| 講演要旨(和文) | | 舗装表面を打撃した際に空気中に漏洩する高周波の漏洩表面波を観測し，その分散特性から舗装構造を推定する計測システムを考案し，実用化を目指して各種実験・装置改良を繰り返してきた．その一環としてマイクロフォンアレイを収納する函体の遮音性を高めることによってS/Nを劇的に向上させることができ，実用化のめどを立てることができた．その結果を報告する． |
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| | 講演要旨(英文) | | We have improved a sound insulation box, a major part of the non-contact surface wave measurement system we developed. The box incorporates a single array composed of 12 or 36 microphones at 5 cm intervals. To reduce direct sound noises but also to lighten the weight of the box, we adopted a single array instead of double lines we had employed, and downsized the width of the box. We tightly packed sound absorbing sponges inside the box, and suppressed direct sound noises by closing the space between the bottom of the box and the pavement surface as narrow as possible. Consequently, the system could successfully measure clean leaky surface waves which propagated from the pavement surfaces. The field tests demonstrated the system cleared one of critical gates for practical use. |
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