Stability Analysis Method for Initial Support Structure of Tunnel in Swelling Loess

Round 1

Reviewer 1 Report

This work mainly studies the influence of the expansion deformation and strength of loess on the stability of the tunnel caused by the change of loess water content based on the theoretical theory. The study represents an interesting topic. However, some key issues should be clarified and the suggestions are listed below.

1、The content is more conventional and the innovation point is not obvious.

2、The practical engineering significance of the research is not prominent. The related content should be supplemented.

3、Some figures are oversimple, such as the size of characters is small. The meaning of horizontal and vertical coordinates of the coordinate axis in Fig. 2,4,5 and 6 should be added.

4、There are only some derivation formulas in the second part of the article without a corresponding curve to show the relationship between the research parameters.

5、The third part of the article only has the relevant content of the derivation formula. The content appears simple and seems lacking the key part. The corresponding support diagram should be added to facilitate an intuitive understanding of the meaning of the formula.

6、In the project case analysis, it is recommended to supplement relevant results about supporting structure section of the tunnel and engineering geology around the tunnel.

7、The theoretical value derived from the formula compared with the actual monitoring value is close. However, is the maximum deformation direction close? How to consider the maximum deformation direction?

8、What are the innovations or advantages of the results derived based on relevant theoretical formulas compared with previous studies? It is suggested to add some comparison of relevant studies.

9、The relevant analysis of “Sensitivity analysis of safety factor” is relatively simple and are not deeply discuessed enough.

10、Syntax and grammar of English used are relatively poor, a major revision is recommended.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

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Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

General comments:

The changes of volume and strength of swelling loess caused by humidification have impact on the tunnel stability. The manuscript focuses on the stability analysis method for initial support structure of tunnel in swelling loess, some interesting results are obtained. In addition, some problems should be addressed before publication.

 

Specific comments：

1. The abstract should reflect the main content of this study. The research results must be detailed, or important data should be used to explain. It is recommended that the author modify and improve the abstract part.

2. The introduction should summarize the cited literature, point out the advantages and disadvantages of the current research and finally fall into the purpose and significance of this study, rather than a simple list of literature.

3. There are some detailed description problems in the manuscript. For example in lines 102-103 ' The parameters a1, a2, a3 and a4 in equations ( 1 ) and ( 2 ) are fitted by the test data. ' should be described as ' equations ( 5 ) and ( 6 ) '.

4. Is there a misrepresentation in lines 209-211 ? When the support design is unreasonable, the support design should be adjusted, such as increasing the reinforcement ratio or material strength to increase the safety factor, rather than directly adjusting the safety factor.

5. The ' Swelling power, cohesion and internal friction angle ' in Fig.3 should correspond to each other, while the value point of Swelling power in Fig.3 does not correspond to the cohesion and internal friction angle.

6. Is it necessary to indicate the unit for "average circular spacing of bolt and Axial average spacing of bolt" in Table 2? And in lines 239-240, spaces should be added between numbers and units. Please check the full text by yourself to correct such errors.

7. In Figure 7, Fs changes obviously with th_c and t_c, but it is not easy to see the weakening trend with E_c and S_c. It is suggested that the author increase the fitting trend line to quantitatively explain the changing trend of F_S with various parameters.

8. The font size in Figure 8 is small and the rendering effect is poor, so the author should unify the font size of the pictures in the whole text. And the expression in Figure 8 is repeated with Table 5. Should it be deleted?

9. The format of references is not uniform, so the author is advised to check all references and unify the format.

10. It is recommended to refer to the following two literatures:

 Lan, H.X., Peng, J.B., Zhu, Y.B., Li, L.P., Pan, B.T., Huang Q.B., Li, J.H., Zhang, Q. (2022). Research on geological and surfacial processes and major disaster effects in the Yellow River Basin. SCIENCE CHINA Earth Sciences, 65(2), 234–256.

Lan, H.X., Zhao, X.X., Macciotta, R., Peng, J.B., Li, L.P., Wu, Y.M., Zhu, Y.B., Liu, X., Zhang, N., Liu, S.J., Zhou, C.H., Clague, J.J. (2021). The cyclic expansion and contraction characteristics of a loess slope and implications for slope stability. Scientific Reports, 11, 2250.

Zhu, J., Zhang, H., Wang, Z., Yang, S., & Ding, Z. (2021). Physico-mechanical properties of thick paleosol in Q1 strata of the Chinese Loess Plateau and their variations during tunnel excavation. Engineering Geology, 295, 106426.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Please see in the attached file.

 

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx