A New Technology for Smooth Blasting without Detonating Cord for Rock Tunnel Excavation

Round 1

Reviewer 1 Report

In the paper entitled “A New Technology for Smooth Blasting Without Detonating Cord for Rock Tunnel Excavation”, a new technology for smooth blasting without detonating cord is explored. A series of sympathetic detonation experiments were conducted in the tunnel face to determine the critical distance. Based on the critical distance, a new charging structure was designed for tunnel excavation. To assess the influence of the new charging structure on blasting performance, its economic benefits, and its feasibility, full-section tests were performed in the East Tianshan Tunnel. The application of the new charging structure produced good smooth blasting results. It not only simplified the charging process and produced smooth blasting without detonating cord in peripheral holes, but also guaranteed normal excavation, an appropriate tunnel profile, and reasonable overbreak and underbreak volumes. This had remarkable economic benefits and possesses better promotional value.

Comments

Some editing of the English language and style is required.

For example:

LINES 16-18:

“Abstract: We seek to achieve safe, rapid excavation of an extra-long, large-cross-section highway tunnel in Eastern Tianshan. We also seek to reduce production costs, simplify production processes, reduce cycle time, and improve the production efficiency.”

COULD BE BETTER WRITTEN AS:

“Abstract: In this paper, the aim is to achieve safe, rapid excavation of an extra-long, large-cross-section highway tunnel in Eastern Tianshan, as well as to reduce production costs, simplify production processes, reduce cycle time, and improve production efficiency.”

Author Response

Dear Reviewer:

Thank you for your comments concerning our manuscript. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. We use the "Track Changes" function in Microsoft Word to clearly highlighted revisions. The main corrections in the paper and the responds to comments are as flowing:

Comments: Some editing of the English language and style is required.

Response :

1. Line 16-18, “We seek to achieve safe, rapid excavation of an extra-long, large-cross-section highway tunnel in Eastern Tianshan. We also seek to reduce production costs, simplify production processes, reduce cycle time, and improve the production efficiency.” was corrected as “In this paper, the aim is to achieve safe, rapid excavation of an extra-long, large-cross-section highway tunnel in Eastern Tianshan, as well as to reduce production costs, simplify production processes, reduce cycle time, and improve production efficiency.”
2. Line 25, “the” was added.
3. Line 36, “achieving” was corrected as “achieve”.
4. Line 46, “the” was added.
5. Line 55, “One of the characteristics of sympathetic detonation is that” was corrected as “According to the characteristics of sympathetic detonation”.
6. Line 242, “the” was added.
7. Line 261, “cross section” was corrected as “cross-section”.
8. Line 268, “the” was added.
9. Line 290 and Line 297, “excavation circulation” was corrected as “excavation round”.
10. Line 307, “the” was added.
11. Line 310, “explosive” was corrected as “explosives”.

We appreciate for your work earnestly, and hope that the correction will meet with approval. The revised version has been uploaded from the attachment

Kind regards,

Dr, Zelin

Author Response File: Author Response.docx

Reviewer 2 Report

Thank you for this well-written and interesting paper. Below, please find my comments:

• Please provide more details about the rock type and the quality fo the rock mass, as the grading type presented in section 2.1 may not be well known to all readers. 
• In section 2.1 you mentioned that the geological conditions are quite complex. How did you evaluate that the local geology and geomechanical conditions do not influence the test results? Did the conditions change in the various test rounds?
• In row 290, you have used the term "excavation circulation", but the more appropriate term "excavation round" should be used. Please correct accordingly.
• For a proper economic benefit analysis of the new charging scheme, it would be beneficial to compare the cost reduction due to savings in det. cord use vs. overbreak/underbreak volumes and their effect on excavation. One method to quantify overbreak and underbreak of each blasting round more precisely is laser scanning or photogrammetry (for details, please refer for example to Uotinen et al. 2019, Photogrammetry for recording rock surface geometry and fracture
  characterization, ISRM2019). Therefore, the tunnel profile would be scanned after each blasting round and the volume after blasting would be compared against the ideal, designed tunnel profile in 3D, rather than in 2D sections. Please elaborate on this topic in the discussion.
• Also, in Table2 and in the conclusions section, please add how much total cost savings in relation to typical blasting cost (for example in %), the new charging scheme has. 

