Abrasion Behavior and Anti-Wear Measures of Debris Flow Drainage Channel with Large Gradient
Round 1
Reviewer 1 Report
I found this a hard paper to read and I am still not sure what it is about. I gather it is the experience of protecting steep channels on erosive soils in China. The first point of difficulty was the use of gradients such as 506%. What does this mean - the channel falls vertically for 506m for every 100m horizontal distance? This would mean slopes of around 70 degrees? In fact, Figure 5 indicates a gradient of around 40%.There are a lot of such values quoted and it makes it hard for the reviewer to take it seriously.
The paper itself is nicely presented with excellent illustrations. However I can't work out whether it is an account of their experience or an attempt at some sort of theoretical analysis. The presentation seems to assume that the readers know all about the theory (dangerous). Equations such as (1) should, at a minimum, have the units being used. I found the complex illustrations difficult and think that they should be "unpacked" - the reader will struggle to comprehend them still but less so.
The paper talks a lot about the "design method" but this is not really laid out well.
Although the work does concentrate on modes of failure of the in-channel structure, I believe that foundation -failure/undercutting by the water is not adequately dealt with.
I think that the paper needs a hard "going over" . Terms such as gradient can be defined. The illustrations tend to be too complex. I am not at all sure what Figure 2 is meant to show. Ditto Figure 4. If it is laying out a "design method" then it should be laid out more carefully. As it stands I don't think it is suitable for your journal.
Author Response
I found this a hard paper to read and I am still not sure what it is about. I gather it is the experience of protecting steep channels on erosive soils in China. The first point of difficulty was the use of gradients such as 506%. What does this mean - the channel falls vertically for 506m for every 100m horizontal distance? This would mean slopes of around 70 degrees? In fact, Figure 5 indicates a gradient of around 40%.There are a lot of such values quoted and it makes it hard for the reviewer to take it seriously.
Response：Thank you very much for your kind comment. Firstly, as you mentioned, this paper is an experiential and theoretical discussion, while it is not about soils eroded by water, but about a concrete channel abrased by debris flow. Secondly, the gradient you mentioned is not 506 %, but 506 ‰, and this gradient of 506 ‰ is not in the drainage channel, it is in the formation area of the gully (Line 106 in the revised manuscripts). The mean gradient of the whole gully is 412‰ (Table 1), and the maximum gradient of the drainage channel is 349‰. However, the mean gradient of the drainage channel is 264.64‰ (Table 2). In other words, it averagely falls vertically for 264.64 m for every 1000 m horizontal distance. Thank you again for your understanding.
The paper itself is nicely presented with excellent illustrations. However I can't work out whether it is an account of their experience or an attempt at some sort of theoretical analysis. The presentation seems to assume that the readers know all about the theory (dangerous). Equations such as (1) should, at a minimum, have the units being used. I found the complex illustrations difficult and think that they should be "unpacked" - the reader will struggle to comprehend them still but less so.
Response：Thank you for comment. Equation (1) is the expression form of abrasion, which is used to show the influencing factors related with abrasion process. It is not an accurate formula for calculating, so the units of the variables were not given here. Illustrations have been revised in detail and been given further explanation in the text.
The paper talks a lot about the "design method" but this is not really laid out well.
Response：Thank you for comment. In this paper, we firstly introduced the of characteristics of geomorphology background and loose accumulation in the gully. Secondly, the disaster mitigation needs were analyzed, which indicated that a drainage channel was needed. And then, abrasion behavior and anti-wear measures of DCLG was put forward in detail. This article has focused on abrasion behavior, the anti-wear measures and their performance in practice. So the "design method" in common of a drainage channel is not the emphasis to be discussed.
Although the work does concentrate on modes of failure of the in-channel structure, I believe that foundation -failure/undercutting by the water is not adequately dealt with.
Response：Thank you for comment. The Xiaogangjian gully is a seasonal dry ditch, in which the torrents and debris flow only generated in summer. In fact, there is no perennial water in the gully. So the foundation of the DCLG was not eroded by water.
I think that the paper needs a hard "going over" . Terms such as gradient can be defined. The illustrations tend to be too complex. I am not at all sure what Figure 2 is meant to show. Ditto Figure 4. If it is laying out a "design method" then it should be laid out more carefully. As it stands I don't think it is suitable for your journal.
