| 講演要旨(和文) | | 筆者らが新たに提唱したハイブリッド表面波探査を，交通量の多い幹線道路脇で実施した．同探査法は，従来の多チャンネル表面波探査と2次元微動アレイ探査を組み合わせて同時測定することを特徴とする．直線状の測線上に展開した地震計アレイで取得したデータに対して，MASW法およびSPAC法を適用して分散曲線を別個に求め，両者を結合することで2Hzから60Hz程度までの周波数領域での解析を可能にする．車両振動を積極的に利用することから，道路盛土に対する表面波探査の適用拡大が期待できる．本講演では実際の適用事例を紹介し，現地測定条件およびデータ解析処理条件に関わる検討結果を報告する． |
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| | 講演要旨(英文) | | Hybrid surface wave surveys were successfully applied along operational highways which had traffic flows of 300 to 1,500 vehicles per hour. The hybrid surface wave survey consists of an active multichannel surface wave survey and a 2-D linear array microtremor survey. A 10-kg wooden hammer was used to generate surface waves in active surveys. In contrast, vibration noises from traffic vehicles were recorded in passive surveys. The hybrid surface wave survey is characterized by using the same geophone array set along a roadside and by continuous data acquisition of active and passive surveys. Two dispersion curves, one is for a higher frequency part calculated from active data and the other is for a lower frequency part from passive data, are combined to form a single dispersion curve for a specific CMP in a survey line. Consequently, we could obtain clean dispersion curves not only from the active but also from the passive survey data, and successfully reconstruct 2-D S-wave velocity profiles along lines from shallow layers to substrata up to 50 m. The field tests demonstrated the hybrid surface wave method was quite capable for the delineation of diverse structure in embankments of highways even under heavy traffic condition. |
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