Analysis of Slope Stability with Different Vegetation Types under the Influence of Rainfall

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Comments:

1) Table 1: Please complete the list of symbols provided as footnote below the table.

2) Section 2.2: Please provide a GIS or geographical location map where the samples were roughly taken as a general appreciation of the site.

3) Discuss in greater details how your residual volume soil moisture and saturated soil moisture, alpha, n, m shape parameters come about so that these values can be appropriately chosen and also for the benefit of the readers. At the moment no explanation nor references are provided for these key parameters that will govern the stability of the slopes.

4) Fig 2: How do you provide the natural moisture content values to your slope being analysed?

5) As most slope stability analyses are governed by saturation due to diminishing suction under sustained rain intensity, can your model show the fluctuation of the phreatic surface that is being developed in the slope body? This is important as the location of the phreatic surface will dictate the failure location.

6) Line 163: Please discuss with greater clarity how your SWCC curve can be input into the software and in what format? Did you just punch in the respective values or you upload a file to the software?

7) Fig 3b: Please insert the c’ and phi’ values on your respective shear strength plots.

8) Fig 3b. Y-axis should be ‘shear stress’ not ‘shear strength’.

Comments on the Quality of English Language

Good, but check again for typo, as commented.

Author Response

Dear reviewers:

     Thank you for your review comments, we read your comments carefully and made the following changes and responses based on your suggestions.

Question（1）：Table 1: Please complete the list of symbols provided as footnote below the table.

Answer: Changes have been made in response to your suggestion to explain the symbols in the table, see notes. See lines 101-102.

Question（2）：Section 2.2: Please provide a GIS or geographical location map where the samples were roughly taken as a general appreciation of the site.

Answer: Sampling point locations, on-site vegetation sample plots, and sampling profiles have been added in response to your suggestions. See Figures 1 and 2.

Question（3）：Discuss in greater details how your residual volume soil moisture and saturated soil moisture, alpha, n, m shape parameters come about so that these values can be appropriately chosen and also for the benefit of the readers. At the moment no explanation nor references are provided for these key parameters that will govern the stability of the slopes.

Answer: Our soil-water characteristic curves are obtained by VG model fitting using RETC data analysis software. α is related to the inlet state of the soil, the parameter n is related to the pore size distribution of the soil, and the parameter m is related to the overall symmetry of the soil characteristic curves. Because our slope model uses the coupling of the solid mechanical properties of the soil with the hydraulic properties, for the hydraulics part we use the unsaturated infiltration model-Richards' equation model, all the control equations we have discussed so far assume that the porous medium is fully saturated, while the Richards' equation describes the movement of water in unsaturated soils, and it is necessary to input these parameters into the model as well. In the text we have added corresponding explanations, see lines 135-142.

Question（4）： Fig 2: How do you provide the natural moisture content values to your slope being analysed?

Answer: Since soil moisture content is different under different vegetation types in the field, to exclude the effect of initial moisture content, we standardise that the natural moisture content is the same.

Question（5）： As most slope stability analyses are governed by saturation due to diminishing suction under sustained rain intensity, can your model show the fluctuation of the phreatic surface that is being developed in the slope body? This is important as the location of the phreatic surface will dictate the failure location.

Answer:In order to explain more clearly, we added the rainfall conditions, the effective saturation inside the slope changes in the map, we initially set up a 10m submerged layer, after 5 days of rainfall different soil effective saturation performance of different soils, the submerged surface of the soil also changed, as shown in Figure 7 as shown.

Question（6）： Line 163: Please discuss with greater clarity how your SWCC curve can be input into the software and in what format? Did you just punch in the respective values or you upload a file to the software?

Answer:The soil-water characteristic curves were obtained by VG model fitting using RETC data analysis software. Data files were uploaded to the RETC data analysis software in RET format. See lines 181-183.

Question（7）： Fig 3b: Please insert the c’ and phi’ values on your respective shear strength plots.

Answer: Figure 3b has been changed and the values c' and phi' have been inserted.

Question（7）： Fig 3b. Y-axis should be ‘shear stress’ not ‘shear strength’.

Answer: Thanks for the suggestion, it was our mistake. It has been changed, see figure 3b.

Comments on the Quality of English Language ：Good, but check again for typo, as commented.

Answer:The article has been checked

Thank you for your advice on my post and I look forward to your response.

 Kind regards,

Wei Shui

 

Reviewer 2 Report

Comments and Suggestions for Authors

Notes:

1. The manuscript lacks a subsection on the main limitations of the study. Are the findings universal? I doubt it. Be critical of your results.

2. In the Discussion section, I recommend strengthening the discussion of the results in the context of international experience of similar studies.

3. Figures 2 and 5. The horizontal and vertical axes should have titles.

4. The authors need to improve the readability of Figure 4.

Comments on the Quality of English Language

Improvement of the English language of the manuscript is required.

Author Response

Dear reviewers:

     Thank you for your review comments, we read your comments carefully and made the following changes and responses based on your suggestions.

Qustion1. The manuscript lacks a subsection on the main limitations of the study. Are the findings universal? I doubt it. Be critical of your results.

Answer: In response to your suggestion, we have added subsections related to the limitations of the study, see lines 362-366 of the article.

Qustion2. In the Discussion section, I recommend strengthening the discussion of the results in the context of international experience of similar studies.

Answer: Changes have been made in response to the suggestion to add a comparison, see the Discussion section of the article, lines 320-324.

Qustion3. Figures 2 and 5. The horizontal and vertical axes should have titles.

Answer: A corresponding explanation has been added to Figure 2, the image is derived from the model and is not a coordinate but a scale of the slope, representing the scale size of the slope.

