Installation of Bored Piles with a Protective Silicate Shell of a New Design in Saline Silty-Clayey Soils

Round 1

Reviewer 1 Report

The article contains very interesting and valuable information on technological solutions for the protection of piles against the aggressive action of a saline soil medium with a simultaneous significant increase in the load-bearing capacity of these piles.

The scientific side of the article is unfortunately at a lower level. The research results have been analyzed superficially and partially incorrectly, and some elements of these analyzes are considered redundant in the reviewer's opinion.

Technological issues are interesting and well described. The reviewer does not feel himself as an expert in the field of chemistry and will not judge the article from this side, trusting that there are no significant errors in this regard.

Returning to the technological aspects, there is no information in Fig. 2 and in the paper text as to whether the steel pipe (2) remains permanently or not.

On the formal side, the article is written a bit carelessly. There are quite a few bugs and shortcomings in it:

- in Table 1, the value of c is given in MPa, whereas c is probably the cohesion of the soil,

- in Fig. 5, the pile numbers are probably incorrectly assigned - instead of 2 it should be 3 (looking at the presence of irrigation wells (6)),

- line 195 - the value of 10 mm is irrational - maybe it should be 0.1 mm?

- line 202 - there is a marking (s/Q), whereas in Fig. 7 to 10 instead of Q there is P [kN],

- in Table 2 there are probably units in Russian - instead of κH there should be kN, similarly in several further parts of the article,

- there are no legends in fig. 11 and 12 - it is not known what the black and gray points mean,

- the grid lines are too dense in figures 7 to 12 - the main grid lines would suffice

- line 279 - it should be 0.0 ≤ R2 ≤ 1.0,

- line 295 - it should be Fig. 13, not Fig. 12,

- lines 306 to 310 - probably repeated sentences,

- line 314 should be x-axis = 0 and y-axis = 0

- Table 5 – units in Russian,

- line 337 - it should be Fig. 14 instead of Fig. 13, the same in line 350,

- generally, the list of literature is too long (the most important items would suffice), and besides, items [6, 7, 13, 14, 19, 20, 26, 27, 28, 31] are not cited in the article

 

Substantive comments:

- the test loads were performed in the standard way, it is a pity that no additional instrumentation was used in tested piles; the measurement of the force was determined not by means of a dynamometer, but by measuring the hydraulic oil pressure on the pressure gauge,

- it is difficult to say whether the analyzes carried out in lines 254 to 273 bring anything significant,

- describing the points in Fig. 11 and 12 with trend lines of the type y = ax + b is physically irrational, only lines with the function y = ax should be left,

- numerical analyzes were carried out at the basic level (student or engineering level)

- from Fig. 13 it can be seen that too rare mesh of finite elements was applied,

- the simplest Coulomb-Mohr constitutive model was used for the soil - not very adequate for the analysis of pile-soil interaction (the HS or HSs model would be better),

- Table 5 is entitled "Accepted simulation parameters"; is it to be understood that these parameters have been adjusted for a good simulation result?

- it is a pity that ordinary piles have not been simulated numerically, for comparison,

- describing the graphs in Fig. 13 (should be 14) with polynomials of the 5th and 6th degree - is it not an exaggeration?

 

The conclusions in the article are generally well performed. Perhaps point 5 in the conclusions concerning the results of numerical simulations is formulated too optimistic.

 

Summary

The results of the experimental research of the project described in the article are valuable and should certainly be disseminated, and thus the article should be published. Various formal shortcomings should be corrected, which should not be difficult. It should also be considered improving the substantive and scientific elements of the article.

 

The article can be published after corrections have been made.

Author Response

Answer to REVIEWER 1

The author's team is very grateful for such a high-quality level of reviewing and in many places absolutely agree with the opinion and remarks of the reviewer. The first author will try to take into account the proposed scientific approaches when writing the final version of the doctoral dissertation.

