Adaptability Evaluation of Rotary Jet Grouting Pile Composite Foundation for Shallow Buried Collapsible Loess Tunnel
Round 1
Reviewer 1 Report
Based on the shallow buried section of Fujiayao Tunnel with a buried depth of 20 m, this paper systematically studies the base deformation control and post construction settlement control in the construction process by using the numerical simulation method, analyses the differential deformation control, and evaluates the reinforcement effect of the tunnel bottom. According to below comments, my decision would be Minor Revision.
1) There are some occasional grammar errors through the manuscript especially the article ''the'', ''a'' and ''an'' is missing in many places, please make a spellchecking in addition to these minor issues.
2) Abstract must contain four important elements including (1) state clearly the objectives of the study (2) concisely describe the methodology or method employed in gathering the data, processing, and analysis (3) summarize the results, and (4) state the principal conclusions of the research. For your manuscript, Abstract should be more quantitative. The performance of the model should be presented.
3) Please modify the keywords. The repetition of keywords and words in the title should not match.
4) Fig. 1 which shows the geological condition of the study could be improved and more informative. Please also check the sharpness and the quality of the figures throughout the manuscript
5) In Figure 4, there is a display error in the variable unit, and the author is suggested to check and modify it.
6) Is the evaluation result of reinforcement effect of loess tunnel valuable for other types of tunnels (such as soft soil tunnel, rock soil tunnel, etc.)?
Author Response
Reviewer #1
Based on the shallow buried section of Fujiayao Tunnel with a buried depth of 20 m, this paper systematically studies the base deformation control and post construction settlement control in the construction process by using the numerical simulation method, analyses the differential deformation control, and evaluates the reinforcement effect of the tunnel bottom. According to below comments, my decision would be Minor Revision.
- Comments:
There are some occasional grammar errors through the manuscript especially the article ''the'', ''a'' and ''an'' is missing in many places, please make a spellchecking in addition to these minor issues.
Response:
The authors appreciate the reviewer for pointing this out. Appropriate changes have been made in the manuscript.
- Comments:
Abstract must contain four important elements including (1) state clearly the objectives of the study (2) concisely describe the methodology or method employed in gathering the data, processing, and analysis (3) summarize the results, and (4) state the principal conclusions of the research. For your manuscript, Abstract should be more quantitative. The performance of the model should be presented.
Response:
The authors appreciate the reviewer for pointing this out. Appropriate changes have been made in the manuscript. The summary of the article has been rectified according to the suggestions
- Comments:
Please modify the keywords. The repetition of keywords and words in the title should not match.
Response:
The authors appreciate the reviewer for pointing this out. The author replaced some key words and arranged them according to the format of the journal.
- Comments:
Fig. 1 which shows the geological condition of the study could be improved and more informative. Please also check the sharpness and the quality of the figures throughout the manuscript
Response:
The authors appreciate the reviewer for pointing this out. Appropriate changes have been made in the manuscript. To make the handwriting in Figure 1 clear, the author adjusted the size of the picture.
- Comments:
In Figure 4, there is a display error in the variable unit, and the author is suggested to check and modify it.
Response:
The authors appreciate the reviewer for pointing this out. Appropriate changes have been made in the manuscript.
- Comments:
Is the evaluation result of reinforcement effect of loess tunnel valuable for other types of tunnels (such as soft soil tunnel, rock soil tunnel, etc.)?
Response:
The authors appreciate the reviewer for pointing this out. The reinforcement effect of loess tunnels can provide an important reference value for the foundation reinforcement of loess tunnels in similar regions in the future, as well as for other types of tunnels, such as clay tunnels, soft soil tunnels or rock tunnels.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper presents an interesting study on the adaptability evaluation of rotary jet grouting pile composite foundation. In this paper, numerical simulation method is used to systematically study the control of base deformation during construction and settlement after construction, analyse different deformation control, and evaluate the reinforcement effect of tunnel bottom. It is a good study with innovation. The manuscript should be published after minor revision.
1. There are some latest research findings on surrounding rock failure and tunnel face stability which are ignored in the Introduction. Please improve the introduction.
