Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1.  In  Table 2 (Mechanical Properties of the Coal–Rock Mass), the unit notation in the column header "Bulk densityKN/m3" is not standardized (missing space and non-superscript), and it should be revised to "Bulk density (kN/m³)" and checked for consistency throughout the manuscript.  

2. In Section 3.2 (Numerical Modeling), the model geometry is described (e.g., 100 m axial length, ~25 m lateral boundaries, 50 m height), but the manuscript does not report the mesh/zone discretization (near-field refinement range, minimum element size, total number of zones, etc.) before moving to  "Boundary conditions" ; please add these details to ensure reproducibility.  

3. The numerical model is suggested to be presented as a figure in the appropriate position in the manuscript.  

4. The titles of Section 3.2 and Section 3.3 are the same. Please check.

5.  After the field monitoring summary in Section 4.2 (average side convergence ~15 mm and roof subsidence ~11 mm), please provide a quantitative comparison against the simulated maximum displacements in Table 3, report the percentage error(s), and briefly explain potential sources of discrepancy to strengthen model validation.  

6. After introducing the engineering case "North Wing Main Roadway of Shaanxi Jinyuan Zhaoxian Mining" in the Introduction, it would be helpful to add a location map showing the mine's position within China (at least at the province/city/county scale) and to emphasize the importance of coal production for reliable energy supply, thereby strengthening the background and motivation.

7. In the reference by Guo Zhibiao et al. (2017), the word is incorrectly merged as "roadwayin" ; please correct it to "roadway in" and run a general spelling/spacing check for the entire reference list. 

Author Response

Comments 1:In Table 2 (Mechanical Properties of the Coal–Rock Mass), the unit notation in the column header "Bulk densityKN/m3" is not standardized (missing space and non-superscript), and it should be revised to "Bulk density (kN/m³)" and checked for consistency throughout the manuscript.

Response 1:
Thank you for pointing this out. We agree with this comment; therefore, we have revised the column header from “Bulk densityKN/m3” to “Bulk density (kN/m³)”  and checked unit formatting consistency throughout the manuscript. 

Comments 2:
In Section 3.2 (Numerical Modeling), the model geometry is described (e.g., 100 m axial length, ~25 m lateral boundaries, 50 m height), but the manuscript does not report the mesh/zone discretization (near-field refinement range, minimum element size, total number of zones, etc.) before moving to "Boundary conditions"; please add these details to ensure reproducibility.

Response 2 :
Thank you for the suggestion. We agree with this comment; therefore, we have added mesh/zone discretization details in Section 3.2, including the near-field refinement strategy around the roadway, the minimum zone size, and the total number of zones to improve reproducibility. The revision can be found on [Line 251–259] in the revised manuscript.

Comments 3 :
The numerical model is suggested to be presented as a figure in the appropriate position in the manuscript.

Response 3:
Thank you for this helpful suggestion. We agree; therefore, we have added a figure illustrating the numerical model geometry (dimensions and layout) and placed it next to the numerical modeling description to improve clarity. The revision can be found on  [Line 268] (Figure [5]) in the revised manuscript.

Comments 4 :
The titles of Section 3.2 and Section 3.3 are the same. Please check.

Response 4 :
Thank you for noting this issue. We agree; therefore, we have corrected the duplicated titles by revising the heading of Section 3.3 to a content-consistent title.  [Line 319] 

Comments 5 :
After the field monitoring summary in Section 4.2 (average side convergence ~15 mm and roof subsidence ~11 mm), please provide a quantitative comparison against the simulated maximum displacements in Table 3, report the percentage error(s), and briefly explain potential sources of discrepancy to strengthen model validation.

Response 5 :
Thank you for this constructive comment. We agree; therefore, we added a quantitative comparison between the monitored averages (side convergence ~15 mm; roof subsidence ~11 mm) and the simulated maximum displacements in Table 3, reported the percentage errors, and briefly discussed plausible discrepancy sources (e.g., peak vs. average metrics, mismatch between numerical peak locations and monitoring points, and modeling idealizations/construction disturbances). The revision can be found on  [Line 539–547] in the revised manuscript.
[Updated text in the manuscript if necessary:] “For scheme (d), the simulated maximum roof displacement is 11 mm, matching the monitored average (~11 mm; error ~0%). The equivalent maximum side convergence derived from Table 3 is 40 mm versus the monitored average of ~15 mm (overestimation ~167%), mainly due to peak-versus-average definitions and other uncertainties.”

