Evaluation of the Effect of Varying the Angle of Asphaltic Concrete Core on the Behavior of the Meijaran Rockfill Dam

Round 1

Reviewer 1 Report

The manuscript entitled "Evaluation of the effect of varying the angle of an asphaltic concrete core on the static and dynamic behavior of a rockfill dam: A case study of the Meijaran dam” evaluated the static and seismic behavior of the Meijaran dam in Iran, Mazandaran, for three core angles of 90°, 60° and 45°. The evaluation was conducted using the FLAC 2d software.

The manuscript lacks quality and clarity and cannot be accepted in the current format. I highly suggest rejecting this manuscript in the current format.

Comments:

• Technical writing is very poor to be accepted. Therefore, it should be improved throughout the manuscript.
• Most of the abstract described the problem and a little about the used methodology. Moreover, the main conclusion of this study should be highlighted in the abstract.
• Line 12: I think, no need for "its".
• Lines 20-21: It is a general conclusion. Do you think any inclined angle will give the same behavior? I mean angle 60 will be the same as angle 45?
• Lines 21-22: If the results from the dynamic analysis are available from tests, why did the authors conduct this analysis? Did you conduct a parametric study?
• Lines 101-102: The authors confirmed that "several FEM are available". What is the new approach that this manuscript presents? The authors should highlight the novelty of this research work. The authors mentioned in lines 137-139 that "the effect of changing the angle of the core on the static and dynamic behavior of the dam has rarely been investigated". Are the authors sure about this?
• Section 2: In Figure 1, this reviewer can see different components in the dam cross-section. However, a blank mesh was provided in Figure 2. The authors should provide more illustrations and details about the generated model in Figure 2 and in the text.
• Lines 166-167: Why did the authors choose this depth for foundation? More information about the boundary conditions that represent the continuity of soil should be provided.
• Section 3: More information about the used elements in this model as well as the material properties. How did the authors model the contact between the different layers of the dam, where the authors mentioned that the dam consists of 25 layers.
• Line 172: A reference for the used software should be cited to define which version is used.
• Line 193: The order of this sub-section is not matching with the previous one. This should be corrected throughout the manuscript.
• Lines 211-212: How did the authors apply this static pressure?
• Lines 215-216: How did the authors represent the contact between these parts to capture this differential settlement?
• Line 234: The word "cor" should be "core".
• All contour figures (4, 5, ……): Why the authors did not include the contours of the soil under the dam? The soil is included in Figure 2.
• Figure 10: The dam looks like a triangle in all other figures. Why it is different in this figure?
• Section 4: Where is the comparison? The authors did not provide any comparisons in terms of vertical or lateral displacements. This reviewer cannot understand the purpose of this section.
• The authors provided nine conclusion bullets. This reviewer believes that the provided model and results are not supporting these bullets.

Author Response

First of all, I would like to thank you for taking the time to read our article. Certainly, your advice is very valuable to us and will make this article better. Efforts have been made to follow and respond to all the comments made by you step by step.

The manuscript entitled "Evaluation of the effect of varying the angle of an asphaltic concrete core on the static and dynamic behavior of a rockfill dam: A case study of the Meijaran dam” evaluated the static and seismic behavior of the Meijaran dam in Iran, Mazandaran, for three core angles of 90°, 60° and 45°. The evaluation was conducted using the FLAC 2d software.

The manuscript lacks quality and clarity and cannot be accepted in the current format. I highly suggest rejecting this manuscript in the current format.

Comments:

• Technical writing is very poor to be accepted. Therefore, it should be improved throughout the manuscript.

The article has been completely reviewed by a native English person. However, the whole article was reviewed by someone else and the minor problems in the text were fixed. However, if there is a problem, please mention it specifically to fix it.

• Most of the abstract described the problem and a little about the used methodology. Moreover, the main conclusion of this study should be highlighted in the abstract.

According to your advice and of course the limitation of the number of words, in the summary of the article, the software used, the constitutive model and the purpose and the main conclusion of the article were added. Changes are visible with red highlight.

• Line 12: I think, no need for "its".

Thanks for your attention. Action done.

• Lines 20-21: It is a general conclusion. Do you think any inclined angle will give the same behavior? I mean angle 60 will be the same as angle 45?

This conclusion is presented specifically for the Meijaran dam. As mentioned in line 116 of the revised manuscript, the International Commission on Large Dams (ICOLD) recommends the use of angled cores, as they perform better. The main purpose of this article is to examine this issue, which ultimately matches to the ICOLD recommendation. However, studies have shown usually 60 degrees angled core is better than 45 degrees angled core. This topic is mentioned in section 3 of the manuscript and specifically in the conclusion of the article in lines 387 and 392.

