| 講演要旨(和文) | | PWRIと河川堤防の統合物理探査適用検討委員会では,堤体の比抵抗分布と弾性波速度分布を連続的に測定し両者を総合的に評価することによって堤防脆弱部の抽出を行う手法を提案し,千曲川河川堤防における開削箇所において堤体測定を行った.堤防天端での測定結果では,堤体は高比抵抗,低S波速度を示すことから,主に締固めの緩んだ砂質土ないし砂礫で構成されると推測された.開削面における調査結果,堤体は低含水比の砂礫の混入量が多い砂礫や細粒分まじり砂で構成され,これが高比抵抗,低S波速度を示していることが検証された.天端からの探査結果によるクロスプロットと開削面で得られたデータが,概ね良好な整合性を示し、天端での統合物理探査の有効性を示唆するものとなった.今後,全国の河川堤防での比抵抗,弾性波速度の計測データを集積し,様々な条件下で適用できるパラメータを求めていかなければならない. |
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| | 講演要旨(英文) | | SEGJ Levee Consortium reported on five volumes in the former SEGJ Conference, and proposed that the ratio resistivity distribution and the elastic wave velocity of the bank body were continuously measured, and the crossing technique of each physical property for plotting them be effective as a physical inquiry that extracted the abnormality part in the river embankment here. We acquired the resistivity distribution and the elastic wave velocity at the cutting slope where the restoration for the infiltration damage from the embankment during the downpour of the summer of 2006. Furthermore the grain size test was conducted for the soil samples obtained at the cutting slope of the bank body by the PWRI.The previously reports proposed the crossing plotting of the electric resistivity and the elastic wave velocity of the bank body and extracting the high resistivity and the low velocity area as a needed attention part (gravel bed where the tightening loosened). We verified the validity of the extraction technique of the attention part by the crossing plot by comparing the soil grain size examination result with the crossing plot chart. |
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