Comments 6 :
After introducing the engineering case "North Wing Main Roadway of Shaanxi Jinyuan Zhaoxian Mining" in the Introduction, it would be helpful to add a location map showing the mine's position within China (at least at the province/city/county scale) and to emphasize the importance of coal production for reliable energy supply, thereby strengthening the background and motivation.

Response 6:
Thank you for the helpful suggestion. We agree; therefore, we added a location map at the China–province–city/county scale and strengthened the Introduction by adding brief statements highlighting the engineering significance of roadway stability for production continuity and reliable energy supply. The revision can be found on [Line 103–106] (Figure [1]) in the revised manuscript.

Comments 7:
In the reference by Guo Zhibiao et al. (2017), the word is incorrectly merged as "roadwayin"; please correct it to "roadway in" and run a general spelling/spacing check for the entire reference list.

Response 7:
Thank you for catching this typographical error. We agree; therefore, we corrected “roadwayin” to “roadway in” and performed a general spelling/spacing consistency check across the entire reference list. 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

1. Introduction

Most of the literatures cited in the introduction are studies before 2022. High-quality literatures in related fields from 2023 to 2025 can be supplemented (such as the latest theories on cumulative damage of surrounding rock under repeated disturbances, and the application of new support materials or structures) to enhance the timeliness and cutting-edge nature of the research.

 

3. Optimization of the Support Scheme

The parameter design of the four support schemes lacks the logic of "single variable control", and the superposition of some variables leads to insufficient accuracy in the attribution analysis of the differences in support effects.

Although the four support schemes designed in the paper (a: rock bolts + cable bolts; b: rock bolts + cable bolts + floor cable bolts; c: rock bolts + cable bolts + floor cable bolts + U-shaped closed steel sets; d: rock bolts + cable bolts + floor cable bolts + U-shaped closed steel sets + grouting) show a progressive relationship of "gradually adding support measures", there is not only the "addition of a certain type of support component" between scheme (a) and (b), (b) and (c), (c) and (d), but also the problem of unclear consistent control of other parameters. This makes it difficult to separately quantify the individual contributions of "floor cable bolts", "U-shaped closed steel sets", and "grouting" to the stability of surrounding rock.

For example: The core difference between scheme (a) and (b) is "whether to add floor cable bolts", but it is not clearly stated whether the basic parameters such as bolt density and cable bolt prestress are completely consistent between the two; when adding "U-shaped closed steel sets" in scheme (b) and (c), it is not clear whether the coordinated stress parameters between the sets and the original rock bolts and cable bolts (such as the contact pressure between the sets and the surrounding rock, and the spacing matching relationship between the bolts and the sets) maintain a unified benchmark; after adding "grouting" in scheme (c) and (d), the improvement effect of grouting on the mechanical parameters of surrounding rock (such as the increase in cohesion and elastic modulus) is not distinguished from the bearing effect of the support components themselves. It is impossible to accurately judge whether grouting improves the support effect by improving the performance of the surrounding rock itself or through the coordinated effect with the sets and bolts.

This kind of scheme design with multiple variable superposition makes the paper only able to draw the overall conclusion that "scheme d is optimal", but it is difficult to clarify the independent effect of a single support measure (such as grouting). This weakens the guiding value of the research results for "on-demand combination of support measures" in similar projects—in engineering practice, there may be scenarios where only adding a certain type of key support can meet the stability requirements, but the paper does not provide a quantitative basis for the effect of a single measure.

