Ha E., Kawamura Y., Mizutani K.

The purpose of this research is to detect underground piping, which are buried from 60 cm to 124 cm below using seismic method. Seismic method is generally used to inquire underground condition by receiving the reflection waves. Generally as a seismic source a hammer or gunpowder is used. However they are not capable of generating an arbitrary seismic wave. In this research, as a seismic source giant-magnetostriction vibrator was used. This vibrator can generate an arbitrary elastic wave in various frequency domains. As a conventional method, cross-correlation analysis is applied to distinguish reflection waves and other waves. However it is not sufficient to get better result. Therefore as a new analysis Magnified Cross-Correlation Analysis in Frequency Domain was proposed. To consider effectiveness of this analysis, the experiments of detecting underground concrete blocks and piping were conducted using that analysis. Underground concrete blocks and piping are buried the depth of from 60cm to 124cm. As a result, the depth of underground piping and concrete blocks were estimated in high precision, and the effectiveness of Magnified Cross-Correlation Analysis in Frequency Domain was confirmed.