| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To effectively reduce blast noise without decreasing work efficiency of a tunnel excavation work. <P>SOLUTION: A tunnel silencer 1 comprises: a duct 11 which is installed inside a tunnel almost parallel to a direction of a tunnel axis and has many through-holes on a periphery of the duct; and two bulkheads 12 and 13 which are installed around openings at both ends of the duct 11 in the direction orthogonal to the tunnel axis. Blast noise is muffled by reflection on the bulkhead 13 at a face side and sectional changes in a blast noise transmission path inside the tunnel due to the duct 11 and the bulkheads 12 and 13. In addition, the blast noise is resonantly absorbed by an action between the many through-holes 110 on the periphery of a passage 10 formed by the duct 11 and a closed hollow space 14 behind the through-holes 110. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