 

4. Analysis of Surrounding Rock Control Measures and Engineering Practice Effects

This section only shows the short-term monitoring data (from October 18 to November 25, about 1.5 months) of the optimized combined support scheme of "29U-type closed steel sets + grouted bolts + bundle-type grouted cable bolts". It does not set up simultaneous comparative monitoring with the original support schemes (such as "rock bolts + cable bolts" and "U-shaped steel sets alone support" mentioned in the paper), so it is impossible to intuitively quantify the specific advantages of the optimized scheme over the traditional schemes in deformation control and stability improvement. At the same time, the monitoring period is relatively short, which does not cover the secondary disturbances that may be encountered during the long-term service of the roadway (such as surrounding mining activities and long-term effects of groundwater), making it difficult to verify the long-term resistance of the optimized scheme to "repeated repair disturbances". In addition, the pressure cell monitoring only shows that "the pressure reading maintains the initial value", and does not conduct a linkage analysis with the mechanical response data of the support structure in the numerical simulation (such as the stress of the sets and the axial force of the bolts and cable bolts). It is impossible to clarify the stress matching and potential failure risks of the support system, leading to an incomplete and rigorous demonstration of the engineering practice effect.

Author Response

Comments 1 :
Most of the literatures cited in the Introduction are studies before 2022. High-quality literatures in related fields from 2023 to 2025 can be supplemented (such as the latest theories on cumulative damage of surrounding rock under repeated disturbances, and the application of new support materials or structures) to enhance the timeliness and cutting-edge nature of the research.

Response 1 :
Thank you for this constructive suggestion. We agree with this comment; therefore, we have updated the Introduction by incorporating recent (2023–2025) high-quality studies related to cumulative/time-dependent damage of surrounding rock under repeated disturbances, as well as advances in new support materials/structures for deep or highly disturbed roadways. These additions strengthen the timeliness and motivation of the study. The revisions (highlighted in yellow) can be found on [Line 36-100] in the revised manuscript.[References1-4 and 17-26]

Comments 2:
The parameter design of the four support schemes lacks the logic of “single variable control”, and the superposition of some variables leads to insufficient accuracy in the attribution analysis of the differences in support effects. […] It is difficult to separately quantify the individual contributions of “floor cable bolts”, “U-shaped closed steel sets”, and “grouting” to the stability of surrounding rock.

Response 2:
Thank you for the detailed comments. We agree with the concern regarding attribution clarity. To address this, we clarified the comparative logic of the four schemes as a progressive “add-on” design and revised the text to interpret results through successive comparisons between neighboring schemes, emphasizing the marginal contribution of the newly introduced measure at each step. Specifically, schemes (a) and (b) are described as two practical bolt–cable configurations, while schemes (b)–(d) are constructed by stepwise introducing floor cable bolts, 29U-type closed steel sets, and grouting on a consistent baseline. We also revised Table 1/2 captions and scheme descriptions to explicitly mark changed items relative to the preceding scheme, thereby reducing confounding interpretation. The revisions (highlighted in yellow) can be found on[Line 220–249] in the revised manuscript.

Comments 3 :
This section only shows short-term monitoring data (Oct 18–Nov 25, ~1.5 months) for the optimized combined support scheme. No simultaneous comparative monitoring is provided for original schemes, the monitoring period is short, and the pressure-cell monitoring lacks linkage analysis with numerical mechanical responses (set stress, bolt/cable axial force). Therefore, the demonstration of engineering practice effect is incomplete/insufficiently rigorous.

Response 3 :
Thank you for this important comment. We agree that the field verification should be presented more rigorously. Although simultaneous comparative monitoring for the original schemes was not available due to site constraints, we strengthened Section 4.2/Discussion by (i) explicitly stating the monitoring duration and its limitation, (ii) adding an indirect comparison based on documented historical deformation/repair characteristics of the roadway and the monitored response under the optimized system, and (iii) discussing how the monitored deformation trends correspond to the numerical indicators (displacements/yield extent), together with plausible reasons for discrepancies (short monitoring window, construction disturbance, differences between peak numerical response and averaged monitoring metrics). We also clarified the interpretation of pressure-cell readings and explained the scope of linkage with numerical results within the available dataset. The revisions (highlighted in yellow) can be found on [Line 520-526, 572–592] in the revised manuscript.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This paper investigates the deformation and failure mechanisms of roadway surrounding rock subjected to repeated repair–induced disturbances and proposes optimized control measures based on numerical simulation and engineering practice. A three-dimensional numerical model was established to compare different support schemes in terms of stress distribution, plastic zone evolution, displacement characteristics, and shear strain increments of the surrounding rock. The results indicate that support systems relying solely on rock bolts and cable bolts lead to pronounced stress concentration zones and are ineffective for long-term stability control. Grouting significantly enhances the integrity and self-bearing capacity of the surrounding rock, while U-shaped closed steel sets effectively restrain deformation of the roof, ribs, and floor. The combined support scheme integrating U-shaped closed steel sets with grouted bolts and bundle-type grouted cable bolts exhibits the best performance in reducing roof subsidence, rib convergence, and floor heave. Field application confirms that this composite support system provides reliable control of roadway deformation under repeated disturbance conditions, thereby reducing repair frequency and improving operational stability

