Fundamental Research on Shallow Underground Exploration Technology by Acoustic Irradiation Induced Vibration from UAV

In order to verify whether or not it is possible to perform a shallow underground exploration from a long distance, we conducted a basic study of a noncontact acoustic exploration method by acoustic irradiation induced vibration using a plane speaker that can be installed in UAV. From the experimental results using silica sand soil, it was found that the detection frequency is inversely proportional to the size of the buried object, but it does not change much even if the buried depth is changed. We also examined the irradiation angle of the laser Doppler vibrometer and clarified that the buried object can be detected even at an angle of about 20 degrees when the angle at vertical incidence is 90 degrees. From the experimental results using Kanto loam soil, it was confirmed that the shallow underground exploration is possible from a distance of 10 m or more. From these results, the effectiveness of the proposed method was confirmed.