• Lines 21-22: If the results from the dynamic analysis are available from tests, why did the authors conduct this analysis? Did you conduct a parametric study?

In line 21, the results of dynamic analyses refer to the analyzes performed in this article. Analyses of the Meijaran dam with three different core angles have not been done before this article.

• Lines 101-102: The authors confirmed that "several FEM are available". What is the new approach that this manuscript presents? The authors should highlight the novelty of this research work. The authors mentioned in lines 137-139 that "the effect of changing the angle of the core on the static and dynamic behavior of the dam has rarely been investigated". Are the authors sure about this?

According to your recommendation, in lines 112-129, the purpose and innovation of the article have been added. In embankment dams, the effect of angled core on dynamic and static behavior has been studied, but in rockfill dams, it has been rarely considered. This sentence was also added to the text of the introduction in manuscript.

• Section 2: In Figure 1, this reviewer can see different components in the dam cross-section. However, a blank mesh was provided in Figure 2. The authors should provide more illustrations and details about the generated model in Figure 2 and in the text.

In FLAC software, the model generated for the dam is the same as figure 2, and the characteristics and constitutive models are applied in each area using the material tool. After applying the constitutive models, FLAC software is displayed in the below figure and has no more details than Figure 2. The details of this modeling are also explained in Section 3. Due to this issue, the only dam mesh is presented in articles related to the dam.

• Lines 166-167: Why did the authors choose this depth for foundation? More information about the boundary conditions that represent the continuity of soil should be provided.

Thank you for your attention, unfortunately, the reason for using this depth was not mentioned in the manuscript, which was added in line 152 with a red highlight. The reason for using this depth is the recommendation of ICOLD, which recommends that in the studies conducted, the depth of the modeled foundation be at least equal to the height of the dam.

• Section 3: More information about the used elements in this model as well as the material properties. How did the authors model the contact between the different layers of the dam, where the authors mentioned that the dam consists of 25 layers.

In dams with asphaltic concrete cores, the shell of the dam and the core are made simultaneously at the same levels. In numerical modeling and in articles related to the dam, to bring the dam behavior closer to the real behavior, the dam is not built together and is done as an embankment layer. In this paper, by considering the height of the dam, 25 layers are suitable for the embankment. In this method, each layer of the dam is embanked on the previous layer and the necessary analyzes are performed. In this research, the elements and their contact between them are not discussed at all, and only the embankment in 25 layers is meant.

• Line 172: A reference for the used software should be cited to define which version is used.

Action done. Reference 27 notes the software version.

• Line 193: The order of this sub-section is not matching with the previous one. This should be corrected throughout the manuscript.

Thanks for your attention. Action done.

• Lines 211-212: How did the authors apply this static pressure?

There is a command called apply pressure in FLAC software. Using this command, water pressure can be applied as hydrostatic pressure on the dam.

• Lines 215-216: How did the authors represent the contact between these parts to capture this differential settlement?

Unfortunately, I did not understand exactly what you meant. But in general, meshing related to the body and core is created in FLAC software. Then the constitutive model is applied and after the analysis, the plot is received. If you mean something else, please let us know.

• Line 234: The word "cor" should be "core".

Thanks for your attention. Action done.

• All contour figures (4, 5, ……): Why the authors did not include the contours of the soil under the dam? The soil is included in Figure 2.

Since the main purpose was to study the behavior of the dam body due to changes in the angle of the core and to try not to lengthen the text for no reason, the software output figure contain only the important and discussed parts.

• Figure 10: The dam looks like a triangle in all other figures. Why it is different in this figure?

This figure is also triangular, but in FLAC software, the stress plot is displayed in this way.

• Section 4: Where is the comparison? The authors did not provide any comparisons in terms of vertical or lateral displacements. This reviewer cannot understand the purpose of this section.

The purpose of Section 4 is to compare the results of numerical analysis with existing laboratory results to confirm the accuracy of the modeling and also to get a better view of this type of dam. The only available laboratory data was the centrifuge test on the Meijaran dam with a vertical core and no test was performed on the angled core. Therefore, it is not possible to compare different angles of the cores and only the analysis performed on the vertical cores can be compared with the experimental results. To clarify this issue, changes were made in this section, which can be seen in red highlight.

• The authors provided nine conclusion bullets. This reviewer believes that the provided model and results are not supporting these bullets.