General Comments

The quality of Figure 1 a), b), c), and Figure 2 b) is very poor – the photos are too dark and difficult to see.

Is the 29U a yielding or rigid support?

The modulus of elasticity unit is MPa – definitely not. However, for GPa, the values are too high.

The cohesion value for coal, 3.85 MPa, seems significantly overestimated.

What program was used for the numerical calculations?

Section 3.3.1 and Figure 4. What are these stresses? Are they only positive (tension)? Where exactly are the cross-section lines? Figure 4 is illegible and incomprehensible.

Table 3 – what displacements? Only positive? At what points are they read?

The comments regarding Section 3.3.2 and Figure 5 are similar.

Figure 5 – apart from the fact that it is too small and illegible, what is the shear strain increment distribution supposed to show? Why aren't the yield indices shown in the elements? This would at least show the extent of the yield zones (failure).

Line 292 - Figure 8 is missing from the article.

Figure 7 - What are these displacements (horizontal, vertical, total?)? At what points are they read?

Editorial remarks

Minor editorial errors are highlighted in yellow in the attached document.

Comments for author File: Comments.pdf

Author Response

Comments 1:
The quality of Figure 1 a), b), c), and Figure 2 b) is very poor – the photos are too dark and difficult to see.

Response 1:
Thank you for pointing this out. We agree with this comment; therefore, we have improved the visibility and resolution of Figure 1(a–c) and Figure 2(b) by adjusting brightness/contrast and replacing them with higher-resolution images. We also ensured that all labels and captions are legible at the final manuscript size. The revisions (highlighted in [blue]) can be found on [Line 171–208] (Figures 1 and 2).

Comments 2 :
Is the 29U a yielding or rigid support?

Thank you for the question. The 29U-type steel sets used in this study represent a yielding (deformable) steel support system (a “yieldable” metal support widely used in coal mines), which provides confinement while allowing controlled deformation. We have clarified this definition in the manuscript to avoid ambiguity. The revision can be found on[Line 215].

Comments 3:
The modulus of elasticity unit is MPa – definitely not. However, for GPa, the values are too high.

Response 3 :

Thank you for the careful check. We agree that the unit presentation required correction. We have corrected the unit of elastic modulus in Table 2/3 to the proper standardized unit and re-checked the numerical values accordingly.

Comments 4:
The cohesion value for coal, 3.85 MPa, seems significantly overestimated.

Response 4:
Thank you for this comment. We re-checked the coal cohesion parameter against the laboratory mechanical test results and the parameter calibration used in the numerical model. 

Comments 5:
What program was used for the numerical calculations?

Response 5:
Thank you for the question. The numerical simulations were performed using FLAC3D. We have explicitly stated the software name and the solution approach in Section 3.2 to improve clarity and reproducibility. The revision can be found on[Line 251].

Comments 6:
Section 3.3.1 and Figure 4. What are these stresses? Are they only positive (tension)? Where exactly are the cross-section lines? Figure 4 is illegible and incomprehensible.

Response 6:
Thank you for the detailed comment. We agree; therefore, we have clarified in the text and caption that Figure 4 (or Figure 8, as renumbered) plots vertical compressive stress (σv) extracted along specified measurement lines from a fixed cross-section (y = 50 m) of the 3D model. We also stated the sign convention (compressive stress taken as positive) and added a schematic figure showing the coordinate system, the cross-section location, and the definition of depth d from the excavation boundary for roof/floor/ribs. In addition, we re-generated Figure 4 at higher resolution with enlarged axis labels to ensure readability. The revisions can be found on [Line 322–358] 

Comments 7:
Table 3 – what displacements? Only positive? At what points are they read?

