| 講演要旨(和文) | | 荒川下流部において堤防の安全性評価の基礎資料取得を目的として統合物理探査を実施した.適用した物理探査はランドストリーマー方式表面波探査,牽引式比抵抗探査,および高分解能S波反射法探査である.調査の結果,堤体は一部を除き低比抵抗・低S波速度で特徴付けられる難透水性材料が使用されていることがわかった.また深さ30m程度までの基礎地盤に局所的に変形構造が発達することが見出された. |
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| | 講演要旨(英文) | | Integrated geophysical survey was conducted along the levee of the lower stream of Arakawa River for the safety assessment of the levee system. The adopted geophysical methods involved the surface wave survey, capacitively-coupled resistivity measurement, and Land Streamer S-wave reflection survey. Two 3-km long lines were set on the top of the right side levee and a road on the high water bed along the levee. The integrated survey revealed the levee body at the site was mainly composed of fine-grained, or low resistivity and low S-wave velocity materials. In addition, the survey delineated a 100-m wide small flexure which deformed a reflection event at 25 m in depth up to 2 m. |
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