Effects of Acidic/Alkaline Contamination on the Physical and Mechanical Properties of Silty Clay
Round 1
Reviewer 1 Report
1- Mention some results numerically in the abstract.
2- Mention some recently published works in the introduction section with more details about findings of previous researchers.
3- Add gradation curve of soil.
4- Mention the gap of previous studies and the main goal of this study in the last paragraph of the introduction section.
5- How did you find the values of Table 1?
6- Explain this sentence: “To keep every sample the same and eliminate structural effects, the silty clay was remodeled.”
7- Mention the standards for all tests performed in the manuscript.
8- Write the name of SiO2, Al2O3, Fe2O3, K2O, Ca2+, Al3+ , Fe3+ ….
9- Rewrite this sentence: “Further analyze the above test results and findings of studies, and further discuss the mechanism and effect of the pore solution on the soil.”
10- Mention some examples of previous studies in line 350: “According to previous studies,….”
11- Compare your findings with the results of previous studies in the discussion section.
12-Rewrite the statement in conclusion part (4):” By observing the microscopic…… geotechnical properties of the soil.”
13-Add some numerical results in conclusion.
14- What are the limitation and application of this study?
15- In Ref. (29): what is this? “16-18+47.”
16- In figure 4, use “magnification” instead of “Magnify”
17- Explain why “The shear deformation rate was set to 1 mm/min.”? How did you find this rate?
18- Draw shear stress-shear strain and vertical strain-horizontal strain for some samples in direct shear test and discus about strength and dilatancy of some samples.
19- In Table 5, what are the units of cohesion and friction angle? In addition, write the values of friction angle instead of their tangent values.
20- Why linear fittings were used in Figure 3? In Figure 3(b), some seems bilinear.
Author Response
Response Letter
Dear Assigned Editor and Reviewer:
On behalf of my co-authors, we are very grateful to you for giving us an opportunity to revise our manuscript. We appreciate you very much for your positive and constructive comments and suggestions on our manuscript entitled “Effects of acid/alkali contamination on physical and mechanical properties of silty clay” with the reference number sustainability-2081582.
We have studied reviewers’ comments carefully and tried our best to revise our manuscript according to the comments. The following are the responses and revisions we have made in response to the reviewers' questions and suggestions on an item-by-item basis. Any revisions to the manuscript have been marked up using the “Track Changes” function. Again, we are very grateful to Editor and Reviewers for reviewing the paper so carefully!
Comment No. 1: Mention some results numerically in the abstract.
Response: Thanks to Reviewer for reminder, we have mainly rewritten the conclusion of the abstract.
Comment No. 2: Mention some recently published works in the introduction section with more details about findings of previous researchers.
Response: Thanks to Reviewer for reminder, we have added some new documents and introduced some of them in detail.
Comment No. 3: Add gradation curve of soil.
Response: Thanks to Reviewer for reminder, we added the particle size distribution of remolded silty clay in paragraph 2.
Comment No. 4: Mention the gap of previous studies and the main goal of this study in the last paragraph of the introduction section.
Response: Thanks to Reviewer for reminder, we added the region to the manuscript.
Comment No. 5: How did you find the values of Table 1?
Response: Descriptions of methods for obtaining the chemical compositions and mineral composition have been added in paragraph 2.
Comment No. 6: Explain this sentence: “To keep every sample the same and eliminate structural effects, the silty clay was remodeled.”
Response: We have paid attention to this question and it is clearer.
Comment No. 7: Mention the standards for all tests performed in the manuscript.
Response: Explanations of the standards of tests have been added for the liquid and plastic limits, specific gravity, compressive properties, shear strength, and scanning electron microscopy test.
Comment No. 8: Write the name of SiO2, Al2O3, Fe2O3, K2O, Ca2+, Al3+ , Fe3+ ….
Response: The chemical formulas of various compounds and ions mentioned in the paragraph of this paper have been replaced by chemical names.
Comment No. 9: Rewrite this sentence: “Further analyze the above test results and findings of studies, and further discuss the mechanism and effect of the pore solution on the soil.”
