| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a concrete duct crushing method capable of easily exposing a duct positioned under a top duct without damaging a cable. <P>SOLUTION: First, drill holes 200a, 200b, and 200c are bored in a concrete duct 1000. Then, two semicircular spacers 700 are inserted into the drill holes 200a, 200b, and 200c. Thereafter, water-pressure expansion tube 500 is inserted between the semicircular spacers 700. Then, water is fed into the expansion tube 500. This causes the expansion tube 500 to expand. Owing thereto, the pressure of the water in the expansion tube 500 is applied via the spacers 700 to the concrete duct 1000. As a result, cracks 1000b open in the concrete duct 1000. Consequently, the concrete duct 1000 is crushed. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
