, FLAC3D (Fast Lagrangian Analysis of Continua 3D).

I carefully check the sentence on line 126 (now 156) for some corrections. Other paragraphs were checked and corrected accordingly.

The related formulas have also been modified, see lines 194-211 and line 241.

The data collection method for numerical simulation, and the data needed for the model I have added in rows 100-113 and Table 1

(5) Section 3,4:

I did not find any specific section for reporting your results; if it is possible please rename the title the "Sections 3,4"

Please discuss the results in detail and make a comparison with the results of other research (cite related reference in this field)

It would be better to show the position of the roof, floor, and surrounding rocks in Line 108 in Figure 4.

The content from Lines 227-243 is not clear; please double-check and rewrite.

Response: Thank you for your kind suggestion, we agree with this comment. I have made some adjustments to Section 3 and Section 4 by making the content of Section 4 the result validation and discussion part, adding 4.3 the Result analysis part, and also comparing the research results with other related references to highlight the superiority of the improved model.

I have also labeled the corresponding text in Figure 4 as shown.

And Lines 227-243 (now 285-301) have been checked and revised.

(6) Discussion:

please add a discussion section to compare your method with other methods, e.g., numerical [Smart Construction and Sustainable Cities, 1: 19(2023)], artificial intelligence [Smart Construction and Sustainable Cities, 1: 16(2023)][ Smart Construction and Sustainable Cities, 1: 8(2023)] etc. and also discuss the strength and limitation of your proposed method.

Response: Thank you for your kind suggestion, we agree with this comment. At the end of the results validation and analysis section in Section 4, I add a corresponding results analysis section that analyzes and discusses the results of the study and compares them to other methods, highlighting the superiority of the improved models.

(7) Section 5 (conclusio。n):

Please rewrite the first sentence of the conclusion; It is not clear grammatically

Please write the conclusion as a single paragraph; it should be as a home-taking message.

Please write your methodology in detail in the conclusion and focus on your result.

It is necessary to highlight the novelty of your research in the conclusion

Please add a section before the conclusion and write about the limitations and also insert a section before, within, or after the conclusion for recommendations for future studies.

Response: Thank you for your kind suggestion, we agree with this comment. I organized the conclusion section into a single paragraph and rewrote the first sentence of the conclusion to provide an overview of the article's research methodology and findings, to emphasize the novelty of the article, and added a paragraph at the end of the conclusion describing future research directions. And the limitations are described accordingly in the analysis part of section 4.3.

(8) References:

Please delete the “[J]” in each reference;

Response: Thank you for your kind suggestion, we agree with this comment. I have removed "[J]" in various places.

(9) Specific comments:

Please double-check the manuscript grammatically.

Response: I am so sorry for the inconvenience caused by the grammatical errors, your suggestions are very important for the revision of our paper, I have gone through the whole manuscript and corrected some grammatical errors.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript appears to have been revised diligently.

Table 1 indicates that a nonlinear simulation was performed, but crucial details such as the constitutive model and yield criterion used in the analysis were not explicitly provided in the text. Given their importance, we recommend including this information.

Author Response

(1) Table 1 indicates that a nonlinear simulation was performed, but crucial details such as the constitutive model and yield criterion used in the analysis were not explicitly provided in the text. Given their importance, we recommend including this information.

Response: Thank you for your kind suggestion. We agree with this comment. Therefore, we have added the constitutive model and yield criterion in lines 114 through 116. The elastoplastic model serves as the constitutive mechanical model, with the Mohr-Coulomb yield criterion constitutive model being chosen for calculation. Thanks again for your valuable advice.

Author Response File: Author Response.pdf

Round 3

Reviewer 1 Report

There is no innovation.

English is poor.