Response: We are extremely grateful to Reviewer for pointing out this problem. We have revised this sentence where marked up using the “Track Changes” function. The revised sentence is “Attempts were made to further discuss the mechanism and effect of the pore solution on the soil by analysing the above test results and findings of studies.”
Comment No. 10: Mention some examples of previous studies in line 350: “According to previous studies,….”
Response: We sincerely appreciate the valuable comments. We have checked the literature carefully and added more references into “the previous studies” in the revised manuscript.
Comment No. 11: Compare your findings with the results of previous studies in the discussion section.
Response: We think this is an excellent suggestion. By comparing the results of this paper with those of previous studies, the reliability of experimental conclusions can be enhanced.
Comment No. 12: Rewrite the statement in conclusion part (4):” By observing the microscopic…… geotechnical properties of the soil.”
Response: We have re-written this part according to the Reviewer’s suggestion. The specific modifications are as follows: (4) By observing the microscopic structure of the soil samples under different magni-fications, the results indicate that the surface of acidified soil particles is smooth and flat, while the surface of alkalized soil particles is rough and uneven. This also reflects the in-fluence on the mechanical properties of soil that the internal friction angle of alkalized silty clay is slightly above that of acidified silty clay.
Comment No. 13: Add some numerical results in conclusion.
Response: The relevant description has been enriched in conclusion.
Comment No. 14: What are the limitation and application of this study?
Response: We have added Section 5.1 Application and Limitation to the discussion the applicability and limitations of this article.
Comment No. 15: In Ref. (29): what is this? “16-18+47.”
Response: Since this reference was published a long time ago, we replaced it with two new references.
Comment No. 16: In figure 4, use “magnification” instead of “Magnify”
Response: We are very sorry for our incorrect writing and it is rectified in Figure 4.
Comment No. 17: Explain why “The shear deformation rate was set to 1 mm/min.”? How did you find this rate?
Response: The shear deformation rate was determined following the Clause 4 of Article 21.3.2 of the China National Standard for Geotechnical Testing Method (GB/T 50123-2019). The shear deformation rate is 1 mm/min in keeping with the specification requirements of 0.8mm/min~1.2mm/min. We have marked the standard on which the direct shear test is based before introducing it.
Comment No. 18: Draw shear stress-shear strain and vertical strain-horizontal strain for some samples in direct shear test and discus about strength and dilatancy of some samples.
Response: We agree with your comments that preliminary experiments are also necessary. Your suggestion provides a direction for our next research. Due to the limitations of direct shear instrument, we have not been able to record relatively complete load sensing signals and vertical displacement sensor readings during the displacement of shear box. In this study, we aimed at explore the relationship of direct shear strength for soils contaminated by acid/ alkali. Thus, we mainly focus on the stable value of shear stress.
Comment No. 19: In Table 5, what are the units of cohesion and friction angle? In addition, write the values of friction angle instead of their tangent values.
Response: We think this is an excellent suggestion. We have made corresponding corrections.
Comment No. 20: Why linear fittings were used in Figure 3? In Figure 3(b), some seems bilinear.
Response: We feel great thanks for your professional review work on our article. As you are concerned, the bilinear fitting effect is more accurate, but it is easy to cause overfitting under the less amount of sample points. While, linear fitting is more suitable to solve the problem with fewer sample points. The goodness of fit of linear fitting is mostly above 0.96, close to 1, which can well and simply illustrate the relationship between vertical pressure and shear strength. Thus we prefer to adopt the linear fitting in Figure 3.
