| abstract |
A method and an apparatus for excavating a tunnel, hole, channel or the like in the rock mass or in the ground by using pressurized water spouted from nozzles. n The method comprises the steps of digging a hole in the rock mass, inserting a rod of a fracturing apparatus in the hole, the rod having a communicating hole formed therein and nozzles formed at the leading end thereof, jetting pressurized water from the nozzles so as to produce grooves in the hole impinged by the water jet, sealing a space around the nozzles defined by the outer periphery of the rod and an inner peripheral wall of the hole, and again allowing pressurized water to spout from the nozzles into the space thereby forming cracks in the rock mass. |