NN	Reviewers note	Authors’ answer
1	- in Table 1, the value of c is given in MPa, whereas c is probably the cohesion of the soil,	Corrected to kPa
2	- in Fig. 5, the pile numbers are probably incorrectly assigned - instead of 2 it should be 3 (looking at the presence of irrigation wells (6)),	Yes, you are right! Thank you very much – corrected.
3	- line 195 - the value of 10 mm is irrational - maybe it should be 0.1 mm?	Yes, it should be = 0.1 mm. The Static load tests (SLT) of the driven piles were carried out with the addition of a load of 120 kN for each step. The settlement was recorded until it stabilized at each stage, i.e., until the sediment per hour did not exceed 0.1 mm.
4	- line 202 - there is a marking (s/Q), whereas in Fig. 7 to 10 instead of Q there is P [kN],	The labeling of loading was marked to a single designation P, kN.
5	- in Table 2 there are probably units in Russian - instead of κH there should be kN, similarly in several further parts of the article,	Corrected to kN
6	- there are no legends in fig. 11 and 12 - it is not known what the black and gray points mean,	The explanation was added in Lines 267-269 «The results of bearing capacity of the soils are represented by blue dots in Figures 11 and 12. The values obtained according to , where kx equal to 0.911 and 0.723 respectively are represented by crosses. The trend lines and corresponding formulas are figured out accordingly». Previously the black points were values of the bearing capacity of the piles (blue dots now), and grey dots were just shadows (removed now).
7	- the grid lines are too dense in figures 7 to 12 - the main grid lines would suffice	The insufficient minor grid lines were removed.
8	- line 279 - it should be 0.0 ≤ R2 ≤ 1.0,	Correlation coefficient formula was used according to https://en.wikipedia.org/wiki/Pearson_correlation_coefficient and ranges between -1 and 1 (from directly proportional to inversely proportional correlation)
9	- line 295 - it should be Fig. 13, not Fig. 12	Corrected, duplicate numbering fixed, thank you very much.
10	- lines 306 to 310 - probably repeated sentences	Thank you very much, the repeated sentence was removed
11	- line 314 should be x-axis = 0 and y-axis = 0	Thank you very much, corrected
12	- Table 5 – units in Russian,	Corrected, all the units placed in English
13	- line 337 - it should be Fig. 14 instead of Fig. 13, the same in line 350	Corrected, duplicate numbering fixed, thank you very much.
14	generally, the list of literature is too long (the most important items would suffice), and besides, items [6, 7, 13, 14, 19, 20, 26, 27, 28, 31] are not cited in the article	All of the references were cited, [6] – Line 58, [7] – Line 58, [14] – Line 62, [19] – Line 64, [20] – Line 64, [26] – Line 73, [27] – Line 73, [28] – Line 73. [31] now changed to [32] – Line 176 GOST 5686-2012 "Field test methods for piles. New Literature added [29] – and shifted down the further References.
15	- the test loads were performed in the standard way, it is a pity that no additional instrumentation was used in tested piles; the measurement of the force was determined not by means of a dynamometer, but by measuring the hydraulic oil pressure on the pressure gauge	As noted in the cover letter, the work was carried out within the framework of strengthening the foundation of the Koktobe TV tower in Almaty. The available field data are applied in the doctoral dissertation. Due to the complexity and high cost of production manipulations, not all scientific types of research appeared to be possible for implementation. The team of authors partly agrees with the opinion of the reviewer.
16	- it is difficult to say whether the analyzes carried out in lines 254 to 273 bring anything significant	Here is a detailed calculation path, the results of which are then used in Figures 11 and 12
17	- describing the points in Fig. 11 and 12 with trend lines of the type y = ax + b is physically irrational, only lines with the function y = ax should be left	The trend line does not intersect the origin of coordinates, so it is presented with +b. Linear trend line y = ax + b formula was suggested by Excel automatically.
18	-numerical analyzes were carried out at the basic level (student or engineering level)	Agree
19	-from Fig. 13 it can be seen that too rare mesh of finite elements was applied	This was because a screenshot of the simulation was taken by snipping tool and then it was simply enlarged for a detailed description.
20	-the simplest Coulomb-Mohr constitutive model was used for the soil - not very adequate for the analysis of pile-soil interaction (the HS or HSs model would be better)	The Coulomb-Mohr model is the most common model used in geotechnical calculations.
21	-Table 5 is entitled "Accepted simulation parameters"; is it to be understood that these parameters have been adjusted for a good simulation result?	In the simulation, real field conditions were used to determine the bearing capacity of 4-meter piles under static load.
22	-it is a pity that ordinary piles have not been simulated numerically, for comparison	The first author was interested in the behavior and modeling of a pile with a protective shell, since this is the use of a new protective technique.
23	-Describing the graphs in Fig. 13 (should be 14) with polynomials of the 5th and 6th degree – is it not an exaggeration?	Agree, the polynomial equation for the best fitting curve line was used for loading-settlement relationship.