In order to make the article readable and tightly organized, we carefully read through the whole article several times, and modified the abstract, introduction, conclusion, references (added 19 articles, deleted 2 articles), misspellings and other improper points. We sincerely thank the editor and all reviewers for their valuable feedback that we have used to improve the quality of our manuscript. Once again, thank you very much for your comments and suggestions. Correspondence should be directed to Guoqing Cai at the following address:
Institution and address: School of Civil Engineering, Beijing Jiaotong University, Haidian, Beijing 100044, China
Telephone: +86 010 51683462
Email: [email protected]
Thanks very much for your attention to our paper. Very sincerely yours,
Yepeng Shan, Guoqing Cai, Ce Zhang, Xiao Wang, Yehui Shi, Jian Li
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Effects of acid/alkali contamination on physical and mechanical properties of silty clay
Yepeng Shan 1,2 , Guoqing Cai 1,2,*, Ce Zhang 1,2 , Xiao Wang 2 , Yehui Shi 3,4 , Jian Li 1,2
Abstract:
The abstract deals with the main problems related to anthropogenic contamination with acidic and alkaline products of natural soil materials. The presented presentation refers us to a study of the soil bearing capacity of the earth in the conditions of a similar type of pollution. The main physical and mechanical characteristics of the considered soil varieties have been studied, and a series of results have been presented for the purposes of a scientific investigation.
Here the strength properties are examined, but also the bearing capacity and global deformability (long term deformability) of soil massifs.
Here it is necessary to refine the abstract by focusing on the studies and their volume.
Keywords:
Keywords include basic aspects of contaminated soil - acid/alkaline contaminated soil; shear strength; compressibility and (absence of swelling); environmental geotechnical engineering. Here one should consider the issue of extremely rich diversity in terms of the mineral and chemical composition of soils as a major factor influencing the physical and mechanical properties of soils.
Main text:
.
Paragraph 1
The paragraph begins with a general review of the problems of solid waste landfills, specifically mentioning the use of clay layer as the main insulator of the base of the landfills. In the specified references from 1 to 5, the elements of influence of the different regimes of the environment temperature and humidity with influence on the physical and mechanical indicators of the anthropogenic material are considered.
I recommend that the authors review this publication –
Torretta, Vincenzo, Navarro Ferronato, Ioannis A. Katsoyiannis, Athanasia K. Tolkou, and Michela Airoldi. 2017. "Novel and Conventional Technologies for Landfill Leachates Treatment: A Review" Sustainability 9, no. 1: 9. https://doi.org/10.3390/su9010009
Timothy G. Townsend, Jon Powell, Pradeep Jain, Qiyong Xu, Thabet Tolaymat, Debra Reinhart, Sustainable Practices for Landfill Design and Operation, 2015, ISBN : 978-1-4939-2661-9 DOIhttps://doi.org/10.1007/978-1-4939-2662-6
M. Todorov, V. Kostov, “Prediction Of The Development Of Long Term Deformations In Deposit Bodies”, SGEM2017 Vienna GREEN Conference Proceedings, ISBN 978-619-7408-28-7 / ISSN 1314-2704, 27 - 29 November, 2017, Vol. 17, Issue 43, 139-146 pp; DOI: 10.5593/sgem2017H/43/S18.018
Line 40 - I don't really find reference 8 to be appropriate as it deals with the problems of organic soils which are very rarely used as waterproofing screens.
Please note the publication series of these authors
D. Karathanasis, Fred Adams, B. F. Hajek , Stability Relationships in Kaolinite, Gibbsite, and Al-hydroxyinterlayered Vermiculite Soil Systems, https://doi.org/ 10.2136/sssaj1983.03615995004700060036x
Line 63 - The conclusion presented here should also be considered in the context of long-term deformability of the soil, and in such cases an increased prominence of creep effects is also to be expected, entirely omitted in the study..
Line 69 - the conclusion drawn from the study Yang et al. [23] on the interaction of the calcium base with laterite minerals demonstrates a process that is not usually found in municipal solid waste landfills. These processes practically accompany the deposits of materials from several flotation processes in the field of metallurgy. A number of publications can be found in the literature where the use of Calcium hydroxide depending on the chemical composition (absence of alkali metals, sulphur, phosphorus, etc.) of the basic materials can be treated as an improvement process.
Line 90 - What is presented here has an undeniable basis, but the study of such an area, in my opinion, requires as a first step to cover the chemical and mineral composition of the components that are exposed to the effects of acids or alkali. Next, macro-processes – the tendency to filter fluids and gases or absorb them – can be considered in the context of the long-term impact of secondary leachates.