Response：The definition of gradient is the degree of steepness of surface elements, which is the ratio of vertical height H to horizontal distance L of a slope or a structure. The illustrations have been amended in details and been given further explanation in the text. And other comments and suggestions have been revised carefully in the article. Maybe there are still some omissions in this paper. Therefore, I sincerely apply for review of the journal. Whether I am lucky enough to be employed in the journal or not, it will be a great achievement to improve the quality of the paper.
Thank you for the opportunity, and thank you again for your kind suggestions.
Author Response File: 
Author Response.doc
Reviewer 2 Report
Please see the attachment
Comments for author File: 
Comments.pdf
Author Response
Considerations:
-Line 83: extra space between "of" and "drainage"
Response：Thank you for your kind comment. The extra space has been deleted.
-Figure1: words in light blue are unreadable. Do the numbers 810 and 1987 represent the altitude? it is not clear.
Response：The Figure 1 has been revised by altering the blue color to yellow, and a legend was added to explain the altitude point. Thank you a lot.
-Line 118: Replace (Bovis [23]) with [23]
Response：The (Bovis [23]) has been replaced with [23].
-Figure 2: Which is the difference between the dashed arrows and the continuous ones? It is not clear. What does the different color of the blocks mean?
Response：Figure 2 has been revised in arrows and blocks color, and some words and expressions were adjusted for easier comprehended. And an explain of “The continuous arrows indicate a DCLG is needed for the mitigation and it will encounter abrasion, and the dashed ones show the countermeasures for reducing the abrasion; the two blocks with different colors mean key nodes in the design” is added following of the figure title.
-Line 143: the section "analysis" should be included in Materials and Methods while the results should be a separate chapter
Response：The section "analysis" has been moved into Materials and Methods as “2.3. Analysis of the Abrasion Behavior of DCLG”, and the original “2.3 Research Procedures” is turned into “2.4. Research Procedures”. The result has been a separate chapter now.
-Lines 148-150: The sentence is not clear. Where is the verb of the sentence?
Response：The sentence has been amended to “Debris flow with high bulk density and high viscosity have the characteristics of wide gradation, huge particles, complex interactions and energy exchange between solid and liquid phases”. Thank you.
-Line 165: replace "generally appears" with "that generally appears"
Response：The sentence has been amended by adding a “that”.
-Figure 3: Please define the acronyms in the caption
Response：The acronyms in the caption have been defined in the previous paragraph upon Figure 3. And the sites of the 4 pictures were added following of the figure title.
-Line 183: invert "of or" with "or of"
Response：The sentence has been amended by inverting "of or" with "or of".
-Figure 4: Subfigures should be numbered by Latin letters. Please add the caption for each subfigure. Subfigure 4b requires further explanation in the text.
Response：Subfigures of Figure 4 have been numbered by Latin letters and caption for each subfigure has been add: (a) Profile of debris flow in the drainage channel; (b) Elements of abrasion system of DCLG. The subfigure 4b has been given a additional paragraph for further explanation in the text of Line 202 to 212.
-Lines 189-193: The definition of System dependence, time dependence and multidisciplinary coupling should be moved in an appendix
Response：An appendix has been added in the ending of the paper to explain the definition of System dependence, time dependence and multidisciplinary coupling.
-Line 204: please write what d90 and d10 mean, you simply said they are the particle size. Please insert "," between ϑ and α.
Response：The meaning of the d90 and d10 has been defined: d90 and d10 represent particle size of debris flow, which refers to the particle size of a sample when the cumulative percentage of particle size distribution reaches 90% and 10%. And every “、”has been replaced with a “,” between each variable.
-Equation (2): The bracket should contain both the equations.
Response：The bracket has been revised in MathType to contain both the equations.
-Lines 230-233: Please insert the unit of measurement of each variable
Response：The unit of measurement of each variable are inserted: where Iα is the concrete weight loss rate of abrasion (％); α is the scouring angle (°); αs is the critical angle of abrasion (°); Vs is the velocity of large particles in debris flow (m/s); γ, γs and γw are the bulk density of debris flow, solid particles and water (g/cm3); K, ε, φ and n are the critical velocity (m/s), the energy consumption factor of impact wear, the energy factor of micro cutting wear and the horizontal resilience factor (dimensionless).
-Line 231: Please insert "," between ϒ and ϒs
Response：The“、”has been replaced with a “,” between γ and γs.
