An Experimental and Numerical Investigation of the Characteristics and Mechanism of Spacing Cracks in Loess Considering the Size Effect
Round 1
Reviewer 1 Report
Cracks are known to form easily in loess under arid and semi-arid climates, creating preferential channels for water flow and reducing the mechanical properties of the soil. The objective of this study is to investigate the different modes of cracking and the laws governing the spacing of cracks, such as their insertion and saturation. However, the paper requires significant improvements in its writing. The authors should carefully consider and address the following comments:
1. The introduction should provide a clearer explanation of why cracks are more likely to develop in loess under arid and semi-arid climates.
2. The objectives of the study should be stated more explicitly, focusing on the specific aspects of cracking modes and spacing crack laws that will be investigated.
3. The writing style throughout the paper needs improvement, with a particular emphasis on clarity and coherence. Complex ideas should be expressed in a concise and straightforward manner.
4. The methodology section should be expanded to provide a detailed description of the experimental setup and the procedures used to analyze the cracking modes and spacing crack laws.
5. Results should be presented in a more organized manner, using clear headings and subheadings to guide the reader through the findings. Tables, graphs, or diagrams can be included to enhance the presentation of data.
6. The discussion section should thoroughly analyze the results and relate them back to the research objectives. It should also discuss the implications of the findings and their significance in the broader context of soil mechanics.
7. The conclusion should summarize the main findings of the study and provide a clear statement of their implications. It should also identify any limitations or potential areas for further research.
8. Careful proofreading is needed throughout the paper to correct any grammatical or typographical errors.
9. By addressing these comments, the authors can significantly improve the clarity and quality of their paper.
10. Absolutely, improving the English language usage in the entire manuscript is crucial for enhancing clarity, coherence, and grammatical accuracy, which will greatly enhance the overall quality of the document. It is important to carefully revise the text, ensuring that ideas are expressed clearly and concisely, and that the grammar and sentence structure are correct. This will help to convey the research findings effectively and facilitate better understanding for the readers.
11. The introduction section would greatly benefit from incorporating previous works to highlight the progressive nature of this research. By including references to relevant studies, methodologies, or theoretical frameworks that have contributed to the field, the authors can establish the context and significance of their study. Here are a few suggested references for the authors to consider: https://doi.org/10.1016/j.probengmech.2022.103315; http://dx.doi.org/10.1080/10807039.2016.1278518; https://doi.org/10.1007/s10653-019-00293-8
12. By incorporating these references, the authors can provide a solid foundation for their research and demonstrate how their study builds upon existing knowledge in the field. This will enhance the credibility and relevance of their work.
13. In Fig. 1, it would be beneficial to include maps of China and its provinces to provide geographical context to the study. This will help readers understand the specific locations where the research was conducted and the distribution of arid and semi-arid regions within China.
14. Regarding Fig. 2, if it is deemed not useful or does not contribute significantly to the study, it can be removed from the manuscript. It is important to prioritize figures and visuals that effectively support the research findings and enhance the understanding of the study.
15. Additionally, including real photos of the experimental setup would be a valuable addition to the manuscript. Visual representations of the experimental apparatus can provide readers with a clearer understanding of the research setup and aid in the interpretation of the results. These photos can be included as separate figures or incorporated into the relevant sections of the manuscript as deemed appropriate.
16. By incorporating maps of China and its provinces, removing unnecessary figures, and adding real photos of the experimental setup, the authors can enhance the clarity and visual presentation of their research, improving the overall quality of the manuscript.
17. The conclusions section should indeed be rewritten to provide more meaningful and quantitative results. It is crucial to summarize the main findings of the study and highlight their implications. By discussing the significance of the results and their contributions to the broader field, the authors can provide a comprehensive understanding of the research outcomes.
18. To strengthen the conclusions, it is advisable to include quantitative data or statistical analysis where applicable. This will provide solid evidence and support for the conclusions drawn. However, it is important to remain concise and avoid introducing new information in this section, as the conclusions should primarily focus on summarizing the findings and their implications.
There are many minor grammar problems.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
I think that the title “An experimental and numerical investigation of characteristics and mechanism of spacing cracks in loess considering size effect” of the manuscript is acceptable. The title fully describes the subject matter of the article. I believe the presented information in the manuscript is valuable and reliable. The abstract covers the most critical points.