Paragraph 2
Line 95 – The presented material with LL - 31.2% and PL of 18.4% determine the PI of these materials equal to 12.8%. According to the classification of EN ISO 14688 2:2018, these indicators define the material as a low-plasticity clay. Chemical and mineral composition predetermine the soil as probably represented by a high content of silty fractions (2 to 63 mm) of the terrigenous component and a significant content of calcium and magnesium carbonates. From a geotechnical point of view, these markers presuppose the high absorbent properties of the material and thereby its volume instability.
Paragraph 3
Line 114 – The description in this paragraph needs serious revision. In the context of the assessment, separately (for the two attacking environments) both the change of the mineral composition reflected as a colour reaction and the separation of the gas phase and volume changes, or other marks should be considered.
Line 128 – Briefly describes how bulk density is determined. A legitimate question arises - is the structure of the material preserved after saturation of the samples with the acid or alkaline solution. Serious doubts also arise because the material has not softened as a result of saturation and drying/swelling.
Line 147 - Looking at the reaction of the material it should be noted the fundamental substitution reaction of sodium with respect to calcium. And since the new sodium compounds are highly water-soluble, significant changes would develop when considered in desiccation processes, permeabilities, and water saturation.
Line 170 - The results presented in Figure 2 consider the acid and alkali treatment of the material conducted in an oedometer test. Contains 2 groups of results treated with an acid and one with a base. The results of the two acid tests differ significantly. The manifestation of linear void ratio degradation is somewhat disconcerting. I advise the authors to carefully review the results and present them separately for the two groups (acidic and alkaline attack).
In the same figure, in the absence of data at very low values of the normal stresses in the odometer test, the question of the unambiguous determination of the parameter b from equation (1) arises. It should also be noted that the graphs are presented in a decimal semi-logarithmic (log) scale.
Line 174 and following - The conclusion presented here has long been known and traditionally used in mining processes. Also revise the title of Figure 2.
Line 219 - Results presented in Figure 3 cover both groups of materials treated with acidic and alkaline agents. Regardless of concentration, in figure 3a the slope of the Mohr-Coulomb line is almost the same (with a concentration of 1-5%). When treated with acidic products, a significant change in the mineral composition is observed and this usually leads to a flattening of the curve. With regard to these comments, I ask the authors to carefully examine the obtained results.
Line 226 – The results presented here show no clear trends. This can be due to both the concentration of the reagents and the mineral composition.
Line 256 –
Keep the following in mind CaCO3 + 2HCl = CaCl2 + H2CO3
Paragraph 4
The discussion of paragraph 4 generally highlights elements of known behaviour of the materials presented (of only one type of soil). All reactions demonstrated are expected. In the abstract, oedometer soil behaviour was mentioned. This also raises questions related to rheological behaviour.
A qualitative limit is also established in cases where the soil is treated with acidic solutions with a concentration of more than 5%.
It is interesting from a geotechnical point of view that tests in triaxial conditions, where volume deformations, potential changes in permeability properties, changes in deformation moduli and Poisson ratios, strength parameters (friction angle, cohesion, and undrained shear strength) will be observed more precisely.
Line 299 - The conclusion about friction is indisputable, but in this case, there are other processes dictated by the colloidal interactions and the surface activity of the newly formed compounds. There is no basis for such attacks to affect silicon dioxide in crystalline or amorphous form.
Line 334 - "For alkaline solutions, since alkali does not cause erosion of soil particles, it will instead produce precipitates and reduce internal pores." This conclusion affects the first step of the interaction, but with water filtration things will change as migration of highly water-soluble compounds.
Potential collapses of the soil skeleton can also be expected.
Paragraph 5
The presented conclusions synthesize the findings of the previous paragraphs. Such conclusions are fully expected and do not demonstrate qualitatively different behaviour of soil clay materials. I advise the authors to judge based on the comments made by me, with which they can draw other important conclusions about the mechanical behaviour of the dispersed soil medium.