-Figure 6: Can you show in the figure the length of each section?
Response：The length of each section has been showed on the top of the Figure 6, with a chainage in each point.
-Lines 251 to253: the line spacing seems higher than in the other parts of the text
Response：Thank you for kind comment. The line spacing seems higher than in the other parts of the text is duo to the MathType format of variables, and now they have been replaced with text format.
-Lines 263-272: Please add a bullet list
Response：A bullet list has been added in the text. Thank you.
Lines 331: Where are the sections located in figure 6?
Response：The located of each section has been showed on the top of the Figure 6.
-Figure 11-13-14: Subfigures should be numbered by Latin letters. Please add the caption for each subfigure. -Lines 350,353,363,364: Subfigures should be numbered by Latin letters, so when you refer to the subfigures, you can write Figure 11(a) or Figure 11(b).
Response：Subfigures of Figure 11-13-14 have been numbered by Latin letters (a) and (b), as well as their caption added following the title of figures. What’s more, references to the subfigures of Figure 11-13-14 in the original Lines 350,353,363,364 have been replaced with (a) and (b).
Thank you again for your kind suggestions.
Author Response File: Author Response.doc
Reviewer 3 Report
Overall the paper is of significant interest. However I consider that there are a number of edits and changes that should be made before publication. Of particular concern is the referencing. Two errors were found, but not all references were checked. Detailed comments are as follows:
Line 36 - need reference for statement “according to relevant research..”
Line 39 - need to define “integrity coefficient” and provide a reference.
Line 40 - the word “larger” should be replaced with “higher”
Line 44 - delete “etc”
Line 52 - define “large size boulders”. What size are they?
Table 1 - do not need the first column. The word “length” is misspelt.
Line 148 – The sentence “For debris flow with high bulk density and high viscosity, having the characteristics of wide gradation, huge particles, complex interactions between solid and liquid phase and energy exchange” is not a proper sentence, as it has no conclusion of what these factors mean. Needs updating.
Line 168 – what is “bed rock of sand” – is it a sandstone bed?
Line 226 – reference 33 is not Bittern et al.
Line 231 – vs, should this be Vs?
Line 232 – should Ψ be ϕ ?
Table 2 – do not need the first column
Line 244 – the e is missing from “accelerat”
Line 249 – equation 3 is not found in reference 13. Proper reference should be given.
Line 272 – does all of section B have a 50mm wear resistant layer? I would have though only B1 and B3 would.
Paragraph commencing line 328 – written in present tense “is’, should be written in past tense “was” etc. Such as “each control section was”, in this section “can be” and “debris flows were found”
Figure 10b – need to define the “attenuation rate of velocity”. What is it?
General in Observation and Discussion, there is no mention of any damage to the ED structure? How did it perform? What maintenance is required following a debris flow? I can imagine that the ED section would fill with debris that may not be remobilised, and thus performance would not be as good.
Author Response
Detailed comments are as follows:
Line 36 - need reference for statement “according to relevant research..”
Response：Thank you for your kind comment. I’m very sorry that this sentence and the next one are referred to the reference [3], but I laid it on the mistake location of the end of next sentence. Now the reference [3] has been inserted in the proper place.
Line 39 - need to define “integrity coefficient” and provide a reference.
Response： The “integrity coefficient” has been defined to a parameter representing the shape of a basin, which can be calculated from the watershed area divided by square of the length of gully, and usually marked as “δ”. A reference [4] has been provided in the article.
Line 40 - the word “larger” should be replaced with “higher”
Response：The word “larger” has been replaced with “higher”. Thank you.
Line 44 - delete “etc”
Response：The “etc” has been deleted. Thank you.
Line 52 - define “large size boulders”. What size are they?
Response：The large-sized boulders is defined as boulders with a grain size≥1.0 m, and an example of the largest boulder found in Sanyanyu debris flow gully is 12.9m×8.6m×7.2m is given (reference [7]).
Table 1 - do not need the first column. The word “length” is misspelt.
Response：The first column of Table 1 has been deleted and the word “length” has been amended. Thank you.
Line 148 – The sentence “For debris flow with high bulk density and high viscosity, having the characteristics of wide gradation, huge particles, complex interactions between solid and liquid phase and energy exchange” is not a proper sentence, as it has no conclusion of what these factors mean. Needs updating.
