| 講演要旨(和文) | | 地盤工学分野で利活用が期待される浅部物理探査は，これまで陸域での適用が主であり，音波探査を除き水域で実施される浅部物理探査手法は数少なかった．一方で近年地球規模での温暖化に起因するとされる大規模水災害が多発しており，ダム貯水池，河道，港湾などの水域での地盤・構造物の内部物性構造調査へのニーズが高まっている．本報告ではまず探査対象ごとに期待される探査課題を整理する．つぎに出水期の小貝川で実施した水域浅部物理探査の予察的調査の概要について述べる． |
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| | 講演要旨(英文) | | Water covered areas such as river streams, dam reservoirs, and harbors have been left behind as the blank areas for near surface geophysics, in contrast to inland lakes and the shallow offshore areas, mainly due to its large cost-benefit ratio, or expensive costs as for the public works. Underwater parts of earthen structures, which bound town side with water side safely, have been left behind too. Recent severe geohazards stricken Japan remind us the importance of safety assessment of underwater parts of earthen structures along with land parts of them. Integrated geophysical investigations have been requested to be applied to the underwater parts of earthen structures. The authors have proposed an integrated geophysics for the safety assessment of levee systems, and developed Hybrid Surface Wave Survey (HSWS) method as the major component of it. Thus, we conducted needs analysis on underwater survey of earthen structures and carried out a preliminary study of integrated geophysics in a river channel which was seasonally submerged. As a result, we could successfully obtain near surface S-wave velocity and resistivity structures through 50 cm to 2 m deep river water. |
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