Study on the Restraint Effect of Isolation Pile on Surface Settlement Trough Induced by Shield Tunnelling

Round 1

Reviewer 1 Report

The paper investigated the restraint mechanism of isolation piles in a pile-soil-tunnel structure. Based on the Melan solution and the Loganathan formula, the analytical solution of surface settlement trough under the influence of adjacent isolation piles is derived. In order to satisfy the engineering analysis scale and reflect the friction characteristics between isolation pile and soil particles simultaneously, the FDM-DEM coupling technique is introduced to establish a numerical model including discrete medium and continuum medium. Finally, the applicability and reliability of the analytical solution and the FDM-DEM coupling numerical solution are verified by comparing field measured data. The results of revised analytical and numerical methods are in good agreement with the filed data.  The paper can be published as a journal paper after addressing the below comments.

The English of the paper needs to be improved by a native English speaker. Some words can be replaced to make the paper content more understandable.

Discussing the results in a discussion section can improve the paper.

Line 156: Please elaborate Φ character. If it means diameter please change the Φ1000 to 1000 mm diameter pile.

Line 161: Please elaborate on characters (Φ800@600) used for describing the pile geometry. If it means a pile with 800 mm diameter and 600 mm spacing please describe it instead of using “Φ@” characters.

Line 162: Please briefly define “C30 underwater concrete” in the footing or the appendix.

Line 215: Please rewrite the sentence “From the results of Melan solution, it can be found that the closer to the isolation pile is, the more obvious the restraint effect is”. The sentence has grammar issues.

Lines 269, 270, and 271: please rewrite the sentence “The analytical solution under the impact of isolation pile is derived based on the Melan solution and Loganathan formula, which could reflect the restraint effect of isolation pile on the surface settlement trough from the internal mechanism.” The sentence is too long. In addition, the “trough from” looks a typo. Please check “trough from”.

Author Response

Please see the attachment. Thank you very much.

Author Response File: Author Response.docx

Reviewer 2 Report

For this paper, in order to satisfy the engineering analysis scale and reflect the friction characteristics between isolation pile and soil particles simultaneously, the FDM-DEM coupling technique is introduced to establish a numerical model including discrete medium and continuum medium. I found that the manuscript is very informative and presents useful results.

General comment
1. Suitable keyword for the paper.
2. Well written for the abstract.


However, I would like the authors please correct and explain some comments and questions as followings.

1. Recheck the minor English spelling errors.  The language of the paper should be rechecked. There are several grammar error.   

2. In order to make the paper more useful for the reader, the authors should report a comparison of the novel proppant in comparison with the ones actually used for the same process. (give more information about it). Even if, of course, this is not a review on the proppants, in order to understand why this one is important and how its characteristic make it a useful product. Introduction should be enhanced and needs to correlate between paragraph to paragraph. The application of this research output is not well highlighted. Suggest to propose and link the research output toward engineering application.
3.                                                                                                           However, in my point of view there is some points which have to be taken in account in order to improve the work. Firstly, the Introduction has to be reviewed. It is too summarized and the sentences need to be better linked.
4. The authors should manage the order of descriptions in all Tables and Figures. Explanation of any figures and tables should be placed as close as possible.                                                        
5. Conclusions are weak and not supported by comparisons with previous studies. The Conclusion should be rewritten; as presented it is not full representative of the entire work done.

Author Response

Please see the attachment. Thank you very much.

Author Response File: Author Response.docx

Reviewer 3 Report

The paper presents a theoretical and experimental analysis aiming to examine the restraint mechanism of isolation pile on soil displacement induced by shield tunneling. The main purpose of the study is to gain a better prediction of the surface settlement trough and accurately evaluate the protection effect of isolation pile on the adjacent buildings.

The authors have provided a detailed theoretical analysis model of the mechanism causing the restraint of isolation pile and then have applied it in an actual case study of metro line.

The results of the work are very interesting and provide a detailed overview on how the affected zone of soil above the tunnel top is restricted under the influence of isolation piles.

The discussion and explanations provided by the authors about the findings are quite analytical and sufficient, stand in the appropriate level and do not extend into useless details. Quality of presentation is quite good and the reader of the paper obtains easily and quickly an overview of the findings of the investigation performed. The subject of this investigation is quite important and offers several important conclusions concerning the examined mechanism of isolation panel and its application. Therefore the paper is suggested for publication.

Author Response

We are very grateful to the reviewer for giving us a high degree of review. We have revised the introduction to highlight the significance of this study.

Round 2

Reviewer 2 Report

The manuscript can be accepted in present form.