# The Efficiency of Large Hole Boring (MSP) Method in the Reduction of Blast-Induced Vibration
## 6 Conclusions  
In this study, we studied how much the MSP method using large empty holes could efficiently reduce the vibration generated during tunnel blasting. The vibration reduction efficiency of this method was analyzed through the real-scale test blasting of five patterns, using the traditional cylinder-cut and MSP methods, at a tunnel construction site.  
The MSP method creates relatively large free faces compared to the traditional parallel hole cut method in the cut area before the main blasting, significantly reducing blast-induced vibration by up to 72% compared to general blasting utilizing the traditional cylinder-cut method. Thus, the MSP method could be used as an excellent alternative method for non-vibration excavation sections, which are highly sensitive to blast-induced vibration, to reduce construction duration and costs. However, even when the stress level around the cut area was released through the application of the MSP method, there was a limit in reducing blast-induced vibration due to drilling error in the contour areas. Therefore, an improved blasting pattern using large empty holes should be considered to be located in each section of the stoping area instead of concentrating the large empty hole on the cut area.  
Since it is difficult to determine the vibration reduction effect of the MSP method due to insufficient field data and lack of experimental controls in this study, we hope to reproduce our findings through continuous data collection and controlled field-scale experiments. We hope to demonstrate that the MSP method can efficiently control blast-induced vibration across various site conditions and is a viable and effective method for blast-induced vibration control. Furthermore, we expect that utilizing electronic detonators that exhibit enhanced precision of detonation delay compared to electric/non-electric detonators will maximize vibration reduction efficiency of the MSP method. Lastly, the MSP method not only reduces blast-induced vibration compared to the traditional cut blasting (pattern B) adopted in this paper but also can collect geological information without additional guide holes through the use of a real-time boring monitoring system and a borehole alignment tracking and ground exploration system and presents as a great resource for drill and blast tunneling methods.  
Conceptualization, S.S.L.; methodology, M.S.K.; validation, M.S.K.; formal analysis, M.S.K.; data collection, M.S.K.; writing--original draft preparation, M.S.K.; writing--review, S.S.L.; supervision, S.S.L.; project administration, S.S.L.; funding acquisition, S.S.L. All authors have read and agreed to the published version of the manuscript.  
This work is supported by the Korea Agency for Infrastructure Technology Advancement (KAIA) grant funded by the Ministry of Land, Infrastructure and Transport (Grant 21 UUTI-B157786-02).  
Not applicable.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.