Field Experiments on 3D Groundwater Flow Patterns in the Deep Excavation of Gravel-Confined Aquifers in Ancient Riverbed Areas

Round 1

Reviewer 1 Report (Previous Reviewer 3)

This work is a field case study conducted at the deep foundation pit of the Qianjiang Century City station that is notable for its unclosed waterproof curtain. It is a very interesting research.

In the end of the study it was founded that the use of longer filters, higher pump rates, and filters placed nearer to aquifer roofs enhances dewatering efficiency and minimizes impact on the surrounding geological environment. This paper introduces a novel concept known as the diaphragm wallpumping well effect, which regulates the water head outside the pit and the subsidence, thereby optimizing the drawdown of the deep foundation pit with an unclosed waterproof curtain.

In my opinion it is suitable to accept in the present form.

Author Response

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Reviewer 2 Report (Previous Reviewer 1)

The paper presents a field case study conducted at the deep foundation pit of the Qianjiang Century City station on Hangzhou Metro Line 6, which is notable for its unclosed waterproof curtain. The research included two sets of multi-depth pumping tests, which differed in terms of their filter lengths, aimed at investigating the flow pattern around pump wells and the roots of diaphragm walls. I found that the manuscript is very informative and presents the useful results of the experiment.

 

General comment
1. The title is clear and focuses to output research.
2. Suitable keyword for the paper.
3. Well written for the abstract.
4. The contribution of this work to solve the limitation/problems is clearly highlighted.

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

1. Recheck the minor English spelling errors.                                                                                                                       
2. The authors should manage the order of descriptions in all Tables and Figures.
3. Explanation of any figures and tables should be placed as close as possible.                                                        

4. Conclusions are weak and not supported by comparisons with previous studies.

Recheck the minor English spelling errors. 

Author Response

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Reviewer 3 Report (New Reviewer)

The manuscript "Investigating 3D Groundwater Flow Patterns near Diaphragm Walls and Pumping Wells", presents a field case study that aims to investigate 3D groundwater flow patterns around diaphragm walls and pumping wells within deep excavation sites. The study focuses on the interaction between groundwater movement, diaphragm walls, and pumping rates, providing insights into optimizing dewatering efficiency and minimizing environmental impact. The research addresses an important practical concern in urban underground construction, and the findings may have broader implications for similar engineering projects. However, while the manuscript demonstrates promise, there are certain areas that require attention before publication. I recommend the following aspects be carefully reviewed and revised:

-The abstract lacks specific details about the experimental setup and the significance of the research. A brief mention of the real-world implications or applications of the findings would enhance the abstract's clarity and relevance.

-The introduction falls short in fully explaining the motivation behind investigating the 3D flow phenomenon and nonlinear effects near the diaphragm wall and pumping well. It's important to clearly state the research gap or problem that the study aims to address. Additionally, the introduction should provide a more comprehensive and up-to-date literature review to contextualize the study within the existing body of knowledge.

-The methodology lacks critical details required for replication. The description of the field multi-depth pumping tests is insufficient. Essential information such as the experimental setup, equipment used, data collection techniques, and analytical methods are missing. This lack of detail makes it difficult for other researchers to understand and reproduce the experiments. Furthermore, the paper does not address potential sources of error or limitations in the experimental design.

-The authors need to elaborate more on the interpretation of data trends and patterns observed in the experimental results. While the manuscript mentions the occurrence of a 3D flow phenomenon and the maximum drawdown locations, there is a need to connect these observations to the underlying hydrogeological mechanisms. A detailed discussion of why certain drawdown patterns emerge and how they relate to factors like diaphragm wall placement and aquifer characteristics will enhance the significance of the findings.

-The manuscript could benefit from a more comprehensive comparison of the data collected from different pumping tests. Specifically, addressing similarities and differences between pumping tests conducted in Pit A and Pit B would provide a deeper understanding of how site-specific conditions influence the observed groundwater flow patterns. Discussing why certain patterns emerge in one pit but not the other can provide valuable insights.

-The data analysis should be more explicitly linked to the practical implications for construction and urban planning. How can the observed groundwater flow patterns inform dewatering strategies? Are there specific insights that practitioners can take away from these findings? Furthermore, connecting the observed results to existing hydrogeological theories or models will anchor the study within the broader scientific context.

-The conclusion lacks a comprehensive assessment of the implications and significance of the results. The paper should explicitly address how the findings contribute to the understanding of 3D flow phenomena, nonlinear effects, or their practical implications. Additionally, the conclusion does not effectively discuss the limitations of the study, which is important for transparency and credibility.

The manuscript titled "Investigating 3D Groundwater Flow Patterns near Diaphragm Walls and Pumping Wells" demonstrates a commendable effort in terms of its technical content and scientific findings. However, there are certain areas where the quality of English language could be improved to enhance the overall readability and clarity of the manuscript.