Author Response
Response Letter
Dear Assigned Editor and Reviewer:
On behalf of my co-authors, we are very grateful to you for giving us an opportunity to revise our manuscript. We appreciate you very much for your positive and constructive comments and suggestions on our manuscript entitled “Effects of acid/alkali contamination on physical and mechanical properties of silty clay” with the reference number sustainability-2081582.
We have studied reviewers’ comments carefully and tried our best to revise our manuscript according to the comments. The following are the responses and revisions we have made in response to the reviewers' questions and suggestions on an item-by-item basis. Any revisions to the manuscript have been marked up using the “Track Changes” function. Again, we are very grateful to Editor and Reviewers for reviewing the paper so carefully!
Comment No. 1:
Abstract:
The abstract deals with the main problems related to anthropogenic contamination with acidic and alkaline products of natural soil materials. The presented presentation refers us to a study of the soil bearing capacity of the earth in the conditions of a similar type of pollution. The main physical and mechanical characteristics of the considered soil varieties have been studied, and a series of results have been presented for the purposes of a scientific investigation.
Here the strength properties are examined, but also the bearing capacity and global deformability (long term deformability) of soil massifs.
Here it is necessary to refine the abstract by focusing on the studies and their volume.
Response: Thanks for your comments and suggestions, we have mainly rewritten the abstract to clarify the research focus.
Comment No. 2:
Keywords:
Keywords include basic aspects of contaminated soil - acid/alkaline contaminated soil; shear strength; compressibility and (absence of swelling); environmental geotechnical engineering. Here one should consider the issue of extremely rich diversity in terms of the mineral and chemical composition of soils as a major factor influencing the physical and mechanical properties of soils.
Response: We feel great thanks for your professional review work on our article. We have added to the discussion the application and limitation of Section 5.1, in which the issue of the extremely rich diversity of mineral and chemical constituents in soils is attributed to the limitations of this paper.
Comment No. 3:
Main text:
Paragraph 1
The paragraph begins with a general review of the problems of solid waste landfills, specifically mentioning the use of clay layer as the main insulator of the base of the landfills. In the specified references from 1 to 5, the elements of influence of the different regimes of the environment temperature and humidity with influence on the physical and mechanical indicators of the anthropogenic material are considered.
I recommend that the authors review this publication
Torretta, Vincenzo, Navarro Ferronato, Ioannis A. Katsoyiannis, Athanasia K. Tolkou, and Michela Airoldi. 2017. "Novel and Conventional Technologies for Landfill Leachates Treatment: A Review" Sustainability 9, no. 1: 9. https://doi.org/10.3390/su9010009
Timothy G. Townsend, Jon Powell, Pradeep Jain, Qiyong Xu, Thabet Tolaymat, Debra Reinhart, Sustainable Practices for Landfill Design and Operation, 2015, ISBN : 978-1-4939-2661-9 DOIhttps://doi.org/10.1007/978-1-4939-2662-6
- Todorov, V. Kostov, “Prediction Of The Development Of Long Term Deformations In Deposit Bodies”, SGEM2017 Vienna GREEN Conference Proceedings, ISBN 978-619-7408-28-7 / ISSN 1314-2704, 27 - 29 November, 2017, Vol. 17, Issue 43, 139-146 pp; DOI: 10.5593/sgem2017H/43/S18.018
Response: As Reviewer suggested that it is indeed better to give some reference for
practices for landfill design, operation and stability analysis. Those references (reference 6 to 8) were added to confirm that the stability research of landfill plays an important role in daily operation and maintenance.
Comment No. 4: Line 40 - I don't really find reference 8 to be appropriate as it deals with the problems of organic soils which are very rarely used as waterproofing screens.
Please note the publication series of these authors
- Karathanasis, Fred Adams, B. F. Hajek , Stability Relationships in Kaolinite, Gibbsite, and Al-hydroxyinterlayered Vermiculite Soil Systems, https://doi.org/ 10.2136/sssaj1983.03615995004700060036x
Response: On the basis of your suggestion, we have replaced a new reference. Although the literature you provided is classic, it was published earlier, so we choose a more recent one as a supplement.