 

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors
Presented study is well composed, follows the IMRaD structure of scientific contribution and is formatted to MDPI template. It is also well fitted to Applied Sciences goals (aims and scope).
I appreciate your research as it may have real applications (practical outcomes) and it provides some new ideas concerning improvements of piling technologies in saline soils. I was pretty surprised that you did not refer to your previous work "Cast-in-situ piles encasements based on oil-bituminous rocks (kirs) in saline soils" on similar issues. Of course, it is not mandatory but it could just point the importance of the subject. 
My only doubt is the local importance of your research. Even a properly designed research program may have limited attraction to worldwide audience, when the problem is presented as local. 
Paper will need a cautious proof reading and above all a good editorial check. Some issues were not translated from Russian. Concerning the reference list, non-English sources should be precisely marked, as they are not "readable" for international Readers.
The list of major editorial issues is given below:

line 35 - (M.T. Adikov, V.V. Podkolzin, 1976) - I am not sure if it is necessary concerning format of referring

line 41 - (2011) - not necessary

line 73 - [26-28] - please avoid "group references" introducing cited papers. It is better to address every single paper individually when you want to emphasise its importance for the discipline and your research.

line 105 and further - please use subscripts in chemical formulas e.g., Na₂O, CaCO₃,   

line 181 - 800 kgf/cm² - please use consequently SI system of units e.g., MPa

line 189 - capacity 200 t); - please use consequently SI system of units e.g., kN

line 237 - Table 2 - use kN instead of кН

lines 274 and 277 - Figures 11 and 12. Please explain, what is the sense of applying a trendline with R²=0,039 or R²=0,060 respectively? 

line 279 - in the range: 1,0≤?²≤+1,0. - It is a very narrow range :-)

line 301 - Figure 13 - please provide English translation of Figure's description.

line 329 - table 5 - please use English translation of "Units" - please check the proper English parameter names (column 1). I suppose that "Specific gravity of dry soil/ Density in dried condition" is just a "unit weight" γ

line 350 - Figure 13 - please explain, why you use polynomials for approximation of load-displacement curve. It is pretty original as usually other functions are used for extrapolation of load-displacement curves. Please comment on Brinch-Hansen, Chin-Kondner, Decourt or other methods. 

line 413 - References - please mark clearly the sources that are probably not available in English [1-3, 29-33]

Please check again and use proper format of references. Please provide some English proof-reading. As a non-native speaker I cannot judge for English grammar and style, but some sentences look strange to me.

Best regards

 

Author Response

Answer to REVIEWER 2

The authors’ team is very grateful for a detailed and high-quality level of reviewing and in many places agree with the opinion and remarks of the reviewer.

This study was presented as an example of an engineering solution for construction in flooded and chemically aggressive environments. A method for forming of a protective shell for a pile was presented, which also improves the bearing capacity. The team of authors hopes that this study can be useful for construction in difficult soil conditions.

The recent authors’ contribution was referenced:

29. Unaibayev, B.B., Unaibayev, B.Zh., Andreyachshenko, V. Cast-in-situ piles encasements based on oil-bituminous rocks (kirs) in saline soils, Scientific Review Engineering and Environmental Sciences, 30(1), 2021; pp. 51-61. https://doi.org/10.22630/pniks.2021.30.1.5.

Units of measurement have been corrected thorough the paper.

This research was presented as an example of engineering solution.