Ref.:
(1) K. Han, J.W.W. Ju, H. Kong, M. Wang, Functional Catastrophe Analysis of progressive failures for deep tunnel roof considering variable dilatancy angle and detaching velocity, Rock Mech. Rock Eng. 52 (2019) 3987-3997.
(2) K. Han, L. Wang, D. Su, C. Hong, X. Chen, X.T. Lin, An analytical model for face stability of tunnels traversing the fault fracture zone with high hydraulic pressure, Comput. Geotech. 140 (2021) 104467.
2. The Model section is well written. Please check all the formulas used in the manuscript to ensure that all the variables are interpreted.
3. The Data description section is also well written and the figures are completely interpreted and data visualisation is in a standard level.
4. Please specify the reason for selecting tunnel numerical model parameters.
5. Where is the reinforcement opportunity shown in Figure 5 specifically reflected in the text? If not, please supplement and improve.
6. Before and after optimizing the pile length, what are the most prominent advantages of loess tunnel construction?
7. Conclusion is well written and involve all the important points in this study. However, it should be revised to have more quantitative description of the results.
Author Response
Reviewer #2
This paper presents an interesting study on the adaptability evaluation of rotary jet grouting pile composite foundation. In this paper, numerical simulation method is used to systematically study the control of base deformation during construction and settlement after construction, analyse different deformation control, and evaluate the reinforcement effect of tunnel bottom. It is a good study with innovation. The manuscript should be published after minor revision.
- Comments:
- There are some latest research findings on surrounding rock failure and tunnel face stability which are ignored in the Introduction. Please improve the introduction.
Ref.:
(1) K. Han, J.W.W. Ju, H. Kong, M. Wang, Functional Catastrophe Analysis of progressive failures for deep tunnel roof considering variable dilatancy angle and detaching velocity, Rock Mech. Rock Eng. 52 (2019) 3987-3997.
(2) K. Han, L. Wang, D. Su, C. Hong, X. Chen, X.T. Lin, An analytical model for face stability of tunnels traversing the fault fracture zone with high hydraulic pressure, Comput. Geotech. 140 (2021) 104467.
Response:
The authors appreciate the reviewer for pointing this out. Appropriate changes have been made in the manuscript. The recommended references have been mentioned in the introduction of the article
- Comments:
The Model section is well written. Please check all the formulas used in the manuscript to ensure that all the variables are interpreted.
Response:
The authors appreciate the reviewer for pointing this out. Appropriate changes have been made in the manuscript.
- Comments:
The Data description section is also well written and the figures are completely interpreted and data visualisation is in a standard level.
Response:
The authors appreciate the reviewer for pointing this out.
- Comments:
Please specify the reason for selecting tunnel numerical model parameters.
Response:
When selecting the model scale, the following two factors must be considered: â‘ measurement accuracy requirements; â‘¡ Test equipment conditions. In terms of measurement accuracy, the strain values of most measuring points of the model should be within the optimal range of the strain gauge as far as possible. In addition, the strain value of the main measuring points of the model should not be too low, and the possible tensile stress should not exceed the tensile strength of similar materials. The displacement value of the model shall be similarly estimated. In terms of test equipment conditions, on the one hand, it is necessary to estimate that the maximum strain and displacement of the model cannot exceed the range of the test element; on the other hand, it is necessary to meet the accuracy requirements; at the same time, it is more important to consider whether the loading conditions and test bench can meet the test requirements. In fact, when selecting the model scale, in addition to the measurement and loading conditions, it must also be considered from the perspective of test cost. These parameters selected based on site conditions and previous experience are representative.
- Comments:
Where is the reinforcement opportunity shown in Figure 5 specifically reflected in the text? If not, please supplement and improve.
Response:
The authors appreciate the reviewer for pointing this out. Appropriate changes have been made in the manuscript.
- Comments:
Before and after optimizing the pile length, what are the most prominent advantages of loess tunnel construction?
Response:
By changing the pile length of jet grouting pile composite foundation and in-creasing the replacement rate, the uplift displacement and settlement under the unfa-vorable condition of tunnel bottom flooding can be controlled in a very small range.