According to your recommendations, the conclusion was revised, which is shown in the red highlight.

Reviewer 2 Report

Interesting study with good data presentation, however improvement is required as follow:

1. Title lengthy and seem like abstract. Should be brief and reflected to main content of article.
2. Abstract not enough information. Background study, problem statement & points out research gaps, aims & objectives, summary of methods, and novelty of research study are not clearly presented.
3. Citations too old and not acceptable for current study ((1991, 1999, 2002 and etc.). 5 years old are required to verified the research study.
4. Conclusions lengthy and not reflected to aims of study.

Author Response

Interesting study with good data presentation, however improvement is required as follow:

First of all, I would like to thank you for taking the time to read our article. Certainly, your advice is very valuable to us and will make this article better. Efforts have been made to follow and respond to all the comments made by you step by step.

1. Title lengthy and seem like abstract. Should be brief and reflected to main content of article.

According to your recommendations, the title of the article has been modified and “Evaluation of the effect of varying the angle of asphaltic concrete core on the behavior of the Meijaran rockfill dam” is the new title.

1. Abstract not enough information. Background study, problem statement & points out research gaps, aims & objectives, summary of methods, and novelty of research study are not clearly presented.

According to your recommendations, revisions were made to the structure of the abstract and introduction of the manuscript. Also, the gaps in previous research and the purpose and innovation of this article were clearly stated. These changes can be seen in red highlighted in the summary and introduction.

1. Citations too old and not acceptable for current study ((1991, 1999, 2002 and etc.). 5 years old are required to verified the research study.

In this article, an attempt has been made to use new articles as well. Unfortunately, in recent years, attention to rockfill dams and their behavior has decreased. Almost all articles related to the static and dynamic behavior of rockfill dams are presented in this article.

1. Conclusions lengthy and not reflected to aims of study.

According to your recommendations, the conclusion was revised, which is shown in the red highlight.

Reviewer 3 Report

The performance of using asphaltic concrete cores in dams under static and dynamic behavior was simulated and discussed in this study. It adds important values to the durable design of rockfill dams. The research program was well planned and the research findings were presented and discussed properly. Therefore it can be accepted for publication after carrying on minor revision. Here are some recommendations for improvement: 1) Line 382 mentioned Figure 16, so where is this figure? 2) Table 2 shows that the differences between numerical model and centrifuge model is larger than 10%. Could this accuracy be improved? 3) are there any laboratory works to approve the simulation findings? Lab tests, including deformation resistance, moisture resistance, ageing resistance and fatigue behavior, would be nice to verify the simulation results. 4) Horizontal displacement at several specified locations show be provided, instead of only giving the distribution mapping figures as Figure 5 shows. Same comments for Figure 4, Figure 8, Figure 10 and Figure 11.

Author Response

The performance of using asphaltic concrete cores in dams under static and dynamic behavior was simulated and discussed in this study. It adds important values to the durable design of rockfill dams. The research program was well planned and the research findings were presented and discussed properly. Therefore, it can be accepted for publication after carrying on minor revision. Here are some recommendations for improvement:

First of all, I would like to thank you for taking the time to read our article. Certainly, your advice is very valuable to us and will make this article better. Efforts have been made to follow and respond to all the comments made by you step by step.

 1) Line 382 mentioned Figure 16, so where is this figure?

Thanks for your hint. Figure 15 should have been mentioned and corrected in the text.

2) Table 2 shows that the differences between numerical model and centrifuge model is larger than 10%. Could this accuracy be improved?

In Table 2, the difference between the numerical analysis and the centrifuge test for Shear strain of asphaltic core and Lateral displacement of asphaltic core is about 9%, which is less than 10. (For example in shear strain 32/35=0.9)

3) are there any laboratory works to approve the simulation findings? Lab tests, including deformation resistance, moisture resistance, ageing resistance and fatigue behavior, would be nice to verify the simulation results.

Unfortunately, not many laboratory tests have been performed on the Meijaran dam, and the only available lab test is the centrifuge test performed by Baziar et al., which has only examined the behavior of the dam for the vertical core. In section 4 of this article, this test is compared with numerical results.

4) Horizontal displacement at several specified locations show be provided, instead of only giving the distribution mapping figures as Figure 5 shows. Same comments for Figure 4, Figure 8, Figure 10 and Figure 11.

Based on your recommendation, values were added to all figures.

Round 2

Reviewer 1 Report

The authors have addressed most of the reviewer's comments.

Reviewer 2 Report

The revised manuscript is acceptable.