Comment No. 5: Line 63 - The conclusion presented here should also be considered in the context of long-term deformability of the soil, and in such cases an increased prominence of creep effects is also to be expected, entirely omitted in the study.
Response: Your understanding and thinking of the reference is the direction of our progress. In the context of long-term deformability of the soil, creep effect is indeed an important influencing factor. This paper focuses on the mechanical properties of soil contaminated by acid and alkali without considering the influence of long time scale on the mechanical properties. After considering the creep effect, it will be a new complex issue, which will be further explored in the follow-up research.
Comment No. 6: Line 69 - the conclusion drawn from the study Yang et al. [23] on the interaction of the calcium base with laterite minerals demonstrates a process that is not usually found in municipal solid waste landfills. These processes practically accompany the deposits of materials from several flotation processes in the field of metallurgy. A number of publications can be found in the literature where the use of Calcium hydroxide depending on the chemical composition (absence of alkali metals, sulphur, phosphorus, etc.) of the basic materials can be treated as an improvement process.
Response: Thank you for discussing with us the mechanism of calcium hydroxide as an activator in the field of metallurgy. Yang et al. 's literature is listed in this paper to show that alkaline materials have long-term erosive effect on laterite. The effect is just about fountainhead that economic life of earth dam is inconsequently shortened behind alkaline materials reinforcing in laterite area. Through this paper, we hope to convey to readers an idea that unreasonable acid and base pollution has a huge impact on the environment and engineering.
Comment No. 7: Line 90 - What is presented here has an undeniable basis, but the study of such an area, in my opinion, requires as a first step to cover the chemical and mineral composition of the components that are exposed to the effects of acids or alkali. Next, macro-processes – the tendency to filter fluids and gases or absorb them – can be considered in the context of the long-term impact of secondary leachates.
Response: We agree with your comments that the context of the long-term impact of secondary leachates are also necessary. Relevant expressions have been added to the introduction, which provides a practical engineering background for this study.
Comment No. 8:
Paragraph 2
Line 95 – The presented material with LL - 31.2% and PL of 18.4% determine the PI of these materials equal to 12.8%. According to the classification of EN ISO 14688 2:2018, these indicators define the material as a low-plasticity clay. Chemical and mineral composition predetermine the soil as probably represented by a high content of silty fractions (2 to 63 mm) of the terrigenous component and a significant content of calcium and magnesium carbonates. From a geotechnical point of view, these markers presuppose the high absorbent properties of the material and thereby its volume instability.
Response: The mineral composition and chemical composition of the remolded silty clay have been described in detail in Section 2 Materials and methods. From the chemical composition of view, the main body is silicon oxide and alumina, and magnesium oxide only accounts for 12.63% of the total mass. A small amount of magnesium hydroxide precipitation generated by the reaction of magnesium oxide with water will not have a fundamental effect on the volume of soil. Therefore, it is certain that the silty clay volume used is stable enough to avoid potential influence on the conclusions of this paper.
Comment No. 9:
Paragraph 3
Line 174 and following - The conclusion presented here has long been known and traditionally used in mining processes. Also revise the title of Figure 2.
Response: We agree with the comment. The conclusions presented here are consistent with the cognitive law. This will be linked to subsequent conclusions. We have modified the title of Figure 2.
Comment No. 10:
Line 219 - Results presented in Figure 3 cover both groups of materials treated with acidic and alkaline agents. Regardless of concentration, in figure 3a the slope of the Mohr-Coulomb line is almost the same (with a concentration of 1-5%). When treated with acidic products, a significant change in the mineral composition is observed and this usually leads to a flattening of the curve. With regard to these comments, I ask the authors to carefully examine the obtained results.