Conclusions are presented appropriately and are supported by the data. The article is presented in an intelligible fashion and is written in standard English. The research meets all applicable standards for the ethics of experimentation and research integrity. The article adheres to appropriate reporting guidelines and community standards for data availability. I recommend the article for publication.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Due date 05/07/2023
Journal: Sustainability (MDPI)
Title: An experimental and numerical investigation of characteristics and mechanism of spacing cracks in loess considering size effect
The authors have presented a research concept that aims to justify the novelty of the research by highlighting the current state of research on spacing cracks and pointing out the gaps or limitations in existing studies. It establishes that most previous research has focused on materials with high stiffness, such as rocks or concretes, rather than soils. By referencing specific studies conducted on spacing cracks in different materials, it shows that the research on spacing cracks in soils is relatively limited. Overall, the introduction provides a good foundation for the study of spacing cracks in soils but could benefit from some major revisions to improve clarity and make it publishable as a scientific research journal. The concerns are presented as follows:
Key comments
1. The introduction section covers the background and importance of investigating spacing cracks in loess, and the sources support the claims and show the existing research. However, summaries or significant conclusions from some of these references might be beneficial. Thus, readers may quickly grasp current field information. Extensive research from Karihaloo and Bazant should be added in the introduction. See the following refs:
· Karihaloo, B. L., & Nallathambi, P. (1990). Effective crack model for the determination of fracture toughness (KICe) of concrete. Engineering Fracture Mechanics, 35(4-5), 637-645.
· Karihaloo, B. L., Abdalla, H. M., & Imjai, T. (2003). A simple method for determining the true specific fracture energy of concrete. Magazine of concrete research, 55(5), 471-481.
· Bažant, Z. P., & Xiang, Y. (1997). Crack growth and lifetime of concrete under long time loading. Journal of Engineering Mechanics, 123(4), 350-358.
2. Although the paragraph establishing the research objectives and methods is concise and clear, it would be good to include additional detailed data about the research process. What will be explored about loess spacing cracks? Discrete element and Digital Image Correlation (DIC) methods: how will they be used?
3. There is still room to stress the importance of the study. What impact will the discoveries have on the study of loess behavior or the field of geotechnical engineering? Emphasize any potential applications or ramifications of the findings that are relevant to daily life.
4. In experimental setup:
while the experimental setting is provided, more details and considerations are needed to address potential constraints and improve the study's rigor. More information about the compaction procedure, drying conditions, camera settings, and electronic balancing integration would clarify and reproduce the experimental setup.
5. The experimental setup only focuses on the drying test without considering the wetting process. Since the introduction mentions that loess is highly water-sensitive and prone to collapse under rainfall or irrigation, it would be important to consider the effects of wetting and subsequent drying cycles on spacing cracks. This would provide a more comprehensive understanding of crack evolution in loess.
6. parameters such as temperature, humidity, and airflow should be specified to ensure consistent and controlled drying conditions across all tests. These factors can significantly influence the drying behavior and crack formation in loess, and their control is essential for reliable experimental results; else should provide limitation of the studies.
7. Suggested to explain the nature of the graphs (Figure and 10 and 11).
8. Rewrite the DIC configuration and add setup figure to replicate the experimental work for readers. Which algorithm used to measure the displacement, how the tracking of speckles was performed (if it’s by camera specify the brand), what’s the maximum resolution, FOV, how many LED lamps. For better explanation regarding fracture mechanics and DIC test setup please refer and cite this top journal/ key paper: https://doi.org/10.1016/j.cemconres.2023.107181 and https://www.fracturae.com/index.php/fis/article/view/1299
9. Result and conclusion
The conclusion section summarizes the study's main findings but could improve by discussing the significance and implications of the identified characteristics and mechanisms of spacing cracks in loess. It should provide specific details about crack patterns, sizes, or orientations to better understand the findings. The Digital Image Correlation (DIC) method interpretation should be elaborated on, and numerical simulations using the discrete element method should be summarized to complement or support the experimental results.
10. The conclusion lacks a clear closing statement that summarizes the overall significance of the study. Consider adding a final sentence or paragraph that highlights the main contributions and importance of the research.
11. Check the guidelines and rewrite the reference and add the doi in the references.
12. The overall writing style is clear and easy to understand. However, some sentences could be rephrased for clarity or improved flow. Additionally, consider breaking up long sentences or separating ideas into separate sentences for easier readability.
Minor editing of English language required
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Well done.
