Method and apparatus for fracturing rock beds

A preliminary fracturing method of a rock bed, comprising the steps of:

• (a) drilling a hole in said rock bed to be fractured by means of a drilling rod, said drilling rod having a bit mounted thereon at the leading end thereof and a passage formed therein along the entire length of said rod, said bit having a slanted surface formed at an intermediate portion thereof and said passage leading to a nozzle formed in said bit;
• (b) dumping a powder material such as rock muck or sand in the drilled hole with said drilling rod remaining inserted in the hole thereby allowing the powder material to accumulate on the slated surface of said bit;
• (c) causing a vibration to said drilling rod thereby tightly sealing a leading end portion of the hole by the powder material by consolidating the powder material accumulated on the slated surface of said bit, said leading end portion including said nozzle;
• (d) spouting a high viscosity fluid from said nozzle thereby allowing said high viscosity fluid to intrude into cracks existing in said rock bed and clogging them;
• and
• (e) spouting a highly pressurized water from said nozzle thereby expanding said cracks and producing a lot of new cracks in said rock bed.

A preliminary fracturing method of a rock, bed, comprising the steps of:

• (a) drilling a hole in said rock bed to be fractured by means of a drilling rod, said drilling rod having a bit mounted thereon at the leading end thereof and a passage formed therein along the entire length of said rod, said bit having a slanted surface formed at an intermediate portion thereof and said passage leading to a nozzle formed in said bit;
• (b) dumping a powder material such as rock muck or sand in the drilled hole with said drilling rod remaining inserted in the hole thereby allowing the powder material to accumulate on the slated surface of said bit;
• (c) causing a vibration to said drilling rod thereby tightly sealing a leading end portion of the hole by the powder material by consolidating the powder material accumulated on the slanted surface of said bit, said leading end portion including said nozzle;
• (d) spouting highly pressurized high viscosity fluid from said nozzle thereby allowing said highly pressurized high viscosity fluid to intrude into cracks existing in said rock bed and clogging them;
• and
• (e) continuously spouting said highly pressurized high viscosity fluid from said nozzle thereby expanding said cracks and producing a lot of new cracks in said rock bed.

An apparatus for preliminary fracturing a rock bed, comprising:

• (a) a guide member adapted to be mounted on a construction vehicle;
• (b) drifter means movably mounted on said guide member;
• (c) drilling rod means slidably and rotatably mounted in said drifter means, said drilling rod means having a passage formed therein throughout its length, a bit mounted thereon at the leading end thereof and a nozzle leading to said passage;
• (d) shock generating means mounted in said drifter means for giving a shock to said drilling rod means;
• (e) rotation imparting means mounted to said drifter means for imparting a rotation to said drilling rod means;
• (f) a tank containing a high viscosity fluid;
• (g) booster means connected to said tank for pressurizing said high viscosity fluid, said booster means being communicated with said passage formed in said drilling rod means;
• and
• (h) powder material supplying means for supplying a powder material such as rock muck or sand into said hole to seal the leading end of said drilled hole including said nozzle.