Pipe Piles and Key Stratum Modeling for Grouting Reinforcement of Mine Floors under Mining Disturbance and Microseismic Monitoring Evaluation

Round 1

Reviewer 1 Report

After analyzing the prevention and control effect of water inrush from the working face floor under different grouting reinforcement and transformation modes, this paper establishs a sub-model of “pipe pile” and a sub-model of “water-resistant key stratum”, and simulate the concrete function of the structural models formed by the two grouting modes. The purpose is to provide a basis for evaluating the grouting reinforcement effect.

After some minor changes, this manuscript can be published.

 Notes and comments:

-The theory of floor failure is underdemonstrated, please add some relevant literature.

-Please explain how microseismic affects the effectiveness and precision of floor grouting reinforcement.

-There are some formatting problems in references. Please check and revise these carefully.

Author Response

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Reviewer 2 Report

In this paper, a model for reinforcing casing, known as "pipe pile," is introduced. The model involves drilling and grouting through each layer, and the spatial stress characteristics of the casing are analyzed. According to the numerical simulation results, the casing has a significant impact on the deformation of the rock mass in the transition zone. To improve the deformation and failure resistance of the floor rock mass, it is recommended to apply the casing in this area. While floor failure may still occur, the strength of the rock mass in the transition zone is reinforced due to the casing impedance, which effectively controls floor deformation.

A manuscript has a practical application and also provides important theoretical for the next studies.

In your research authors must discuss below mentioned issues (indicate lines):

- What is the "pipe pile" model of casing reinforcement and how is it used for grouting reinforcement of mine floor under mining disturbance?

- What are the spatial stress characteristics of the casing and how do they affect the deformation of the rock mass in the transition zone?

- How can the application of the casing in the transition zone improve the deformation and failure resistance of the floor rock mass?

- How can microseismic monitoring be used to evaluate the effectiveness of grouting reinforcement in the mine floor?

- What are the key factors that should be considered when implementing grouting reinforcement using the pipe pile and key stratum model for mine floor stability?

The introductory section of this paper requires improvement in order to better engage and inform the reader about the topic at hand.

Line 36-38. “Mo conducted parametric research on the mechanism of floor heave in coal mine roadways using a numerical model [4]”. Enhance this part with more current studies. Here I would like to bring your attention to the paper (Sakhno, I.; Liashok, Ia.; Sakhno, S.; Isaienkov, O. Method for controlling the floor heave in mine roadways of underground coal mines. Min. Miner. Depos. 2022, 16(4), 1-10. https://doi.org/10.33271/mining16.04.001). Please consider it and add more relevant information.

Please provide a short description of further research.

It is essential to emphasize the novelty and significance of the research in the conclusions section of the paper. This will enable readers to better understand the original contribution of the study and its potential implications for future research and practical applications. Therefore, it is important to clearly and effectively articulate the innovative aspects of the research in the concluding section of the paper.

Overall, the article presented has left a favorable impression, and with the incorporation of the suggested revisions and considerations put forth, it is highly recommended for publication in the "Sustainability" journal.

Author Response

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Reviewer 3 Report

Minor editorial errors are highlighted in grey.

Notes to the article:

The developed analytical model of the phenomenon has not been analyzed in any way. The authors concluded their considerations by giving the final formulas.

There is no description of cooperation between the FLAC3D and PFC3D models

Fig. 11 requires more comment regarding the spatial location of the joint systems

Fig. 13 - the too small size of 9 drawings makes it impossible to analyze them.

What are the seismic energy values of events?

There is no data on the location of the events.

The reader finds several gaps in the text of the paper which makes him feel confused.

Comments for author File: Comments.pdf

Author Response

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Reviewer 4 Report

The study involves a lot of work, inculding stress analysis solutions, numerical modeling, and microseismic event analysis, but it does not seem to closely connect to the theme of grouting reinforcement. The paper appears to be more heavily focused on the stress states and failure characteristics of the rock mass, with no direct relation to grouting reinforcement.

The numerical modelling lacks clarity. Critical details such as the engineering case upon which the model is based, boundary conditions, and the specific reason behind employing the coupled modeling method of PFC3D-FLAC3D have been omitted. Furthermore, the manuscript is expected to provide more information about the roles PFC3D and FLAC3D play in the modeling, the respective constitutive models used, and whether grouting simulation has been considered.

From the limited information provided, it appears the authors only set up different inclination angles of prefabricated cracks in the PFC3D discrete element model, followed by pressurizing the model to observe fracture development and the condition of rock mass failure. This modeling approach is somewhat simplistic and crude, lacking consideration for underground engineering structures in the rock mass or the mentioned pipe pile, and grouting. Figure 13, showcasing the effects of failure, does not provide useful information nor clearly illustrates differences in the failure of the various model groups. Moreover, there is an absence of quantitative data such as the number of fractures and stress distribution, making the simulation results less convincing.

The parameters of the PFC3D modeling should be listed in detail.

Author Response

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Round 2

Reviewer 2 Report

Dear authors, I am more than satisfied with the corrections provided by you.

This study is an important contribution to sustainable mining.

Author Response

Reviewer 4 Report

Please confirm the accuracy of the data in Table 1. Is the unit of particle radius meters (m) or millimeters (mm)? Why is the density 1000kg/m^3? Please clarify what exactly "Ball-ball contact modulus" and "Parallel bond modulus" refer to?

I suggest that the authors provide the evolution curves of the number of cracks or stress distribution curves under different conditions and analyze them in conjunction with Figure 13

Author Response

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