| 摘要 |
PURPOSE: A digging method of a pre-stressing nail tunnel is provided to reduce boring amount and to excavate inner gang pre-stressing and inner gang pre-stressing nail tunnel at once blasting. CONSTITUTION: A digging method of a pre-stressing nail tunnel is composed like next. A pre-stressing nail is drilled on the face supposed to be drilled and a pre-support guide hole(30) at a pilot tunnel by additionally assembling a horizontal contour hole(40), a horizontal stopping hole(50), and a horizontal bottom hole. Those are blasted a pre-support empty hole, a horizontal outer hole, a horizontal magnifying hole, and a horizontal base ball.
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