1987 Fiscal Year Final Research Report Summary

Development of Rock Excavation Method Assisted by High Pressure Water Jet

Research Project

Project/Area Number	61850112
Research Category	Grant-in-Aid for Developmental Scientific Research
Allocation Type	Single-year Grants
Research Field	資源開発工学
Research Institution	The University of Tokyo
Principal Investigator	NISHIMATSU Yuichi The University of Tokyo, 工学部, 教授 (70010741)
Co-Investigator(Kenkyū-buntansha)	AKIYAMA Masao The University of Tokyo, 工学部, 助手 (00011172) OKUBO Seisuke The University of Tokyo, 工学部, 助教授 (90092155)
Project Period (FY)	1986 – 1987
Keywords	Rock / Water jet / Cutting / ブームヘッダ
Research Abstract	A laboratory investigation was made of the effests of high pressure water jets on the cutting force of point asstack bit. About 400 cuts using Sanjome-andesite were carried out at different water pressures and cutting speeds to determine the reduction of cutting forces on the bit. The cutting forces shoewed continuous change with wear of bit. The greatest reduction in cugging force were with severely worn bits; the drag force was reduced about 25% and the normal force about 40% at 100MP water pressure. The method was less effective in case of sharp bit. Together with the reduction of cutting force, the water jet was found gto be effective to prolong the bit life; the bit life becoms about 3 times. An important benefit may be the cooling and lubricationg action of the water jet.

(2 results)