1999 Fiscal Year Final Research Report Summary
Development of a High-Speed Rock Excavation System using Water Jet
| Project/Area Number |
10555352
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
資源開発工学
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| Research Institution | Kumamoto University |
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Principal Investigator |
SUGAWARA Katsuhiko Faculty of Engineering, KUMAMOTO University, Professor, 工学部, 教授 (60109668)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Akira Facukty of Engineering, KUMAMOTO University, Research Associate, 工学部, 助手 (40305008)
OBARA Yuzo Facukty of Engineering, KUMAMOTO University, Professor, 工学部, 教授 (50135315)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Water Jet / Drilling / Rock Mass / Erosion / Chipping / Erosion Strength |
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| Research Abstract |
Study on water jet drilling and chipping upon drilling was performed to develop a new system available for hard rock excavation at a great depth. A new scheme named the Third Power Method was proposed for the drilling process analysis, and the pressure attenuation of water jet upon drilling was evaluated as well as the erosion strength of materials. The chipping potential defined by the erosion strength and the effective pressure of incident water jet was presented to evaluate the incidence of chipping upon drilling, from a specific fixed depth chipping experiment. A formulation of the erosion strength was presented from the dimensional analysis, including the effect of rock stresses. The validity of the formulation was successfully confirmed by the water jet drilling experiment under a biaxial compression, and the incidence of chipping was shown to increase with increasing of the confining pressure, resulting in an excavation larger than that in no-load condition. A latticed multi-point drilling experiment was successfully conducted using the fun-size specimen of hard rock, to evaluate the specific energy. The specific energy and the optimum drilling interval was given along with the repetition model to calculate the specific energy. It has been concluded that the continuous chipping upon water jet drilling results in an excavation of higher efficiency than the conventional water jet cutting.
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