NN	Reviewer’s note	Authors’ answer
1	line 35 - (M.T. Adikov, V.V. Podkolzin, 1976) - I am not sure if it is necessary concerning format of referring	Thank you very much, removed the surnames, [1] format left
2	line 41 - (2011) - not necessary	Removed unnecessary Ref information.
3	line 73 - [26-28] - please avoid "group references" introducing cited papers. It is better to address every single paper individually when you want to emphasise its importance for the discipline and your research.	Thank you very much. These three works have been cited as an example of soil treatment and prevention from collapsible deformations under loading in wetting conditions  by methods, listed in their order correspondently (i.e. with silicate cement [26], geopolymers [27] on the base of fly ash and slag[28]). Corrected now.
4	line 105 and further - please use subscripts in chemical formulas e.g., Na2O, CaCO3,	Corrected. Used symbols to fix the subscripts in a proper way.
5	line 181 - 800 kgf/cm2 - please use consequently SI system of units e.g., MPa	Corrected to 785 MPa.
6	line 189 - capacity 200 t); - please use consequently SI system of units e.g., kN	Corrected. Thank you for the thorough revision.
7	line 237 - Table 2 - use kN instead of кН	Corrected, all the units placed in English
8	lines 274 and 277 - Figures 11 and 12. Please explain, what is the sense of applying a trendline with R2=0,039 or R2=0,060 respectively?	If the value of the coefficient satisfies the condition then the relationship between the two variables is weak, if - the relationship is average,  - the relationship is close. In this case the relationship between bearing capacity of the pile without and after prolonged wetting is moderate. Therefore, it is possible to estimate the weakening of the bearing capacity of the pile (or group of piles) after wetting.
9	line 279 - in the range: 1,0≤?2≤+1,0. - It is a very narrow range :-)	Correlation coefficient formula was used according to https://en.wikipedia.org/wiki/Pearson_correlation_coefficient and ranges between -1 and 1 (from directly proportional to inversely proportional correlation)
10	line 301 - Figure 13 - please provide English translation of Figure's description.	Corrected, placed the description in English.
11	line 329 - table 5 - please use English translation of "Units" - please check the proper English parameterames (column 1). I suppose that "Specific gravity of dry soil/ Density in dried condition" is just a "unit weight" γ	Corrected “Specific gravity of dry soil/ Dry unit weight” was used according to Basic definitions and terminology of soils
12	line 350 - Figure 13 - please explain, why you use polynomials for approximation of load-displacement curve. It is pretty original as usually other functions are used for extrapolation of load-displacement curves. Please comment on Brinch-Hansen, Chin-Kondner, Decourt or other methods.	In Figure 13 the best fitting curve line was used to express the load-displacement relationship.   J. Brinch Hansen (1963) proposed a definition for pile capacity as the load that gives four times the movement of the pile head as obtained for 80 % of that load. Decourt (1999) proposed the method by dividing each load with its corresponding movement and plot the resulting value against the applied load. All of them: Decourt, Chin-Kondner and Hansen methods - an ‘ideal’ curve can be calculated and compared to the actual load-movement curve of the test. Standard SP RK 5.01-103-2013 “Pile foundations” (2013) consider the criterion for maximum permissible settlement S, in Lines 226.  So the maximum permissible settlement according to Standard =0.2*80 mm= 16mm (limiting value of the average settlement of the foundation of the designed structures, for industrial and civil one-story and multi-storey buildings with a full frame is taken equal to 8 cm). The loading value at 16 mm settlement was considered as the bearing capacity of the pile. And polynomial equation was used as the best fitting curve for the loading-settlement relationship. All of the methods have the similar goal to estimate the bearing capacity by loading the pile in situ.
13	line 413 - References - please mark clearly the sources that are probably not available in English [1-3, 29-33]	Yes, [In Russian] label added for these Standards and resources.

Author Response File: Author Response.docx

Reviewer 3 Report

This is an interesting experimental and numerical research conducted on bored piles with and without protective silicate shells. The outcome of this study is interesting for practitioners and engineers in the field. Minor improvements require to deemed worthy of publication in Applied Sciences Journal. Most of the figures have a good quality, except figure 13. Also some figures come with non-English texts. Please fix these issues. conducting full static testing is an advantage of this study. Please provide more details of the testing experiments and a photo if possible. Current photo is not a good representation of the field test. Please elaborate on discussion section this is currently immature. Please compare your results and analysis with similar studies.   

Author Response

Answer to REVIEWER 3

The authors’ team is very grateful for the reviewer’s feedback and in many places agree with the opinion and remarks of the reviewer.

This study was presented as an example of an engineering solution for construction in flooded and chemically aggressive environments. A method for forming of a protective shell for a pile was presented, which also improves the bearing capacity. Unfortunately, the shooting of a detailed photo and its disclosure was not possible due to restriction of the work carried out near the strategically important object of the Koktobe tower in Almaty, which is the main point of transmission of all types of signals for the megalopolis. The team of authors hopes that the proposed study can be useful for construction engineers in difficult soil conditions.

Regarding the comparison of the results with other authors, since the soils are specific for each individual site, it is difficult to compare the results of the new method with other studies, both in terms of economic effect and in terms of technological solutions. This research refers to purely applied research. It was decided to discuss the results obtained specifically for this engineering solution and to introduce the readers with the proposed method. We will take into account these comments and try to make comparisons and analysis with the other existing methods in the further works.

Author Response File: Author Response.docx