| 講演要旨(和文) | | 従来の電気探査計測装置は単点通電・多点受信が主流であったが，通信技術の一種であるCDMT法を用いることで，同時多点通電・多点受信が可能となった．このため，従来の手法と比べると，計測時間を大幅に短縮化することができ，そのため作業性を大幅に向上させることが可能となり，調査に必要な経費を削減できることが期待される．本稿では，高速電気探査装置を2次元探査に適用したところ，二極法における減衰曲線の交差や複数展開における減衰曲線の接続の際に，接続部に段差が生じることが見られた．減衰曲線の交差は，実計測に基づく波形情報から直接分離することで改善されることを確認したが，減衰曲線の段差に関しては原因を特定することができなかった．今後，計測システムを再確認し，原因を特定することが必要である． |
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| | 講演要旨(英文) | | A high-speed resistivity measurement tool using a code division multiple transmission technique was developed and has been utilized in such practical uses as 3D time-lapse monitoring of water infiltration into the vadose zone of levees. The tool can flow electric current at 24 electrodes simultaneously and receive potential at 24 electrodes. Accordingly, we can obtain a total of 576 dataset within only 30 seconds. Because orthogonal matrix is used as the simultaneous current transmission method, we can easily divide individual responses from potential waveforms. When utilizing the tool, we experienced two problems. The one was the crossover of decay curves, and the other was a bias between two decay curves. Originally the tool should have been manufactured to transmit the orthogonal code current appropriately at multiple electrodes. However, insufficient current might distort the orthogonality of signals. So, careful quality check is needful especially to decay curves. |
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