Response 7 :
Thank you for this comment. We agree; therefore, we clarified that Table 3 reports displacement components (roof settlement and rib displacements) extracted from the fixed cross-section at y = 50 m. The reported values correspond to the maximum magnitudes at the roof and rib monitoring lines (or specified points/paths) under each scheme. We also stated the sign convention and clarified whether values are presented as absolute magnitudes for comparison. The revision can be found on [Page __], [Paragraph __], [Line 300–316] 

Comments 8 :
The comments regarding Section 3.3.2 and Figure 5 are similar.

Response 8 :
Thank you. We agree; therefore, we applied the same improvements to Figure 5 and its associated text/caption: we clarified the plotted quantity and extraction location/paths, standardized labels/units, and re-generated the figure at higher resolution with enlarged fonts for readability. The revision can be found on  [Line 393]

Comments 9 :
Figure 5 – apart from the fact that it is too small and illegible, what is the shear strain increment distribution supposed to show? Why aren't the yield indices shown in the elements? This would at least show the extent of the yield zones (failure).

Response 9 (EN):
Thank you for this valuable suggestion. We agree; therefore, we clarified in the text that the incremental shear strain contours are used as an indicator of excavation-induced damage intensity and deformation localization. To explicitly show the extent of yielding, we added a yielded-element/plastic-zone map (based on the Mohr–Coulomb criterion) together with the shear strain increment contours, so that the failure (yield) zones can be directly identified and compared among schemes. We also improved the figure resolution and readability. The revisions can be found on [Line 417–446] (Figure [11] and Section 3.3.4).

Comments 10 :
Line 292 - Figure 8 is missing from the article.

Response 10 :
Thank you for identifying this issue. We agree; therefore, we have inserted the missing Figure 8 at the appropriate position and ensured that all in-text figure citations match the final figure numbering. 

Comments 11:
Figure 7 - What are these displacements (horizontal, vertical, total?)? At what points are they read?

Response 11:
Thank you for the comment. We agree; therefore, we clarified that Figure 7 reports (i) sidewall convergence, defined as the reduction in the horizontal distance between the left and right rib monitoring points, and (ii) roof subsidence, defined as the downward movement of the roof monitoring point relative to the floor reference point. A schematic figure has been added to illustrate the monitoring points and measurement directions. The revision can be found on [Line 316–323] (Figure 7 and the added schematic Figure[12]).

 

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Please consider the following comments:

1. In abstract, replace the letters (d) (c) (b) (a) with corresponding support schemes.
2. Improve Table 1 to clearly delineate 4 support support schemes described in the main text.
3. How the rock mechanical properties in Table 2 are obtained?
4. Describe the numerical methods used for the simulations.
5. Why Mohr-Coulomb instead of Hoek-Brown yield criterion is selected? According to the description of surrounding rock characteristics, Hoek-Brown seems more appropriate. 
6. In Fig. 4, what stresses are plotted against the different depth? Also the y-axis labels for Fig. 4B and 4C are not correct.  Also double check the labels in other Figures.
7. Why in Figure 4A, lowest stress corresponds to complete failure, and intermediate stress corresponds to plastic yield, whereas high stress corresponds to competent rock?
8. Also for the three plots in Fig. 4, are the depths on the X-axis all measure from the tunnel floor?
9. A colorbar scheme needs to be added in Figure 6.
10. Improve the quality and resolution of all Figures. 

Author Response

Comments 1:
In the abstract, replace the letters (d) (c) (b) (a) with corresponding support schemes.

Response 1:
Thank you for the suggestion. We agree with this comment. In the revised manuscript, we have replaced the letters (d), (c), (b), and (a) in the abstract with the corresponding support schemes as listed in the main text. The revision can be found on [Line 14–17].

Comments 2 :
Improve Table 1 to clearly delineate 4 support schemes described in the main text.