Response: We have carefully examined the original data and the test results are correct. The internal friction angle reflects the friction characteristics of soil. The friction strength is divided into sliding friction and occlusal friction. It is true that the internal friction angle will be affected when the mineral composition of soil is eroded by acid. However, there are all kinds of factors that have to be seen about, such as particle size, etc. Generally speaking, the finer the soil particles, the greater the effect, the coarser the particles, the smaller the impact. In this paper, the maximum particle size is 2mm, and the soil with grains greater than 0.075 millimeters accounts for 57.21% of the total mass. This also means that there are more sand, resulting in less influence of the acid solution on the internal friction angle. In order to ensure the correctness of the test law, we also compared the results in this paper with those in reference [A1-A2], and found that the internal friction angle remained constant with the increase of acid concentration.
Comment No. 11:
Line 226 – The results presented here show no clear trends. This can be due to both the concentration of the reagents and the mineral composition.
Response: As the reviewer said, there are many factors affecting the result, such as determining methods, reagents, type, and mineral composition of soil. But we can still shed some light on macro trends from microscopic images. Compared with the microscopic image, the variation of shear strength shown in Table 5 accords with the cognitive law.
Comment No. 12:
Line 256 – Keep the following in mind CaCO3 + 2HCl = CaCl2 + H2CO3
Response: We sincerely appreciate the valuable comments. Through analyzing the chemical equations from some literature, we have added the relevant chemical equations, which are complementary and mutually interpreted with the microscopic image.
Comment No. 13:
Paragraph 4
The discussion of paragraph 4 generally highlights elements of known behaviour of the materials presented (of only one type of soil). All reactions demonstrated are expected. In the abstract, oedometer soil behaviour was mentioned. This also raises questions related to rheological behaviour.
A qualitative limit is also established in cases where the soil is treated with acidic solutions with a concentration of more than 5%.
It is interesting from a geotechnical point of view that tests in triaxial conditions, where volume deformations, potential changes in permeability properties, changes in deformation moduli and Poisson ratios, strength parameters (friction angle, cohesion, and undrained shear strength) will be observed more precisely.
Response: The long-term stability of the project can be analysed by studying the rheological properties of soil. It will be helpful to further understand the cause of rheology of contaminated soil, and thus have some guiding significance to improve and perfect the existing calculation theory of soil deformation. This paper is based on the study of mechanical properties of contaminated soil without considering the time scale, which means that the main line of the study always firmly grasps the effects of acid/alkali contamination on physical and mechanical properties of silty clay. The creep problem is so significant that we plan to focus our subsequent studies on the creep deformation of soils contaminated by acid and alkali.
Triaxial shear test is one of the most reliable methods available in soil mechanics to determine shear stress strength parameters. We are also eager to measure mechanical properties such as volume deformation and strength parameters, etc. with more precise instruments than direct shear instruments. Since the saturated solution of this test has a certain corrosiveness, the triaxial shear instrument cannot work in strong acid or alkali solution, so the triaxial test scheme is rejected by us.
Comment No. 14: Line 299 - The conclusion about friction is indisputable, but in this case, there are other processes dictated by the colloidal interactions and the surface activity of the newly formed compounds. There is no basis for such attacks to affect silicon dioxide in crystalline or amorphous form.
Response: Thank you for your suggestion, we have added your suggestion to Section 5.2. Contamination Mechanism
Comment No. 14: Line 334 - "For alkaline solutions, since alkali does not cause erosion of soil particles, it will instead produce precipitates and reduce internal pores." This conclusion affects the first step of the interaction, but with water filtration things will change as migration of highly water-soluble compounds.
Potential collapses of the soil skeleton can also be expected.
Response: Thank you for your suggestion, we have added your suggestion to Section 5.2. Contamination Mechanism.
Comment No. 15:
Paragraph 5
The presented conclusions synthesize the findings of the previous paragraphs. Such conclusions are fully expected and do not demonstrate qualitatively different behaviour of soil clay materials. I advise the authors to judge based on the comments made by me, with which they can draw other important conclusions about the mechanical behaviour of the dispersed soil medium.