Author Response

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Author Response File: Author Response.docx

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

For this paper, the deep foundation pit with unclosed waterproof curtain at the Qianjiang Century City station on Hangzhou Metro Line 6 was used for the field case study. Two groups of multidepth pumping tests with different filter length were performed to study the flow pattern around pump wells and the roots of diaphragm walls. I found that the manuscript is very informative and presents the useful results of the experiment.

 

General comment
1. The title is clear and focuses to output research.
2. Suitable keyword for the paper.
3. Well written for the abstract.
4. The contribution of this work to solve the limitation/problems is clearly highlighted.

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

1. All commercial names are to be deleted.
2. Recheck the minor English spelling errors.                                                    3. The authors should manage the order of descriptions in all Tables and Figures.
4. 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.

Moderate editing of English language required

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

This manuscript is a report desccribing some pumping tests performed during works for an undergoround station of a metro line in the city of Hangzhou.

The work is written in a poor language and this makes it difficult to follow all the details. Moreover, the manuscript is not properly organized.

The manuscript shows data from an interesting field test, but the data are not presented and discussed in a proper way. Very qualitative comments only are given.

As an example, looking to Figure 6a, it is apparent that the water flow is converging toward the region at a depth between 40 m and 49 m, where the filter is lcoated, with an hydraulic gradient of the order of 8. How is the pressure data influenced by the pump position? Is the drawdown inside the puming well representative of the conditions in the aquifer nearby? Are non-linear effects through the well casing and drain negligible? Is Darcy's law still valid in presence of such a high gradient? No information is given on the groundwater level before the pumping test, is it?

Figure 3. Horizontal and vertical space scales are missing. What is the meaning of the different symbols and filling used in the cross-section?

Table 1. Is it physically significant to give the excavation depth and other quantities with a precision of 1 mm? Frankly speaking, I am afraid this is not scientifically correct.

Table 2. Hydraulic conductivity of gravel is very high. Can you comment on this? Is G_s measured independently of g? Why is G_s smaller for silt than for muddy soil, while g is greater for silt? Is this correct?

Notice that more than 80% of the cited literature is from Chinese researchers. I think this is not appropriate for a work submitted to an international journal, unless the work is related to an item specifically focused on a problem of regional or local interest, and therefore of minor  significance for an international audience.

The Data Availability Statement lists the instructions to authors. It should be filled with proper information. In particular, in the realm of open science, data should be made available on a public repository.

I am sorry, but my opinion is that the manuscript cannot be considered for publicatin on a scientific international journal.

The quality of English is quite poor. Unfortunately, annotating the manuscript would require a very long time. I am sorry, but I think that the manuscript should be thoroughly revised to imprvoe the language and clarify scientific concepts.

Author Response

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Reviewer 3 Report

"Field experiments on 3D groundwater flow pattern in deep excavation of gravel confined aquifer in ancient riverbed area" was studied. A deep foundation pit with an unsealed waterproof curtain at Qianjiang Century City station on Hangzhou Metro Line 6 was used for the field case study. Two sets of multi-depth pumping tests with different filter lengths were performed to examine the flow pattern around the pump wells and the roots of the diaphragm walls. The findings show that using longer filters, greater pump speed, and filters closer to the aquifer roofs for dewatering can increase dewatering efficiency while reducing the impact on the geological environment surrounding the quarry. The diaphragm wall pump well effect, which effectively controls the water height outside the pit and the bottom side, can be used to regulate the fall of the deep foundation pit with an unsealed waterproof curtain. 

I believe that keeping the introduction part of the article shorter and writing the conclusion part in plain text rather than in articles will make it more understandable.

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Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

I am sorry, but I confirm my initial opinion, i.e., the manuscript should be rejected.

The authors claim that they "are trying to improve the language under the help of an English native speaker", but unfortunately, I still found some errors and several unclear sentences.

Moreover, the changes they introduced to answer some of my comments do not provide a precise and rigorous description.

For instance, they state that "the foundation pit of Qianjiang Century City Station is located in a Quaternary alluvial marine sedimentary plain": is it alluvial or marine? These are very different sedimentological environments!

"All the pore pressures observed were calculated as drawdowns" is an imprecise, if not wrong sentence.

The authors state that "pore pressures were observed in the filter material outside well casing and drain instead of inside", but since this is not standard, they should explain how. I can imagine some methods to do this, but such methods could be very sensitive to the design setup and to the realization of the monitoring boreholes.

Figure 2 can be erased, because it does not provide any clear information. It is a simple sketch, which does not support any scientific rigorous statement.

Please, notice that this is a non comprehensive list of flaws of the manuscript, which, in my opinion, suffers from further scientific weaknesses. Therefore, as I wrote above, I am sorry, but I honestly think it cannot be considered for publication.

The language quality is still quite poor.