| 摘要 |
PROBLEM TO BE SOLVED: To provide a rock mass grooving construction method at low cost, low noise, and high working efficiency and to provide a rock mass excavation method using the method. SOLUTION: A hole is bored vertically Z from the surface of the rock mass 3 by 3 drill to form first and third holes 41, 43 and hollow steel pipes 51, 51 having the outside diameters smaller than the inside diameters of the holes are inserted in the respective holes 41, 43. While a vortical ascending current is formed from the bottom of the existing hole toward the rock mass surface side by pumping compressed air to the inside of the hollow steel pipe 51, a position 31 to be drilled sandwiched between the holes 41, 43 is drilled from the surface of the rock mass 3 vertically Z by the drill so that a second hole 42 is formed and communicated with the first and the third holes 41-43 mutually, thereby forming the groove 1 extended in the X direction in the rock mass 3.
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