Response: Thank you for your comments, your comments play a vital role in improving the quality of the article. We have tried our best to explain the experimental phenomena in this paper by combining with the relevant theories on mechanical behaviour of the dispersed soil medium.
Reference
- Han, P., Han, P. J., Yan, Y. B, Bai, X. H. Study on mechanical properties of acidic and alkaline silty soil by electrochemical impedance spectroscopy. Int J Electrochem Sci, 2018, 13, 10548-10563.
- Hu, W. L., Cheng, W. C., Wang, L., Xue, Z. F.. Micro-structural characteristics deterioration of intact loess under acid and saline solutions and resultant macro-mechanical properties. Soil Till Res 2022, 220, 105382.
In order to make the article readable and tightly organized, we carefully read through the whole article several times, and modified the abstract, introduction, conclusion, references (added 19 articles, deleted 2 articles), misspellings and other improper points. Any revisions to the manuscript have marked up using the “Track Changes” function. We sincerely thank the editor and all reviewers for their valuable feedback that we have used to improve the quality of our manuscript. Once again, thank you very much for your comments and suggestions. Correspondence should be directed to Guoqing Cai at the following address:
Institution and address: School of Civil Engineering, Beijing Jiaotong University, Haidian, Beijing 100044, China
Telephone: +86 010 51683462
Email: [email protected]
Thanks very much for your attention to our paper. Very sincerely yours,
Yepeng Shan, Guoqing Cai, Ce Zhang, Xiao Wang, Yehui Shi, Jian Li
Author Response File: Author Response.pdf
Reviewer 3 Report
This is an interesting study investigating mechanical behaviour of an acid alkali soil. Introduction could be improved by adding more recent literature has been in this area.
Author Response
Response Letter
Dear Assigned Editor and Reviewer:
On behalf of my co-authors, we are very grateful to you for giving us an opportunity to revise our manuscript. We appreciate you very much for your positive and constructive comments and suggestions on our manuscript entitled “Effects of acid/alkali contamination on physical and mechanical properties of silty clay” with the reference number sustainability-2081582.
We have studied reviewers’ comments carefully and tried our best to revise our manuscript according to the comments. The following are the responses and revisions we have made in response to the reviewers' questions and suggestions on an item-by-item basis. Again, we are very grateful to Editor and Reviewers for reviewing the paper so carefully!
Comment No. 1: This is an interesting study investigating mechanical behaviour of an acid alkali soil. Introduction could be improved by adding more recent literature has been in this area.
Response: In order to make the article readable and tightly organized, we carefully read through the whole article several times, and modified the abstract, introduction, conclusion, references (added 19 articles, deleted 2 articles), misspellings and other improper points. Any revisions to the manuscript have been marked up using the “Track Changes” function.
We sincerely thank the editor and all reviewers for their valuable feedback that we have used to improve the quality of our manuscript. Once again, thank you very much for your comments and suggestions. Correspondence should be directed to Guoqing Cai at the following address:
Institution and address: School of Civil Engineering, Beijing Jiaotong University, Haidian, Beijing 100044, China
Telephone: +86 010 51683462
Email: [email protected]
Thanks very much for your attention to our paper. Very sincerely yours,
Yepeng Shan, Guoqing Cai, Ce Zhang, Xiao Wang, Yehui Shi, Jian Li
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
English should be improved.
Author Response
Dear Reviewer:
We sincerely thank you for the valuable feedback that English should be improved. We also wish to take this opportunity to thank the reviewer for his constructive comments and valuable recommendations again. According to reviewer's suggestion, we have carefully revised the manuscript to improve the quality of our manuscript.
We tried our best to improve the manuscript and made some changes to the manuscript, including abstract, introduction, content and so on. These changes will not influence the content and framework of the paper. And here we didn’t list the changes but marked up using the “Track Changes” function in the revised paper. We appreciate for your warm work earnestly and hope that the correction will meet with approval.
Thanks very much for your attention to our paper.
Very sincerely yours,
Yepeng Shan, Guoqing Cai, Ce Zhang, Xiao Wang, Yehui Shi, Jian Li
