Journal of Korean Tunnelling and Underground Space Association (한국터널지하공간학회 논문집)

Korean Tunnelling and Underground Space Association (한국터널지하공간학회)
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Analysis of drilling performance and shape for granite according to operating parameters of waterjet nozzles

복수의 워터젯 노즐 운용변수에 따른 화강암 천공성능 및 형상 분석

  • Park, Jun-Sik (Dept. of Civil and Environmental Engineering, Pusan National University (PNU)) ;
  • Cha, Hyun-Jong (Dept. of Civil and Environmental Engineering, Pusan National University (PNU)) ;
  • Hong, Eun-Soo (HBC INC.) ;
  • Jun, Hyung-Woo (Jeyoung Engineering & Construction) ;
  • Oh, Tae-Min (Dept. of Civil and Environmental Engineering, Pusan National University (PNU))
  • 박준식 (부산대학교 사회환경시스템공학과) ;
  • 차현종 (부산대학교 사회환경시스템공학과) ;
  • 홍은수 ((주)에이치비씨) ;
  • 전형우 ((주)제영이엔씨) ;
  • 오태민 (부산대학교 사회환경시스템공학과)
  • Received : 2021.10.26
  • Accepted : 2021.11.17
  • Published : 2021.11.30
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Abstract

Waterjets for rocks have various advantages of the non-contact and eco-friendly excavation using only water and abrasive. To overcome the problems (e.g., dust and noise occurrence) of the conventional drilling methods, waterjet excavation methods are broadly used. It is advantageous to operate a couple of nozzles in order to increase the waterjet excavation efficiency. When multiple nozzles are used, it is essential to analyze the excavation performance and shape according to the nozzle operation method. In this study, nozzle angle, horizontal distance between nozzles, and standoff distance were defined as nozzle operating parameters and the excavation performance and shape were analyzed. As a result of the experiment, when the nozzle angle and standoff distance are increased, the excavation depth is decreased and the effective depth tends to be increased. In addition, based on the experimental results, the excavation shape criteria required for nozzle insertion were proposed and optimal nozzle operating parameters were derived according to the criteria. This study result is expected to be used as useful basic research in the future development of multiple waterjet nozzles for rock drilling.

워터젯 암반 굴착공법은 물과 연마재만을 사용하는 친환경 및 비접촉식 굴착방법으로 다양한 장점을 가지고 있다. 최근에는 기존 천공 공법의 문제점을 보완하고 분진 방지, 소음 저하 등의 이유로 워터젯 공법의 활용이 증가하고 있다. 워터젯 굴착효율을 증대시키기 위해서는 복수의 노즐을 운용하는 것이 유리하다. 복수의 노즐을 사용할 경우, 노즐 운용방법에 따른 굴착성능과 형상을 분석하는 것이 필수적이다. 본 연구에서는 노즐각, 노즐 간 수평거리, 이격거리를 노즐 운용변수로 정의하고 굴착성능과 형상을 분석하였다. 실험결과, 노즐각과 이격거리가 증가할 때 굴착깊이는 감소하였고 유효 굴착깊이는 증가하는 경향을 보였다. 또한, 실험결과를 바탕으로 노즐 삽입에 필요한 굴착형상 기준을 제안하고 기준에 따른 최적 노즐 운용변수를 도출하였다. 본 연구결과는 향후 암반 천공용 다중 워터젯 노즐 개발 시 유용한 기초연구로 활용될 것으로 기대된다.

Keywords

Acknowledgement

본 연구는 국토교통부/국토교통과학기술진흥원의 지원으로 수행되었음(과제번호 21CTAP-C164123-01).

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