| 摘要 |
PROBLEM TO BE SOLVED: To drill a horizontal hole on a continuous wall constructed in the ground safely and securely. SOLUTION: A vertical hole 5 is formed on the continuous wall 3, and a collapse prevention pipe 17 is installed in the ground on an outer side of the continuous wall 3. Then, water jet 23 is jetted from the vertical hole 5 toward the collapse prevention pipe 17 to drill the continuous wall 3 and form a water passing hole 25. When the water jet 23 passes through the continuous wall 3, the water jet 23 collides against the collapse prevention pipe 17 and the ground on the outer side of the continuous wall 3 is not dug. When the water jet 23 collides against the collapse prevention pipe 17, the sound being different from the sound generated when drilling the continuous wall 3 by the water jet 23 is generated to allow a worker to know that the water jet 23 passes through the continuous wall 3 easily. COPYRIGHT: (C)2009,JPO&INPIT
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