Model Test and Numerical Simulation Research of Reinforced Soil Retaining Walls under Cyclic Loads

Round 1

Reviewer 1 Report

The manuscript should be extensively revised before the manuscript could be accepted for publication.

1、More information on the dynamic loads applied in the model test should be given. Please clarify why the three loading amplitudes and four loading frequencies were used in the model test?

2、I think the abstract and conclusion can be more informative. The Abstract and Conclusion should be further improved to include not only the qualitative evaluation but also the quantitative analysis.

3、The language should be double-checked. I have seen several mistakes, and this article should proofread during the possible revision. After a double-check of the English used to try to avoid any typographical error.

4、The introduction and literature review section should be improved. Bring along as much as you can the baseline scientific proof for the knowledge you are going to explore in further sections. The literature is better to be updated based on the most recent works.

5、The results and discussion are suitable to be more described. I think Figure 12-14 requires more discussion. Also, try to remark the influential parameters as a graphical/statistical view.

6、The symbol of Chinese in Fig.16 should be replaced by the English.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The paper is of interest for the readers of Sustainability as it details ax experimental and numerical investigation of the stress diffusion characteristics of reinforced soil retaining walls under dynamic load.

The strength of the paper is mainly attributed to the twofold evaluation, experimental and numerical. Moreover, the results are clearly discussed.

However, the paper is also characterised by some weaknesses. Firstly, both the novely and the practical consequences of the study should have been clearly stated. Moreover, the rationale of the research should have been pointed out. Finally, the literature review is to be completed with more references and the English must be strongly revised and improved.

From the above it follows that, in the Reviewer's opinion, the paper cannot be accepted in this form as it is to be reconsidered after Major Revisions.

Both the major and minor issues of the paper are listed below.

In the Asbtract: 

1) two main things are missing in the abstract, such as highlighting both the novelty and the consequences which may derive in the current practice. It is the Reviewer's opinion that they have to be added in the paper.

 

In the Introduction:

1) line 32: A thorough list of papers on retaining walls is available in the literature and is not covered in this Introduction. Reference to both old and recent papers is required, such as Michalowski (1998), Gaudio et al. (2018) and Halder & Chakraborty (2022). Please add these reference to the Introduction so as to give a deeper framework to the paper.

References:

Halder K, Chakraborty D (2022). Estimation of seismic active earth pressure on reinforced retaining wall using lower-bound limit analysis ansd modified pseudo-dynamic metho. Geotextiles and Geomembranes, in press, doi: 10.1016/j.geotexmem.2022.10.001 

Gaudio D, Masini L, Rampello S (2018). A performance-based approach to design reinforced-earth retaining walls. Geotextiles and Geomembranes 46 (4), 470–485

Michalowski R (1998). Soil reinforcement for seismic design of geotechnical structures. Computer and Geotechnics, 23 (1): 1–17

2) line 33: "makes" should replace "make";

3) line 38: which kind of model tests? Please explain thoroughly;

4) line 38: who did find? Please explain;

5) line 44: "less" than what? Please clarify.

 

In section "2. Experimental study":

1) Table 1: the value reported for the maximum dry unit weight is not correct. It must be checked as it is not realistic;

2) Table 2: which kind of "peak strain"? Is te axial one the Author are referring to? Please clarify;

3) line 66: here a brief remind of 1g scaling laws  is required. Please add, also showing the limitations (as at 1g all the scaling laws cannot be imposed unfortunately);

4) lines 78-79: many more details about the loading scheme are required, i.e. are the loadings applied in terms of accelerations or displacements? Please clarify. Moreover, a key aspect is not clear from the description: is the load applied along the horizontal or the vertical direction?

 

In section "4. Numerical simulation":

1) line 160: which finite element code has been adopted? Which version? Please provide many more details so that the Author would be able, in principle, to reproduce the analyses carried out by the Authors;

2) Table 6: this is a quite crude approximation of the geogrid behaviour, as it is well known from the literature that their strenght may strongly affect the wall behaviour under both cyclic and dynamic loading: please highlight the influence of this strong assumption;

3) Table 7: please replace "frication" with "friction". Moreover, is the elasticity modulus the Young's modulus? Please clarify;

4) line 169: how is Rinter defined? Please either provide its equation or the reference to the manual of the code adopted for the numerical analyses;

5) line 169: did the Author carry out any preliminary analysis to determine the size of the model so as to limit dynamic boundary effects? Please explain thoroughly, as this may affect the validity of all the numerical analyses which are reported in the study;

line 302: here the safety factor of the wall should be reported, referring both to the conditions preceding the earthquake and during the earthquake. Moreover, on this is important stating that the wall is still far from limit conditions under the amplitude of 20 kPa, which is quite demanding indeed.

 

In section "5. Discussion":

1) lines 346-347: this is clearly a potentially dangerous statement: therefore, an example of design should be proposed here to show how much the length of reinforcement layers can be reduced. Moreover, are the conclusions drawn from the results of the paper general or valid for the cases at hand (or similar) only.

 

In section "6. Result":

1) line 348: This section is not to be named "Results" but "Conclusion" or "Concluding remarks" instead. Please edit.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

1. Introduction: The authors should state clearly the technical problems and the limitations of the previous studies. The connections between the previous studies and this study should be improved.

2. Experimental study: More details of the materials used in the model tests should be introduced. What was the size of the pressure cells? Would the pressure cell affect the stress diffusion? Why were 60-80 kPa, 60-100 kPa, and 60-120 kPa stress amplitudes and 4 Hz, 6 Hz, 8 Hz, and 10 Hz loading frequencies applied?

3. Numerical simulation: The behavior of reinforced soil retaining walls subjected to dynamic load is a dynamic problem. In this regard, there are many limitations with the numerical simulation. For example, the Mohr-Coulomb model and displacement boundaries are unsuitable, and a dynamic constitutive model and dynamic boundaries (e.g., infinite element boundary and viscoelastic dynamic boundary) should be used instead. In addition, the detail of the model’s mesh that greatly influences the results is missing.

4. Results: Some key results are poorly explained. The comparison between the numerical results and the monitoring results should be strengthened. The study’s limitations are not described.

5. Conclusion: “Result” should be replaced with “Conclusions”. The conclusion points were not novel.

6. There are many long sentences (e.g., Pages 87-92) that are hard to understand; Some technical terms are not properly expressed, which reduces the paper’s readability.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The manuscript has been sufficiently revised according to the comments. It can be accepted in the present form.

Reviewer 2 Report

The Authors followed all Reviewer's comments and suggestions, which made the presentation and discussion of results strongly improve.

In the Reviewer's opinion, the paper can be now safelyl accepted and published as it is.

Reviewer 3 Report

The manuscript has been improved based on my previous comments. I don't have further comments.