- Comments:
Conclusion is well written and involve all the important points in this study. However, it should be revised to have more quantitative description of the results.
Response:
The authors appreciate the reviewer for pointing this out. Appropriate changes have been made in the manuscript.
Author Response File: Author Response.pdf
Reviewer 3 Report
1. Figure 1 is unacceptable. It only reflects the distribution of stratum, height and mileage are not reflected in the figure, and the quality of Figure 1 is too poor. Figure 1 needs to be modified for reference.
2. In Chapter 2, if there is no corresponding picture of the experiment process in the similar experiment, I don't know what the purpose of the similar experiment is in this chapter.
3. In Chapter 2.3, the boundary conditions of the model, the overburden thickness of the tunnel, and the position of the stratum profile used for modeling are not clearly stated, which makes it difficult for the reader to follow up;
4.229 Wrong row header;
5. So what kind of reinforcement method is finally adopted on site? Is there any data support for field application;
6. The reinforcement effect can be compared by the size of displacement, but the safety of excavation cannot be explained by the size of deformation, unless a control limit from the specification is added;
Author Response
Reviewer #3
- Comments:
Figure 1 is unacceptable. It only reflects the distribution of stratum, height and mileage are not reflected in the figure, and the quality of Figure 1 is too poor. Figure 1 needs to be modified for reference.
Response:
The authors appreciate the reviewer for pointing this out. The purpose of the author to provide Figure 1 is only to explain the geological conditions of the tunnel. The mountain range and tunnel size are both schematic in this figure, so the tunnel size and mountain height cannot be provided completely.
- Comments:
In Chapter 2, if there is no corresponding picture of the experiment process in the similar experiment, I don't know what the purpose of the similar experiment is in this chapter.
Response:
The authors appreciate the reviewer for pointing this out. Appropriate changes have been made in the manuscript. The author added part of the flow chart and description of the indoor test at the appropriate position in the chapter â…¡ of the article based on the suggestions put forward.
- Comments:
In Chapter 2.3, the boundary conditions of the model, the overburden thickness of the tunnel, and the position of the stratum profile used for modeling are not clearly stated, which makes it difficult for the reader to follow up.
Response:
The authors appreciate the reviewer for pointing this out. Appropriate changes have been made in the manuscript. The supporting project of the project is the 1 # tunnel of Lanzhou Qinhuangdao Expressway on the north bank of the Yellow River in Lanzhou City. The total length of the tunnel is 802m, the maximum buried depth is 112m, and the minimum buried depth is 20m. The research object is selected as the 20m shallow buried section, and the whole length range is Grade V surrounding rock. The tunnel passes through the loess ridge. The entrance is arranged in the mountain on one side of the loess gully, and the exit is located in the mountain on the right side of the upstream of Qiujiagou. The excavation span of the tunnel is 17m, and the height is 11m. It belongs to a three-lane tunnel with super large section loess tunnel.
To verify the accuracy of the model test results, the numerical model established is the same size as the model test, with consistent boundary conditions and excavation and support schemes.
- Comments:
229 Wrong row header;
Response:
The authors appreciate the reviewer for pointing this out. Appropriate changes have been made in the manuscript.
- Comments:
So what kind of reinforcement method is finally adopted on site? Is there any data support for field application;
Response:
The authors appreciate the reviewer for pointing this out. Long short pile composite foundation reinforcement method is adopted on site. This research is based on field test and has certain field data support.
- Comments:
The reinforcement effect can be compared by the size of displacement, but the safety of excavation cannot be explained by the size of deformation, unless a control limit from the specification is added.
Response:
The authors appreciate the reviewer for pointing this out. By changing the pile length and increasing the replacement rate, the uplift displacement and the overall settlement of the base under adverse conditions of water immersion during the construction of the base can be controlled within a small range. When the long and short piles are combined at the base, the differential settlement and the range of plastic zone at the base can be significantly reduced. The plastic failure of foundation soil is mainly caused by differential settlement. The differential settlement of 9mm can be used as the evaluation index of the base reinforcement effect.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
This article can be accepted and published
