| 講演要旨(和文) | | 地震探査における非爆薬震源として今日最も多用されているのが油圧式バイブレータである．我々は，技術的に成熟したこの油圧制御型とは異なる方式すなわち，超電導技術を利用した駆動源とシンプルな起振機構の組合せによるバイブレーター震源の試作研究を行った．直接起振方式によるシンプルな構造とし，振動駆動源には従来に比べ格段に大きな電磁力を発生するポテンシャルを持つ超電導コイルを採用することで，応答性に優れ高精度の震源波形を得ることを目標とした．試作機開発は，まず常電導型コイルによる室内実験モデルを製作し，直接起振方式の妥当性や加震機構の評価を行い，その結果を踏まえ，超電導コイルを用いた震源試作機の製作を行った．超電導技術は汎用化には未だ未成熟な技術であり，冷却方法等本来震源とは無関係な技術が要求されたが，野外でのデータ取得による評価まで実施することが出来た． |
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| | 講演要旨(英文) | | There is a long history in the development of non-explosive seismic vibratory source. The objective of this research is to design and study a new type seismic source using superconductive coil in order to generate strong electromagnetic force which is applied for ground vibration. In this new type source, the electromagnetic force is designed to apply vibration force directly on the ground, whereas the inertia force is used in the conventional type. The new source will not cooperate with hydraulic system and therefore it is expected that slow response and complicated control method of the conventional source will be improved. At first, we have made experiment using prototype small model which is composed of normal conductive coil and permanent magnet with generating electromagnetic force of 50N. Based on this first prototype model, the second model is designed, which uses a pair of superconductive coil composed of YBCO type superconducting material and generates 1kN force as a seismic source. The heat loss and cryostat composition are specially considered to keep superconductivity of the coil under the temperature of liquid nitrogen. This prototype seismic source was evaluated comparing with conventional hydraulic vibrator in the actual field operation. |
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