Author Response

Dear Reviewer:

Thank you for your comments concerning our manuscript. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. We use the "Track Changes" function in Microsoft Word to clearly highlighted revisions. The main corrections in the paper and the responds to comments are as flowing:

Comment 1: Please provide more details about the rock type and the quality for the rock mass, as the grading type presented in section 2.1 may not be well known to all readers.

Response 1: We are very sorry for our negligence of the description of grading type. We add a table in line 109 of the paper to detail the rock types and rock quality of each surrounding rock grade. 

Comment 2: In section 2.1 you mentioned that the geological conditions are quite complex. How did you evaluate that the local geology and geomechanically conditions do not influence the test results? Did the conditions change in the various test rounds?

Response 2: In section 2.1, the complex geographical conditions we described were a general description of the entire tunnel. In lines 112-116 of the paper, I made an explanation for the rock conditions of the test rounds. The surrounding rock of the test section is mainly breeze tuffaceous sandstone, which is blue-gray and gray-green, with gray-green diabase and quartz diorite veins distributed locally, and the surrounding rock is grade IV. The rock mass is complete, the rock mass is dense and hard, and the surrounding rock has good self-stability. In the test rounds, the surrounding rock conditions did not change significantly, which ensuring the reliability of the test results. 

Comment 3: In row 290, you have used the term "excavation circulation", but the more appropriate term "excavation round" should be used. Please correct accordingly.

Response 3: We have made correction in line 313 and line 320 according to your comments.

Comment 4: For a proper economic benefit analysis of the new charging scheme, it would be beneficial to compare the cost reduction due to savings in detonating cord use vs. overbreak/underbreak volumes and their effect on excavation. One method to quantify overbreak and underbreak of each blasting round more precisely is laser scanning or photogrammetry (for details, please refer for example to Uotinen et al. 2019, Photogrammetry for recording rock surface geometry and fracture characterization, ISRM2019). Therefore, the tunnel profile would be scanned after each blasting round and the volume after blasting would be compared against the ideal, designed tunnel profile in 3D, rather than in 2D sections. Please elaborate on this topic in the discussion.

Response 4: Thank you for providing us with laser scanning or photogrammetry technology. We discussed this topic in lines 288-300 of the paper. For the two-dimensional tunnel profile scanning, we chose the position is at the bottom of blastholes after blasting. Because the blastholes have a certain extrapolation angle, the overbreak/underbreak volumes at the at the bottom of the hole is the largest. The two-dimensional tunnel profile scanning at the bottom of blastholes can provide a reference for the overbreak/underbreak volumes of one excavation round to a certain extent. Of course, in the future, with the advantages of laser scanning or photogrammetry technology, we will focus on using this technology to improve.

Comment 5: In Table2 and in the conclusions section, please add how much total cost savings in relation to typical blasting cost (for example in %), the new charging scheme has.

Response 5: We have made correction in line 320, 326 and 341 according to your comments.

Other changes:

1. Because we added a table on line 109, the sequence numbers of the following tables changed in turn.
2. Line 424, we add one reference: Uotinen L, Janiszewski M, Baghbanan A, et al. Photogrammetry for recording rock surface geometry and fracture characterization. In Proceedings of the 14th International Congress on Rock Mechanics and Rock Engineering (ISRM 2019), Foz do Iguassu, Brazil, 2019; pp.13-18.

We appreciate for your work earnestly, and hope that the correction will meet with approval. The revised version has been uploaded from the attachment。

Kind regards,

Dr, Zelin

Author Response File: Author Response.docx