| 摘要 |
This invention relates to a method of excavating a tunnel to pierce through a mountain or underground, in which a large number of slits (2) are drilled at spatial intervals along a line (1) designed for defining a tunnel to be excavated as well as on the facing (4) encircled by the abovesaid designed line (1), a large number of auxiliary holes (3) are drilled between these slits (2), and the rock-bed is crushed along the slits (2) with tapered chisels (7) inserted into said auxiliary holes (3) and subjected to impact. In this way, efficient cracking of even the hard rock-bed is possible and a length of time for drilling can be reduced compared with that required in the conventional method, thereby a tunnel excavating speed being greatly increased. This invention ensures reduction of vibration and noise through such processes that slits (2) are drilled along a line defining a desired shape for providing a cut hole (9), powder charging holes (10) are drilled along the line (1) designed for tunnel excavation as well as on the area encircled by the designed line (1) and in the cut holes (9) for loading the powder charging holes (10) with explosives or expansive powder so as to crush the rock-bed with such explosives or expansive powder for cutting, whereby cutting over a wide sectional area can efficiently be performed with the use of a small amount of explosives or expansive powder. |