Thank you for the suggestion. We have revised Table 1 to clearly delineate the four support schemes by using more distinct labeling and additional clarification for each scheme.[table 2]

Comments 3:
How are the rock mechanical properties in Table 2 obtained?

Response 3 :
Thank you for raising this question. The rock mechanical properties listed in Table 2 were obtained from a combination of site investigation and laboratory mechanical testing. The specific parameters were derived from the geological exploration report, and the cohesion, friction angle, and modulus of elasticity were determined based on laboratory tests on representative coal and rock samples. The revision can be found on [Line 299 –305] 

Comments 4 :
Describe the numerical methods used for the simulations.

Response 4:
Thank you for the comment. We have included a description of the numerical methods used in the simulations in Section 3.2[Line 282–291] . 

Comments 5 :
Why Mohr-Coulomb instead of Hoek-Brown yield criterion is selected? According to the description of surrounding rock characteristics, Hoek-Brown seems more appropriate.

Thank you for this insightful question. We selected the Mohr–Coulomb yield criterion for the following reasons: (i) the parameters for Mohr–Coulomb (such as cohesion, friction angle, and modulus of elasticity) were directly obtained from the laboratory tests, which aligns well with our dataset, while the Hoek-Brown criterion requires additional parameters (e.g., GSI, mi, and disturbance factors) that are difficult to reliably obtain for highly fractured coal–rock masses, and (ii) the Mohr–Coulomb model is sufficient for capturing the key trends in deformation, stress redistribution, and yield-zone evolution for our engineering comparison purposes. The revision can be found on [Line 593–609].

Comments 6:
In Fig. 4, what stresses are plotted against the different depths? Also, the y-axis labels for Fig. 4B and 4C are not correct. Also, double-check the labels in other figures.

Response 6 :
Thank you for the observation. We agree and have clarified in the manuscript that Figure 4 plots vertical compressive stress (σv) against depth, with the correct labels on the y-axes for all subfigures. We have also reviewed and corrected the axis labels for all figures to ensure consistency throughout the manuscript. [new Figure 8  ]

Comments 7 :
Why in Figure 4A, lowest stress corresponds to complete failure, and intermediate stress corresponds to plastic yield, whereas high stress corresponds to competent rock?

Response 7 :
Thank you for your question. This phenomenon occurs because post-yielding stress redistribution leads to stress relief in the yielded zone and a concentration of stress in the intact rock. After excavation and yielding, stress is redistributed and the surrounding rock in the near-field region undergoes unloading. The lower stresses near the excavation boundary correspond to the yielding zone, whereas the higher stresses are observed in the intact rock. We have clarified this in the manuscript and updated the figure captions accordingly. The revision can be found on [Line 324–329]

Comments 8 :
Also, for the three plots in Fig. 4, are the depths on the X-axis all measured from the tunnel floor?

Response 8 :
Thank you for the comment. We have clarified that the depth d is measured from the excavation boundary: for the roof, d is measured upward from the roof boundary; for the floor, d is measured downward from the floor boundary; and for the ribs, d is measured outward from the rib boundary. This clarification has been added to the figure caption and manuscript. The revision can be found on [Line 307–316] 

Comments 9:
A colorbar scheme needs to be added in Figure 6.

Response 9 :
Thank you for the suggestion. We have added a colorbar to Figure 6 to represent the shear strain increment distribution, which shows the range of values corresponding to the color scale. The revision can be found on [Line 415] 

Comments 10 :
Improve the quality and resolution of all Figures

Response 10 :
Thank you for the suggestion. We have improved the resolution of all figures to ensure clarity and readability in the final manuscript. 

 

Author Response File: Author Response.pdf

Reviewer 5 Report

Comments and Suggestions for Authors

infrastructures-4090985

Optimization of Control Measures for Rock Mass Disturbed by 2 Repeated Tunnel Repairs and Engineering Practice

Zenghui Liu

Review

This paper reports on the problem of mining-related displacements on the North Wing Main Roadway complex of Shaanxi Jinyuan Zhaoxian Mining. The topic is interesting because the performances of various consolidation techniques are compared, but the research appears rather imprecise and needy of improvement, including the English language and the figures.