Response：The sentence has been amended to “Debris flow with high bulk density and high viscosity have the characteristics of wide gradation, huge particles, complex interactions and energy exchange between solid and liquid phases”. And the conclusion is in the next sentence “As a result, the abrasion mechanism of debris flow drainage channels is also very complex, which is obviously different from other types of abrasion behavior such as mechanical friction, wind sand flow, high sediment flow and so on”.
Line 168 – what is “bed rock of sand” – is it a sandstone bed?
Response：I’m very sorry that there was a clerical error. The correct sentence should be “…on the bed rock of the high sandy rivulets and rivers in mountain area”, and now it has been revised in the article. Thank you very much.
Line 226 – reference 33 is not Bittern et al.
Response：The equation (2) is quoted from a secondary source (reference 33), and the original source is a book published in 1982. But unfortunately, I’m failed to get it. So I listed the reference 33 here. Thank you.
Line 231 – vs, should this be Vs?
Line 232 – should Ψ be ϕ ?
Response：These two mistakes have been revised in the article. Thank you.
Table 2 – do not need the first column
Response：The first column of Table 2 has been deleted.
Line 244 – the e is missing from “accelerat”
Response：The mistake has been revised in the article. Thank you.
Line 249 – equation 3 is not found in reference 13. Proper reference should be given.
Response：The equation 3 has been given an accurate reference of reference 34.
Line 272 – does all of section B have a 50mm wear resistant layer? I would have though only B1 and B3 would.
Response：Thank you for careful advice. The wear-resistant layer is laid on the surface of the channel bottom of Sec.B1 and Sec.B3 to improve the wear resistance of the channel structure, and here has been revised in the article.
Paragraph commencing line 328 – written in present tense “is’, should be written in past tense “was” etc. Such as “each control section was”, in this section “can be” and “debris flows were found”
Response：Paragraphs in section “4.1 Observation and Analysis of ED Effect of PRC Boxes” and “4.2 Observation and Analysis of roughening belt on the bottom of the channel” have been revised in past tense. Thank you a lot.
Figure 10b – need to define the “attenuation rate of velocity”. What is it?
Response: The attenuation rate of velocity has been defined as the rate of velocity reduction in the ED section (sec. B2), and its’ calculating method has been given as equation (4) in the article.
General in Observation and Discussion, there is no mention of any damage to the ED structure? How did it perform? What maintenance is required following a debris flow? I can imagine that the ED section would fill with debris that may not be remobilised, and thus performance would not be as good.
Response：A paragraph about the performance and improvement suggestions of ED structure has been added in the ending of discussion. “The performance of ED structure could be enhanced in the next step. During the flood season of 2012, the PRC boxes in ED structure had been filled with debris flow sediments, and evolved into a stepped structure. In this situation, the sediments should be delivered by follow-up torrential floods, or be removed artificially. On the other hand, the sidewalls of PRC boxes were not thick and strong enough to stand up to the impact force of boulders in debris flow. As a result, the top of the boxes was partially damaged by local impact, and the height of the boxes became uneven, which partly affected the falling range of debris flow. In the future, the structural type of the boxes, the width of the row and the height difference between different rows should be designed more rationally to avoid being damaged by debris flow deposition or impact. For example, the channel bottom of frame formed by the cast-in-place foundation beam should be adopted.”
Thank you again for your kind suggestions.
Author Response File: Author Response.doc
Round 2
Reviewer 1 Report
The paper is rather improved, although it would be better with some English editing. I still worry about their use of gradients – thus the authors in their comment on my review note that a gradient of 264.64% means that the channel falls vertically for 264.64m ever 1000m. This would be a percentage gradient of 264.64 x 100/1000 = 26.464% (not 264% as the authors say). Given this I worry about other numerical aspects of the paper; the editors might care to ask the author to examine this more and/or seek independent advice. In itself it is quite an interesting account of the work done, but it is rather empirical in its nature.
Author Response
Thank you again for your kind comment. We admire your careful review and suggestions, and would edit the English language again carefully. As to the gradients, maybe we should make a clarification about the difference of the two symbols of % and ‰. The former (%) means percentage (per hundred), and the latter (‰) means permillage (per thousand), so “264.64‰”indicates that it averagely falls vertically for 264.64 m for every 1000 m horizontal distance. We will examine all the numerical aspects of the manuscript again carefully.
Thank you very much, and sincerely wish you and your family good health.
