BEDROCK DRILLING DEVICE AND BEDROCK DRILLING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a bedrock drilling device and a bedrock drilling method, suitable for drilling downward extending holes in a bedrock while partly overlapping each other.;SOLUTION: When drilling a third hole 24C partly overlapping a second hole 24B, a guide rod 20 is inserted into the second hole 24B and a drain pipe 30 is inserted into a first hole 24A. Drilling cuttings are guided by a water stream f and introduced into an annular gap 26, and moved from the annular gap 26 into the first hole 24A with the water stream f, but the cuttings hit the drain pipe 30 and drop with its gravity. The drain pipe 30 functions to discharge the cuttings to the outside of the first hole 24A together with water and also functions as a member to gather the cuttings on the bottom of the first hole 24A. The drain pipe 30 efficiently discharges the cuttings from the bottom of the first hole 24A to avoid trouble in filling a slit groove 12 with the cuttings.;COPYRIGHT: (C)2014,JPO&INPIT