In particular:

The abstract should anticipate what are the  cases a), b), c), and d) mentioned.

Figures 2 a), b), and c) are difficult to read and, in any case, do not add significant information and can be eliminated.

Figures 3 a) and b) are difficult to read and, in any case, do not add significant information and can be eliminated.

The model mesh should be presented to understand the influence of boundary conditions. The Mohr–Coulomb yield criterion was adopted to determine rock-mass failure, and dilation omitted: this latter assumption is a serious limitation of the study.

Figure 4 a), b), and c) are unclear. What type of stress is involved? Normal tangential? Are the data referred to the tunnel axis? In what direction is the distance from the tunnel floor (x-axis) considered? A schematic drawing is needed to understand the data in the figure. The stress should be expressed in kPa, and the captions should be much larger and more legible.

Figure 5 a), b), c) present the same limitations of Figure 4: in what direction are the displacements evaluated? Are the data referred to the tunnel axis? In what direction are the distances from the tunnel floor and roof (x-axis) considered? A schematic drawing is needed to understand the data in the figure.

Figure 6 shows the increment of tangential stress in relation to the type of consolidation adopted. At what stage the contour maps refer? What is the role of the excavation face? Is it close to the consolidation zone or distant? How is the progressive relaxation of the cavity simulated?

Figure 7 a) and b) report the monitored convergence displacements and should more properly be referred to as convergences, but what type of consolidation do they refer to? A schematic drawing is needed here too to understand which points are monitored.

A comparison between the measured convergences and those derived from the numerical model is not shown, why?

I believe the paper might only find space in the journal after a very thorough review.

Comments on the Quality of English Language

Must be improved

Author Response

Comments 1 :
The abstract should anticipate what are the cases a), b), c), and d) mentioned.

Response 1 :
Thank you for your suggestion. We have revised the abstract to include a brief description of each of the four support schemes (a), b), c), and d), as mentioned in the manuscript. This helps the reader understand the context of the study from the beginning. The revision can be found on [Line 14–17].

Comments 2 :
Figures 2 a), b), and c) are difficult to read and, in any case, do not add significant information and can be eliminated.

Response 2:
Thank you for your feedback. While we initially considered removing Figures 2 a), b), and c), upon further review, we have decided to retain these figures and improve their clarity. The figures have been enhanced by adjusting the brightness and contrast and replacing them with higher-resolution versions for better legibility. The revision can be found on  [Line 171]

Comments 3:
Figures 3 a) and b) are difficult to read and, in any case, do not add significant information and can be eliminated.

Response 3 :
Thank you for your comment. We initially considered removing Figures 3 a) and b), but after reevaluating, we have chosen to retain them and improve their clarity. We have enhanced the figures' readability by adjusting their contrast and replacing them with higher-resolution versions. The revision can be found on  [Line 208]

Comments 4:
The model mesh should be presented to understand the influence of boundary conditions. The Mohr–Coulomb yield criterion was adopted to determine rock-mass failure, and dilation omitted: this latter assumption is a serious limitation of the study.

Response 4 :
Thank you for your comment. We have included the model mesh details in Section 3.2, which will help to understand the influence of boundary conditions on the model. Regarding the Mohr–Coulomb yield criterion, we acknowledge that the omission of dilation is a limitation, but this simplification was made to focus on the key engineering parameters related to support system optimization. We have clarified this assumption in the manuscript. The revision can be found on [3.2 Numerical Modeling  ,line250-318]

Comments 5  :
Figure 4 a), b), and c) are unclear. What type of stress is involved? Normal tangential? Are the data referred to the tunnel axis? In what direction is the distance from the tunnel floor (x-axis) considered? A schematic drawing is needed to understand the data in the figure. The stress should be expressed in kPa, and the captions should be much larger and more legible.

