| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method of a hydraulic fracture test by which the rigidity of a gauge system is easily enhanced, fracture of a hole wall by stress concentration can be suppressed, and the stress of the ground can be evaluated with a good accuracy even with a bore hole having a large depth and a large diameter. <P>SOLUTION: A pilot hole boring device 11 is inserted into a boring rod 2 inserted into the bore hole 1 and is placed at a front end of the boring rod 2. A test hole 3 having a smaller diameter than that of the bore hole 1 is bored in a bottom of the bore hole 1 by the pilot hole boring device 11. After boring, the pilot hole boring device 11 is pulled out of the boring rod 2. Then, a hydraulic fracture test device 12 having a packer 24 at the front end is inserted into the boring rod 2, and a hole port of the test hole 3 is closed by expanding the packer 24. While high-pressure water is supplied into the test hole 3, the water supply rate and change of water pressure with time inside the test hole 3 are measured by the hydraulic fracture test device 12. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