Qustion4. The authors need to improve the readability of Figure 4.

Answer: In response to your suggestion, we have added formulas for the various agglomerate indicators in Section 3.2 to improve the reader's understanding of Figure 4. See lines 231-239 of the article.

Comments on the Quality of English Language:Improvement of the English language of the manuscript is required.

Answer: The article has been scrutinised and the appropriate agency, touched up.

Thank you for your advice on my post and I look forward to your response.

 Kind regards,

Wei Shui

Reviewer 3 Report

Comments and Suggestions for Authors

The authors analyze the impact of the different vegetation types on the slope analysis. The idea is very nicely explained, and the literature review gives strong insight into the state-of-the-art of the analyzed topic. The methodology is well defined, although some lack in the original manuscript must be in the paper's corrections. I am suggesting the major revisions.

-The authors didn't enclose a map of the analyzed location or pictures of the field situation.

-The authors should provide a sensitive analysis of the amount of rainfall duration, not only two of them. 

-Figure 5 requires titles and units of all axes. 

-Which models were used for the slope stability analysis? 

-all figures are of a not-so-high quality. 

 

Author Response

Dear reviewers:

     Thank you for your review comments, we read your comments carefully and made the following changes and responses based on your suggestions.

Comments and Suggestions for Authors

The authors analyze the impact of the different vegetation types on the slope analysis. The idea is very nicely explained, and the literature review gives strong insight into the state-of-the-art of the analyzed topic. The methodology is well defined, although some lack in the original manuscript must be in the paper's corrections. I am suggesting the major revisions.

Question1-The authors didn't enclose a map of the analyzed location or pictures of the field situation.

Answer: Location maps and site pictures have been added, see Figures 1 and 2.

Question2-The authors should provide a sensitive analysis of the amount of rainfall duration, not only two of them.

Answer: In the model, we can observe each time period, the change of the internal stress and saturation of the slope, and the overall trend of the change is constant, considering too many pictures, we only take the initial and the last day to make a comparison. In order to analyse the changes inside the slope caused by rainfall, we added a cloud diagram of the effective saturation of the slope over time, see Fig. 7. and added the results and analyses of this part of the content, see lines 246-249 and lines 320-324.

Question3-Figure 5 requires titles and units of all axes.

 Answer: A corresponding explanation has been added to Figure 2, the image is derived from the model and is not a coordinate but a scale of the slope, representing the scale size of the slope.

Question4-Which models were used for the slope stability analysis?

Answer: Our slope modelling uses a coupling of the solid mechanics properties of the soil with the hydraulics properties. The solid mechanics interface is based on solving the equations of motion and the intrinsic model of the solid material and calculating results such as displacements, stresses and strains. For the soil hydraulic properties part, we use the unsaturated infiltration model-Richards' equation model; all the governing equations we have discussed so far assume that the porous medium is fully saturated, while the Richards' equation describes the movement of water in unsaturated soils.

Question5-all figures are of a not-so-high quality.

Answer: We have added and modified the pictures, added Figure 1,2,7. The original pictures have also been modified.

Thank you for your advice on my post and I look forward to your response.

 Kind regards,

Wei Shui

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Paper is now ok for publication.

Comments on the Quality of English Language

Paper is now ok for publication.

Author Response

Dear reviewers:

   First of all, I would like to thank you for your valuable comments and suggestions on my thesis, which have played a very important role in improving my thesis and research level. Furthermore, I will keep up the spirit of research and continue to work hard in my future research. Finally, I would like to thank you again for approving my paper and allowing it to be published.

I look forward to your response.

Kind regards,

Wei Shui

Reviewer 3 Report

Comments and Suggestions for Authors

The authors were satisfied with all my comments except this one

In the model, we can observe each time period, the change of the internal stress and saturation of the slope, and the overall trend of the change is constant, considering too many pictures, we only take the initial and the last day to make a comparison. In order to analyse the changes inside the slope caused by rainfall, we added a cloud diagram of the effective saturation of the slope over time, see Fig. 7. and added the results and analyses of this part of the content, see lines 246-249 and lines 320-324.

I am not satisfied with this answer. The first and last days of observing a stochastic event like precipitation are out of the scope of any serious research. 

The authors should provide the mentioned analysis. If there are too many pictures, such should be put in the Appendix. I do not see the problem. 

Author Response

Dear reviewers:

     I would like to thank you for your valuable comments and suggestions on my thesis, which have played a very important role in improving my thesis and research level.We read your comments carefully and made the following changes and responses based on your suggestions.

Reviewers' comments

The authors were satisfied with all my comments except this one.

In the model, we can observe each time period, the change of the internal stress and saturation of the slope, and the overall trend of the change is constant, considering too many pictures, we only take the initial and the last day to make a comparison. In order to analyse the changes inside the slope caused by rainfall, we added a cloud diagram of the effective saturation of the slope over time, see Fig. 7. and added the results and analyses of this part of the content, see lines 246-249 and lines 320-324.

Quetion:

I am not satisfied with this answer. The first and last days of observing a stochastic event like precipitation are out of the scope of any serious research. The authors should provide the mentioned analysis. If there are too many pictures, such should be put in the Appendix. I do not see the problem. 

Answer: Thank you very much for your suggestion, according to your suggestion I have made a modification to increase the number of pictures and also add a graph of the change of effective soil saturation inside the slope after rainfall. In this way, we can have a clearer understanding of the changes in the interior of the slope as the rainfall progresses. According to the results of the experiment, we have also made corresponding analyses, and found that under rainfall conditions, the internal strain and effective saturation of tree slopes change less, and the slopes are also more stable.

Thank you for your advice on my post and I look forward to your response.

 Kind regards,

Wei Shui