Response 5  :
Thank you for your detailed comment. We have clarified the type of stress in the figure as vertical compressive stress (σv) and included a schematic drawing to explain the coordinate system and depth measurements (roof, floor, and ribs). The stress is now expressed in kPa, and the captions have been enlarged and clarified for better legibility. The revision can be found on  [Line307 –351,new figure 7 ,8]

Comments 6 :
Figure 5 a), b), c) present the same limitations of Figure 4: in what direction are the displacements evaluated? Are the data referred to the tunnel axis? In what direction are the distances from the tunnel floor and roof (x-axis) considered? A schematic drawing is needed to understand the data in the figure.

Response 6  :
Thank you for this important comment. We have made the same clarifications in Figure 5 as in Figure 4[new figure 9]

Comments 7 :
Figure 6 shows the increment of tangential stress in relation to the type of consolidation adopted. At what stage the contour maps refer? What is the role of the excavation face? Is it close to the consolidation zone or distant? How is the progressive relaxation of the cavity simulated?

Response 7  :
Thank you for your detailed question. We have clarified in the revised manuscript that the contour maps in Figure 6 represent the stress redistribution after excavation and support installation, showing the tangential stress increments at different stages of the excavation. The excavation face plays a critical role in progressive relaxation by redistributing stresses around the cavity. The revision can be found on [Line 397–405]

Comments 8 :
Figure 7 a) and b) report the monitored convergence displacements and should more properly be referred to as convergences, but what type of consolidation do they refer to? A schematic drawing is needed here too to understand which points are monitored.

Response 8 :
Thank you for your comment. We have clarified that the convergence displacements in Figure 7 correspond to the monitored response after the installation of 29U-type steel sets + grouted bolts + grouted cable bolts support system, which represents the optimized support scheme. We have also added a schematic drawing to illustrate the monitored points and measurement directions. The revision can be found on   [Line 469–490]

Comments 9  :
A comparison between the measured convergences and those derived from the numerical model is not shown, why?

Response 9  :
Thank you for pointing this out. We have now added a quantitative comparison between the monitored convergence (measured in the field) and the simulated displacements from the numerical model in Section 4.3. The percentage errors between the field and model results are provided, and the potential sources of discrepancy (e.g., peak vs. average metrics, mismatch in measurement locations) are discussed. The revision can be found on [Line 527–570].

Comments 10 :
I believe the paper might only find space in the journal after a very thorough review

Response 10  :
Thank you for your suggestion. We appreciate your feedback and are happy to make further revisions to improve the quality of the paper. We believe the revised manuscript is now more robust and will contribute to a clearer understanding of the research outcomes. We look forward to your further comments.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The scope of the proofreading is extensive. The additions are necessary and make the article understandable and clear to the reader. It's safe to say that this is now a completely new article.

Author Response

Thank you for your valuable feedback

Reviewer 4 Report

Comments and Suggestions for Authors

The authors have addressed my comments. 

Author Response

Thank you for your valuable feedback. The figures have been updated, and the results section has been revised accordingly.

Reviewer 5 Report

Comments and Suggestions for Authors

• Redraw fig 6 specifying the meaning of the x and y axes
• Figures 3 and 4 do not provide useful elements for understanding the text and can be eliminated
• Figures 8 and 9 are difficult to read, the legends need to be enlarged
• The modeling procedure followed the following steps: (i) initialization and equilibrium under the in-situ stress state, (ii) gradual excavation, (iii) installation of support elements, and (iv) reaching the new equilibrium.I ask what the distance from the face is when the support elements are installed: in fact, if the face is infinitely distant, the support elements do not come into contact with the load.Therefore, it is necessary to detail how the gradual excavation occurs.

Comments on the Quality of English Language

Must be improved

Author Response

1.Thank you for the comment. Figure 6 has been redrawn and the meanings of both the x（step）- and y-axes（max unbalanced force） are now explicitly labeled to avoid ambiguity.

2.We agree. Figures 3 and 4 have been removed from the revised manuscript, and the related text has been adjusted accordingly.

3.Thank you. Figures 8 and 9 have been remade with enlarged legends and improved readability.

4.Thank you for the important clarification request. We have added a detailed description of the stepwise excavation and support installation procedure, including the effective face-to-support distance (support installed immediately after each excavation step), and clarified that the reported results correspond to the post-excavation equilibrium state.[line 277-288]

Author Response File: Author Response.pdf