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| | Abstract | | 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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